由“单独搭建Mybatis”到“Mybatis与Spring的整合/集成”

在J2EE领域，Hibernate与Mybatis是大家常用的持久层框架，它们各有特点，在持久层框架中处于领导地位。

本文主要介绍Mybatis（对于较小型的系统，特别是报表较多的系统，个人偏向Mybatis），对于它，个人比较喜欢的是：

使用简单、方便；
支持的XML动态SQL的编写，方便浏览、修改，同时降低SQL与应用程序之间的耦合。

不喜欢的是：

出现错误时，调试不太方便

本文主要介绍Mybatis的搭建，是学习Mybatis过程后整理的札记，其中包括“单独搭建Mybaits”和常用的“Mybatis与Spring的整合”。

一、数据库的准备

因为Mybatis是持久层框架，毫无疑问，是需要操作数据库的。所以，在搭建之前，我们需要先创建一个简单的表。

SQL - DDL - Create Table

create table T_USER_TEST_1407
(USERNAME VARCHAR2(255),PASSWORD VARCHAR2(255)
)

插入一些数据，以作查询的测试。

insert into T_USER_TEST_1407 (USERNAME, PASSWORD)
values ('nick', 'Optimistic,Confident,Love - 1');

insert into T_USER_TEST_1407 (USERNAME, PASSWORD)
values ('nick', 'Optimistic,Confident,Love - 1');

二、单独搭建Mybaits

1）环境准备、版本说明

此工程使用JDK1.6 + mybatis-3.2.4 + Oracle11g。

新建一个Web工程，由于只构建Mybatis，只引用Mybatis和Oracle JDBC驱动包

mybatis-3.2.4.jar
ojdbc6.jar

2）程序的搭建

首先，我们将数据源等配置信息放在一个xml，让Mybatis可以根据这个信息去连接数据库、管理事务。

目前我们可只关注environments节点，此节点是用于配置数据源、事务管理的。

其他的节点，如typeAliases、mappers，是用于注册一些信息的，后面会陆续提到。

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

<typeAliases>
<typeAlias alias="user" type="com.nicchagil.mybatisonly.bean.User" />
</typeAliases>

<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@xxx.xxx.xxx.xxx:xxxx:xxxxxx" />
<property name="username" value="xxxx" />
<property name="password" value="xxxx" />
</dataSource>
</environment>
</environments>

<mappers>

<mapper resource="com/nicchagil/mybatisonly/mapper/sqlxml/UserMapper.xml" />
</mappers>

</configuration>

mybatis-config.xml

 1 <?xml version="1.0" encoding="UTF-8" ?>2 <!DOCTYPE configuration3   PUBLIC "-//mybatis.org//DTD Config 3.0//EN"4   "http://mybatis.org/dtd/mybatis-3-config.dtd">5   6 <configuration>7 8     <!-- Register Alias -->9     <typeAliases>
10         <typeAlias alias="user" type="com.nicchagil.mybatisonly.bean.User" />
11     </typeAliases>
12
13     <!-- Data Source -->
14     <environments default="development">
15         <environment id="development">
16             <transactionManager type="JDBC" />
17             <dataSource type="POOLED">
18                 <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
19                 <property name="url" value="jdbc:oracle:thin:@xxx.xxx.xxx.xxx:xxxx:xxxxxx" />
20                 <property name="username" value="xxxx" />
21                 <property name="password" value="xxxx" />
22             </dataSource>
23         </environment>
24     </environments>
25
26     <!-- Register Mapper -->
27     <mappers>
28         <!-- SQL Mapper -->
29         <mapper resource="com/nicchagil/mybatisonly/mapper/sqlxml/UserMapper.xml" />
30     </mappers>
31
32 </configuration>

既然有了配置的xml，下一步就需要让Mybatis加载它了。

首先以输入流的形式加载xml
以“SqlSessionFactoryBuilder -> SqlSessionFactory -> SqlSession”的流程最后构建出SqlSession。
- SqlSession，顾名思义，是一次会话，是应用程序与数据库交互的会话，所以，其生命周期应在一次数据库连接之间，当然，此次数据库连接可以包含一次或多次数据库操作。
- SqlSessionFactory，顾名思义，是SqlSession的工厂类，用于产出SqlSession。我们知道，SqlSession主要用于数据库操作，而数据库操作又是贯穿于应用程序整个生命周期当中的，那么，"产出SqlSession"这个动作也应当贯穿于应用程序整个生命周期当中，所以，SqlSessionFactory的生命周期一般为应用程序的整个生命周期，一般为单例/static的形式存在。
- SqlSessionFactoryBuilder，由代码可见，其主要作用是从配置文件中获取配置信息，然后构建SqlSessionFactory，所以其生命周期可以是临时的，局部的。
通过SqlSession获取UserMapper接口，再调用该接口的数据操纵方法。

