String,StringBuffer,StringBuider测试实例(转)

public class ttssb {


  /**
   * Creates a new instance of testssb
   */

  final static int ttime = 3000000;// 测试循环次数

  public ttssb() {

  }


  public void test(String s) {


    long begin = System.currentTimeMillis();

    for (int i = 0; i < ttime; i++) {

      s += "add";

    }

    long over = System.currentTimeMillis();

    System.out.println(" 操作 " + s.getClass().getName() + " 类型使用的时间为： "

      + (over - begin) + " 毫秒 ");

  }

  public void test(StringBuffer s) {

    long begin = System.currentTimeMillis();

    for (int i = 0; i < ttime; i++) {

      s.append("add");

    }

    long over = System.currentTimeMillis();

    System.out.println(" 操作 " + s.getClass().getName() + " 类型使用的时间为： "

      + (over - begin) + " 毫秒 ");

  }

  public void test(StringBuilder s) {

    long begin = System.currentTimeMillis();

    for (int i = 0; i < ttime; i++) {

      s.append("add");

    }

    long over = System.currentTimeMillis();

    System.out.println(" 操作 " + s.getClass().getName() + " 类型使用的时间为： "

      + (over - begin) + " 毫秒 ");

  }

  // 对 String 直接进行字符串拼接的测试

  public void test2() {

    String s2 = "abadf";

    long begin = System.currentTimeMillis();

    for (int i = 0; i < ttime; i++) {

      String s = s2 + s2 + s2;

    }

    long over = System.currentTimeMillis();

    System.out.println(" 操作字符串对象引用相加类型使用的时间为： "

      + (over - begin) + " 毫秒 ");

  }

  public void test3() {

    long begin = System.currentTimeMillis();

    for (int i = 0; i < ttime; i++) {

      String s = "abadf" + "abadf" + "abadf";

    }

    long over = System.currentTimeMillis();

    System.out.println(" 操作字符串相加使用的时间为： "

      + (over - begin) + " 毫秒 ");

  }


  public static void main(String[] args) {

    String s1 = "abc";

    StringBuffer sb1 = new StringBuffer("abc");

    StringBuilder sb2 = new StringBuilder("abc");

    ttssb t = new ttssb();

//    t.test(s1);

    t.test(sb1);

    t.test(sb2);

//    t.test2();

//    t.test3();

  }

}