Java：jackson处理LocalDateTime序列化的时候报错InvalidDefinitionException

目录

问题描述

解决方法

问题描述

jackson处理LocalDateTime序列化的时候报错

ObjectMapper mapper = new ObjectMapper();

mapper.writeValueAsString(LocalDateTime.now());

报错信息

com.fasterxml.jackson.databind.exc.InvalidDefinitionException:

Java 8 date/time type `java.time.OffsetDateTime` not supported by default:

add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling

如果处理Date对象是不会报错的

ObjectMapper mapper = new ObjectMapper();

mapper.writeValueAsString(new Date());

// 1684480558531

解决方法

按照异常信息提示，引入模块com.fasterxml.jackson.datatype:jackson-datatype-jsr310

引入依赖

<!-- json -->

<dependency>

   <groupId>com.fasterxml.jackson.core</groupId>

   <artifactId>jackson-databind</artifactId>

   <version>2.13.4</version>

</dependency>

<dependency>

   <groupId>com.fasterxml.jackson.datatype</groupId>

   <artifactId>jackson-datatype-jsr310</artifactId>

   <version>2.13.4</version>

</dependency>

注册JavaTimeModule

ObjectMapper mapper = new ObjectMapper();

// 已过时

// mapper.registerModule(new JSR310Module());

// Jackson 2.7 之后使用JavaTimeModule

mapper.registerModule(new JavaTimeModule());

// 默认输出

mapper.writeValueAsString(LocalDateTime.now())

[2023,5,19,15,21,57,337000000]

发现输出的格式不太对，进一步优化

ObjectMapper mapper = new ObjectMapper();

JavaTimeModule javaTimeModule = new JavaTimeModule();

// 设置序列化格式

javaTimeModule.addSerializer(LocalDateTime.class,

       new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));

mapper.registerModule(javaTimeModule);

try {

   System.out.println(mapper.writeValueAsString(LocalDateTime.now()));

   // "2023-05-19 15:29:01"

} catch (JsonProcessingException e) {

   e.printStackTrace();

}

完整测试代码

package com.example.demo;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;

import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;

import org.junit.jupiter.api.Test;

import java.time.LocalDateTime;

import java.time.format.DateTimeFormatter;

public class JsonTest {

   @Test

   public void testJavaTimeModule() {

       ObjectMapper mapper = new ObjectMapper();

       JavaTimeModule javaTimeModule = new JavaTimeModule();

       // 设置序列化格式

       javaTimeModule.addSerializer(LocalDateTime.class,

               new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));

       mapper.registerModule(javaTimeModule);

       try {

           System.out.println(mapper.writeValueAsString(LocalDateTime.now()));

           // "2023-05-19 15:29:01"

       } catch (JsonProcessingException e) {

           e.printStackTrace();

       }

   }

}

参考

使用Jackson JSR310模块反序列化LocalDateTime

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原文链接：https://blog.csdn.net/mouday/article/details/130767915