JSON解析错误:无法构造java.time.LocalDate的实例:否要从字符串值反序列化的字符串参数构造函数/工厂方法

问题描述

我是Spring Data REST项目的新手，我正在尝试创建我的第一个RESTful服务.任务很简单，但是我被困住了.

I am new to Spring Data REST project and I am trying to create my first RESTful service. The task is simple, but I am stuck.

我想使用RESTful API对存储在嵌入式数据库中的用户数据执行CRUD操作.

I want to perform CRUD operations on a user data stored in an embedded database using RESTful API.

但是我无法弄清楚如何使Spring框架将birthData处理为"1999-12-15"并将其存储为LocalDate. @JsonFormat注释无济于事.

But I cannot figure out how to make the Spring framework process the birthData as "1999-12-15" and store it as a LocalDate. The @JsonFormat annotation does not help.

目前我得到了错误:

HTTP/1.1 400 
Content-Type: application/hal+json;charset=UTF-8
Transfer-Encoding: chunked
Date: Thu, 24 Aug 2017 13:36:51 GMT
Connection: close

{"cause":{"cause":null,"message":"Can not construct instance of java.time.LocalDate: 
no String-argument constructor/factory method to deserialize from String value ('1999-10-10')\n 
at [Source: org.apache.catalina.connector.CoyoteInputStream@4ee2a60e; 
line: 1, column: 65] (through reference chain: ru.zavanton.entities.User[\"birthDate\"])"},
"message":"JSON parse error: Can not construct instance of java.time.LocalDate: 
no String-argument constructor/factory method to deserialize from String value ('1999-10-10'); nested exception is com.fasterxml.jackson.databind.JsonMappingException: 
Can not construct instance of java.time.LocalDate: no String-argument constructor/factory method to deserialize from String value ('1999-10-10')\n 
at [Source: org.apache.catalina.connector.CoyoteInputStream@4ee2a60e; line: 1, column: 65] (through reference chain: ru.zavanton.entities.User[\"birthDate\"])"}

如何使其正常工作，以便客户致电:

How to make it work, so that client calls like:

curl -i -X POST -H "Content-Type:application/json" -d "{  \"firstName\" : \"John\",  \"lastName\" : \"Johnson\", \"birthDate\" : \"1999-10-10\", \"email\" : \"[email protected]\" }" http://localhost:8080/users

实际上会将实体存储到数据库中.

will actually store the entity into the database.

下面是有关类的信息.

用户类别:

package ru.zavanton.entities;


import com.fasterxml.jackson.annotation.JsonFormat;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import java.time.LocalDate;

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    private String firstName;
    private String lastName;

    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
    private LocalDate birthDate;

    private String email;
    private String password;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public LocalDate getBirthDate() {
        return birthDate;
    }

    public void setBirthDate(LocalDate birthDate) {
        this.birthDate = birthDate;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

UserRepository类:

The UserRepository class:

package ru.zavanton.repositories;

import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;
import ru.zavanton.entities.User;

@RepositoryRestResource(collectionResourceRel = "users", path = "users")
public interface UserRepository extends PagingAndSortingRepository<User, Long> {

    User findByEmail(@Param("email") String email);

}

应用程序类:

package ru.zavanton;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }
}

推荐答案

此序列化和反序列化需要jackson依赖项.

You need jackson dependency for this serialization and deserialization.

添加此依赖项:

等级:

compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.4")

行家:

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

此后，您需要告诉Jackson ObjectMapper使用JavaTimeModule.要做到这一点，在主类中自动连接ObjectMapper并向其注册JavaTimeModule.

After that, You need to tell Jackson ObjectMapper to use JavaTimeModule.To do that,Autowire ObjectMapper in the main class and register JavaTimeModule to it.

import javax.annotation.PostConstruct;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;

@SpringBootApplication
public class MockEmployeeApplication {

  @Autowired
  private ObjectMapper objectMapper;

  public static void main(String[] args) {
    SpringApplication.run(MockEmployeeApplication.class, args);

  }

  @PostConstruct
  public void setUp() {
    objectMapper.registerModule(new JavaTimeModule());
  }
}

之后，您的LocalDate和LocalDateTime应该正确地序列化和反序列化.

After that,Your LocalDate and LocalDateTime should be serialized and deserialized correctly.

这篇关于JSON解析错误:无法构造java.time.LocalDate的实例:否要从字符串值反序列化的字符串参数构造函数/工厂方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！