Spring 引导：数据库保存值为 Null

Question

I'm new to Spring Boot.

I'm building a Rest API using H2, JPA, Lombok, Spring Web and DevTools.

I'm having the following problem: When inserting a value in the database it receives an id (ok, great) and when saving another data it saves it as null.

My application.properties:

spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.generate-unique-name=false

My controller:

package com.b.c.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import com.b.c.model.Receita;
import com.b.c.repository.ReceitaRepository;
import lombok.AllArgsConstructor;

@RestController
@AllArgsConstructor 
public class ReceitaController {
    
    @Autowired
    private ReceitaRepository receitaRepository;

    @GetMapping("/status")
    public List<Receita> getStatus() {
        return receitaRepository.findAll();
    }
    
    @PostMapping("/cadastrar")
    public Receita setUser(@RequestBody Receita receita) {
        return receitaRepository.save(receita);
    }

}

My model:

package com.b.c.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@AllArgsConstructor
@NoArgsConstructor
@Data
@Entity
@Table(name = "receitas")
public class Receita {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @Column(name="nome")
    private String nome;

}

My repository:

package com.b.c.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.b.c.model.Receita;

@Repository
public interface ReceitaRepository extends JpaRepository<Receita, Long>{

}

When making the post request with the payload in json it generates the id and saves the value of "nome" as null.

I manually entered test values into the database and when doing "receitaRepository.findAll();"it also returns "{}" with no value even after manually entering the values into the database.

So when inserting the values by the post method it is saved as null and when getting the values from the database to return a get it also displays as null, returning empty braces "{}".

Answer 1

Before saving the value you can validate the RequestBody. For this, you can use @Valid annotation along with @RequestBody. It will tell Spring to process validation before making an actual method call. In case validation fails, Spring will throw a MethodArgument NotValidException which, by default, will return a 400 (Bad Request) response. In POST or PUT requests, when we pass JSON payload, Spring automatically converts it into a Java object and now it can validate the resulting object. You can also mark your Model with the proper validation annotations.

@PostMapping("/cadastrar")
public Receita setUser(@Valid @RequestBody Receita receita) {
    return receitaRepository.save(receita);
}