springboot JPA-Hibernate查询数据

1、先在pom.xml文件添加依赖

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

2、再在application.properties文件新增数据库配置

pring.datasource.url = jdbc:mysql://127.0.0.1:3306/数据库名?useSSL=FALSE&serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8

spring.datasource.username = root  用户

spring.datasource.password =  密码

spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.max-active=20

spring.datasource.max-idle=8

spring.datasource.min-idle=8

spring.datasource.initial-size=10


########################################################

### Java Persistence Api

########################################################

# Specify the DBMS

spring.jpa.database = MYSQL

# Show or not log for each sql query

spring.jpa.show-sql = true

# Hibernate ddl auto (create, create-drop, update)

#spring.jpa.hibernate.ddl-auto = create-drop  //如果打开这个注释，重新编译再操作数据表，数据表会删除重新建表导致数据被清

# Naming strategy

#[org.hibernate.cfg.ImprovedNamingStrategy #org.hibernate.cfg.DefaultNamingStrategy]

spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy

# stripped before adding them to the entity manager)

spring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5Dialect

3、前期工作做好之后，先看一下我的目录结构

 

   4、先建一个数据表对应的实体对象class放在domain目录下，Node.java,我的表名是node

@Entity
@Table(name = "node")
public class Node extends JpaRepositoriesAutoConfiguration {
    @Id //主键注解一定要加上，不然要抛异常
    @GeneratedValue
    private long id;
    private String name;
    private String title;
    private  int  status;
    private  int  sort;
    private  int pid;
    private int level;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }
    public String getName(){
     return name;
    }

    public void setName(String name){
        this.name=name;
    }

    public String getTitle(){
        return title;
    }
    public void setTitle(String title){
        this.title=title;
    }
    public int getStatus(){
        return status;
    }
    public void setStatus(int status){
        this.status=status;
    }

    public int getSort(){
        return sort;
    }
    public void setSort(int sort){
        this.sort=sort;
    }
    public void setPid(int pid){
        this.pid=pid;
    }
    public int getPid(){
        return pid;
    }

    public void setLevel(int level){
        this.level=level;
    }
    public int getLevel(){
        return level;
    }
}

5、再建一个interface NodeDao.java放在dao目录下

import java.util.List;
import com.spring.first.domain.Node;

public interface NodeDao extends CrudRepository<Node,Long> {

    //根据编号查询
    public Node findById(long id);
    @Query(value = "select * from node where name like %?1%",nativeQuery = true)
    @Modifying
    public List<Node> findByNameLike(String name);
}


6、再建一个interface NodeService.java放在service目录下

package com.spring.first.service;
import com.spring.first.domain.Node;

import java.util.List;

public interface NodeService {
    public void save(Node node);

    public List<Node> findByNameLike(String name);
}

7、接着建一个NodeServiceImpl.java放在serviceimpl目录下

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.spring.first.service.NodeService;
import com.spring.first.dao.NodeDao;
import com.spring.first.domain.Node;

import java.util.List;

@Service
public class NodeServiceImpl implements NodeService{
    @Autowired
    private NodeDao nodeDao;

    public void save(Node node){

        nodeDao.save(node);
    }

    public List<Node> findByNameLike(String name){
        return nodeDao.findByNameLike(name);
    }

}

8、最后就是写controller了

package com.spring.first.controller;
import javax.annotation.Resource;
import javax.validation.Valid;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import com.spring.first.service.DemoService;
import com.spring.first.service.NodeService;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import com.spring.first.domain.*;
import com.spring.first.vo.NodeVo;
import java.util.List;

@RestController
public class DemoController {
  

    @Resource
    private NodeService nodeService;
    @RequestMapping("/getData")
    @ResponseBody
    //这个方法只能返回单条数据 返回的是json对象
    public ResponseEntity<Object> getData(@RequestParam(name = "name") String name){
        return new ResponseEntity<>(demoService.getDemoByTname(name), HttpStatus.OK);
    }


    @RequestMapping("/getDatas")
    @ResponseBody
    //这个方法可返回多条数据，返回json数组
    public List<Node> findName(@RequestParam(name="name") String name){
        List<Node> bList=nodeService.findByNameLike(name);
        return bList;

    }
}


再浏览器上输入地址访问http://localhost:9090/getDatas?name=same
返回如图格式的数据

 

 

  完结！