capacityexam.java

Java程序设计实用教程源代码 本书源代码按章分别放置在不同的文件夹中,所有程序均在JDK1.6环境下编译运行正常,除了第13章需要建立ODBC数据源之外,其他程序只要有Java运行环境即可直接运行

import javax.swing.*; 
public class capacityExam {
  public static void main(String args[]) {
    StringBuffer sb = new StringBuffer("I love my motherland");
    String output = "buffer = " + sb.toString() +
        "\nlength = " + sb.length() + "\ncapacity = " + sb.capacity();
    sb.ensureCapacity(78);
    output += "\nNew capacity = " + sb.capacity();
    sb.setLength(10); //将sb对象的长度设置为10，即保留前10个字符
    output += "\nNew length = " + sb.length() +
        "\nbuf = " + sb.toString();
    JOptionPane.showMessageDialog(null, output,
                                  "StringBuffer length and capacity Methods",
                                  JOptionPane.INFORMATION_MESSAGE);
    System.exit(0);
  }
}