网站开发公司成都,建设项目环境影响网站,兰州建设局网站,合肥高端网站建设设计公司文章目录使用阿里巴巴的 JSON使用 ObjectMapperJSON字段与实体类属性不一致首先#xff0c;我们建立一个实体类#xff0c;这里简单定义了 name、sex、age 三个属性#xff0c;以及 get、set、tostring方法。public class Student {private String name;private String sex;…
文章目录使用阿里巴巴的 JSON使用 ObjectMapperJSON字段与实体类属性不一致首先我们建立一个实体类这里简单定义了 name、sex、age 三个属性以及 get、set、tostring方法。public class Student {private String name;private String sex;private Integer age;public String getName() {return name;}public String getSex() {return sex;}public Integer getAge() {return age;}public void setName(String name) {this.name name;}public void setSex(String sex) {this.sex sex;}public void setAge(Integer age) {this.age age;}Overridepublic String toString() {return Student [name name , sex sex , age age ];}
}使用阿里巴巴的 JSON
依赖
dependencygroupIdcom.alibaba/groupIdartifactIdfastjson/artifactIdversion1.2.75/version
/dependencyJSON串的字段少于实体类的字段实体类对象中没有匹配到的属性被赋予默认值
Testpublic void testFastjson01() {String jsonStr {\age\:18,\name\:\zhangsan\};Student stu JSON.parseObject(jsonStr, Student.class);System.out.println(stu); // Student [namezhangsan, sexnull, age18]}JSON串的字段多于实体类的字段 Testpublic void testFastjson02() {String jsonStr {\age\:20,\name\:\lisi\,\sex\:\男\,\hobby\:\basketball\};Student stu JSON.parseObject(jsonStr, Student.class);System.out.println(stu); // Student [namelisi, sex男, age20]}上面 JSON 串中的 \ 可以替换成单引号 String jsonStr {id:001,model:A09,picUrl:x001.jpe,description:非常便宜,price:20};使用 ObjectMapper
依赖
dependencygroupIdcom.konghq/groupIdartifactIdunirest-objectmapper-jackson/artifactIdversion4.0.0-RC4/version
/dependencyJSON串的字段少于实体类的字段实体类对象中没有匹配到的属性被赋予默认值 Testpublic void testJackson01() throws Exception{String jsonStr {\age\:18,\name\:\zhangsan\};ObjectMapper om new ObjectMapper();Student stu om.readValue(jsonStr, Student.class);System.out.println(stu); // Student [namezhangsan, sexnull, age18]}JSON串的字段多于实体类的字段会报错 Testpublic void testJackson02() throws Exception{String jsonStr {\age\:20,\name\:\lisi\,\sex\:\男\,\hobby\:\basketball\};ObjectMapper om new ObjectMapper();Student stu om.readValue(jsonStr, Student.class);System.out.println(stu);}错误信息
com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field hobby (class com.cyj.demo03.Student), not marked as ignorable (3 known properties: name, sex, age])at [Source: {age:20,name:lisi,sex:男,hobby:basketball}; line: 1, column: 44] (through reference chain: com.cyj.demo03.Student[hobby])at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:51)at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:817)at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:958)at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1324)at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1302)at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:249)at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:136)at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3564)at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2580)at com.cyj.demo03.TestJson.testJackson02(TestJson.java:40)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:497)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)由此可见在默认情况下ObjectMapper是不支持json串的字段多于实体类字段的但是ObjectMapper也提供了解决方案我们在实体类上添加注解 JsonIgnoreProperties这个注解有一个ignoreUnknown属性默认值为false我们可以将它改为true这样jackson在反序列化的时候就会忽略掉不存在的属性了。
JsonIgnoreProperties(ignoreUnknown true)
public class Student {JSON字段与实体类属性不一致
项目开发过程中有时候可能要对接第三方平台可能就会存在字段名不一样的问题而双方的字段名不一致 而代码开发已经有一段时间勒如果就因为字段名不一样的问题双方改成属性名一致这样改动量太大也不保险下面我来接手一下针对这种场景如果解决。
假设 系统通过http对接传的是json。有一个参数名称
第三方平台name
开发环境userName
直接通过实体类映射不用说肯定有问题。
在实体类的属性上增加一个注解就可以解决这种问题
JsonProperty(name)
private String userName;
