調用Servlet方法時出現錯誤“ java.io.IOException：服務器返回了HTTP響應代碼：406”

Question

我正在處理客戶端服務器應用程序。 當從Servlet請求方法以獲取具有選定名稱的對象時，出現錯誤：“ java.io.IOException：服務器返回了HTTP響應代碼：406”。 在服務器端，我的DataController中包含以下代碼：

 @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;
        }
    }

我在其中調用方法getHarnessType的客戶端源代碼的一部分：

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);

在執行最后一行之后，我已經提到了錯誤...有趣的是，當我將方法getHarnessType的返回類型更改為String時，例如：

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

並僅將String值傳遞給客戶端（而不是整個對象），一切正常

全棧跟蹤：

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

似乎返回的對象HarnessType無法正確解析。 我不確定您是否使用了正確的注釋驅動程序配置。

您可以按照以下步驟修改代碼，以查看其是否有效：

@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

問題似乎與客戶端有關，請嘗試添加accept標頭，我想您未使用瀏覽器。 如果Web服務器檢測到其要返回的數據對於客戶端不可接受，則它將返回包含406錯誤代碼的標頭。 如果問題仍未解決，請添加堆棧跟蹤。

Answer 3

嘗試設置urlConn .setRequestProperty("Content-Type", "application/json"); 錯誤406表示您的客戶端請求有問題。 它不能接受響應。 看這里