Mybatis入门笔记(12)——基于注解方式的代理Dao的CRUD操作

创建步骤：

1. 创建maven工程，什么都不选就ok,并导入坐标；

   <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>
   

2. 编写User实体类，java目录下创建com.ben.domain包，创建User实体类

   public class User implements Serializable {
       private int id;
       private String username;// 用户姓名
       private String sex;// 性别
       private Date birthday;// 生日
       private String address;// 地址
   
       public int getId() {
           return id;
       }
   
       public void setId(int id) {
           this.id = id;
       }
   
       public String getUsername() {
           return username;
       }
   
       public void setUsername(String username) {
           this.username = username;
       }
   
       public String getSex() {
           return sex;
       }
   
       public void setSex(String sex) {
           this.sex = sex;
       }
   
       public Date getBirthday() {
           return birthday;
       }
   
       public void setBirthday(Date birthday) {
           this.birthday = birthday;
       }
   
       public String getAddress() {
           return address;
       }
   
       public void setAddress(String address) {
           this.address = address;
       }
   
       @Override
       public String toString() {
           return "User [id=" + id + ", username=" + username + ", sex=" + sex
                   + ", birthday=" + birthday + ", address=" + address + "]";
       }
   }
   

3. 使用注解方式编写持久层接口

   package com.ben.dao;
   
   import com.ben.domain.User;
   import org.apache.ibatis.annotations.*;
   
   import java.util.List;
   
   /**
    * @ClassName: IUserDao
    * @author: benjamin
    * @createTime: 2019/07/19/21:50
    */
   public interface IUserDao {
   
       /**
       * @Description: 增加用户
       * @Param: User user:类对象
       * @return:  int
       * @Author: benjamin
       * @Date: 2019/7/19
       */
       @Insert("insert into user(username,sex,birthday,address) values (#{username},#{sex},#{birthday},#{address})")
       int insertUser(User user);
   
       /**
       * @Description: 删除用户
       * @Param:
       * @return:
       * @Author: benjamin
       * @Date: 2019/7/19
       */
       @Delete("delete from user where id=#{id}")
       int deleteUser(Integer id);
   
       /**
       * @Description: 修改用户
       * @Param:
       * @return:
       * @Author: benjamin
       * @Date: 2019/7/19
       */
       @Update("update user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday} where id =#{id}")
       int updateUser(User user);
   
       /**
       * @Description: 查询所有用户
       * @Param:
       * @return:
       * @Author: benjamin
       * @Date: 2019/7/19
       */
       @Select("select * from user")
       @Results(id="userMap",
               value = {
                       @Result(id=true,column = "id",property = "id"),
                       @Result(column = "username", property = "username"),
                       @Result(column = "sex", property = "sex"),
                       @Result(column = "address", property = "address"),
                       @Result(column = "birthday", property = "birthday")
               })
       List<User> findAll();
   
       /**
       * @Description: 根据用户ID查询用户
       * @Param:
       * @return:
       * @Author: benjamin
       * @Date: 2019/7/19
       */
       @Select("select * from user where id = #{id}")
       User findUserById(Integer id);
   
       /**
       * @Description: 根据用户名模糊查询用户
       * @Param:
       * @return:
       * @Author: benjamin
       * @Date: 2019/7/19
       */
   //    @Select("select * from user where username like #{username}")
       @Select("select * from user where username like '%${value}%'")
       List<User> findUserByUserName(String username);
       
       /** 
       * @Description: 查询用户的总数
       * @Param: 
       * @return:  
       * @Author: benjamin
       * @Date: 2019/7/19 
       */
       @Select("select count(*) from user")
       int findTotalUser();
   }
   

4. 在resources文件夹中，创建Mybatis的主配置文件SqlMapConfig.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>
       <!---->
       <properties resource="jdbcConfig.properties"></properties>
       <!--配置别名-->
       <typeAliases>
           <package name="com.ben.domain"/>
       </typeAliases>
   
       <!-- 配置环境-->
       <environments default="mysql">
           <!--配置mysql的环境-->
           <environment id="mysql">
               <!--配置事务的类型-->
               <transactionManager type="JDBC"></transactionManager>
               <!--配置连接池-->
               <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-->
       <mappers>
           <package name="com.ben.dao"/>
       </mappers>
   </configuration>
   

5. 在resources文件夹中导入log4j.properties文件

6. 编写测试类com.ben.test.AnnotationTest，6步；

   1.读取配置文件
   in = Resources.getResourceAsStream("SqlMapConfig.xml");
   2.创建SqlSessionFactory工厂
   SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
   3.创建SqlSession工厂对象
   SqlSessionFactory factory = builder.build(in);
   4.使用工厂生产SqlSession对象
   session = factory.openSession();
   5.创建Dao接口的代理对象
   userdao = session.getMapper(IUserDao.class);
   6.执行操作：增删改查等操作
   7.释放资源
   session.commit();
   session.close();
   in.close();
   

   测试类编写：

   public class AnnotationTest {
       private InputStream in;
       private SqlSession sqlSession;
       private IUserDao userDao;
   
       @Before//用于在测试方法执行之前执行
       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.获取SqlSession对象
           sqlSession = factory.openSession(true);
           //4.获取dao的代理对象
           userDao = sqlSession.getMapper(IUserDao.class);
       }
   
       @After//用于在测试方法执行之后执行
       public void destroy()throws Exception{
           //提交事务
           sqlSession.commit();
           //6.释放资源
           sqlSession.close();
           in.close();
       }
   
       //增加用户
       @Test
       public void testSaveUser(){
           User user = new User();
           user.setUsername("笑笑");
           user.setSex("2");
           user.setBirthday(new Date());
           user.setAddress("西安市雁塔区");
           int i = userDao.insertUser(user);
           System.out.println("插入ID："+user.getId());
       }
   
       //删除用户
       @Test
       public void testDeleteUser(){
           int i = userDao.deleteUser(40);
           System.out.println(i);
       }
   
       //修改用户
       @Test
       public void testUpdateUser(){
           User user = new User();
           user.setUsername("笑笑");
           user.setBirthday(new Date());
           user.setAddress("西安市雁塔区");
           user.setId(41);
           userDao.updateUser(user);
       }
   
       //测试查询所有
       @Test
       public void testFindAll(){
           List<User> users = userDao.findAll();
           for(User user : users){
               System.out.println(user);
           }
       }
       //根据用户ID查找用户
       @Test
       public void testFindUserById(){
           User userById = userDao.findUserById(41);
           System.out.println(userById);
       }
   
       //根据用户名模糊查找用户
       @Test
       public void testFindUserByUserName(){
   //        List<User> list = userDao.findUserByUserName("%王%"); //#{}
           List<User> list = userDao.findUserByUserName("王"); //字符串拼接
           for(User user:list){
               System.out.println(user);
           }
       }
   
       //查找用户的总数
       @Test
       public void testTotalCount(){
           int totalUser = userDao.findTotalUser();
           System.out.println(totalUser);
       }
   }