Jackson: deserialization của Bản đồ

Question

Tôi đang sử dụng Jackson để deserialize một tập tin json (mà tôi serialized với jackson). Các json là một HashMap đơn giản, nhưng người vẽ bản đồ là phàn nàn khi tôi cố gắng và deserialize.

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

serialized chuỗi HashMap My .....

{ 
"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" 
} 
} 

Tôi đã thử 2 cách khác nhau để làm cho công việc này, và cả thất bại ...

//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)); 

Các đầy đủ stacktrace

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) 

Answer 1

Đưa bản đồ của bạn vào một đối tượng khác và sau đó là nguyên soái. ví dụ:

class MyObject{ 

    private Map<String,UUIDInfo> map; 

} 

Và chỉ cần làm: mappper.readValue(myInstance, MyObject.class)

Answer 2

Tôi nghĩ vấn đề là một trong những liệt kê dưới 5,5 trên Jackson polymorphic deserialization trang Wiki. Về cơ bản đó là Java Type Erasure cắn bạn khi tuần tự hóa; và khi loại deserializing được tạo sẵn một cách rõ ràng; và sự khác biệt đó đau.

Answer 3

JSON trong câu hỏi ban đầu deserializes tốt cho tôi bằng cách sử dụng Jackson 1.9.2.

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); 
    } 
} 

Answer 4

Làm điều đó như thế này:

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

Answer 5

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>(); 
     } 
    } 
} 

trong lớp tuyên bố

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

Tôi đang sử dụng Jackson 2.4.2.

Hy vọng nó có thể giúp bạn.