Mybatis 注解实现基本 CRUD_mybatis mapper 注解方式编程:针对模型类设计基本的 crud 功

1.User类

package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable{
    private Integer userId;
    private String userName;
    private Date userBirthday;
    private String userSex;
    private String userAddress;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userBirthday=" + userBirthday +
                ", userSex='" + userSex + '\'' +
                ", userAddress='" + userAddress + '\'' +
                '}';
    }
}

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2.IUser接口

package com.itheima.dao;

import com.itheima.domain.User;
import com.sun.xml.internal.bind.v2.model.core.ID;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface IUserDao {
    //查询所有用户
    @Select("select * from user")
    @Results(id = "userMap",
             value = {
                     @Result(id=true,column="id",property="userId"),
                     @Result(column="username",property="userName"),
                     @Result(column="sex",property="userSex"),
                     @Result(column="address",property="userAddress"),
                     @Result(column="birthday",property="userBirthday")
             })
    List<User> getAllUsers();
    /*
    根据用户id查询用户信息
     */
    @Select("select * from user where id = #{uid}")
    @ResultMap("userMap")
    User findUserById(Integer uId);
    /*
    保存用户信息
     */
    @Insert("insert into user(username,sex,birthday,address) values(#{userName},#{userSex},#{userBirthday},#{userAddress})")
    @SelectKey(keyColumn="id",keyProperty="userId",resultType=Integer.class,before =
            false, statement = { "select last_insert_id()" })
    int saveUser(User user);

    /**
     * 更新操作
     * @param user
     * @return
     */
     @Update("update user set\n" +
             "username=#{userName},address=#{userAddress},sex=#{userSex},birthday=#{userBirthday} where id\n" +
             "=#{userId} ")
     int updateUser(User user);
     /*
     删除操作
      */
     @Delete("delete from user where id=#{uId}")
     int deleteUser(Integer uId);

     @Select("select count(*) from user")
     int countTotal();
    /*
    模糊查询
     */
    @Select("Select * from user where username like #{username}")
    @ResultMap("userMap")
    List<User> findByName(String name);

}

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3.配置文件

<?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">


<!---第三步 写 mybatis主配置文件 -->
<configuration>
    <!--mysql外部配置文件路径-->
    <properties url="file:///D:\IdeaProjects\mybatis05\src\main\resources\jdbcConfig.properties">

    </properties>

    <!--配置参数 -->
    <settings>
        <!--开启mybatis支持延迟加载-->
        <setting name="lazyLoadingEnabled" value="true"/>
        <setting name="aggressiveLazyLoading" value="false"></setting>
    </settings>
    <!--取别名-->
    <typeAliases>
        <!-- 批量别名定义，扫描整个包下的类，别名为类名（首字母大写或小写都可以） -->
        <package name="com.itheima.domain"/>
    </typeAliases>

    <!-- 配置环境-->
    <environments default="mysql">
        <!-- 配置mysql的环境-->
        <environment id="mysql">
            <!-- 配置事务-->
            <transactionManager type="JDBC"></transactionManager>

            <!--配置连接池 使用配置文文件外部读取的方式-->
            <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>

    <!-- 配置映射信息 -->
    <mappers>
        <!-- 配置 dao 接口的位置，它有两种方式  注解开发
            第一种：使用 mapper 标签配置 class 属性
            第二种：使用 package 标签，直接指定 dao 接口所在的包
            -->
        <package name="com.itheima.dao"/>
    </mappers>

</configuration>
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jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatisLearn
jdbc.username=root
jdbc.password=root
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4.测试代码

package com.itheima.test;
import com.itheima.dao.IUserDao;
import com.itheima.domain.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.InputStream;
import java.util.Date;
import java.util.List;

/**
 * 第六步 测试mybatis的curd操作
 */
public class UserTest {

    private static InputStream in;
    private static SqlSession sqlSession;
    private static IUserDao userDao;

    /**
     * 初始化函数
     */
    @Before
    public void init() throws Exception {
        //1.读取配置文件，生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获得SqlSession对象
        sqlSession = factory.openSession();
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    /**
     * 最后执行
     *
     * @throws Exception
     */
    @After
    public void finallys() throws Exception {
        //提交事务
        sqlSession.commit();
        //6.关闭连接 释放资源
        sqlSession.close();
        in.close();
    }

    /**
     * 测试查询所有数据功能
     */
    @Test
    public void testFindAll() {
        //5.执行查询方法
        List<User> users = userDao.getAllUsers();
        for (User u : users) {
            System.out.println("-------每个用户的内容---------");
            System.out.println(u.toString());
        }
    }

    /**
     * 测试根据id查询
     */
    @Test
    public void testFindUserById() {
        //5.执行查询方法
        User user = userDao.findUserById(41);
        System.out.println(user);
    }

    /**
     * 测试插入数据
     */
    @Test
    public void testSaveUser() {
        User user = new User();
        user.setUserName("安抚");
        user.setUserSex("女");
        user.setUserBirthday(new Date());
        user.setUserAddress("江西赣州");
       int r = userDao.saveUser(user);
       if(r>0){
           System.out.println("保存成功！");
       }
    }

    /**
     * 测试更新数据
     */
    @Test
    public void testUpdateUser() {
        User user = new User();
        user.setUserId(50);
        user.setUserName("123");
        user.setUserSex("男");
        user.setUserBirthday(new Date());
        user.setUserAddress("江2州");
        int r = userDao.updateUser(user);
        if(r>0){
            System.out.println("更新成功！");
        }
    }
    /**
     * 测试删除数据  通过注解方式，我们就不需要再去编写 UserDao.xml 映射文件了。
     */
    @Test
    public void testDeleteUser() {
        int r = userDao.deleteUser(51);
        if(r>0){
            System.out.println("删除成功！");
        }
    }

    /**
     * 测试模糊查询
     */
    @Test
    public void testFindUserByName() {
        List<User>  userList = userDao.findByName("%王%");
        int count = userDao.countTotal();
        System.out.println(count);
        for (User u : userList) {
            System.out.println(u.toString());
        }
    }
}

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