本文介紹了杰克遜:地圖的反序列化的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我正在使用 Jackson 反序列化一個 json 文件(我用 jackson 序列化了該文件).json 是一個簡單的 HashMap，但是當我嘗試反序列化時映射器會抱怨.
I'm using Jackson to deserialize a json file (that I serialized with jackson). The json is a simple HashMap, but the mapper is complaining when I try and deserialize.
org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.HashMap out of START_ARRAY token
我的序列化 HashMap 字符串.....
My serialized HashMap string.....
{
"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"
}
}
我嘗試了兩種不同的方法來完成這項工作，但都失敗了......
I've tried 2 different ways to make this work, and both fail...
//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));
完整的堆棧跟蹤
org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.LinkedHashMap out of START_ARRAY token
at [Source: java.io.StringReader@32b9bd47; 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)
推薦答案
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>();
}
}
}
在類中聲明
@JsonDeserialize(using = ArrayMapDeserializer.class)
private HashMap<String, UUIDInfo> aliases = new HashMap<String, UUIDInfo>();
我正在使用 Jackson 2.4.2.
I am using Jackson 2.4.2.
希望對你有幫助.
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