Spring-boot 项目中使用 jackson 遇到的一个问题

jackson介绍

　　java代码中实现序列化和反序列化的工具类

jackson使用Demo

　　https://github.com/Naylor55/JavaDebrisCode/tree/branch_Java-Serializable/javaserializable

Ideal控制台报错信息

2019-05-22 15:43:20.333 [main] ERROR org.springframework.boot.SpringApplication.reportFailure:837 - Application run failed
java.lang.AbstractMethodError: com.fasterxml.jackson.core.type.ResolvedType.getReferencedType()Lcom/fasterxml/jackson/core/type/ResolvedType;
	at com.fasterxml.jackson.core.type.ResolvedType.isReferenceType(ResolvedType.java:59)
	at com.fasterxml.jackson.datatype.jdk8.Jdk8TypeModifier.modifyType(Jdk8TypeModifier.java:20)
	at com.fasterxml.jackson.databind.type.TypeFactory._constructType(TypeFactory.java:413)
	at com.fasterxml.jackson.databind.type.TypeFactory.constructType(TypeFactory.java:354)
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.getJavaType(AbstractJackson2HttpMessageConverter.java:323)
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.canRead(AbstractJackson2HttpMessageConverter.java:158)
	at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.canRead(AbstractJackson2HttpMessageConverter.java:150)
	at org.springframework.web.client.RestTemplate$AcceptHeaderRequestCallback.doWithRequest(RestTemplate.java:805)
Disconnected from the target VM, address: '127.0.0.1:57769', transport: 'socket'
	at org.springframework.web.client.RestTemplate$HttpEntityRequestCallback.doWithRequest(RestTemplate.java:868)
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:685)
	at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:644)
	at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:564)
	at org.springframework.cloud.config.client.ConfigServicePropertySourceLocator.getRemoteEnvironment(ConfigServicePropertySourceLocator.java:218)
	at org.springframework.cloud.config.client.ConfigServicePropertySourceLocator.locate(ConfigServicePropertySourceLocator.java:96)
	at org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration.initialize(PropertySourceBootstrapConfiguration.java:94)
	at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:628)
	at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:364)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:305)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1242)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1230)
	at com.leading.WarehouseserviceApplication.main(WarehouseserviceApplication.java:50)

　　

报错原因

　　Spring-Boot框架自身默认就引用了jackson，如果你在自己的开发项目中再次引用，就会有冲突。然而，JVM 不会告诉你是引用有冲突，而是直接给你一个类型有问题的提示。意思就是我只能告诉你类型有问题，具体的你自己查吧。IDEAL 作为一个开发工具，在这点上面也没有做出点贡献。Java这个生态缺陷还是很大的！！！

　　spriing-boot 默认引用

　　自己项目的pom中找到：org.springframework.boot ， 并点击进去。

　　　　 <parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.6.RELEASE</version>
		<relativePath />
	</parent>

　　然后再找：spriing-boot-dependencies ，并点击进去

 <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-dependencies</artifactId>
        <version>2.0.6.RELEASE</version>
        <relativePath>../../spring-boot-dependencies</relativePath>
    </parent>

　　然后就可以看到spring-boot 对jackson 的引用，如下图

　　

解决办法

　　在当前开发项目的pom文件中删除对jackson的依赖，即删除如下图所示