spring boot中的多子句查询

Question

package com.mobile.model;

import javax.persistence.*;


@Entity
@Table(name = "mobile_table")
public class Mobile {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    public int mobileId;

    @Column(name = "mobile_name",nullable = false,length = 20)
    public String mobileName;

    @Column(name = "mobile_brand",nullable = false,length = 15)
    public String mobileBrand;

    @Column(name="mobile_networkType")
    public String mobileNetworkType;

    @Column(name = "mobile_core")
    public Integer mobileAvailableCore;

    @Column(name = "mobile_ram")
    public Integer mobileRAMSize;

    @Column(name = "mobile_os")
    public String mobileOS;

    @Column(name = "mobile_wifif")
    public Boolean mobileWifiAvailability;

    @Column(name = "mobile_bluetooth")
    public Boolean mobileBluethoothAvailablity;

    public Mobile() {
    }

    public Mobile(String mobileName, String mobileBrand, String mobileNetworkType, Integer mobileAvailableCore, Integer mobileRAMSize, String mobileOS, Boolean mobileWifiAvailability, Boolean mobileBluethoothAvailablity) {
        this.mobileName = mobileName;
        this.mobileBrand = mobileBrand;
        this.mobileNetworkType = mobileNetworkType;
        this.mobileAvailableCore = mobileAvailableCore;
        this.mobileRAMSize = mobileRAMSize;
        this.mobileOS = mobileOS;
        this.mobileWifiAvailability = mobileWifiAvailability;
        this.mobileBluethoothAvailablity = mobileBluethoothAvailablity;
    }
}

//Query for multiple selection
    @SuppressWarnings("unchecked")
	public List<Mobile> getMobileSearch(String mobileBrand, Integer mobileRAMSize, String mobileOS){
    	return mobileDao.findAll(Specifications.where((Specification<Mobile>) getAllMobilesByBrand(mobileBrand))
    			.and((Specification<Mobile>) getAllMobilesByOS(mobileOS))
    			.and((Specification<Mobile>) getAllMobilesByRam(mobileRAMSize)));
    }

// calling function for multiple attribute Search in controller class
@RequestMapping(value="/searchMobile", method=RequestMethod.GET)
    public ResponseEntity<List<Mobile>> searchMobile(@RequestParam(value="brand") String mobileBrand, @RequestParam(value="ramSize") Integer ramSize, @RequestParam(value="mobileOs") String MobileOs)
    {
    	List<Mobile> mobileList=mobileService.getMobileSearch(mobileBrand,ramSize,MobileOs);
    	return new ResponseEntity<List<Mobile>>(mobileList,HttpStatus.OK);
    }

// here is how my database is calling database query.
@Repository
public interface MobileDao extends CrudRepository<Mobile, Integer>, JpaSpecificationExecutor<Mobile> {

    public List<Mobile> findByMobileBrand(String mobileBrand);

    @Query("select distinct m.mobileBrand from Mobile m")
    public List<String > getAllDistinctBrand();

    public List<Mobile> findByMobileRAMSize(Integer mobileRAMSize);

    @Query("select distinct m.mobileRAMSize from Mobile m")
    public List<Integer> getAllDistinctRam();

    public List<Mobile> findByMobileOS(String mobileOS);


    @Query("select distinct m.mobileOS from Mobile m")
    public List<String > getAllDistinctMobileOS();

我正在尝试实现对不同电子商务网站（如 Flipkart、亚马逊）中使用的产品的搜索查询，其中用户为产品插入不同的属性。根据产品属性显示结果。对于实现，我使用 Spring Boot 和 JPA 作为数据库。

如何在单个查询中动态搜索多个子句。例如，在 SQL 查询的情况下，我们会像这样搜索多个子句。

如何在 JPA 中实现多个子句。

Select * from table_name where attribute1="Attb" and attribute2="Attb2" and attribute3="Attb3";

Attb、Attb2 和 Attb3 根据客户端输入动态变化。

Answer 1

你的问题不够清楚。如果您需要使用可变数量的条件，则必须使用Criteria API。它允许您有条件地创建谓词列表并将其用于数据提取。 http://www.objectdb.com/java/jpa/query/criteria

看起来像这样：

    myQueryMethod(UserChoices choices){
        if(choices.someChoice1){
         predicates.add(somePredicate)
        }
    .....

Answer 2

您应该实现一个 JPA 存储库并使用方法查询：

public interface MyRepository implements JpaRepository<MODEL_CLASS, Long> {
     MODEL_CLASS findAllByAtttibute1AndAttribute2AndAttribute3(String Attribute1, String Attribute2, String Attribute3);
}