算法Sedgewick第四版-第1章基础-006一封装输出(文件)

1.

 package algorithms.util;

 /******************************************************************************
  *  Compilation:  javac Out.java
  *  Execution:    java Out
  *  Dependencies: none
  *
  *  Writes data of various types to: stdout, file, or socket.
  *
  ******************************************************************************/

 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.net.Socket;
 import java.util.Locale;

 /**
  *  This class provides methods for writing strings and numbers to
  *  various output streams, including standard output, file, and sockets.
  *  <p>
  *  For additional documentation, see
  *  <a href="http://introcs.cs.princeton.edu/31datatype">Section 3.1</a> of
  *  <i>Introduction to Programming in Java: An Interdisciplinary Approach</i>
  *  by Robert Sedgewick and Kevin Wayne.
  *
  *  @author Robert Sedgewick
  *  @author Kevin Wayne
  */
 public class Out {

     // force Unicode UTF-8 encoding; otherwise it's system dependent
     private static final String CHARSET_NAME = "UTF-8";

     // assume language = English, country = US for consistency with In
     private static final Locale LOCALE = Locale.US;

     private PrintWriter out;

    /**
      * Initializes an output stream from a {@link OutputStream}.
      *
      * @param  os the <tt>OutputStream</tt>
      */
     public Out(OutputStream os) {
         try {
             OutputStreamWriter osw = new OutputStreamWriter(os, CHARSET_NAME);
             out = new PrintWriter(osw, true);
         }
         catch (IOException e) {
             e.printStackTrace();
         }
     }

    /**
      * Initializes an output stream from standard output.
      */
     public Out() {
         this(System.out);
     }

    /**
      * Initializes an output stream from a socket.
      *
      * @param  socket the socket
      */
     public Out(Socket socket) {
         try {
             OutputStream os = socket.getOutputStream();
             OutputStreamWriter osw = new OutputStreamWriter(os, CHARSET_NAME);
             out = new PrintWriter(osw, true);
         }
         catch (IOException e) {
             e.printStackTrace();
         }
     }

    /**
      * Initializes an output stream from a file.
      *
      * @param  filename the name of the file
      */
     public Out(String filename) {
         try {
             OutputStream os = new FileOutputStream(filename);
             OutputStreamWriter osw = new OutputStreamWriter(os, CHARSET_NAME);
             out = new PrintWriter(osw, true);
         }
         catch (IOException e) {
             e.printStackTrace();
         }
     }

    /**
      * Closes the output stream.
      */
     public void close() {
         out.close();
     }

    /**
      * Terminates the current line by printing the line-separator string.
      */
     public void println() {
         out.println();
     }

    /**
      * Prints an object to this output stream and then terminates the line.
      *
      * @param x the object to print
      */
     public void println(Object x) {
         out.println(x);
     }

    /**
      * Prints a boolean to this output stream and then terminates the line.
      *
      * @param x the boolean to print
      */
     public void println(boolean x) {
         out.println(x);
     }

    /**
      * Prints a character to this output stream and then terminates the line.
      *
      * @param x the character to print
      */
     public void println(char x) {
         out.println(x);
     }

    /**
      * Prints a double to this output stream and then terminates the line.
      *
      * @param x the double to print
      */
     public void println(double x) {
         out.println(x);
     }

    /**
      * Prints a float to this output stream and then terminates the line.
      *
      * @param x the float to print
      */
     public void println(float x) {
         out.println(x);
     }

    /**
      * Prints an integer to this output stream and then terminates the line.
      *
      * @param x the integer to print
      */
     public void println(int x) {
         out.println(x);
     }

    /**
      * Prints a long to this output stream and then terminates the line.
      *
      * @param x the long to print
      */
     public void println(long x) {
         out.println(x);
     }

    /**
      * Prints a byte to this output stream and then terminates the line.
      * <p>
      * To write binary data, see {@link BinaryOut}.
      *
      * @param x the byte to print
      */
     public void println(byte x) {
         out.println(x);
     }

    /**
      * Flushes this output stream.
      */
     public void print() {
         out.flush();
     }

    /**
      * Prints an object to this output stream and flushes this output stream.
      *
      * @param x the object to print
      */
     public void print(Object x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a boolean to this output stream and flushes this output stream.
      *
      * @param x the boolean to print
      */
     public void print(boolean x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a character to this output stream and flushes this output stream.
      *
      * @param x the character to print
      */
     public void print(char x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a double to this output stream and flushes this output stream.
      *
      * @param x the double to print
      */
     public void print(double x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a float to this output stream and flushes this output stream.
      *
      * @param x the float to print
      */
     public void print(float x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints an integer to this output stream and flushes this output stream.
      *
      * @param x the integer to print
      */
     public void print(int x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a long integer to this output stream and flushes this output stream.
      *
      * @param x the long integer to print
      */
     public void print(long x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a byte to this output stream and flushes this output stream.
      *
      * @param x the byte to print
      */
     public void print(byte x) {
         out.print(x);
         out.flush();
     }

    /**
      * Prints a formatted string to this output stream, using the specified format
      * string and arguments, and then flushes this output stream.
      *
      * @param format the format string
      * @param args   the arguments accompanying the format string
      */
     public void printf(String format, Object... args) {
         out.printf(LOCALE, format, args);
         out.flush();
     }

    /**
      * Prints a formatted string to this output stream, using the specified
      * locale, format string, and arguments, and then flushes this output stream.
      *
      * @param locale the locale
      * @param format the format string
      * @param args   the arguments accompanying the format string
      */
     public void printf(Locale locale, String format, Object... args) {
         out.printf(locale, format, args);
         out.flush();
     }

    /**
      * A test client.
      */
     public static void main(String[] args) {
         Out out;

         // write to stdout
         out = new Out();
         out.println("Test 1");
         out.close();

         // write to a file
         out = new Out("test.txt");
         out.println("Test 2");
         out.close();
     }

 }