mybatis 实现增删改查

A就是一个普通的 maven项目，B项目新建的时候，必须继承的父项目。
比如：在B项目（增删改查的干活）中,引入A项目（提供jar包），

目录结构：

 

Dao

package test.Dao;

import test.entity.User;

import java.util.List;

public interface UserDao {
    List<User> selectAll();
    List<User> selectByName(String name);
    List<User> selectById(int id);
    int  addUser(User user);
    int delete(int id);
//    通过id修改学员信息
    int updateUser(User user);
//    统计班级人数
    int num();
}

User 实体类

import java.io.Serializable;

public class User implements Serializable {
    private int id;
    private String name;
    private int sex ;
    private int age ;
    private String address;
    private String tel;
    private String email;

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">
<!--本文件名-->
 <mapper namespace="test.Dao.UserMapper">
<!-- 方法名，返回类型-->
  <select id="selectAll" resultType="test.entity.User">
-- 查询语句，表名加标号
   select * from `test`
  </select>

    <select id="selectByName" resultType="test.entity.User">
   select * from `test` where name=#{name}
  </select>

    <select id="selectById" resultType="test.entity.User">
   select * from `test` where id=#{id}
  </select>

    <insert id="addUser" parameterType="test.entity.User">
        insert into `test`(id,name,sex,age,address,tel,email)value(#{id},#{name},#{age},#{sex},#{address},#{tel},#{email})
    </insert>

<!--    错误的写法   -->
<!--    <update id="updateUser" parameterType="int">-->
<!--        update `mabatis01` set  uname="小哥" uage="18" where uid=#{uid}-->
<!--    </update>-->
    <delete id="delete" parameterType="int">
        delete from `test` where id=#{id}
    </delete>

<!--     update `mabatis01` set  uname=#{uname},uage=#{uage}  后面跟的参数，无双引号     -->
<!--     注释不要写在sql 语句语句里，否则当成sql语句解析。    -->
    <update id="updateUser" parameterType="test.entity.User">
        update `test` set  name=#{name},sex=#{sex},age=#{age},address=#{address},tel=#{tel},email=#{email}  where id=#{id}
    </update>

    <select id="num" resultType="int">
        select count(1) from `test`
    </select>
</mapper>

jdbcConfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/Test
jdbc.username=root
jdbc.password=root

SqlSessionConfig.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>
<!--    加入这个，意味着要用el表达式-->
<properties resource="jdbcConfig.properties"></properties>

<!--    数据库的配置-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>

            </dataSource>
        </environment>
    </environments>

    <mappers>
        <!--可以用这些代替路径-->
        <mapper resource="test/Dao/UserMapper.xml"></mapper>
<!--        <mapper class="guitar.Dao.UserMapper"></mapper>-->
<!--        <package name="guitar.Dao"/>-->

<!--        原生路径 -->
<!--        <mapper resource="guitar/Dao/UserMapper.xml"></mapper>-->
    </mappers>
</configuration>

package test;

import test.entity.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.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class test {
    @Test
    public void h1() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(is);
        SqlSession session = sf.openSession();
        List<User> userList = session.selectList("test.Dao.UserMapper.selectAll");
        for (User user:userList){
            System.out.println(user);
        }
        session.commit();
        session.close();
    }

    @Test
    public void h2() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
        User user = new User();
        user.setName("小李");
        List<User> userList = session.selectList("test.Dao.UserMapper.selectByName",user);
        for (User user2:userList){
            System.out.println(user2);
        }
        session.commit();
        session.close();
    }

    @Test
    public void h3() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
        User user = new User();
        user.setId(4);
        List<User> userList = session.selectList("test.Dao.UserMapper.selectById",user);
        for (User user2:userList){
            System.out.println(user2);
        }
        session.commit();
        session.close();
    }

    @Test
    public void h4() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
        User user = new User();
        user.setId(6);
        user.setName("小豪");
        user.setAge(22);
        user.setSex(1);
        user.setAddress("望城");
        user.setTel("123456");
        user.setEmail("qwerty");
//        insert 第一个是调用 sql语句的方法，第二个是 插入的参数。
        int num = session.insert("test.Dao.UserMapper.addUser",user);
        System.out.println(num);
        session.commit();
        session.close();
    }

    @Test
    public void h5() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
//        User user = new User();
//        user.setId(3);
//        insert 第一个是调用 sql语句的方法，第二个是 插入的参数。
        int num = session.delete("test.Dao.UserMapper.delete",3);
        System.out.println(num);
        session.commit();
        session.close();
    }

    @Test
    public void h6() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
        User user = new User();
        user.setId(2);
        user.setName("小晴");
        user.setAge(45);
        user.setSex(0);
        user.setAddress("城堡");
        user.setTel("123456987");
        user.setEmail("qwjhgfds");
//        insert 第一个是调用 sql语句的方法，第二个是 插入的参数。
        int num = session.update("test.Dao.UserMapper.updateUser",user);
        System.out.println(num);
        session.commit();
        session.close();
    }

    @Test
    public void h7() throws IOException {
        InputStream is = Resources.getResourceAsStream("SqlSessionConfig.xml");
        SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
        SqlSessionFactory sf = sfb.build(is);
        SqlSession session = sf.openSession();
//    查询记录数，用 selectOne
        int num = session.selectOne("test.Dao.UserMapper.num");
        System.out.println(num);
        session.commit();
        session.close();
    }
}

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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>test</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>
</project>

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