e4_20.java

来自「java 初学者学习实例」· Java 代码 · 共 53 行

// Fig. 11.12: StringBufferChars.java
// StringBuffer methods charAt, setCharAt, getChars and reverse.
import javax.swing.*;
//StringBufferChars
public class E4_20 {

   public static void main( String args[] )
   {
      StringBuffer buffer = new StringBuffer( "hello there" );

      String output = "buffer = " + buffer.toString() +
         "\nCharacter at 0: " + buffer.charAt( 0 ) +
         "\nCharacter at 4: " + buffer.charAt( 4 );

      char charArray[] = new char[ buffer.length() ];
      buffer.getChars( 0, buffer.length(), charArray, 0 );
      output += "\n\nThe characters are: ";

      for ( int count = 0; count < charArray.length; ++count )
         output += charArray[ count ];

      buffer.setCharAt( 0, 'H' );
      buffer.setCharAt( 6, 'T' );
      output += "\n\nbuf = " + buffer.toString();

      buffer.reverse();
      output += "\n\nbuf = " + buffer.toString();

      JOptionPane.showMessageDialog( null, output,
         "StringBuffer character methods", 
         JOptionPane.INFORMATION_MESSAGE );

      System.exit( 0 );
   }

} // end class StringBufferChars


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