杰克逊：地图反序列化

我正在使用杰克逊反序列化一个json文件（我用jackson序列化）。 json是一个简单的HashMap，但是当我尝试并反序列化时，映射器正在抱怨。杰克逊：地图反序列化

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.HashMap out of START_ARRAY token

我系列化的HashMap串.....

{ 
"0f861a9a-0a3e-40a7-8ff3-0b83d8070876" : { 
"name" : "BAR.xml", 
"filePath" : "/FOO/repo/BAR.xml" 
}, 
"f3cbb32e-b7b8-4af1-b48b-7ea393de7971" : { 
"name" : "BLAH.xml", 
"filePath" : "/FOO/repo/BLAH.xml" 
}, 
"012009b6-26e9-4bc1-9050-2a4ac9546c7e" : { 
"name" : "Check System.xml", 
"filePath" : "/FOO/repo/Check System.xml" 
} 
}

我已经试过两种不同的方式，使这项工作，并且都失败...

//doesn't work  
cache = (Map<String,UUIDInfo>) mapper.readValue(bytes.toString(), new TypeReference<HashMap<String,UUIDInfo>>(){}); 

//doesn't work. 
cache = (Map<String,UUIDInfo>) mapper.readValue(bytes.toString(), TypeFactory.mapType(HashMap.class, String.class, UUIDInfo.class));

全stacktrace

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.LinkedHashMap out of START_ARRAY token 
at [Source: [email protected]; line: 1, column: 1] 
    at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163) 
    at org.codehaus.jackson.map.deser.StdDeserializationContext.mappingException(StdDeserializationContext.java:198) 
    at org.codehaus.jackson.map.deser.MapDeserializer.deserialize(MapDeserializer.java:151) 
    at org.codehaus.jackson.map.deser.MapDeserializer.deserialize(MapDeserializer.java:25) 
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2395) 
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1602) 
    at com.hp.oo.studio.shared.UUIDRegistry.UUIDRegistry.<init>(UUIDRegistry.java:63) 
    at com.hp.oo.studio.shared.UUIDRegistry.UUIDRegistry.<clinit>(UUIDRegistry.java:37) 
    at com.hp.oo.studio.shared.StudioShared.loadUUIDRegistry(StudioShared.java:93) 
    at com.hp.oo.studio.shared.StudioShared.start(StudioShared.java:42) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683) 
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381) 
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:299) 
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:440) 
    at org.eclipse.osgi.internal.loader.BundleLoader.setLazyTrigger(BundleLoader.java:268) 
    at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107) 
    at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:462) 
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:216) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:400) 
    at org.eclipse.osgi.internal.loader.SingleSourcePackage.loadClass(SingleSourcePackage.java:35) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:473) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417) 
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356) 
    at com.hp.oo.studio.StudioUI.registerFile(StudioUI.java:133) 
    at com.hp.oo.studio.StudioUI.findFilesInDirectory(StudioUI.java:125) 
    at com.hp.oo.studio.StudioUI.findFilesInDirectory(StudioUI.java:120) 
    at com.hp.oo.studio.StudioUI.start(StudioUI.java:75) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702) 
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683) 
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381) 
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:299) 
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:440) 
    at org.eclipse.osgi.internal.loader.BundleLoader.setLazyTrigger(BundleLoader.java:268) 
    at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107) 
    at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:462) 
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:216) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:400) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:476) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:429) 
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:417) 
    at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356) 
    at org.eclipse.osgi.internal.loader.BundleLoader.loadClass(BundleLoader.java:345) 
    at org.eclipse.osgi.framework.internal.core.BundleHost.loadClass(BundleHost.java:229) 
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadClass(AbstractBundle.java:1207) 
    at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174) 
    at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905) 
    at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243) 
    at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55) 
    at org.eclipse.ui.internal.WorkbenchPlugin$1.run(WorkbenchPlugin.java:268) 
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70) 
    at org.eclipse.ui.internal.WorkbenchPlugin.createExtension(WorkbenchPlugin.java:264) 
    at org.eclipse.ui.internal.registry.EditorDescriptor.createEditor(EditorDescriptor.java:235) 
    at org.eclipse.ui.internal.EditorManager.createPart(EditorManager.java:875) 
    at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:609) 
    at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:465) 
    at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595) 
    at org.eclipse.ui.internal.EditorAreaHelper.setVisibleEditor(EditorAreaHelper.java:271) 
    at org.eclipse.ui.internal.EditorManager.setVisibleEditor(EditorManager.java:1459) 
    at org.eclipse.ui.internal.EditorManager$5.runWithException(EditorManager.java:972) 
    at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31) 
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) 
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) 
    at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563) 
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212) 
    at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803) 
    at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1595) 
    at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31) 
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) 
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) 
     at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563) 
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212) 
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604) 
    at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494) 
    at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674) 
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) 
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667) 
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) 
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123) 
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) 
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110) 
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79) 
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344) 
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:601) 
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622) 
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577) 
    at org.eclipse.equinox.launcher.Main.run(Main.java:1410) 
    at org.eclipse.equinox.launcher.Main.main(Main.java:1386)

来源

2011-12-02 user1078261

完整异常堆栈跟踪请 –

为您添加堆栈跟踪。 – user1078261

将你的地图包裹成另一个对象，然后元帅。例如：

class MyObject{ 

    private Map<String,UUIDInfo> map; 

