接口文件和对应的mapper.xml文件
UsersMapper.java接口文件
package com.example.mapper;
import com.example.pojo.User;
import java.util.List;
/**
* 数据访问层的接口，定义对数据库完成的CRUD的操作
*/
public interface UsersMapper {
//获取全部用户信息
List<User> getAll();
//根据用户主键查取用户信息
User getById(int id);
//根据用户名模糊查询用户信息
List<User> getByName(String name);
//向用户表中增加用户信息
int insert(User user);
//根据id更新用户信息
int update(User user);
//根据id删除用户信息
int delete(int id);
}
UsersMapper.xml映射文件
<?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.example.mapper.UsersMapper">
<!--
//获取全部用户信息
List<Users> getAll();
-->
<select id="getAll" resultType="user">
select
id, username, birthday, sex, address
from
users
</select>
<!--
//根据用户主键查取用户信息
User getById();
-->
<select id="getById" resultType="user" parameterType="int">
select
id, username, birthday, sex, address
from
users
where
id=#{id}
</select>
<!--
//根据用户名模糊查询用户信息
List<User> getByName(String name);
-->
<select id="getByName" parameterType="string" resultType="user">
select
id, username, birthday, sex, address
from
users
where username like '%${name}%'
</select>
<!--
//向用户表中增加用户信息
int insert(User user);
-->
<insert id="insert" parameterType="user">
insert into
users(username, birthday, sex, address)
values(#{userName}, #{birthday}, #{sex}, #{address})
</insert>
<!--
//根据id更新用户信息
int update(User user);
-->
<update id="update" parameterType="user">
update
users
set
username=#{userName}, birthday=#{birthday}, sex=#{sex}, address=#{address}
where
id=#{id}
</update>
<!--
//根据id删除用户信息
int delete(int id);
-->
<delete id="delete" parameterType="int">
delete from
users
where
id=#{id}
</delete>
</mapper>
mapper.xml文件注册的优化
<!--注册mapper.xml文件-->
<mappers>
<mapper class="com.example.mapper.UsersMapper"/>
</mappers>
<!--注册mapper.xml文件-->
<mappers>
<!--
当com.example.mapper文件夹下有许多映射文件时，批量注册
-->
<package name="com.example.mapper"/>
</mappers>
测试代码
package com.example.mapper;
import com.example.pojo.User;
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 java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
public class TestUsersMapper {
//时间刷
SimpleDateFormat date = new SimpleDateFormat("yyyy-MM-dd");
//SqlSession对象
SqlSession sqlSession;
//mybatis动态代理对象
UsersMapper usersMapper;
//获取SqlSession
@Before
public void getSqlSession() throws IOException {
//读取核心配置文件
InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
//创建SqlSessionFactory对象
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
//获取SqlSession
sqlSession = factory.openSession();
//获取mybatis动态代理对象
usersMapper = sqlSession.getMapper(UsersMapper.class);
}
//归还SqlSession
@After
public void closeSession(){
sqlSession.close();
}
@Test
public void testGetAll(){
//调用代理的功能
List<User> users = usersMapper.getAll();
//输出查询结果
users.forEach(System.out::println);
}
@Test
public void testGetById(){
//调用代理功能
User user = usersMapper.getById(2);
//输出查询结果
System.out.println(user);
}
@Test
public void testGetByName(){
//调用代理功能
List<User> users = usersMapper.getByName("小");
//输出查询结果
users.forEach(System.out::println);
}
@Test
public void testInsert() throws ParseException {
//时间字符串
String dateStr = "2001-03-14";
int num = usersMapper.insert(new User("小昕", date.parse(dateStr), "女", "忻州"));
sqlSession.commit();
if (num == 1) {
System.out.println("插入成功!");
}else{
System.out.println("插入失败!");
}
}
@Test
public void testUpdate() throws ParseException {
String dateStr = "2002-8-23";
int num = usersMapper.update(new User(1, "荷包蛋", date.parse(dateStr), "女", "黑河"));
sqlSession.commit();
if (num == 1) {
System.out.println("更新成功!");
}else{
System.out.println("更新失败!");
}
}
@Test
public void testDelete(){
int num = usersMapper.delete(4);
sqlSession.commit();
if (num == 1) {
System.out.println("删除成功!");
}else{
System.out.println("删除失败!");
}
}
}
输出结果示例
1.查询所有用户信息
Checking to see if class com.example.pojo.Users matches criteria [is assignable to Object]
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 1548946718.
