二次开发实现自定义Dao层

案例描述

平台自身的查询不满足查询需求时，可自定义Dao层自己写SQL来查询

实现思路

1. 自定义Dao层接口与XML映射

2. Service实现类中调运Dao层接口

3. 自定义的Controller中，调运service层接口查询数据，并返回数据

具体代码类

1、Controller

package com.project.demo.controller;

import com.je.core.base.AbstractDynaController;
import com.je.core.base.MethodArgument;
import com.project.demo.service.DemoSsmService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;


@Controller
@RequestMapping(value = "/je/ssmDemo")
public class DemoController extends AbstractDynaController {

    @Autowired
    DemoSsmService demoSsmService;

    /**
     * 查询所有数据
     * @param param
     */
    @RequestMapping(
            value = {"/doDemo"},
            method = {RequestMethod.POST},
            produces = {"application/json; charset=utf-8"}
    )
    @ResponseBody
    public void doDemo(MethodArgument param) {
        demoSsmService.doDemo();
    }
}

2、Service与ServiceImpl

//Servcie
package com.project.demo.service;

public interface DemoSsmService {

    public String doDemo();

}
//ServiceImpl
package com.project.demo.service;

import com.project.demo.dao.DemoDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.Map;

@Component("demoSsmService")
public class DemoServiceImpl implements DemoSsmService {

    @Autowired
    DemoDao demoDao;

    @Override
    public String doDemo() {
        List<Map> list = demoDao.selectAll();
        System.out.println(list.size());
        return null;
    }
}

3、Dao层

package com.project.demo.dao;

import org.apache.ibatis.annotations.Mapper;

import java.util.List;
import java.util.Map;

@Mapper
public interface DemoDao {
    public List<Map> selectAll();
}

4、Dao层映射xml

注意：Dao层映射的xml需要放在resources/public目录下，才能被扫描到>注意：Dao层映射的xml需要放在resources/public目录下，才能被扫描到

<?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.project.demo.dao.DemoDao">

    <select id="selectAll" resultType="java.util.Map">
        select * from je_core_enduser
    </select>

</mapper>

5、 配置文件更改

注意：在public/beans.xml加上dao层映射的xml扫描

<property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml"></property>

 <!-- MapperScanner 扫描Mapper 创建代理 -->
<property name="basePackage" value="com.je.**.mapper,com.project.demo.mapper" />

6、修改je-web.xml

<resource>
     <directory>src/main/resources/public/mybatis</directory>
     <targetPath>mybatis</targetPath>
 </resource>