String 与StringBuffer比较

package String比较;

/*

 * String 与StringBuffer比较

 * String 不可变,一旦赋值，就不能被修改

 * StringBuffer可变的字符串。

 * StringBuffer的追加效率更高

 */

public class Test8 {

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        String str = "abc";

        str.replace("a", "b");

        System.out.println(str);// abc

        StringBuffer sbf = new StringBuffer("abc");

        sbf.replace(0, 1, "de");

        System.out.println(sbf);// debc

        String s1 = "chinasofti";

        int time = 10000;

        @SuppressWarnings("unused")

        String tempstr = "";

        long start1 = System.currentTimeMillis();

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

            tempstr += s1;

        }

        long end1 = System.currentTimeMillis();

        System.out.println("String：" + (end1 - start1) + "ms");// 876ms

        StringBuffer tempsbf = new StringBuffer();

        long start2 = System.currentTimeMillis();

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

            tempsbf.append(s1);

        }

        long end2 = System.currentTimeMillis();

        System.out.println("StringBuffer:" + (end2 - start2) + "ms");// 1ms

    }

}