Setting autocommit to false on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@5c530d1e]
==> Preparing: select id, username, birthday, sex, address from users
==> Parameters:
<== Columns: id, username, birthday, sex, address
<== Row: 1, 小涵, 2000-09-10, 2, 黑河市
<== Row: 2, 小王, 2001-07-12, 1, 芜湖市
<== Row: 3, 小张, 1999-02-22, 1, 长沙
<== Row: 4, 小吴, 2002-11-19, 1, 成都
<== Row: 5, 段, 2001-03-10, 1, 太原
<== Row: 6, 范成群, 2002-01-19, 1, 鲅鱼圈
<== Row: 7, 学委, 2001-05-13, 2, 平顶山市
<== Total: 7
Users{id=1, userName='小涵', birthday=Sun Sep 10 00:00:00 CST 2000, sex='2', address='黑河市'}
Users{id=2, userName='小王', birthday=Thu Jul 12 00:00:00 CST 2001, sex='1', address='芜湖市'}
Users{id=3, userName='小张', birthday=Mon Feb 22 00:00:00 CST 1999, sex='1', address='长沙'}
Users{id=4, userName='小吴', birthday=Tue Nov 19 00:00:00 CST 2002, sex='1', address='成都'}
Users{id=5, userName='段', birthday=Sat Mar 10 00:00:00 CST 2001, sex='1', address='太原'}
Users{id=6, userName='范成群', birthday=Sat Jan 19 00:00:00 CST 2002, sex='1', address='鲅鱼圈'}
Users{id=7, userName='学委', birthday=Sun May 13 00:00:00 CST 2001, sex='2', address='平顶山市'}
Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@5c530d1e]
Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@5c530d1e]
Returned connection 1548946718 to pool.
Process finished with exit code 0
2.根据用户id删除用户信息
Checking to see if class com.example.pojo.User matches criteria [is assignable to Object]
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 472991420.
Setting autocommit to false on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1c3146bc]
==> Preparing: delete from users where id=?
==> Parameters: 4(Integer)
<== Updates: 1
Committing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1c3146bc]
删除成功!
Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1c3146bc]
Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1c3146bc]
Returned connection 472991420 to pool.
Process finished with exit code 0
3.根据用户id更改用户信息
Checking to see if class com.example.pojo.User matches criteria [is assignable to Object]
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 1985938863.
Setting autocommit to false on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@765f05af]
==> Preparing: update users set username=?, birthday=?, sex=?, address=? where id=?
==> Parameters: 荷包蛋(String), 2002-08-23 00:00:00.0(Timestamp), 女(String), 黑河(String), 1(Integer)
<== Updates: 1
Committing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@765f05af]
更新成功!
Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@765f05af]
Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@765f05af]
Returned connection 1985938863 to pool.
Process finished with exit code 0
4.添加用户信息
Checking to see if class com.example.pojo.User matches criteria [is assignable to Object]
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 1178290888.
Setting autocommit to false on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@463b4ac8]
==> Preparing: insert into users(username, birthday, sex, address) values(?, ?, ?, ?)
==> Parameters: 小昕(String), 2001-03-14 00:00:00.0(Timestamp), 女(String), 忻州(String)
<== Updates: 1
Committing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@463b4ac8]
插入成功!
Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@463b4ac8]
Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@463b4ac8]
Returned connection 1178290888 to pool.
Process finished with exit code 0
