Spring学习笔记

Spring简介

1, 只用IOC

spring.jar , jarkata-commons/commons-loggin.jar

2,IOC容器

实例化具体bean

动态装配

3,AOP支持

安全检查

管理transaction

Spring配置

1,注入类型

　　setter（重要）
构造方法（可以忘记）
　　 接口注入（可以忘记）

<bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl"><!-- new UserDAOImpl()--></bean><bean id="userService" class="com.bjsxt.service.UserService"><!-- <property name="userDAO" ref="u" />  setter注入 ，调用setxxx方法--><constructor-arg>  <!-- 构造方法注入，需要在UserService里面写构造方法，相当于调用了构造方法--><ref bean="u"/>   <!-- 参考了另外一个已经new 的bean--></constructor-arg></bean>

public class UserService {private UserDAO userDAO;  public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}public void setUserDAO(UserDAO userDAO) {this.userDAO = userDAO;}public UserService(UserDAO userDAO) {//用于构造方法注入super();this.userDAO = userDAO;}
}

2,id vs. name

　　name可以用特殊字符

<bean name="u" class="com.bjsxt.dao.impl.UserDAOImpl"></bean><bean id="userService" class="com.bjsxt.service.UserService"><!-- <property name="userDAO" ref="u" />--><constructor-arg><ref bean="u"/></constructor-arg></bean>

3,简单属性的注入

bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl"><property name="daoId" value="8"></property><property name="daoStatus" value="good"></property></bean>

public class UserDAOImpl implements UserDAO {private int daoId;private String daoStatus;public int getDaoId() {return daoId;}public void setDaoId(int daoId) {this.daoId = daoId;}public String getDaoStatus() {return daoStatus;}public void setDaoStatus(String daoStatus) {this.daoStatus = daoStatus;}public void save(User user) {System.out.println("user saved!");}@Overridepublic String toString() {return this.daoId + ":" + this.daoStatus;}
}

4,bean 中的scope属性

　　singleton:只有一个

　　prototype:每一个都不同

5,集合注入

　　很少用，不重要！

public class UserDAOImpl implements UserDAO {/* (non-Javadoc)* @see com.bjsxt.dao.UserDAO#save(com.bjsxt.model.User)*/private Set<String> sets;private List<String> lists;private Map<String , String> maps;public Set<String> getSets() {return sets;}public void setSets(Set<String> sets) {this.sets = sets;}public List<String> getLists() {return lists;}public void setLists(List<String> lists) {this.lists = lists;}public Map<String, String> getMaps() {return maps;}public void setMaps(Map<String, String> maps) {this.maps = maps;}public UserDAOImpl() {}public void save(User user) {System.out.println("user saved!");}@Overridepublic String toString() {return "sets size:" + sets.size() + "| lists size:" + lists.size() + "| maps size:" + maps.size() ; }}

<bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl"><property name="sets"><set><value>1</value><value>2</value></set></property><property name="lists"><list><value>1</value><value>2</value><value>3</value></list></property><property name="maps"><map><entry key="1" value="1"></entry><entry key="2" value="2"></entry><entry key="3" value="3"></entry><entry key="4" value="4"></entry></map></property></bean><bean id="userService" class="com.bjsxt.service.UserService"><!-- <property name="userDAO"><ref bean="userDAO"/></property>--><constructor-arg><ref bean="userDAO"/></constructor-arg></bean>

6,自动装配

byName
byType
如果所有的bean都用同一种，可以使用beans的属性：default-autowire

 <bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl"><property name="daoId" value="1"></property></bean><bean name="userDAO2" class="com.bjsxt.dao.impl.UserDAOImpl"><property name="daoId" value="2"></property></bean><bean id="userService" class="com.bjsxt.service.UserService" scope="prototype" autowire="byName"><!-- 未指定property， 若是byname则自动匹配name等于userDAO的bean, 若是bytype则匹配类型为userDAO的bean--></bean>

public class UserDAOImpl implements UserDAO {private int daoId;public int getDaoId() {return daoId;}public void setDaoId(int daoId) {this.daoId = daoId;}public void save(User user) {System.out.println("user saved!");}@Overridepublic String toString() {return "daoId=" + daoId;}}

