multipartrequest.java

来自「很好的文件处理程序」· Java 代码 · 共 490 行 · 第 1/2 页

    while ((part = parser.readNextPart()) != null) {
      String name = part.getName();
      if (part.isParam()) {
        // It's a parameter part, add it to the vector of values
        ParamPart paramPart = (ParamPart) part;
        String value = paramPart.getStringValue();
        Vector existingValues = (Vector)parameters.get(name);
        if (existingValues == null) {
          existingValues = new Vector();
          parameters.put(name, existingValues);
        }
        existingValues.addElement(value);
      }
      else if (part.isFile()) {
        // It's a file part
        FilePart filePart = (FilePart) part;
        String fileName = filePart.getFileName();
        if (fileName != null) {
          filePart.setRenamePolicy(policy);  // null policy is OK
          // The part actually contained a file
          filePart.writeTo(dir);
          files.put(name, new UploadedFile(dir.toString(),
                                           filePart.getFileName(),
                                           fileName,
                                           filePart.getContentType()));
        }
        else { 
          // The field did not contain a file
          files.put(name, new UploadedFile(null, null, null, null));
        }
      }
    }
  }

  /**
   * Constructor with an old signature, kept for backward compatibility.
   * Without this constructor, a servlet compiled against a previous version 
   * of this class (pre 1.4) would have to be recompiled to link with this 
   * version.  This constructor supports the linking via the old signature.
   * Callers must simply be careful to pass in an HttpServletRequest.
   * 
   */
  public MultipartRequest(ServletRequest request,
                          String saveDirectory) throws IOException {
    this((HttpServletRequest)request, saveDirectory);
  }

  /**
   * Constructor with an old signature, kept for backward compatibility.
   * Without this constructor, a servlet compiled against a previous version 
   * of this class (pre 1.4) would have to be recompiled to link with this 
   * version.  This constructor supports the linking via the old signature.
   * Callers must simply be careful to pass in an HttpServletRequest.
   * 
   */
  public MultipartRequest(ServletRequest request,
                          String saveDirectory,
                          int maxPostSize) throws IOException {
    this((HttpServletRequest)request, saveDirectory, maxPostSize);
  }

  /**
   * Returns the names of all the parameters as an Enumeration of 
   * Strings.  It returns an empty Enumeration if there are no parameters.
   *
   * @return the names of all the parameters as an Enumeration of Strings.
   */
  public Enumeration getParameterNames() {
    return parameters.keys();
  }

  /**
   * Returns the names of all the uploaded files as an Enumeration of 
   * Strings.  It returns an empty Enumeration if there are no uploaded 
   * files.  Each file name is the name specified by the form, not by 
   * the user.
   *
   * @return the names of all the uploaded files as an Enumeration of Strings.
   */
  public Enumeration getFileNames() {
    return files.keys();
  }

  /**
   * Returns the value of the named parameter as a String, or null if 
   * the parameter was not sent or was sent without a value.  The value 
   * is guaranteed to be in its normal, decoded form.  If the parameter 
   * has multiple values, only the last one is returned (for backward 
   * compatibility).  For parameters with multiple values, it's possible
   * the last "value" may be null.
   *
   * @param name the parameter name.
   * @return the parameter value.
   */
  public String getParameter(String name) {
    try {
      Vector values = (Vector)parameters.get(name);
      if (values == null || values.size() == 0) {
        return null;
      }
      String value = (String)values.elementAt(values.size() - 1);
      return value;
    }
    catch (Exception e) {
      return null;
    }
  }

  /**
   * Returns the values of the named parameter as a String array, or null if 
   * the parameter was not sent.  The array has one entry for each parameter 
   * field sent.  If any field was sent without a value that entry is stored 
   * in the array as a null.  The values are guaranteed to be in their 
   * normal, decoded form.  A single value is returned as a one-element array.
   *
   * @param name the parameter name.
   * @return the parameter values.
   */
  public String[] getParameterValues(String name) {
    try {
      Vector values = (Vector)parameters.get(name);
      if (values == null || values.size() == 0) {
        return null;
      }
      String[] valuesArray = new String[values.size()];
      values.copyInto(valuesArray);
      return valuesArray;
    }
    catch (Exception e) {
      return null;
    }
  }

  /**
   * Returns the filesystem name of the specified file, or null if the 
   * file was not included in the upload.  A filesystem name is the name 
   * specified by the user.  It is also the name under which the file is 
   * actually saved.
   *
   * @param name the file name.
   * @return the filesystem name of the file.
   */
  public String getFilesystemName(String name) {
    try {
      UploadedFile file = (UploadedFile)files.get(name);
      return file.getFilesystemName();  // may be null
    }
    catch (Exception e) {
      return null;
    }
  }

  /**
   * Returns the original filesystem name of the specified file (before any
   * renaming policy was applied), or null if the file was not included in 
   * the upload.  A filesystem name is the name specified by the user.
   *
   * @param name the file name.
   * @return the original file name of the file.
   */
  public String getOriginalFileName(String name) {
    try {
      UploadedFile file = (UploadedFile)files.get(name);
      return file.getOriginalFileName();  // may be null
    }
    catch (Exception e) {
      return null;
    }
  }

  /**
   * Returns the content type of the specified file (as supplied by the 
   * client browser), or null if the file was not included in the upload.
   *
   * @param name the file name.
   * @return the content type of the file.
   */
  public String getContentType(String name) {
    try {
      UploadedFile file = (UploadedFile)files.get(name);
      return file.getContentType();  // may be null
    }
    catch (Exception e) {
      return null;
    }
  }

  /**
   * Returns a File object for the specified file saved on the server's 
   * filesystem, or null if the file was not included in the upload.
   *
   * @param name the file name.
   * @return a File object for the named file.
   */
  public File getFile(String name) {
    try {
      UploadedFile file = (UploadedFile)files.get(name);
      return file.getFile();  // may be null
    }
    catch (Exception e) {
      return null;
    }
  }
}


// A class to hold information about an uploaded file.
//
class UploadedFile {

  private String dir;
  private String filename;
  private String original;
  private String type;

  UploadedFile(String dir, String filename, String original, String type) {
    this.dir = dir;
    this.filename = filename;
    this.original = original;
    this.type = type;
  }

  public String getContentType() {
    return type;
  }

  public String getFilesystemName() {
    return filename;
  }

  public String getOriginalFileName() {
    return original;
  }

  public File getFile() {
    if (dir == null || filename == null) {
      return null;
    }
    else {
      return new File(dir + File.separator + filename);
    }
  }
}