通过@JsonProperty注解解析多级对象的解决方法

我会带着你远行 2021-06-11 15:14 1207阅读 0赞

### 背景： ###

接口对接时第三方接口返回的JSON报文中存在多层对象，如\{\\"name\\":\\"hello\\",\\"body\\":\{\\"age\\":\\"12\\",\\"height\\":\\"33\\"\}\}，json中还嵌套着body对象

### 解决方法： ###

上示例代码

package com.goods.evaluate.test;
    
    import com.fasterxml.jackson.annotation.JsonProperty;
    import com.fasterxml.jackson.databind.ObjectMapper;
    
    import java.io.IOException;
    
    public class Test {
    	public static void main (String[] args ) throws IOException {
    		String a ="{\"name\":\"hello\",\"body\":{\"age\":\"12\",\"height\":\"33\"}}";
    		ObjectMapper objectMapper = new ObjectMapper();
    		Person person = objectMapper.readValue(a, Person.class);
    		System.out.println("name: "+person.name);
    		System.out.println("age: "+person.body.age);
    		System.out.println("height: "+person.body.height);
    		String labelString = objectMapper.writeValueAsString(person);
    		System.out.println(labelString);
    	}
    
    	public static class Person{
    		@JsonProperty("name")
    		public String name;
    
    		@JsonProperty("body")
    		public Body body;
    		public Person(){
    		}
    	}
    	public static class Body{
    		@JsonProperty("age")
    		public String age;
    
    		@JsonProperty("height")
    		public String height;
    
    		public Body() {
    		}
    	}
    }

运行结果为：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNzk2ODYxMw_size_16_color_FFFFFF_t_70][]

解析成功！

就是将对象json串对应到相应的对象属性上，其对象属性也相应地用 @JsonProperty注解标注,可见@JsonProperty注解支持将json串多级解析

### 注意点： ###

@JsonProperty使用时要将返回的json串中属性一一对应，如将name注释掉

public static class Person{
    /*		@JsonProperty("name")
    		public String name;*/
    
    		@JsonProperty("body")
    		public Body body;
    		public Person(){
    		}
    	}
    	public static class Body{
    		@JsonProperty("age")
    		public String age;
    
    		@JsonProperty("height")
    		public String height;
    