7,生命周期

lazy-init (不重要) 容器初始化时（ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml")），不初始化，只有用到时才初始化

<bean id="lazy" class="com.foo.ExpensiveToCreateBean" lazy-init="true"/>

init-method destroy-methd 不要和prototype一起用（了解）

<bean id="userService" class="com.bjsxt.service.UserService" init-method="init" destroy-method="destroy" scope="singleton"><!-- <property name="userDAO" ref="u" />--><constructor-arg><ref bean="u"/></constructor-arg></bean>

public class UserService {private UserDAO userDAO;  public void init() {System.out.println("init");}public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}public void setUserDAO(UserDAO userDAO) {this.userDAO = userDAO;}public UserService(UserDAO userDAO) {super();this.userDAO = userDAO;}public void destroy() {System.out.println("destroy");}
}

8,Annotation第一步：

修改xml文件，参考文档<context:annotation-config />

<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.5.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-2.5.xsd"><context:annotation-config />
<bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl"></bean><bean id="u2" class="com.bjsxt.dao.impl.UserDAOImpl"></bean><bean id="userService" class="com.bjsxt.service.UserService" ></bean></beans>

9,@Autowired(自动装配)

默认按类型by type
如果想用byName，使用@Qulifier
写在private field（第三种注入形式）（不建议，破坏封装）
如果写在set上，@qualifier需要写在参数上

public class UserService {private UserDAO userDAO;  public void init() {System.out.println("init");}public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}@Autowiredpublic void setUserDAO(@Qualifier("u") UserDAO userDAO) {this.userDAO = userDAO;}public void destroy() {System.out.println("destroy");}
}

10,@Resource（重要）

加入：j2ee/common-annotations.jar
默认按名称，名称找不到，按类型 @Resource
可以指定特定名称 @Resource(name="u2")
推荐使用
不足：如果没有源码，就无法运用annotation，只能使用xml

<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.5.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-2.5.xsd"><context:annotation-config /><bean id="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl"></bean><bean id="u2" class="com.bjsxt.dao.impl.UserDAOImpl"></bean><bean id="userService" class="com.bjsxt.service.UserService" ></bean></beans>

public class UserService {private UserDAO userDAO;  public void init() {System.out.println("init");}public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}@Resource(name="u2")//@Resourcepublic void setUserDAO( UserDAO userDAO) {this.userDAO = userDAO;}public void destroy() {System.out.println("destroy");}
}

11,@Component @Service @Controller @Repository 在spring2.5.6中这四个目前没有区别

初始化的名字默认为类名首字母小写
可以指定初始化bean的名字 @Component("u")

<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.5.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-2.5.xsd"><context:annotation-config /><context:component-scan base-package="com.bjsxt"/>
</beans>

@Component("u") //u=new UserDAO()
public class UserDAOImpl implements UserDAO {public void save(User user) {System.out.println("user saved!");}}

@Component("userService")
public class UserService {private UserDAO userDAO;  public void init() {System.out.println("init");}public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}@Resource(name="u") //把name=u的UserDAO注入public void setUserDAO( UserDAO userDAO) {this.userDAO = userDAO;}public void destroy() {System.out.println("destroy");}
}

12,@Scope

13,@PostConstruct = init-method; @PreDestroy = destroy-method;

@Scope("singleton")
@Component("userService")
public class UserService {private UserDAO userDAO;  @PostConstructpublic void init() {System.out.println("init");}public void add(User user) {userDAO.save(user);}public UserDAO getUserDAO() {return userDAO;}@Resource(name="u")public void setUserDAO( UserDAO userDAO) {this.userDAO = userDAO;}@PreDestroypublic void destroy() {System.out.println("destroy");}
}

转载于:https://www.cnblogs.com/enjoy-life-clh/p/4227485.html

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