Rest分页接口开发

简单描述：需求说后端写一个XX数据的分页接口，给前端口调用，其实有一个PageHelper的工具类可以直接使用但是老大不让用，得用sql写，。小Kiss啦。直接上代码

代码：

//Controller代码
import com.github.pagehelper.PageInfo;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@Api(value = "CourseController",tags = "课程查询")
@RestController
@RequestMapping("/client/course")
public class CourseController extends BaseController {
    @Autowired
    private CourseService courseService;
    
    @ApiOperation(value = "获取分页列表")
    @RequestMapping(value = "/queryPage", method = RequestMethod.GET, produces = "application/json;charset=utf-8")
    public ResultDto queryPage(Integer page,Integer rows,String categoryId){
        PageInfo<CourseVo> pageInfo = new PageInfo<CourseVo>();
        try {
            pageInfo = courseService.queryPage(page,rows);
            if(pageInfo.getList().size()< 0){
                return ResultDto.success("返回结果无内容");
            }
        } catch (Exception e) {
            e.printStackTrace();
            return ResultDto.error();
        }
        return ResultDto.success(pageInfo);
    }
    
} 

//Service代码
import com.github.pagehelper.PageInfo;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
public class CourseService {
    @Resource
    private CourseMapper courseMapper;
 
    public PageInfo<CourseVo> queryPage(Integer page,Integer rows)throws Exception{
        Map<String,Integer> param = new HashMap<String,Object>();
        Integer firstIndex = (page - 1) * rows;
        Integer lastIndex = page * rows;
        // 从第几条数据开始 int firstIndex = (currPage - 1) * pageSize;
        // 到第几条数据结束 int lastIndex = currPage * pageSize;
        param.put("page",firstIndex);
        param.put("rows",lastIndex);
    
        List<CourseVo> reList = courseMapper.findByPage(param);
        // 取分页信息
        PageInfo<CourseVo> pageInfo = new PageInfo<CourseVo>(reList);
        return pageInfo;
    }
} 

//Mapper接口
import com.xx.xxx.xxxx.util.MyMapper;
import java.util.List;
import java.util.Map;

public interface CourseMapper extends MyMapper<Course> {
    List<CourseVo> findByPage(Map<String,Integer> param);
} 

//Mapper.xml中的sql 
<select id="findByPage" parameterType="Map" resultMap="CourseVoResultMap">
   select * from table_course where is_del = '1' limit #{page},#{rows}
</select> 

<resultMap id="CourseVoResultMap" type="CourseVo" >
   <result column="course_id" property="courseId" jdbcType="CHAR" />
   <result column="course_code" property="courseCode" jdbcType="VARCHAR" />
　　``````
</result> 

That's all !!!   下边来说一说PageHelper的方式

//仅仅是调用就OJBK啦 不过这种查询方式使用的是mybatis的example动态生成sql查询的，不需要你写mapper.xml中的sql了，只需要在对应的类上加上注解
public PageInfo<CourseVo> queryPage(Integer page,Integer rows)throws Exception{
    Example example = new Example(CourseVo.class);
    example.createCriteria().andEqualTo("isDel", 1);
    PageHelper.startPage(page, rows);
    List<CourseVo> list = courseMapper.selectByExample(example);//查询
    return pageInfo;
}