package String比较;

/*

 * StringBuffer与StringBuilder有什么区别

 * StringBuilder是JDK5增加的一个新类，功能几乎与StringBuffer相同。区别在于StringBuffer是线程安全的，

 * 多个线程同时操作StringBuffer时，能保证同步，而Stringbuilder是线程非安全的。如果只在单线程环境下使用，StringBuilder

 * 的效率会更高

 */

public class Test9 {

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        String strtemp = "watch_free";

        int time = 12000;

        @SuppressWarnings("unused")

        String str = "";

        long start1 = System.currentTimeMillis();

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

            str+=strtemp;

        }

        long end1 = System.currentTimeMillis();

        System.out.println("String:"+(end1-start1)+"ms");//1218ms

        StringBuffer sbf = new StringBuffer();

        long start2 = System.currentTimeMillis();

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

            sbf.append(strtemp);

        }

        long end2 = System.currentTimeMillis();

        System.out.println("StringBuffer:"+(end2-start2)+"ms");//2ms

         StringBuilder sbd = new StringBuilder();

         long start3 = System.currentTimeMillis();

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

             sbd.append(strtemp);

         }

         long end3 = System.currentTimeMillis();

         System.out.println("StringBuilder:"+(end3-start3)+"ms");//1ms

    }

}