    		public Body() {
    		}
    	}

就会报json解析错误

"C:\Program Files\Java\jdk1.8.0_131\bin\java.exe" -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:57294,suspend=y,server=n -javaagent:D:\ideaIU-2018.2.5.win\lib\rt\debugger-agent.jar=file:/C:/Users/chenwb/AppData/Local/Temp/capture14352.props -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_131\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_131\jre\lib\rt.jar;D:\version\code\evaluate\target\classes;D:\repository\org\springframework\boot\spring-boot-starter-data-jpa\2.1.3.RELEASE\spring-boot-starter-data-jpa-2.1.3.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-starter-aop\2.1.3.RELEASE\spring-boot-starter-aop-2.1.3.RELEASE.jar;D:\repository\org\springframework\spring-aop\5.1.5.RELEASE\spring-aop-5.1.5.RELEASE.jar;D:\repository\org\aspectj\aspectjweaver\1.9.2\aspectjweaver-1.9.2.jar;D:\repository\org\springframework\boot\spring-boot-starter-jdbc\2.1.3.RELEASE\spring-boot-starter-jdbc-2.1.3.RELEASE.jar;D:\repository\com\zaxxer\HikariCP\3.2.0\HikariCP-3.2.0.jar;D:\repository\org\springframework\spring-jdbc\5.1.5.RELEASE\spring-jdbc-5.1.5.RELEASE.jar;D:\repository\javax\transaction\javax.transaction-api\1.3\javax.transaction-api-1.3.jar;D:\repository\javax\xml\bind\jaxb-api\2.3.1\jaxb-api-2.3.1.jar;D:\repository\javax\activation\javax.activation-api\1.2.0\javax.activation-api-1.2.0.jar;D:\repository\org\hibernate\hibernate-core\5.3.7.Final\hibernate-core-5.3.7.Final.jar;D:\repository\org\jboss\logging\jboss-logging\3.3.2.Final\jboss-logging-3.3.2.Final.jar;D:\repository\javax\persistence\javax.persistence-api\2.2\javax.persistence-api-2.2.jar;D:\repository\org\javassist\javassist\3.23.1-GA\javassist-3.23.1-GA.jar;D:\repository\net\bytebuddy\byte-buddy\1.9.10\byte-buddy-1.9.10.jar;D:\repository\antlr\antlr\2.7.7\antlr-2.7.7.jar;D:\repository\org\jboss\jandex\2.0.5.Final\jandex-2.0.5.Final.jar;D:\repository\com\fasterxml\classmate\1.4.0\classmate-1.4.0.jar;D:\repository\org\dom4j\dom4j\2.1.1\dom4j-2.1.1.jar;D:\repository\org\hibernate\common\hibernate-commons-annotations\5.0.4.Final\hibernate-commons-annotations-5.0.4.Final.jar;D:\repository\org\springframework\data\spring-data-jpa\2.1.5.RELEASE\spring-data-jpa-2.1.5.RELEASE.jar;D:\repository\org\springframework\data\spring-data-commons\2.1.5.RELEASE\spring-data-commons-2.1.5.RELEASE.jar;D:\repository\org\springframework\spring-orm\5.1.5.RELEASE\spring-orm-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-context\5.1.5.RELEASE\spring-context-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-tx\5.1.5.RELEASE\spring-tx-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-beans\5.1.5.RELEASE\spring-beans-5.1.5.RELEASE.jar;D:\repository\org\slf4j\slf4j-api\1.7.25\slf4j-api-1.7.25.jar;D:\repository\org\springframework\spring-aspects\5.1.5.RELEASE\spring-aspects-5.1.5.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-starter-web\2.1.3.RELEASE\spring-boot-starter-web-2.1.3.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-starter\2.1.3.RELEASE\spring-boot-starter-2.1.3.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-starter-logging\2.1.3.RELEASE\spring-boot-starter-logging-2.1.3.RELEASE.jar;D:\repository\ch\qos\logback\logback-classic\1.2.3\logback-classic-1.2.3.jar;D:\repository\ch\qos\logback\logback-core\1.2.3\logback-core-1.2.3.jar;D:\repository\org\apache\logging\log4j\log4j-to-slf4j\2.11.2\log4j-to-slf4j-2.11.2.jar;D:\repository\org\apache\logging\log4j\log4j-api\2.11.2\log4j-api-2.11.2.jar;D:\repository\org\slf4j\jul-to-slf4j\1.7.25\jul-to-slf4j-1.7.25.jar;D:\repository\org\yaml\snakeyaml\1.23\snakeyaml-1.23.jar;D:\repository\org\springframework\boot\spring-boot-starter-json\2.1.3.RELEASE\spring-boot-starter-json-2.1.3.RELEASE.jar;D:\repository\com\fasterxml\jackson\core\jackson-databind\2.9.8\jackson-databind-2.9.8.jar;D:\repository\com\fasterxml\jackson\core\jackson-annotations\2.9.0\jackson-annotations-2.9.0.jar;D:\repository\com\fasterxml\jackson\core\jackson-core\2.9.8\jackson-core-2.9.8.jar;D:\repository\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.9.8\jackson-datatype-jdk8-2.9.8.jar;D:\repository\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.9.8\jackson-datatype-jsr310-2.9.8.jar;D:\repository\com\fasterxml\jackson\module\jackson-module-parameter-names\2.9.8\jackson-module-parameter-names-2.9.8.jar;D:\repository\org\hibernate\validator\hibernate-validator\6.0.14.Final\hibernate-validator-6.0.14.Final.jar;D:\repository\javax\validation\validation-api\2.0.1.Final\validation-api-2.0.1.Final.jar;D:\repository\org\springframework\spring-web\5.1.5.RELEASE\spring-web-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-webmvc\5.1.5.RELEASE\spring-webmvc-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-expression\5.1.5.RELEASE\spring-expression-5.1.5.RELEASE.jar;D:\repository\javax\annotation\javax.annotation-api\1.3.2\javax.annotation-api-1.3.2.jar;D:\repository\org\springframework\spring-core\5.1.5.RELEASE\spring-core-5.1.5.RELEASE.jar;D:\repository\org\springframework\spring-jcl\5.1.5.RELEASE\spring-jcl-5.1.5.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-devtools\2.1.3.RELEASE\spring-boot-devtools-2.1.3.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot\2.1.3.RELEASE\spring-boot-2.1.3.RELEASE.jar;D:\repository\org\springframework\boot\spring-boot-autoconfigure\2.1.3.RELEASE\spring-boot-autoconfigure-2.1.3.RELEASE.jar;D:\repository\mysql\mysql-connector-java\8.0.13\mysql-connector-java-8.0.13.jar;D:\ideaIU-2018.2.5.win\lib\idea_rt.jar" com.goods.evaluate.test.Test
    Connected to the target VM, address: '127.0.0.1:57294', transport: 'socket'
    Exception in thread "main" com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "name" (class com.goods.evaluate.test.Test$Person), not marked as ignorable (one known property: "body"])
     at [Source: (String)"{"name":"hello","body":{"age":"12","height":"33"}}"; line: 1, column: 10] (through reference chain: com.goods.evaluate.test.Test$Person["name"])
    	at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61)
    	at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:823)
    	at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1153)
    	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1589)
    	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1567)
    	at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294)
    	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
    	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013)
    	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3004)
    	at com.goods.evaluate.test.Test.main(Test.java:12)
    Disconnected from the target VM, address: '127.0.0.1:57294', transport: 'socket'
    
    Process finished with exit code 1

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNzk2ODYxMw_size_16_color_FFFFFF_t_70]: /images/20210518/0144b6a0a58a4c688a26d98c7abd794a.png