java jettison_java – 使用Jettison进行JSON解析

我试图使用Jettison解析JSON对象.

这是我正在使用的代码

String s =”{\”appUsage\”:[{\”appName\”:\”ANDROID\”,\”totalUsers\”:\”0\”},{\”appName\”:\”IOS\”,\”totalUsers\”:\”4\”}]}”;

JSONObject obj = new JSONObject(s);

ArrayList l1 = (ArrayList) jsonParser(ArrayList.class, obj);

public static Object jsonParser(Class c, JSONObject obj)

throws JSONException, XMLStreamException, JAXBException {

JAXBContext jc = JAXBContext.newInstance(c);

Configuration config = new Configuration();

MappedNamespaceConvention con = new MappedNamespaceConvention(config);

XMLStreamReader xmlStreamReader = new MappedXMLStreamReader(obj, con);

Unmarshaller unmarshaller = jc.createUnmarshaller();

ArrayListcustomer = (ArrayList) unmarshaller.unmarshal(xmlStreamReader);

return customer;

}

我收到了这个错误

Exception in thread “main” javax.xml.bind.UnmarshalException

– with linked exception: [javax.xml.bind.UnmarshalException: unexpected element (uri:””, local:”appUsage”). Expected elements are

(none)] at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.handleStreamException(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(Unknown

Source) at com.json.UnmarshalDemo.jsonParser(UnmarshalDemo.java:56)

at com.json.UnmarshalDemo.main(UnmarshalDemo.java:33) Caused by:

javax.xml.bind.UnmarshalException: unexpected element (uri:””,

local:”appUsage”). Expected elements are (none) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.StAXStreamConnector.handleStartElement(Unknown

Source) at

com.sun.xml.internal.bind.v2.runtime.unmarshaller.StAXStreamConnector.bridge(Unknown

Source) … 4 more Caused by: javax.xml.bind.UnmarshalException:

unexpected element (uri:””, local:”appUsage”). Expected elements are

(none) … 14 more

如何解决这个问题

解决方法:

如果您最终正在寻找使用JAXB(JSR-222)实现与JSON交互的方法,那么以下是使用MOXy完成它的方法. Jettison是一个有趣的库,但是你会遇到一些问题：

演示

仅使用标准Java SE API.需要在Unmarshaller上设置两个MOXy特定属性：“eclipselink.media-type”指定“application / json”,“eclipselink.json.include-root”指示没有根节点.

package forum;

import java.io.StringReader;

import java.util.ArrayList;

import javax.xml.bind.*;

import javax.xml.transform.stream.StreamSource;

public class Demo {

private static final String s =”{\”appUsage\”:[{\”appName\”:\”ANDROID\”,\”totalUsers\”:\”0\”},{\”appName\”:\”IOS\”,\”totalUsers\”:\”4\”}]}”;

public static void main(String[] args) throws Exception {

JAXBContext jc = JAXBContext.newInstance(Root.class);

Unmarshaller unmarshaller = jc.createUnmarshaller();

unmarshaller.setProperty(“eclipselink.media-type”, “application/json”);

unmarshaller.setProperty(“eclipselink.json.include-root”, false);

StreamSource json = new StreamSource(new StringReader(s));

Root root = unmarshaller.unmarshal(json, Root.class).getValue();

ArrayList customer = root.appUsage;

for(MiAppUsage miAppUsage : customer) {

System.out.print(miAppUsage.appName);

System.out.print(‘ ‘);

System.out.println(miAppUsage.totalUsers);

}

}

}

根

我不得不介绍这个课程来满足你的用例.如果你的JSON看起来像我们可以消除这个类：[{“appName”：“ANDROID”,“totalUsers”：“0”},{“appName”：“IOS”,“totalUsers”：“4”}].

package forum;

import java.util.ArrayList;

import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)

public class Root {

ArrayList appUsage;

}

MiAppUsage

package forum;

import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)

public class MiAppUsage {

String appName;

int totalUsers;

}

jaxb.properties

要将MOXy指定为JAXB提供程序,您需要添加一个名为java.properties的文件,并在与您的域类相同的包中添加以下条目：

javax.xml.bind.context.factory = org.eclipse.persistence.jaxb.JAXBContextFactory

产量

以下是运行演示代码的输出：

ANDROID 0

IOS 4

欲获得更多信息

标签：json,java,jettison

来源： https://codeday.me/bug/20190621/1250473.html