HAP框架--自己写查询语句

迈不过友情╰ 2022-05-17 23:40 191阅读 0赞

刚接触HAP框架，水平很菜，这篇文章用来记录如何在HAP框架中写自己的查询语句。

**第一步、查询语句的编写：**

在Hec20500DemoMapper.xml里编写SQL语句，可以先在数据库里跑跑，看SQL语句有没有写对。

<?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="wht.hec20500.mapper.Hec20500DemoMapper">
        <resultMap id="BaseResultMap" type="wht.hec20500.dto.Hec20500Demo">
            <result column="id" property="id" jdbcType="DECIMAL" />
            <result column="name" property="name" jdbcType="VARCHAR" />
        </resultMap>
        
        <select id="selectAllOrderByName" resultMap="BaseResultMap"
                parameterType="wht.hec20500.dto.Hec20500Demo">
            SELECT a.id,a.name FROM hap_demo_b a order by a.name
        </select>
    </mapper>

定义mapper映射文件

**第二步、编写Hec20500DemoMapper.java-接口文件**

package wht.hec20500.mapper;
    
    import com.hand.hap.mybatis.common.Mapper;
    import wht.hec20500.dto.Hec20500Demo;
    
    import java.util.List;
    
    public interface Hec20500DemoMapper extends Mapper<Hec20500Demo>{
        /**
         *
         * @param dto
         * @return
         */
        List<Hec20500Demo> selectAllOrderByName(Hec20500Demo dto);
    
    
    }

**注意：**

Mapper接口定义有如下特点：

1、Mapper接口方法名与Mapper.xml中定义的statement的id相同

2、Mapper接口方法的输入参数类型和mapper.xml中定义的statement的parameterType的类型相同

3、 Mapper接口方法的输出参数类型和mapper.xml中定义的statement的resultType的类型相同

**第三步、在IHec20500DemoService.java定义方法：**

代码如下：

package wht.hec20500.service;
    
    import com.hand.hap.core.IRequest;
    import com.hand.hap.core.ProxySelf;
    import com.hand.hap.system.service.IBaseService;
    import wht.hec20500.dto.Hec20500Demo;
    
    import java.util.List;
    
    public interface IHec20500DemoService extends IBaseService<Hec20500Demo>, ProxySelf<IHec20500DemoService>{
    
        /**
         *
         * @param iRequest
         * @param hec20500Demo
         * @param i
         * @param i1
         * @return
         */
        List<Hec20500Demo> selectAllOrderByName(IRequest iRequest, Hec20500Demo hec20500Demo, int i, int i1);
    }

**第四步、在Hec20500DemoServiceImpl.java里实现service层的方法**

代码如下：

package wht.hec20500.service.impl;
    
    import com.github.pagehelper.PageHelper;
    import com.hand.hap.core.IRequest;
    import com.hand.hap.system.service.impl.BaseServiceImpl;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import wht.hec20500.dto.Hec20500Demo;
    import wht.hec20500.mapper.Hec20500DemoMapper;
    import wht.hec20500.service.IHec20500DemoService;
    import org.springframework.transaction.annotation.Transactional;
    
    import java.util.List;
    
    @Service
    @Transactional(rollbackFor = Exception.class)
    public class Hec20500DemoServiceImpl extends BaseServiceImpl<Hec20500Demo> implements IHec20500DemoService {
    
        @Autowired
        private Hec20500DemoMapper hec20500DemoMapper;
        @Override
        public List<Hec20500Demo> selectAllOrderByName(IRequest iRequest, Hec20500Demo hec20500Demo, int i, int i1) {
            PageHelper.startPage(i,i1);
            return hec20500DemoMapper.selectAllOrderByName(hec20500Demo);
        }
    }

**第五步、到这里就可以在控制层调用我们写的方法了。**

代码如下：

@RequestMapping(value = "/hap/demo/query/byorder")
        @ResponseBody
        public ResponseData queryByOrderName(Hec20500Demo dto, @RequestParam(defaultValue = DEFAULT_PAGE) int page,
                                  @RequestParam(defaultValue = DEFAULT_PAGE_SIZE) int pageSize, HttpServletRequest request) {
            IRequest requestContext = createRequestContext(request);
            return new ResponseData(service.selectAllOrderByName(requestContext,dto,page,pageSize));
        }

**最后看一下运行效果：**

![70][]

[70]: /images/20220518/8e5d49a61d5a49b7a7d29b2fd1ac49bc.png