Call

package com.nicchagil.mybatisonly;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import com.nicchagil.mybatisonly.bean.User;
import com.nicchagil.mybatisonly.mapper.UserMapper;

public class Call {

public static SqlSessionFactory sqlSessionFactory = null;

public static void main(String[] args) throws IOException {

// Query User
/*
kickStartMybatis();
queryUser("nick");
*/

// Inser User
kickStartMybatis();
insertUser("user004", "hello world.");

}

public static void kickStartMybatis() throws IOException {
String resource = "com/nicchagil/mybatisonly/mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}

/**
* Query User
* @param username
* @return
*/
public static User queryUser(String username) {

User user = null;
SqlSession session = sqlSessionFactory.openSession();
try {

/* Un-recommended Method */
/*
user = (User)session.selectOne("com.nicchagil.mybatisonly.mapper.UserMapper.queryUser", username);
*/

/* Recommended Method */
UserMapper userMapper = session.getMapper(UserMapper.class);
user = userMapper.queryUser(username);

System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());

} finally {
session.close();
}

return user;
}

/**
* Insert User
* @param username
* @param password
*/
public static void insertUser(String username, String password) {

SqlSession session = sqlSessionFactory.openSession();

try {

UserMapper userMapper = session.getMapper(UserMapper.class);

User user = new User();
user.setUsername(username);
user.setPassword(password);

userMapper.insertUser(user);

// Flushes batch statements and commits database connection.
// Note that database connection will not be committed if no updates/deletes/inserts were called.
session.commit();

System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());

} catch (Exception e) {
session.rollback();
e.printStackTrace();

//TODO Print the exception logs
//TODO Prompts fail to execute for user

} finally {
session.close();
}

}

/**
* Insert User
* @param username
* @param password
*/
public static void insertUserBySQL(String username, String password) {

SqlSession session = sqlSessionFactory.openSession();

try {

User user = new User();
user.setUsername(username);
user.setPassword(password);

session.insert("com.nicchagil.mybatisonly.mapper.UserMapper.insertUser", user);

// Flushes batch statements and commits database connection.
// Note that database connection will not be committed if no updates/deletes/inserts were called.
session.commit();

} catch (Exception e) {
session.rollback();
e.printStackTrace();

//TODO Print the exception logs
//TODO Prompts fail to execute for user

} finally {
session.close();
}

}

Call

package com.nicchagil.mybatisonly;import java.io.IOException;
import java.io.InputStream;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import com.nicchagil.mybatisonly.bean.User;
import com.nicchagil.mybatisonly.mapper.UserMapper;public class Call {public static SqlSessionFactory sqlSessionFactory = null;public static void main(String[] args) throws IOException {// Query User/*kickStartMybatis();queryUser("nick");*/// Inser UserkickStartMybatis();insertUser("user004", "hello world.");}public static void kickStartMybatis() throws IOException {String resource = "com/nicchagil/mybatisonly/mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);}/*** Query User* @param username* @return*/public static User queryUser(String username) {User user = null;SqlSession session = sqlSessionFactory.openSession();try {/* Un-recommended Method *//*user = (User)session.selectOne("com.nicchagil.mybatisonly.mapper.UserMapper.queryUser", username);*//* Recommended Method */UserMapper userMapper = session.getMapper(UserMapper.class);user = userMapper.queryUser(username);System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());} finally {session.close();}return user;}/*** Insert User* @param username* @param password*/public static void insertUser(String username, String password) {SqlSession session = sqlSessionFactory.openSession();try {UserMapper userMapper = session.getMapper(UserMapper.class);User user = new User();user.setUsername(username);user.setPassword(password);userMapper.insertUser(user);// Flushes batch statements and commits database connection. // Note that database connection will not be committed if no updates/deletes/inserts were called.session.commit();System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());} catch (Exception e) {session.rollback();e.printStackTrace();//TODO Print the exception logs//TODO Prompts fail to execute for user} finally {session.close();}}/*** Insert User* @param username* @param password*/public static void insertUserBySQL(String username, String password) {SqlSession session = sqlSessionFactory.openSession();try {User user = new User();user.setUsername(username);user.setPassword(password);session.insert("com.nicchagil.mybatisonly.mapper.UserMapper.insertUser", user);// Flushes batch statements and commits database connection. // Note that database connection will not be committed if no updates/deletes/inserts were called.session.commit();} catch (Exception e) {session.rollback();e.printStackTrace();//TODO Print the exception logs//TODO Prompts fail to execute for user} finally {session.close();}}}

