springbootjpaRepository为何一定要对Entity序列化

inventory(id, name, quantity, type, comment)

inventory(id, comment，name, quantity, type )

package com.example.demo; 
import java.io.Serializable; 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
 
@Entity
public class Inventory implements Serializable{ 
    private static final long serialVersionUID = 1L; 
    @Id
    @SequenceGenerator(name="inventory_generator", sequenceName="inventory_sequence", initialValue = 2)
    @GeneratedValue(generator = "inventory_generator")
    private Integer id;
    @Column(nullable = false)
    private String name;
    @Column(nullable = false)
    private Integer quantity;
    @Column(nullable = false)
    private Integer type;
    @Column(nullable = false)
    private String comment;
    public Inventory(Integer id, String name, Integer quantity, Integer type, String comment) {
        super();
        this.id = id;
        this.name = name;
        this.quantity = quantity;
        this.type = type;
        this.comment = comment;
    }
    public Inventory() {
        super();
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getQuantity() {
        return quantity;
    }
    public void setQuantity(Integer quantity) {
        this.quantity = quantity;
    }
    public Integer getType() {
        return type;
    }
    public void setType(Integer type) {
        this.type = type;
    }
    public String getComment() {
        return comment;
    }
    public void setComment(String comment) {
        this.comment = comment;
    }
    @Override
    public String toString() {
        return "Inventory [id=" + id + ", name=" + name + ", quantity=" + quantity + ", type=" + type + ", comment="
                + comment + "]";
    }
}

package com.example.demo; 
import org.springframework.data.jpa.repository.JpaRepository; 
public interface InventoryRepository extends JpaRepository<Inventory, Integer> { 
    Inventory findById(Integer id); 
}

package com.example.demo; 
import java.time.LocalTime; 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.WEB.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
 
@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class InventoryApplication { 
    public static void main(String[] args) {
        SpringApplication.run(InventoryApplication.class, args);
    }
    @Autowired
    private InventoryRepository inventoryRepository;
 
    @Value("${server.port}")
    private Integer port; 
    @RequestMapping("/info")
    public String info(){
        inventoryRepository.save(new Inventory(1, "火锅底料", 10000, 1, "你吃火锅，我吃底料"));
        inventoryRepository.save(new Inventory(2, "微服务架构", 100, 2, "微服务还是要考虑 一波"));
        return "{Inventory[port:"+port+", info:库存微服务"+"]}";
    }
 
    @GetMapping("/get/{id}")
    @ResponseBody
    @Transactional
    public String getById(@PathVariable("id")Integer id){
        return inventoryRepository.findById(id).toString();
    }
 
    @GetMapping("/")
    @ResponseBody
    @Transactional
    public String re(){
        return inventoryRepository.findAll().toString();
    }
 
    @GetMapping("/delete/{id}")
    @ResponseBody
    @Transactional
    public String delete(@PathVariable("id")Integer id){
        inventoryRepository.delete(id);
        return "delete successfully";
    }
 
    @GetMapping("/save/id={id}&name={name}&quantity={quantity}&type={type}&comment={comment}")

    public String save(@PathVariable("id")Integer id,@PathVariable("name")String name,
            @PathVariable("quantity")Integer quantity,@PathVariable("type")Integer type,
            @PathVariable("comment")String comment){
        inventoryRepository.save(new Inventory(id,name,quantity,type,comment));
        System.out.println(new Inventory(id,name,quantity,type,comment));
        //强调一下identity和auto
        return "save successfully";
    }
 
    @GetMapping("/update/id={id}&name={name}&quantity={quantity}&type={type}&comment={comment}")
    @ResponseBody
    @Transactional
    public String update(@PathVariable("id")Integer id,@PathVariable("name")String name,
            @PathVariable("quantity")Integer quantity,@PathVariable("type")Integer type,
            @PathVariable("comment")String comment){
        Inventory inventory=inventoryRepository.findById(id);
        if(inventory.getComment().length()<LocalTime.now().toString().length()){
            inventory.setComment(inventory.getComment()+LocalTime.now());
        }else{
            inventory.setComment(inventory.getComment().substring(0,inventory.getComment().length()-
                    LocalTime.now().toString().length())+LocalTime.now());
        }
        inventoryRepository.save(inventory);
        inventoryRepository.flush();
        return "update successfully";
    }
}

spring.jpa.show-sql=true
logging.pattern.level=trace
server.port=8765
spring.application.name=inventory
server.Tomcat.max-threads=1000
eureka.instance.leaseRenewalIntervalInSeconds= 10
eureka.client.reGIStryFetchIntervalSeconds= 5
eureka.client.serviceUrl.defaultZone=Http://localhost:8889/eureka
#eureka.client.service-url.defaultZone=http://${eureka.instance.hostname}:${eureka.instance.server.port}/eureka
 
#spring.thymeleaf.prefix=classpath:/templates/  
#spring.thymeleaf.suffix=.html  
#spring.thymeleaf.mode=HTML5  
#spring.thymeleaf.encoding=UTF-8  
# ;charset=<encoding> is added  
#spring.thymeleaf.content-type=text/html  
# set to false for hot refresh  
spring.h2.console.enabled=true
spring.thymeleaf.cache=false  
spring.jpa.hibernate.ddl-auto=update
#这里是把h2持久化到本地文件夹，这可以保持数据
spring.datasource.url=jdbc:h2:file:C\:/h2/h2cache;AUTO_SERVER=TRUE;DB_CLOSE_DELAY=-1
logging.file=c\:/h2/logging.log
logging.level.org.hibernate=debug
#spring.datasource.data=classpath:import.sql

insert into inventory(id, name, quantity, type, comment) values (1, "火锅底料", 10000, 1, "你吃火锅，我吃底料")
insert into inventory(id, name, quantity, type, comment) values (2, "微服务架构", 100, 2, "微服务还是要考虑 一波")

package com.example.demo; 
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner; 
@RunWith(SpringRunner.class)
@SpringBootTest
public class InventoryApplicationTests {
 
    @Autowired
    private InventoryRepository inventoriRepository;
 
    @Test
    public void test2() {
        System.out.println(inventoriRepository.findAll());
    } 
}

@Entity
@Table(name = "mission_info")

 @Id
 @GeneratedValue(strategy = IDENTITY)
 @Column(name = "id", nullable = false)