1.项目的相关路径

2.Mybatis的配置文件

3.Mybatis的工具类

/**

*

*/

/**

* @author lmy

*

*/

package com.util;

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;

public class Util {

private static SqlSessionFactory sqlSessionFactory = null;

/**

* 初始化Session工厂

* @throws IOException

*/

private static void initialFactory() throws IOException {

String resource = "Mybatis-config.xml";

InputStream inputStream = Resources.getResourceAsStream(resource);

sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

}

/**

* 获取Session

* @return

*/

public static SqlSession getSession() {

if(sqlSessionFactory == null) {

try {

initialFactory();

} catch (IOException e) {

e.printStackTrace();

}

}

return sqlSessionFactory.openSession();

}

}

4.创建实体类以及对应的Mapping.xml文件

/**

*

*/

/**

* @author lmy

*

*/

package com.model;

public class Users {

private Integer id;

private String name;

private int age;

public Integer getId()

{ return id; }

public void setId(Integer id)

{ this.id = id; }

public String getName()

{ return name; }

public void setName(String name)

{ this.name = name; }

public int getAge()

{ return age; }

public void setAge(int age)

{ this.age = age; }

@Override

public String toString()

{ return "User [id=" + id + ", name=" + name + ", age=" + age + "]"; } }

select * from Users

insert into Users (id,name,age) values (#{id},#{name},#{age})

insert into Users (id,name,age)

SELECT

#{item.id} id,

#{item.name} name,

#{item.age} age

FROM dual

insert into Users (id,name,age)

SELECT

#{item.id} id,

#{item.name} name,

#{item.age} age

FROM dual

insert into Users (id,name,age)

SELECT

#{item.id} id,

#{item.name} name,

#{item.age} age

FROM dual

select u.id id,u.name name from Users u

select * from Users where id=#{id}

delete from Users where id=#{id}

delete from Users where id in (

select

#{item.id}

from dual

)

update Users set name=#{name} where id=#{id}

5.测试类

/**

*

*/

package com.test;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

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 org.junit.After;

import org.junit.Before;

import org.junit.Test;

import com.model.Users;

import com.util.Util;

public class TestMybatis{

private SqlSession session = null;

@Before

public void before() {

session = Util.getSession();

}

@After

public void after() {

session.commit();

session.close();

}

//1.查询(数字对应Mapping.xml的数字方法)

@SuppressWarnings("unchecked")

@Test

public void testSelectUser() throws IOException {

List userList = session.selectList("com.mapping.UserMapping.getUser");

for(Users each : userList) {

System.out.println("each->" + each);

}

}

//2.插入

@Test

public void testInsert() {

Users user = new Users();

user.setId(200);

user.setName("路飞");

user.setAge(23);

session.insert("com.mapping.UserMapping.insertUser" , user);

}

//7.根据id查询数据

@Test

public void testSelectUserById() throws IOException {

Users user = (Users) session.selectOne("com.mapping.UserMapping.getUserById",1);

System.out.println("each->" + user.toString());

}

//8.根据id删除数据

@Test

public void testDeleteUserById() throws IOException {

session.delete("com.mapping.UserMapping.deleteUserById",1);

System.out.println("删除成功！");

}

// 10.更新数据

@Test

public void testUpdateUserById() throws IOException {

Users user = (Users) session.selectOne("com.mapping.UserMapping.getUserById",1);

user.setName("11111111");

session.update("com.mapping.UserMapping.updateUserById",user);

System.out.println("更新成功！");

}

//3.批量插入list

@Test

public void testInsertUserList() throws IOException {

Users user = new Users();

user.setId(100);

user.setName("路飞");

user.setAge(23);

Users user1 = new Users();

user1.setId(101);

user1.setName("路飞");

user1.setAge(23);

List userList = new ArrayList();

userList.add(user);

userList.add(user1);

session.insert("com.mapping.UserMapping.insertUserList" , userList);

System.out.println("插入成功！");

}

//4.批量插入map

@Test

public void testInsertUserMap() throws IOException {

Users user = new Users();

user.setId(106);

user.setName("路飞");

user.setAge(23);

Users user1 = new Users();

user1.setId(104);

user1.setName("路飞");

user1.setAge(23);

List list =new ArrayList();

list.add(user1);

list.add(user);

Map> map = new HashMap>();

map.put("map",list);//map存放的key值要与mapper.xml文件中的的collection名称一致

session.insert("com.mapping.UserMapping.insertUserMap" , map);

System.out.println("插入成功！");

}

// 5.批量插入List>数据

@Test

public void testInsertUserListMap() throws IOException {

List> list =new ArrayList>();

Map map = new HashMap();

map.put("id",23);

map.put("name", "ui0");

map.put("age", 21);

list.add(map);

session.insert("com.mapping.UserMapping.insertUserMapList" , list);

System.out.println("插入成功！");

}

//6.返回值类型为List>

@Test

public void testSelectUserListData() throws IOException {

List> list = session.selectList("com.mapping.UserMapping.ListMapData");

for (int i=0;i

System.out.println(list.get(i).toString());

}

}

//9.批量删除

@Test

public void testDeleteUserByList() throws IOException {

// List userList =new ArrayList();

// userList.add(23);

// userList.add(24);

List userList = new ArrayList();

Users user = new Users();

user.setId(1);

Users user2 = new Users();

user2.setId(2);

userList.add(user2);

userList.add(user);

session.delete("com.mapping.UserMapping.deleteUser",userList);

System.out.println("删除成功！");

}

}

5.foreach知识小总结

foreach的主要用在构建in条件中，它可以在SQL语句中进行迭代一个集合。

foreach元素的属性主要有 item，index，collection，open，separator，close。

item表示集合中每一个元素进行迭代时的别名，index指定一个名字，用于表示在迭代过程中，每次迭代到的位置，open表示该语句以什么开始，separator表示在每次进行迭代之间以什么符号作为分隔符，close表示以什么结束，在使用foreach的时候最关键的也是最容易出错的就是collection属性，该属性是必须指定的，但是在不同情况 下，该属性的值是不一样的，主要有一下3种情况：

1.如果传入的是单参数且参数类型是一个List的时候，collection属性值为list

2.如果传入的是单参数且参数类型是一个array数组的时候，collection的属性值为array

3.如果传入的参数是多个的时候，我们就需要把它们封装成一个Map了，当然单参数也可以封装成map