调用Servlet方法时出现错误“ java.io.IOException：服务器返回了HTTP响应代码：406”

Question

I am working on client-server application. I am getting error: "java.io.IOException: Server returned HTTP response code: 406" when requesting method from servlet, to get object with selected name. On my server side I got following code in my DataController:

 @Controller
    public class DataController {

         @RequestMapping(value = "/getHarnessType")
         @ResponseBody
         public HarnessType getHarnessType(
               @RequestParam("harnessTypeName") String harnessTypeName) {
             GeneratorService generatorService=new GeneratorServiceImpl();
             HarnessType harnessType=generatorService.getHarnessType(harnessTypeName);
             return harnessType;
        }
    }

part of source code of my client where I am calling method getHarnessType:

String harnessTypeName=jTextField.getText();
url = new URL("http://localhost:8080/getHarnessType?harnessTypeName="+harnessTypeName);
urlConn = (HttpURLConnection) url.openConnection();
OutputStream baos = new ByteArrayOutputStream();                
IOUtils.copy(urlConn.getInputStream(), baos);

after proceeding last line I am getting already mentioned error... interesting is, that when i change return type of method getHarnessType to String like:

...
public String getHarnessType(
...
return harnessType.getName();

and pass only String value to client (not whole object), everything works fine

full stack trace:

java.io.IOException: Server returned HTTP response code: 406 for URL: http: //localhost:8080/getHarnessType?harnessTypeName=7
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1245)
at formular.Formular2.actionPerformed(Formular2.java:100)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6038)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
at java.awt.Component.processEvent(Component.java:5803)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4410)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2429)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

Answer 1

It seems like the returned object HarnessType cannot be parsed correctly. I am not sure if you are using the right configuration of annotation driver.

You can modify your code as following first to see if it works:

@Controller
public class DataController {

     @RequestMapping(value = "/getHarnessType", method = RequestMethod.GET)
     public @ResponseBody HarnessType getHarnessType(
           @RequestParam("harnessTypeName") String harnessTypeName) {
         GeneratorService generatorService=new GeneratorServiceImpl();
         HarnessType harnessType=generatorService.getHarnessType(harnessTypeName);
         return harnessType;
    }
}

Answer 2

Problem seems to be with the client, try adding accept headers, I guess you are not using browser. If the Web server detects that the data it wants to return is not acceptable to the client, it returns a header containing the 406 error code. If the problem is still not solved, please add the stack trace.

Answer 3

try setting urlConn .setRequestProperty("Content-Type", "application/json"); Error 406 means something wrong in your client side request. It is not capable of accepting the response. See here