UserMapper是一个DAO的接口，是定义作哪些数据库操作的。

UserMapper.java

package com.nicchagil.mybatisonly.mapper;

import com.nicchagil.mybatisonly.bean.User;

public interface UserMapper {

public User queryUser(String username);

}

1 package com.nicchagil.mybatisonly.mapper;
2
3 import com.nicchagil.mybatisonly.bean.User;
4
5 public interface UserMapper {
6
7     public User queryUser(String username);
8
9 }

UserMapper只是供调用的接口，那么具体的实现逻辑在哪里呢？

我们可见UserMaper.xml，它定义的SQL就是用于定义UserMapper接口的实现。我们需在mybatis-config.xml注册UserMaper.xml，可见mybatis-config.xml的mappers节点。

我们可以看到id为queryUser，与接口的方法名对应；
SQL我们很熟悉了，就是一个简单的SQL，而#{username}，就是接口方法的入参；
resultType为"user"，这个user是一个别名，具体对应com.nicchagil.mybatisonly.bean.User这个类，我们可以看到在mybatis-config.xml文件的typeAliases节点中已经注册它们的映射关系。

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nicchagil.mybatisonly.mapper.UserMapper">

<select id="queryUser" resultType="user">
select * from t_user_test_1407 t where t.username = #{username}
</select>

<insert id="insertUser" parameterType="user">
INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password})
</insert>

</mapper>

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nicchagil.mybatisonly.mapper.UserMapper"><select id="queryUser" resultType="user">select * from t_user_test_1407 t where t.username = #{username}</select><insert id="insertUser" parameterType="user">INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password})</insert></mapper>

而com.nicchagil.mybatisonly.bean.User是实体类，用于装载数据。

User.java

package com.nicchagil.mybatisonly.bean;

public class User {

private String username;
private String password;

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((password == null) ? 0 : password.hashCode());
result = prime * result
+ ((username == null) ? 0 : username.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (password == null) {
if (other.password != null)
return false;
} else if (!password.equals(other.password))
return false;
if (username == null) {
if (other.username != null)
return false;
} else if (!username.equals(other.username))
return false;
return true;
}

}

User.java

 1 package com.nicchagil.mybatisonly.bean;2 3 public class User {4 5     private String username;6     private String password;7 8     public String getUsername() {9         return username;
10     }
11
12     public void setUsername(String username) {
13         this.username = username;
14     }
15
16     public String getPassword() {
17         return password;
18     }
19
20     public void setPassword(String password) {
21         this.password = password;
22     }
23
24     @Override
25     public int hashCode() {
26         final int prime = 31;
27         int result = 1;
28         result = prime * result
29                 + ((password == null) ? 0 : password.hashCode());
30         result = prime * result
31                 + ((username == null) ? 0 : username.hashCode());
32         return result;
33     }
34
35     @Override
36     public boolean equals(Object obj) {
37         if (this == obj)
38             return true;
39         if (obj == null)
40             return false;
41         if (getClass() != obj.getClass())
42             return false;
43         User other = (User) obj;
44         if (password == null) {
45             if (other.password != null)
46                 return false;
47         } else if (!password.equals(other.password))
48             return false;
49         if (username == null) {
50             if (other.username != null)
51                 return false;
52         } else if (!username.equals(other.username))
53             return false;
54         return true;
55     }
56
57 }

最后，我们运行Call.java，将能成功查询、插入数据库。我们可通过打印的信息和查询数据库，以查看是否成功查询、插入数据。

3）事务说明

对于数据库有写操作的应用程序，一般来说，事务是不可或缺的一部分。因为未使用其他框架，这里使用编程式事务，即使用SqlSession.commit()和SqlSession.rollback()方法，可见Call.java。

由于本程序对事务有异常回滚的要求，所以，需要获取非自动提交的SqlSession
如程序执行正常，则最后执行session.commit()以提交事务。
- session.commit()有个需注意的地方，参考其如下注释，即如果当前会话中不涉及updates/deletes/insert等写数动作则不提交事务。所以，如果要触发Mybatis提交事务，就需执行明确的触发动作，如“执行session.insert(...)方法”或“执行对应的SQL Mapper配置中的insert、update、delete等标签”等操作。（本人曾尝试在SQL Mapper配置中用select标签包含INSERT的SQL，使用SqlSession.commit()后，执行正常，但没有提交事务，可见并未触发，所以，需规范使用标签）。如需强制提交，可用SqlSession.commit(boolean)。
  
  Flushes batch statements and commits database connection. Note that database connection will not be committed if no updates/deletes/inserts were called. To force the commit call SqlSession.commit(boolean)
如程序执行异常，则回滚事务，session.rollback()

单独搭建Mybaits完毕！

二、 Mybatis与Spring的整合

一个项目中，单独使用Mybatis的情况并不多；更多的情况下，我们需要将Mybatis与其他框架进行整合，以便更好地使用。比如Mybatis + Spring，就是一个流行的整合组合。

1）环境准备、版本说明

本次用Mybatis3 + Spring3进行整合。注意，并不包含MVC框架的配置，因为本文的目的是学习Mybatis，所以尽量不引用其他框架，以避免影响代码的理解。

需引入的类库详情如下:

MVN dependencies

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.2.10.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework.webflow</groupId>
<artifactId>spring-webflow</artifactId>
<version>2.4.0.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-oracle</artifactId>
<version>1.0.0.RELEASE</version>
</dependency>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.4</version>
</dependency>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.2</version>
</dependency>

</dependencies>

<dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>test</scope></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>3.2.10.RELEASE</version></dependency><dependency><groupId>org.springframework.webflow</groupId><artifactId>spring-webflow</artifactId><version>2.4.0.RELEASE</version></dependency><dependency><groupId>org.springframework.data</groupId><artifactId>spring-data-oracle</artifactId><version>1.0.0.RELEASE</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.2.4</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.2.2</version></dependency></dependencies>

2）程序的搭建

首先，我们在Spring中配置关于Mybatis数据源的信息。

这里以applicationContext-mybatis.xml来体现，配置了如下信息：

注册数据源，常见的有JDBC或JNDI，根据具体情况择一。
注册sqlSessionFactory
- sqlSessionFactory是用来生产sqlSession以操作数据库的，所以，需指定sqlSessionFactory所引用的数据源
- 指定相应的SQL Mapper文件在哪里。我们自命名“_mapper后缀的xml文件”，主要用来定义SQL；“_resultmap后缀的xml文件”，则主要用来定义DB字段与应用程序实体属性的映射。
- 指定相应的应用程序实体在哪里，并自动注册不包含package名的别名
在哪些package下扫描Mapper接口，即DAO接口

applicationContext-mybatis.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>JNDI_TEST_DB</value>
</property>
</bean>

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="mapperLocations">
<list>
<value>classpath:com/nicchagil/mybatis3spring3intg/mapper/sqlxml/*_mapper.xml</value>
<value>classpath:com/nicchagil/mybatis3spring3intg/bean/resultmapxml/*_resultmap.xml</value>
</list>
</property>
<property name="typeAliasesPackage" value="com.nicchagil.mybatis3spring3intg.bean" />
</bean>

</beans>

applicationContext-mybatis.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:context="http://www.springframework.org/schema/context"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsd"><!-- JDBC Data Source --><!-- <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource" ><property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" /><property name="url"value="jdbc:oracle:thin:@hostname:port:sid" /><property name="username" value="username" /><property name="password" value="password" /></bean>--><!-- JNDI Data Source --><bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean"><property name="jndiName"><value>JNDI_TEST_DB</value></property></bean><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource" /><property name="mapperLocations"><list><value>classpath:com/nicchagil/mybatis3spring3intg/mapper/sqlxml/*_mapper.xml</value><value>classpath:com/nicchagil/mybatis3spring3intg/bean/resultmapxml/*_resultmap.xml</value></list></property><property name="typeAliasesPackage" value="com.nicchagil.mybatis3spring3intg.bean" /></bean><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.nicchagil.mybatis3spring3intg.mapper" /><property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /></bean></beans>

