fileproperties.java

利用java发EMAIL的代码.里面有详细注释

package SendMail;
import java.io.*;
import java.util.*;

/**
 * The <CODE>FileProperties</CODE> class extends <CODE>Properties</CODE>,
 * "a persistent set of properties [that] can be saved to a stream
 * or loaded from a stream". This subclass attends to all the mundane
 * details of opening the Stream(s) for actually saving and loading
 * the Properties.
 *
 * <P>This subclass preserves the useful feature that
 * a property list can contain another property list as its
 * "defaults"; this second property list is searched if
 * the property key is not found in the original property list.
 *
 * @author Ian F. Darwin, [e-mail]
 * @version $Id: FileProperties.java,v 1.5 2001/04/28 13:22:37 ian Exp $
 */
public class FileProperties
    extends Properties {
  protected String fileName = null;

  /**
   *  Construct a FileProperties given a fileName.
   *  @param loadsaveFileName the progerties file name
   *  @throws IOException
   */
  public FileProperties(String loadsaveFileName) throws IOException {
    super();
    fileName = loadsaveFileName;
    load();
  }

  /** Construct a FileProperties given a fileName and
   * a list of default properties.
   * @param loadsaveFileName the properties file name
   * @param defProp the default properties
   * @throws IOException
   */
  public FileProperties(String loadsaveFileName, Properties defProp) throws
      IOException {
    super(defProp);
    fileName = loadsaveFileName;
    load();
  }

  /** The InputStream for loading */
  protected InputStream inStr = null;

  /** The OutputStream for loading */
  protected OutputStream outStr = null;

  /** Load the properties from the saved filename.
   * If that fails, try again, tacking on the .properties extension
   * @throws IOException
   */
  public void load() throws IOException {
    try {
      if (inStr == null) {
        inStr = new FileInputStream(fileName);
      }
    }
    catch (FileNotFoundException fnf) {
      if (!fileName.endsWith(".properties")) {
        inStr = new FileInputStream(fileName + ".properties");
        // If we succeeded, remember it:
        fileName += ".properties";
      }
      else {

        // It did end with .properties and failed, re-throw exception.
        throw fnf;
      }
    }
    // now message the superclass code to load the file.
    load(inStr);
  }

  /** Save the properties for later loading. *
   *  @throws IOException
   */

  public void save() throws IOException {
    if (outStr == null) {
      outStr = new FileOutputStream(fileName);
    }
    // Get the superclass to do most of the work for us.
    store(outStr, "# Written by FileProperties.save() at " + new Date());
  }

  public void close() {
    try {
      if (inStr != null) {
        inStr.close();
      }
      if (outStr != null) {
        outStr.close();
      }
    }
    catch (IOException e) {
      // don't care
    }
  }
}
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