03mybatis使用类型--基于传统方式statementid方式

谁践踏了优雅 2022-06-02 02:27 128阅读 0赞

# mybatis使用类型03–基于传统方式statementid方式 #

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### 具体实现 ###

1.  传统的statementid方式，使用时包含四个模块：pojo.java、mapper.xml、dao接口、daoImpl。  
    1.1 pojo.java 如下：

@Getter
    @Setter
    @ToString
    public class BusinessApply { 
        private Integer id;
        private String name;
        private String businessNo;
        private String businessType;
        private Integer businessSum;
    }

1.2 mapper.xml文件：

<?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="businessApply">
        <select id="findByNo" parameterType="java.lang.String" resultType="com.cmhy.model.BusinessApply">
            select * from business_apply where business_no = #{value}
        </select>
        <select id="findByName" parameterType="java.lang.String" resultType="com.cmhy.model.BusinessApply">
            select * from business_apply where name like '%${value}%'
        </select>
        <select id="findIdByName" parameterType="java.lang.String" resultType="java.lang.Integer">
            select id from business_apply where name like #{value}
        </select>
        <update id="updateById" parameterType="int">
            update business_apply set business_sum = 12.00 where id = #{value}
        </update>
        <update id="deleteById" parameterType="int">
            delete from business_apply where id = #{value}
        </update>
    </mapper>

其中namespace可以任意，但要唯一。select、update、insert和delete模块中的id要和mapper.java中的方法名一直，parameterType约定输入参数类型，resultType预定输出参数的类型。  
2.3 dao接口

public interface BusinessApplyDao {
        public BusinessApply findByNo(String businessNo);
    }

2.4 daoImpl

package com.cmhy.dao;
    
    import java.util.List;
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    
    import com.cmhy.model.BusinessApply;
    
    import lombok.Setter;
    @Setter
    public class BusinessApplyDaoImpl implements BusinessApplyDao{ 
        private SqlSessionFactory sqlSessionFactory;
        @Override
        public BusinessApply findByNo(String businessNo) {
            // TODO Auto-generated method stub
            SqlSession sqlSession = sqlSessionFactory.openSession();
            BusinessApply ba = sqlSession.selectOne("businessApply.findByNo",businessNo);
            sqlSession.close();
            return ba;
        }
        @Override
        public List<BusinessApply> findByName(String name) {
            // TODO Auto-generated method stub
            SqlSession sqlSession = sqlSessionFactory.openSession();
            List<BusinessApply>  list = sqlSession.selectList("businessApply.findByName", name);
            sqlSession.close();
            return list;
        }
        @Override
        public List<Integer> findIdByName(String name) {
            // TODO Auto-generated method stub
            SqlSession sqlSession = sqlSessionFactory.openSession();
            List<Integer> list = sqlSession.selectList("businessApply.findIdByName", name);
            sqlSession.close();
            return list;
        }
        @Override
        public void updateById(Integer id) {
            // TODO Auto-generated method stub
            SqlSession sqlSession = sqlSessionFactory.openSession();
            sqlSession.update("businessApply.updateById", id);
            sqlSession.commit();
            sqlSession.close();
        }
        @Override
        public void deleteById(Integer id) {
            // TODO Auto-generated method stub
            SqlSession sqlSession = sqlSessionFactory.openSession();
            sqlSession.delete("businessApply.deleteById", id);
            sqlSession.commit();
            sqlSession.close();
        }
    
    }

2.5 测试类

package org.cmhy.dao;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.List;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.junit.Before;
    import org.junit.Test;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import com.cmhy.dao.BusinessApplyDaoImpl;
    import com.cmhy.model.BusinessApply;
    
    public class BusinessApplyDaoImplTest {
        private final Logger logger = LoggerFactory.getLogger(BusinessApplyDaoImplTest.class);
        private SqlSessionFactory sqlSessionFactory;
        @Before
        public void getSqlSessionFactory() throws IOException {
            InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        }
        @Test
        public void findByNoTest() {
            BusinessApplyDaoImpl businessApplyDao = new BusinessApplyDaoImpl();
            businessApplyDao.setSqlSessionFactory(sqlSessionFactory);
            String returnStr = businessApplyDao.findByNo("1").toString();
            System.out.println(returnStr);
    
        }
        @Test
        public void findByNameTest() {
            BusinessApplyDaoImpl businessApplyDao = new BusinessApplyDaoImpl();
            businessApplyDao.setSqlSessionFactory(sqlSessionFactory);
            List<BusinessApply> list = businessApplyDao.findByName("个贷");
            list.forEach(ba->System.out.println(ba.toString()));
        }
        @Test
        public void findIdByNameTest() {
            BusinessApplyDaoImpl businessApplyDao = new BusinessApplyDaoImpl();
            businessApplyDao.setSqlSessionFactory(sqlSessionFactory);
            List<Integer> list = businessApplyDao.findIdByName("%个贷%");
            list.forEach(ba->System.out.println(ba.toString()));
        }
        @Test
        public void updateByIdTest() {
            logger.debug("updateByIdTest 开始了 ******* ");
            BusinessApplyDaoImpl businessApplyDao = new BusinessApplyDaoImpl();
            businessApplyDao.setSqlSessionFactory(sqlSessionFactory);
            businessApplyDao.updateById(1);
        }
        @Test
        public void deleteByIdTest() {
            logger.debug("updateByIdTest 开始了 ******* ");
            BusinessApplyDaoImpl businessApplyDao = new BusinessApplyDaoImpl();
            businessApplyDao.setSqlSessionFactory(sqlSessionFactory);
            businessApplyDao.deleteById(1);
        }
    
    }

### 缺点 ###

此种方式，现在基本不再使用，缺陷有以下三个：  
2.1 存在大量的重复的代码。  
2.2 需要实现dao和daoImpl代码  
2.3 需要把statementid的id硬编码

List<Integer> list = sqlSession.selectList("businessApply.findIdByName", name);

2.4 由于sqlSession使用泛型，即使变量使用错误，编译阶段不能暴露出错误。