看完以下內容接着看:https://blog.csdn.net/lgz0921/article/details/104228639
目錄結構:
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>mybatis-study</artifactId>
<groupId>org.kuang</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>mybatis-02</artifactId>
</project>
UserMapper:
package com.kuang.dao;
import com.kuang.pojo.User;
import java.util.List;
import java.util.Map;
public interface UserMapper {
//查詢全部用戶
List<User> getUserList();
//根據id查詢用戶
User getUserById(int id);
//insert一個用戶
int addUser(User user);
//修改用戶
int updateUser(User user);
//刪除一個用戶
int deleteUser(int id);
}
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">
<!-- namespace 綁定一個Dao/Mapper接口 與接口名字一致-->
<mapper namespace="com.kuang.dao.UserMapper">
<!-- select查詢語句-->
<select id="getUserList" resultType="User">
select * from mybatis.user;
</select>
<select id="getUserById" parameterType="int" resultType="com.kuang.pojo.User">
select * from mybatis.user where id = #{id};
</select>
<insert id="addUser" parameterType="com.kuang.pojo.User">
insert into mybatis.user (id, name, pwd) values (#{id},#{name},#{pwd});
</insert>
<update id="updateUser" parameterType="com.kuang.pojo.User">
update mybatis.user set name=#{name},pwd=#{pwd} where id=#{id};
</update>
<delete id="deleteUser" parameterType="int">
delete from mybatis.user where id=#{id};
</delete>
</mapper>
User:
package com.kuang.pojo;
import org.apache.ibatis.type.Alias;
@Alias("user")
public class User {
private int id;
private String name;
private String pwd;
public User() {
}
public User(int id, String name, String pwd) {
this.id = id;
this.name = name;
this.pwd = pwd;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", pwd='" + pwd + '\'' +
'}';
}
}
MybatisUtils:
package com.kuang.utils;
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 java.io.IOException;
import java.io.InputStream;
//SqlSessionFactory -> SqlSession
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
//獲取使用Mybatis第一步SqlSessionFactory對象
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
}
}
db.properties:
driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/mybatis?useSSL=true&usUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false&serverTimezone=UTC
username = root
password = lgz0921
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">
<!--configuration 核心配置文件 -->
<configuration>
<!--引入外部配置文件-->
<properties resource="db.properties" />
<!--可以給實體類起別名-->
<typeAliases>
<typeAlias type="com.kuang.pojo.User" alias="User"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<!--每一個Mapper.xml都需要在Mybatis核心配置文件中註冊!-->
<mappers>
<mapper resource="com/kuang/dao/UserMapper.xml"/>
<!-- <mapper class="com.kuang.dao.UserMapper"/> -->
<!-- <package name="com.kuang.dao"/> -->
</mappers>
</configuration>
UserMapperTest:
package com.kuang.dao;
import com.kuang.pojo.User;
import com.kuang.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class UserMapperTest {
@Test
public void test(){
//第一步:獲得SqlSession對象
SqlSession sqlSession = MybatisUtils.getSqlSession();
//第二步:執行SQL
//方式一:getMapper
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
List<User> userList = userMapper.getUserList();
//方式一:getMapper
// List<User> userList = sqlSession.selectList("com.kuang.dao.UserDao.getUserList");
for (User user : userList) {
System.out.println(user);
}
//關閉sqlSession
sqlSession.close();
}
@Test
public void getUserById(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.getUserById(1);
System.out.println(user);
sqlSession.close();
}
@Test
public void addUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int res = mapper.addUser(new User(4, "哈哈", "123333"));
if(res>0) {
System.out.println("插入成功");
}
else System.out.println("插入失敗");
//提交事務
sqlSession.commit();
sqlSession.close();
}
@Test
public void updateUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int res = mapper.updateUser(new User(4, "呵呵", "123123"));
if(res>0) System.out.println("修改成功!");
else System.out.println("修改失敗!");
sqlSession.commit();
sqlSession.close();
}
@Test
public void deleteUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int res = mapper.deleteUser(5);
if(res>0) System.out.println("刪除成功!");
else System.out.println("刪除失敗!");
sqlSession.commit();
sqlSession.close();
}
}