使用MyBatis框架实现对数据库增删改查

第一步：首先需要新建一个数据库，然后建一个表在表里面可以随便插入几条数据，不插入也可以，等下直接用程序插入，今天就用下面这个表举例

第二步：创建一个Java工程；

第三步：创建一个实体类User，将数据库中的字段名get、set。

package com.zhiyuan.pojo;

public class User {
    private int id;
    private String name;
    private String sex;
    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 getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }

}

第四步：写连接数据库的config.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "mybatis-3-config.dtd" >
<configuration>

    <typeAliases>
        <typeAlias alias="User" type="com.zhiyuan.pojo.User"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="liuxi" />  
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/zhiyuan/pojo/User.xml" />
    </mappers>
</configuration>

第五步：配置对应实体类的user.XML文件，里面写MySQL增删改查语句：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd" >
<mapper namespace="com.zhiyuan.dao.Inter">

    <!-- 插入数据，这里ID是自动递增的，所有不需要插入 -->
    <insert id="getInsert" parameterType="User">
        insert into nb(name,sex) values(#{name},#{sex})
    </insert>

    <!-- 查询表中所有的数据 -->
    <select id="getUserList" resultType="com.zhiyuan.pojo.User">
        select * from nb
    </select>

    <!-- 根据ID查询表数据 -->
    <select id="getUser" parameterType="int" resultType="com.zhiyuan.pojo.User">
        select * from nb where id=#{id}
    </select>

    <!-- 根据ID更新表数据 -->
    <update id="getUpdate" parameterType="com.zhiyuan.pojo.User">
        update nb set name=#{name},sex=#{sex} where id=#{id}
    </update>

    <!-- 根据ID删除表数据 -->
    <delete id="getDelete" parameterType="int">
        delete from nb where id=#{id}
    </delete>
</mapper>

第六步：写对应user.xml的接口类。

package com.zhiyuan.dao;

import java.util.List;

import com.zhiyuan.pojo.User;

public interface Inter {
    public List<User> getUserList();
    public User getUser(int id);
    public void getInsert(User user);
    public void getUpdate(User user);
    public void getDelete(int id);
}

最后一步写测试类：

package com.zhiyuan.main;

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

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 com.zhiyuan.dao.Inter;
import com.zhiyuan.pojo.User;

public class Main {
    static SqlSessionFactory ssf;
    static SqlSession ss;
    public static void main(String[] args) throws IOException {
        Reader re = Resources.getResourceAsReader("conf.xml");
        ssf = new SqlSessionFactoryBuilder().build(re);
        ss = ssf.openSession();
        insert();
//      userList();
//      user();
//      update();
//      delete();
    }

    //根据ID删除字段
    private static void delete() {
        ss = ssf.openSession();
        Inter ie = ss.getMapper(Inter.class);
        ie.getDelete(1);
        ss.commit();
        System.out.println("删除后：");
        userList();
    }

    //根据ID更新表数据
    private static void update() {
        ss = ssf.openSession();
        Inter ite = ss.getMapper(Inter.class);
        User us = ite.getUser(3);
        us.setName("徐深何");
        us.setSex("不详");
        ite.getUpdate(us);
        ss.commit();
        System.out.println("更新后:");
        userList();
    }

    //条件查询
    private static void user() {
        ss = ssf.openSession();
        Inter it = ss.getMapper(Inter.class);
        User user = it.getUser(3);
        if(user != null){
            System.out.println("姓名：" + user.getName());
            System.out.println( "性别：" + user.getSex());
        }
    }

    //查询全部
    private static void userList() {
        ss = ssf.openSession();
        Inter is = ss.getMapper(Inter.class);
        print(is.getUserList());
    }
    private static void print(List<User> userList) {
        for(User us : userList){
            System.out.println("编号：" + us.getId());
            System.out.println("姓名：" + us.getName());
            System.out.println("性别：" + us.getSex());
        }
    }

    //插入
    private static void insert() {
        ss = ssf.openSession();
        Inter in = ss.getMapper(Inter.class);
        User user = new User();
        user.setName("CSDN");
        user.setSex("????");
        in.getInsert(user);
        ss.commit();
        System.out.println("插入成功");
        userList();
    }

}

最后输出结果为：

这里值得注意得到地方就是写配置文件时一定要细心，不然写到最后一运行一定会出现各种各样的错，找起来头痛。