mybatis增删改查的写法集合

• 增删改查的写法集合

  注意：xml文件尽量不要注释

  • Usermapping

    public interface UserMapping {
    
        //查询
        List<User> getUserlist();
        User getUserById(int id);
    
        //增加元素
        int insertItem(User user);
    
        //删除元素
        int deleteItem(int i);
    
        //更改元素
        int updataItem(User user);
    }
    
    

  • 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">
    <mapper namespace="com.yunjiu.dao.UserMapping">
    
    
        <select id="getUserlist" resultType="com.yunjiu.pojo.User">
            select * from mybatis.user;
        </select>
    
        <select id="getUserById" parameterType="int" resultType="com.yunjiu.pojo.User">
          select  * from mybatis.user where id=#{id};
        </select>
    
    
        <insert id="insertItem" parameterType="com.yunjiu.pojo.User">
            insert into mybatis.user(id,name,pwd) values(#{id},#{name},#{pwd})
        </insert>
    
        <delete id="deleteItem" parameterType="int">
            delete from mybatis.user where id=#{i};
        </delete>
    
        <update id="updataItem" parameterType="com.yunjiu.pojo.User">
            update mybatis.user set name=#{name},pwd=#{pwd} where id=#{id};
        </update>
    </mapper>
    

  • Mytest(测试文件)

  import com.yunjiu.dao.UserMapping;
  import com.yunjiu.pojo.User;
  import com.yunjiu.utils.MybatisUtils;
  import org.apache.ibatis.session.SqlSession;
  import org.junit.Test;
  
  import java.util.List;
  
  public class MyTest {
      @Test
      public void selectUser() {
          SqlSession session = MybatisUtils.getSession();//使用工具类的方法
  
          //方法一:（不推荐使用）
          //List<User> users = session.selectList("com.kuang.mapper.UserMapper.selectUser");
  
  
          //方法二:
          UserMapping mapper = session.getMapper(UserMapping.class);//导入接口类
          List<User> users = mapper.getUserlist();//使用接口类的方法
  
          for (User user: users){
              System.out.println(user);
          }
          session.close();//注意，记得关
      }
      @Test
      public  void selectById(){
          SqlSession session = MybatisUtils.getSession();//使用工具类的方法
  
          UserMapping mapper = session.getMapper(UserMapping.class);//导入接口类
       User users = mapper.getUserById(1);//使用接口类的方法
  
  
              System.out.println(users);
  
          session.close();
      }
      @Test
      public  void insertItem(){
          SqlSession session = MybatisUtils.getSession();//使用工具类的方法
  
          UserMapping mapper = session.getMapper(UserMapping.class);//导入接口类
          int users = mapper.insertItem(new User(1,"白","15151"));//使用接口类的方法
  
  if(users>0){
      System.out.println("增加成功");
      session.commit();//注意增删改查都需要提交才行
      session.close();
  }
        else {
      System.out.println("增加失败");
      session.rollback();
      session.close();
        }
  
      }
  
      @Test
      public  void deleteItem(){
          SqlSession session = MybatisUtils.getSession();//使用工具类的方法
  
          UserMapping mapper = session.getMapper(UserMapping.class);//导入接口类
          int users = mapper.deleteItem(01);//使用接口类的方法
  
          if(users>0){
              System.out.println("删除成功");
              session.commit();//注意增删改查都需要提交才行
              session.close();
          }
          else {
              System.out.println("删除失败");
              session.rollback();
              session.close();
          }
  
      }
      @Test
      public  void updateItem(){
          SqlSession session = MybatisUtils.getSession();//使用工具类的方法
  
          UserMapping mapper = session.getMapper(UserMapping.class);//导入接口类
          int users = mapper.updataItem(new User(02,"白边","545"));//使用接口类的方法
  
          if(users>0){
              System.out.println("更新成功");
              session.commit();//注意增删改查都需要提交才行
              session.close();
          }
          else {
              System.out.println("更新失败");
              session.rollback();
              session.close();
          }
  
      }
  }
  
  

• 核心配置文件

  <?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">
  <configuration>
      <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://localhost:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                  <property name="username" value="root"/>
                  <property name="password" value="123456"/>
              </dataSource>
          </environment>xml
      </environments>l
      <mappers>
          <mapper resource="com/yunjiu/dao/UserMapper.xml"/>
      </mappers>
  </configuration>
  

  • 实体类

    public class User {
    
        private int id;  //id
        private String name;   //姓名
        private String pwd;   //密码
    
        public User() {
    
        }
    
        public User(int id, String name, String pwd) {
            this.id = id;
            this.name = name;
            this.pwd = pwd;
        }
    
        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 getPwd() {
            return pwd;
        }
    
        public void setPwd(String pwd) {
            this.pwd = pwd;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +java
                    ", name='" + name + '\'' +
                    ", pwd='" + pwd + '\'' +
                    '}';
        }
    }