Question

我一直在尝试将一些对象序列化为System.out（用于调试）。我一打电话

final JsonSerializer serializer = new JsonSerializer();
serializer.serialize( System.out, myObj );
System.out.println("done");

它打印出json，但“完成”永远不会被打印出来。调试这些行，清楚地表明第3行被执行，但输出从不显示。

这是杰克森的错误，还是我做错了什么？

编辑：

public class JsonSerializer
{

private ObjectMapper getConfiguredObjectMapper()
{
  final ObjectMapper mapper = new ObjectMapper();
  mapper.enable( SerializationConfig.Feature.INDENT_OUTPUT );
  mapper.setVisibility( JsonMethod.FIELD, Visibility.ANY );
  mapper.setVisibility( JsonMethod.GETTER, Visibility.NONE );
  mapper.configure( SerializationConfig.Feature.AUTO_DETECT_GETTERS, false );
  mapper.configure( SerializationConfig.Feature.AUTO_DETECT_IS_GETTERS, false );
  mapper.configure( SerializationConfig.Feature.AUTO_DETECT_FIELDS, false );



  final SimpleModule module = new SimpleModule( "ConnectorSerialization", new Version( 0, 1, 0, null ) );
  module.addSerializer( new InputConnectorSerializer() );
  module.addSerializer( new OutputConnectorSerializer() );
  module.addSerializer( new StateSerializer() );
  mapper.registerModule( module );

  return mapper;
  }


public void serialize( final OutputStream outputStream, final Object root )
{


  final ObjectMapper mapper = getConfiguredObjectMapper();


  try
  {
     mapper.writeValue( outputStream, root );

  }
  catch (final JsonGenerationException e)
  {
     // TODO Auto-generated catch block
     e.printStackTrace();
  }
  catch (final JsonMappingException e)
  {
     // TODO Auto-generated catch block
     e.printStackTrace();
  }
  catch (final IOException e)
  {
     // TODO Auto-generated catch block
     e.printStackTrace();
  }

}
}

Answer 1

由于其他用户的所有答案都已删除，我将回答我自己的问题。感谢用户声明这是jackson自动关闭输入流的问题。

解决方案是将JsonGenerator.Feature.AUTO_CLOSE_TARGET添加到配置中，并将其设置为false：

mapper.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);

Answer 2

如果不想将Mapson的JsonGenerator.Feature.AUTO_CLOSE_TARGET标志设置为false，则可以通过以下方式包装System.out以防止其被映射器关闭。

public <T> void println(T t) throws IOException {
    objectMapper.writeValue(new OutputStream() {
        @Override
        public void write(int i) throws IOException {
            System.out.write(i);
        }
    }, t);
    System.out.println();
}

在Jackson序列化之后，System.out搞砸了

2 个答案: