Mybatis 注解实现基本 CRUD（十一）

项目结构图：

红框标记的和之前的项目相同

1.mybatis 的常用注解说明

@Insert:实现新增 
@Update:实现更新
@Delete:实现删除 
@Select:实现查询 
@Result:实现结果集封装
@Results:可以与@Result 一起使用，封装多个结果集 
@ResultMap:实现引用@Results 定义的封装
@One:实现一对一结果集封装
@Many:实现一对多结果集封装 
@SelectProvider: 实现动态SQL映射 
@CacheNamespace:实现注解二级缓存的使用

2.编写实体类

User.java

package com.wd.entity;

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

public class User implements Serializable {

    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;


    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthyday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

3.使用注解方式开发持久层接口

UserMapper.java

package com.wd.mapper;

import com.wd.entity.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;


/**
 * 用户的持久层接口
 * 在mybatis中针对,CRUD一共有四个注解
 *  @Select @Insert @Update @Delete
 */
public interface UserMapper {

    /**
     * 查询所有操作
     * @return
     */
    @Select("select * from user")
    List<User> findAll();

    /**
     * 保存用户
     * @param user
     */
    @Insert("insert into user (username, address, sex, birthday) values (#{username}, #{address}, #{sex}, #{birthday})")
    void saveUser(User user);

    /**
     * 更新用户
     * @param user
     */
    @Update("update user set username = #{username}, address = #{address}, sex = #{sex}, birthday = #{birthday} where id = #{id}")
    void updateUser(User user);

    /**
     * 删除用户
     * @param id
     */
    @Delete("delete from user where id = #{id}")
    void deleteUser(Integer id);

    /**
     * 根据id查询用户
     * @param id
     * @return
     */
    @Select("select * from user where id = #{id}")
    User findById(Integer id);

    /**
     * 根据用户名称模糊查询
     * @param name
     * @return
     */
    //@Select("select * from user where username like #{name}")
    @Select("select * from user where username like '%${value}%' ")
    List<User> findUserByName(String name);

    /**
     * 查询总用户数量
     * @return
     */
    @Select("select count(*) from user ")
    int findTotalUser();
}

4.编写 SqlMapConfig 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">

<!--mybatis的主配置文件-->
<configuration>

    <!--引入外部配置文件-->
    <properties resource="jdbcConfig.properties"></properties>

    <!--配置别名-->
    <typeAliases>
        <package name="com.wd.entity"/>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql环境-->
        <environment id="mysql">
            <!--配置事务的类型-->
            <transactionManager type="jdbc"></transactionManager>
            <!--配置数据源(连接池)-->
            <dataSource type="pooled">
                <!--配置连接数据库的4个基本信息-->
                <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>


    <!--指定映射配置文件的位置，映射配置文件指的是每个mapper独立的配置文件
        如果是用注解来配置的话，此处应该使用class属性指定被注解的mapper全限定类名
        -->
    <mappers>
        <mapper class="com.wd.mapper.UserMapper"></mapper>
    </mappers>


</configuration>

5.编写测试方法

AnnotationCRUDTest.java

public class AnnotationCRUDTest {
    private InputStream in;
    private SqlSessionFactory factory;
    private SqlSession session;
    private UserMapper userMapper;

    @Before
    public  void init()throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(in);
        session = factory.openSession();
        userMapper = session.getMapper(UserMapper.class);
    }

    @After
    public  void destroy()throws  Exception{
        session.commit();
        session.close();
        in.close();
    }


    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("mybatis annotation");
        user.setAddress("beijing changpingqu");

        userMapper.saveUser(user);
    }

    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(54);
        user.setUsername("mybatis annotation update");
        user.setAddress("beijingshi haidianqu");
        user.setSex("m");
        user.setBirthday(new Date());

        userMapper.updateUser(user);
    }


    @Test
    public void testDelete(){
        userMapper.deleteUser(51);
    }

    @Test
    public void testFindOne(){
        User user = userMapper.findById(54);
        System.out.println(user);
    }


    @Test
    public  void testFindByName(){
        //List<User> users = userMapper.findUserByName("%mybatis%");
        List<User> users = userMapper.findUserByName("mybatis");
        for(User user : users){
            System.out.println(user);
        }
    }

    @Test
    public  void testFindTotal(){
        int total = userMapper.findTotalUser();
        System.out.println(total);
    }
}

6.测试结果

testFindOne

testFindByName

testFindTotal

7.项目源代码

源代码地址
https://github.com/Qreply/mybatisAnno.git