除了Mybatis的信息，还有一些Spring的信息需要配置：

根据注解自动扫描并注册bean
Spring的声明式事务管理（用以替代上一章节的“编程式事务”）
由于本程序没有集成MVC框架，在Servlet是通过Spring编程式地获得Spring管理的bean，所以这里注册一个Spring的工具类。（使用了MVC框架并将框架交由Spring IOC容器管理的，可忽视此点配置）

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

<context:component-scan base-package="com.nicchagil.mybatis3spring3intg" />

<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>

</beans>

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:context="http://www.springframework.org/schema/context"xmlns:tx="http://www.springframework.org/schema/tx"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsdhttp://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx-3.0.xsd"><context:component-scan base-package="com.nicchagil.mybatis3spring3intg" /><!-- Transaction Support --><tx:annotation-driven transaction-manager="transactionManager" /><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource" /></bean><bean id="SpringContextUtil" class="com.nicchagil.util.SpringContextUtil"/></beans>

众所周知，以上是Spring的配置文件，那么我们需要告诉应用程序“这些配置文件在哪里”，所以我们需要在web.xml中告诉应用程序。另外，此web.xml注册了一个Servlet，用于接收页面的请求。

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>mybatis3spring3Intg</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:config/applicationContext*.xml</param-value>
</context-param>
<servlet>
<description></description>
<display-name>UserServlet</display-name>
<servlet-name>UserServlet</servlet-name>
<servlet-class>com.nicchagil.mybatis3spring3intg.servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/UserServlet</url-pattern>
</servlet-mapping>
</web-app>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"><display-name>mybatis3spring3Intg</display-name><welcome-file-list><welcome-file>index.html</welcome-file></welcome-file-list><listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener><context-param><param-name>contextConfigLocation</param-name><param-value>classpath*:config/applicationContext*.xml</param-value></context-param><servlet><description></description><display-name>UserServlet</display-name><servlet-name>UserServlet</servlet-name><servlet-class>com.nicchagil.mybatis3spring3intg.servlet.UserServlet</servlet-class></servlet><servlet-mapping><servlet-name>UserServlet</servlet-name><url-pattern>/UserServlet</url-pattern></servlet-mapping>
</web-app>

我们还需要定义Mapper的接口，即DAO接口。此处的Mapper的接口，我们已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

UserMapper.java

package com.nicchagil.mybatis3spring3intg.mapper;

import com.nicchagil.mybatis3spring3intg.bean.User;

public interface UserMapper {

public User find(String username);

public void save(User user);

}

UserMapper.java

package com.nicchagil.mybatis3spring3intg.mapper;import com.nicchagil.mybatis3spring3intg.bean.User;public interface UserMapper {public User find(String username);public void save(User user);}

而Mapper的实现是如何的呢？

Mybatis会帮我们实现，我们只需要通过user_mapper.xml文件告诉Mybatis对应的SQL，此处的mapper文件，已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

user_mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"><select id="find" resultType="user" resultMap="userResultMap">select * from t_user_test_1407 t where t.username = #{username}</select><insert id="save" parameterType="user">INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password})</insert></mapper>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"><select id="find" resultType="user" resultMap="userResultMap">select * from t_user_test_1407 t where t.username = #{username}</select><insert id="save" parameterType="user">INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password})</insert></mapper>

可以看到，Mapper和SQL配置文件中都引用到了实体类，我们也需要定义。此处的实体类，已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

User.java

package com.nicchagil.mybatis3spring3intg.bean;

public class User {

private String username;
private String password;
private String childhoodName;

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

public String getChildhoodName() {
return childhoodName;
}

public void setChildhoodName(String childhoodName) {
this.childhoodName = childhoodName;
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((childhoodName == null) ? 0 : childhoodName.hashCode());
result = prime * result
+ ((password == null) ? 0 : password.hashCode());
result = prime * result
+ ((username == null) ? 0 : username.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (childhoodName == null) {
if (other.childhoodName != null)
return false;
} else if (!childhoodName.equals(other.childhoodName))
return false;
if (password == null) {
if (other.password != null)
return false;
} else if (!password.equals(other.password))
return false;
if (username == null) {
if (other.username != null)
return false;
} else if (!username.equals(other.username))
return false;
return true;
}