}

而简单地做：mappper.readValue(myInstance, MyObject.class)

来源

2011-12-02 21:59:12

我试过了，并没有工作，以及.... { “缓存”：{ “0f861a9a-0a3e-40a7-8ff3-0b83d8070876”：{ “名”： “BAR.xml” ， “文件路径”： “/FOO/repo/BAR.xml” }， “f3cbb32e-b7b8-4af1-b48b-7ea393de7971”：{ “名”： “BLAH.xml”， “文件路径”：“ /FOO/repo/BLAH.xml“ }， ”012009b6-26e9-4bc1-9050-2a4ac9546c7e“：{ ”name“：”Check System.xml“， ”filePath“：”/ FOO/repo/Check的System.Xml” }} } org.codehaus.jackson.map.JsonMappingException：无法将com.hp.oo.studio.shared.UUIDRegistry.UUIDMap的实例反序列化为START_ARRAY令牌 – user1078261

解决方法错误，因为Map的声明应该是Map ，而不是无类型的地图。如果添加泛型类型，实际上可能会起作用。 – StaxMan

以及我的UUIDMap封装器将地图声明为Map cache; – user1078261

我认为这个问题是一个在Jackson polymorphic deserialization Wiki页面下5.5上市。基本上它是序列化时Java类型的擦除咬你;并且当反序列化类型明确可用时;而且这种差异很大。

来源

2011-12-02 22:14:02 StaxMan

我，因为添加了@JsonTypeInfo到我的POJO和那些获得书面出去JSON，但它仍然无法正常工作。:( org.codehaus.jackson.map.JsonMappingException：意外标记（START_ARRAY），预计START_OBJECT：需要JSON对象来包含As.PROPERTY类型信息（对于com.hp.oo.studio.shared.UUIDRegistry.UUIDMap类） – user1078261

这里的神秘之处在于，目前的JSON在任何地方都没有START_ARRAY标记（“[”），所以我很难相信JSON被用于反序列化。Btw，这是哪个Jackson版本？ – StaxMan

原始问题中的JSON使用Jackson 1.9.2对我进行反序列化很好。

import java.io.File; 
import java.util.HashMap; 
import java.util.Map; 

import org.codehaus.jackson.annotate.JsonAutoDetect.Visibility; 
import org.codehaus.jackson.annotate.JsonMethod; 
import org.codehaus.jackson.map.ObjectMapper; 
import org.codehaus.jackson.type.TypeReference; 

public class JacksonFoo 
{ 
    public static void main(String[] args) throws Exception 
    { 
    ObjectMapper mapper = new ObjectMapper().setVisibility(JsonMethod.FIELD, Visibility.ANY); 
    Map<String, UUIDInfo> cache = 
     mapper.readValue(new File("input.json"), new TypeReference<HashMap<String, UUIDInfo>>() {}); 
    System.out.println(cache); 
    // output: 
    // {0f861a9a-0a3e-40a7-8ff3-0b83d8070876=UUIDInfo: name=BAR.xml, filePath=/FOO/repo/BAR.xml, 
    // f3cbb32e-b7b8-4af1-b48b-7ea393de7971=UUIDInfo: name=BLAH.xml, filePath=/FOO/repo/BLAH.xml, 
    // 012009b6-26e9-4bc1-9050-2a4ac9546c7e=UUIDInfo: name=Check System.xml, filePath=/FOO/repo/Check System.xml} 
    } 
} 

class UUIDInfo 
{ 
    String name; 
    String filePath; 

    @Override 
    public String toString() 
    { 
    return String.format("UUIDInfo: name=%s, filePath=%s", name, filePath); 
    } 
}

来源

2011-12-06 04:23:02

做这样的：

ArrayList<LinkedHashMap<?, ?>> companymap = mapper.readValue(jsonCompany, ArrayList.class);

来源

2013-03-29 11:10:34 Avinash

我建议也要避免把实现类：列表> companymap = mapper.readValue（jsonCompany，List.class）; –

A. Masson：如果我避免这个问题，那么问题就不会解决。没有其他答案正在处理这个..我已经测试过它和它的工作得很好。 – Avinash

public class ArrayMapDeserializer extends JsonDeserializer<Map<String, UUIDInfo>> { 

    @Override 
    public Map<String, UUIDInfo> deserialize(JsonParser jp, DeserializationContext context) 
      throws IOException { 
     ObjectMapper mapper = (ObjectMapper) jp.getCodec(); 
     if (jp.getCurrentToken().equals(JsonToken.START_OBJECT)) { 
      return mapper.readValue(jp, new TypeReference<HashMap<String, UUIDInfo>>() { 
      }); 
     } else { 
      //consume this stream 
      mapper.readTree(jp); 
      return new HashMap<String, UUIDInfo>(); 
     } 
    } 
}

类声明

@JsonDeserialize(using = ArrayMapDeserializer.class) 
private HashMap<String, UUIDInfo> aliases = new HashMap<String, UUIDInfo>();

我使用杰克逊2.4.2。

希望它能帮助你。

来源

2014-09-05 09:16:29 Jason

伟大的解决方案！非常感谢你！ –

杰克逊：地图反序列化

回答

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