近期在项目中遇到了一个问题

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type `java.time.Duration` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: com.cmft.common4es.config.CustomElasticsearchProperties["connectionTimeout"])

一般使用打印json数据如下

System.out.println(new ObjectMapper().writeValueAsString(properties));

发现网上很多写法是

@Bean
public ObjectMapper objectMapper() {
	ObjectMapper objectMapper = new ObjectMapper();
	objectMapper.registerModule(new JavaTimeModule());
	return objectMapper;
}

其实是将 ObjectMapper 注入到 ioc 容器中，但是源码中很多地方用了 new ObjectMapper() 的方式来获取 ObjectMapper 对象，对于需要 java 8 时间的情况需要特殊处理。

@Resource
private ObjectMapper objectMapper;


System.out.println(objectMapper.writeValueAsString(properties));

可以采用省事的办法

@Bean
@Primary
public ObjectMapper objectMapper() {
	ObjectMapper objectMapper = new ObjectMapper();
	objectMapper.findAndRegisterModules();
	return objectMapper;
}

或者工具类中创建静态变量的方式来处理