}

User.java

package com.nicchagil.mybatis3spring3intg.bean;public class User {private String username;private String password;private String childhoodName;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getChildhoodName() {return childhoodName;}public void setChildhoodName(String childhoodName) {this.childhoodName = childhoodName;}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result+ ((childhoodName == null) ? 0 : childhoodName.hashCode());result = prime * result+ ((password == null) ? 0 : password.hashCode());result = prime * result+ ((username == null) ? 0 : username.hashCode());return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;User other = (User) obj;if (childhoodName == null) {if (other.childhoodName != null)return false;} else if (!childhoodName.equals(other.childhoodName))return false;if (password == null) {if (other.password != null)return false;} else if (!password.equals(other.password))return false;if (username == null) {if (other.username != null)return false;} else if (!username.equals(other.username))return false;return true;}}

实体的属性与DB的字段之间的映射/匹配，我们需要定义一下。此处的resultmap.xml文件已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

user_resultmap.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

user_resultmap.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"><resultMap type="user" id="userResultMap"><result property="username" column="USERNAME" /><result property="password" column="PASSWORD" /><result property="childhoodName" column="USERNAME" /></resultMap>
</mapper>

完成了DAO，那么接着写Service。

首先一个Service的接口。

UserService.java

package com.nicchagil.mybatis3spring3intg.service;

import com.nicchagil.mybatis3spring3intg.bean.User;

public interface UserService {

public User query(String username);

public void save(User user);

public void testTransaction(User user1, User user2);

}

UserService.java

package com.nicchagil.mybatis3spring3intg.service;import com.nicchagil.mybatis3spring3intg.bean.User;public interface UserService {public User query(String username);public void save(User user);public void testTransaction(User user1, User user2);}

Service的实现类如下，这里只简单地测试查询、保存、事务是否能正常处理。

UserServiceImpl.java

package com.nicchagil.mybatis3spring3intg.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.nicchagil.mybatis3spring3intg.bean.User;
import com.nicchagil.mybatis3spring3intg.mapper.UserMapper;
import com.nicchagil.mybatis3spring3intg.service.UserService;

@Service
public class UserServiceImpl implements UserService {

@Autowired
private UserMapper mapper;

@Override
public User query(String username) {
return mapper.find(username);
}

@Override
public void save(User user) {
mapper.save(user);
}

@Override
@Transactional
public void testTransaction(User user1, User user2) {
mapper.save(user1);

// Code a NullPointerException to test transaction setting
String str = null;
str.charAt(0);

mapper.save(user2);
}

}

UserServiceImpl.java

由于没有整合MVC框架，此处由一个Servlet(此Servlet已于web.xml中注册）获取页面请求并调用Service，

那么如何在Servlet中获得Spring IOC管理下Service的bean呢？这里借助SpringContextUtil（implements ApplicationContextAware），此SpringContextUtil于以上提及的applicationContext.xml中注册。

UserServlet.java

package com.nicchagil.mybatis3spring3intg.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.nicchagil.mybatis3spring3intg.bean.User;
import com.nicchagil.mybatis3spring3intg.service.UserService;
import com.nicchagil.util.SpringContextUtil;

/**
* Servlet implementation class UserServlet
*/
public class UserServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public UserServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

String action = request.getParameter("action");

UserService service = (UserService)SpringContextUtil.getBean("userServiceImpl");

if ("find".equals(action)) {
User user = service.query(request.getParameter("username"));
System.out.println(user.getUsername() + " - " + user.getPassword() + " - " + user.getChildhoodName());

}

if ("save".equals(action)) {
User user = new User();
user.setUsername(request.getParameter("username"));
user.setPassword(request.getParameter("password"));

service.save(user);
System.out.println(user.getUsername() + " - " + user.getPassword());

}

if ("testTransaction".equals(action)) {
User user1 = new User();
user1.setUsername(request.getParameter("username"));
user1.setPassword(request.getParameter("password"));

