[转]利用HttpServletResponseWrapper获取jsp输出内容

时间  2019-12-06 标签 转 利用 httpservletresponsewrapper 获取 jsp 输出 内容
转载: bianbian coding life。


有时候咱们须要获得某个jsp的输出内容。好比说在servlet里处理了Module Controller后，须要不一样的jsp页面来展现view；又或者获得不一样的模板内容（jsp自己能够做为模板语言）并将其缓冲到内存里。
利用 javax.servlet.http.HttpServletResponseWrapper 能够很好地实现咱们所须要的功能。下面是使用方法：java

  1. ....
  2. public static String getJspOutput(String jsppath, HttpServletRequest request, HttpServletResponse response)
  3. throws Exception
  4. {
  5. WrapperResponse wrapperResponse = new WrapperResponse(response);
  6. request.getRequestDispatcher(jsppath).include(request, wrapperResponse);
  7. return wrapperResponse.getContent();
  8. }

能够看到，使用起来仍是挺方便的。getJspOutput(”/view/header.jsp”, request, response) 就完成了对”/view/header.jsp”的输出内容获取，以后能够进行其余操做。
附WrapperResponse类代码：app

  1. import java.io.ByteArrayOutputStream;
  2. import java.io.IOException;
  3. import java.io.PrintWriter;
  4. import java.io.UnsupportedEncodingException;
  6. import javax.servlet.ServletOutputStream;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpServletResponseWrapper
  9. /**
  10. * @see http://bianbian.sunshow.net/
  11. * @author dannyzhu, bianbian
  12. * @version 1.0
  13. */
  14. public class WrapperResponse extends HttpServletResponseWrapper
  15. {
  16. private PrintWriter tmpWriter;
  17. private ByteArrayOutputStream output;
  18. private ByteArrayServletOutputStream servletOutput;
  20. public WrapperResponse(HttpServletResponse httpServletResponse)
  21. {
  22. super(httpServletResponse);
  23. output = new ByteArrayOutputStream();
  24. tmpWriter = new PrintWriter(output);
  25. servletOutput = new ByteArrayServletOutputStream(output);
  26. }
  28. public void finalize() throws Throwable
  29. {
  30. super.finalize();
  31. servletOutput.close();
  32. output.close();
  33. tmpWriter.close();
  34. }
  36. public String getContent()
  37. {
  38. try{
  39. String s = output.toString("UTF-8");
  40. reset();
  41. return s;
  42. } catch(UnsupportedEncodingException e) {
  43. return "UnsupportedEncoding";
  44. }
  45. }
  47. public PrintWriter getWriter() throws IOException
  48. {
  49. // return servletResponse.getWriter();
  50. return tmpWriter;
  51. }
  53. public ServletOutputStream getOutputStream() throws IOException
  54. {
  55. return servletOutput;
  56. }
  58. public byte[] toByteArray()
  59. {
  60. return output.toByteArray();
  61. }
  63. public void flushBuffer() throws IOException
  64. {
  65. tmpWriter.flush();
  66. servletOutput.flush();
  67. }
  69. public void reset()
  70. {
  71. output.reset();
  72. }
  74. public void close() throws IOException
  75. {
  76. tmpWriter.close();
  77. }
  79. private static class ByteArrayServletOutputStream extends ServletOutputStream
  80. {
  82. ByteArrayOutputStream baos;
  84. public ByteArrayServletOutputStream(ByteArrayOutputStream baos)
  85. {
  86. this.baos = baos;
  87. }
  89. public void write(int i) throws IOException
  90. {
  91. baos.write(i);
  92. }
  94. }
  95. }

转载:bianbian coding life。jsp

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