[JavaScript知识库]Vue-SpringBoot分页查询以及条件查询解决方案

前端写好页数和每页显示多少数据，如果搜索条件不为空的话，加上搜索条件。

initEvaluations(){
	let url = '/evaluation/?page=' + this.page + '&size=' + this.size;
	if (this.employeeName) {
    	url += '&employeeName=' + this.employeeName;
    }
    this.getRequest(url).then(resp=>{
    	if(resp){
        	this.evaluations = resp.data;
            this.total = resp.total;
        }
    });
}

Controller层接收请求，调用Service处理。

@RestController
@RequestMapping("/evaluation")
public class EvaluationController {
@Autowired
    EvaluationService evaluationService;
    @GetMapping("/")
    public RespPageBean getEvaluationByPage(@RequestParam(defaultValue = "1") Integer page, @RequestParam(defaultValue = "10") Integer size, Evaluation evaluation, Date[] beginDateScope) {
        return evaluationService.getAllEvaluation(page,size,evaluation,beginDateScope);
    }
}

Service层把页数和每页条数进行处理，变成从第几条开始，需要几条数据。一般除了数据本身外，还需要数据总数，方便展示。

@Service
public class EvaluationService {
    @Autowired
    EvaluationMapper evaluationMapper;

    public RespPageBean getAllEvaluation(Integer page, Integer size, Evaluation evaluation, Date[] dateScope){
        if (page != null && size != null) {
            page = (page - 1) * size;
        }
        List<Evaluation> data = evaluationMapper.selectAllEvaluationByPage(page,size,evaluation,dateScope);
        Long total = evaluationMapper.count(evaluation,dateScope);
        RespPageBean bean = new RespPageBean();
        bean.setData(data);
        bean.setTotal(total);
        return bean;
    }
}    

Mapper接口声明方法。

public interface EvaluationMapper {
    // 查全部  搜索其实也在里面
    List<Evaluation> selectAllEvaluationByPage( Integer page,  Integer size,  Evaluation evaluation,  Date[] dateScope);

    //查某个条件下，数据总量
    Long count(Evaluation evaluation,  Date[] dateScope);
}

xml文件实现接口，其实就是创建了一个代理类，来实现Mapper接口。实现的方式是用SQL写的。
这里的page其实已经不是页数的意思了，为了代码可读性可以不用这么做。
用<if test标签来实现条件查询。

	<resultMap id="EvaluationWithName" type="org.javaboy.vhr.model.Evaluation">
            <id column="id" property="id" jdbcType="INTEGER"/>
            <result column="evaluation" property="evaluation" jdbcType="LONGVARCHAR"/>
            <result column="evaluationTime" property="evaluationTime" jdbcType="TIMESTAMP"/>
            <result column="employeeName" property="employeeName" jdbcType="VARCHAR"/>
            <result column="hrName" property="hrName" jdbcType="VARCHAR"/>
    </resultMap>
    <select id="selectAllEvaluationByPage" resultMap="EvaluationWithName">
        select evaluation.id,evaluation.evaluation,evaluation.evaluationTime,employee.`name` 'employeeName',hr.`name` 'hrName',hr.`id` 'hrId'
        from evaluation,employee,hr
        where evaluation.employeeId = employee.id
        and evaluation.hrId = hr.id
        <if test="evaluation.employeeName !=null and evaluation.employeeName!=''">
            and employee.`name` like concat('%',#{evaluation.employeeName},'%')
        </if>
        ORDER BY evaluationTime desc
        <if test="page !=null and size!=null">
            limit #{page},#{size}
        </if>
    </select>

	<select id="count" resultType="java.lang.Long">
        select count(1)
        from evaluation,employee,hr
        where evaluation.employeeId = employee.id
        and evaluation.hrId = hr.id
        <if test="evaluation.employeeName !=null and evaluation.employeeName!=''">
            and employee.`name` like concat('%',#{evaluation.employeeName},'%')
        </if>
    </select>