User user2 = new User();
user2.setUsername(request.getParameter("username") + " - Double");
user2.setPassword(request.getParameter("password") + " - Double");

service.testTransaction(user1, user2);
System.out.println(user1.getUsername() + " - " + user1.getPassword());
System.out.println(user2.getUsername() + " - " + user2.getPassword());

}

UserServlet.java

package com.nicchagil.mybatis3spring3intg.servlet;import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.nicchagil.mybatis3spring3intg.bean.User;
import com.nicchagil.mybatis3spring3intg.service.UserService;
import com.nicchagil.util.SpringContextUtil;/*** Servlet implementation class UserServlet*/
public class UserServlet extends HttpServlet {private static final long serialVersionUID = 1L;/*** @see HttpServlet#HttpServlet()*/public UserServlet() {super();// TODO Auto-generated constructor stub}/*** @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)*/protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);}/*** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)*/protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String action = request.getParameter("action");UserService service = (UserService)SpringContextUtil.getBean("userServiceImpl");if ("find".equals(action)) {User user = service.query(request.getParameter("username"));System.out.println(user.getUsername() + " - " + user.getPassword() + " - " + user.getChildhoodName());}if ("save".equals(action)) {User user = new User();user.setUsername(request.getParameter("username"));user.setPassword(request.getParameter("password"));service.save(user);System.out.println(user.getUsername() + " - " + user.getPassword());}if ("testTransaction".equals(action)) {User user1 = new User();user1.setUsername(request.getParameter("username"));user1.setPassword(request.getParameter("password"));User user2 = new User();user2.setUsername(request.getParameter("username") + " - Double");user2.setPassword(request.getParameter("password") + " - Double");service.testTransaction(user1, user2);System.out.println(user1.getUsername() + " - " + user1.getPassword());System.out.println(user2.getUsername() + " - " + user2.getPassword());}}}

SpringContextUtil.java

package com.nicchagil.util;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class SpringContextUtil implements ApplicationContextAware {

private static ApplicationContext applicationContext = null;

@Override
public void setApplicationContext(ApplicationContext ac)
throws BeansException {
applicationContext = ac;

}

public static ApplicationContext getApplicationContext() {
return applicationContext;
}

public static Object getBean(String beanName) {
return applicationContext.getBean(beanName);
}

public static boolean containsBean(String beanName) {
return applicationContext.containsBean(beanName);
}

}

SpringContextUtil.java

package com.nicchagil.util;import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;public class SpringContextUtil implements ApplicationContextAware {private static ApplicationContext applicationContext = null;@Overridepublic void setApplicationContext(ApplicationContext ac)throws BeansException {applicationContext = ac;}public static ApplicationContext getApplicationContext() {return applicationContext;}public static Object getBean(String beanName) {return applicationContext.getBean(beanName);}public static boolean containsBean(String beanName) {return applicationContext.containsBean(beanName);}}

几乎大功告成。

这里写了些触发测试的页面，执行结果可通过“查看控制台”或“查询数据库”获得。哈哈！~~

导航页

index.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<a href="find.html">find</a>
<br/>
<a href="save.html">save</a>
<br/>
<a href="testTransaction.html">testTransaction</a>

</body>
</html>

index.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body><a href="find.html">find</a>
<br/>
<a href="save.html">save</a>
<br/>
<a href="testTransaction.html">testTransaction</a></body>
</html>

输入username查询记录的触发页面

find.html

</body>
</html>

find.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body><form action="UserServlet"><input type="hidden" name="action" value="find"><input type="text" name="username"><input type="submit"></form></body>
</html>

保存页面

save.html

</body>

</body>
</html>

save.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<body><form action="UserServlet"><input type="hidden" name="action" value="save"><input type="text" name="username"> <input type="password" name="password"> <input type="submit"></form></body></body>
</html>

测试事务的触发页面

testTransaction.html

</body>

</body>
</html>

testTransaction.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<body><form action="UserServlet"><input type="hidden" name="action" value="testTransaction"><input type="text" name="username"> <input type="password" name="password"> <input type="submit"></form></body></body>
</html>

大功告成！！

分享于：

https://github.com/nicchagil/mybatis3spring3Intg/tree/mybatis3spring3Intg_branch_initialization

转载于:https://www.cnblogs.com/telwanggs/p/5403165.html

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