String和StringBuffer

import java.sql.Time;

public class Javatest72 {
    /**
     * String和StringBuffer性能对比
     * 练习1：写代码测试字符串拼接的性能，比如拼接10万次
     * 输出结果：
     * String拼接时间：14863.0
     * StringBuffer拼接时间：0.0
     */
    public static void main(String[] args) {
        String s = "abc";
        String s2 = "";
        double start = System.currentTimeMillis();
        for (int i = 0; i < 100000; i++) {
            s2 += s;
        }
        double end = System.currentTimeMillis();
        System.out.println("String拼接时间：" + (end - start));
        StringBuffer s1 = new StringBuffer("abc");
        StringBuilder s3 = new StringBuilder("");
        double start1 = System.currentTimeMillis();
        for (int i = 0; i < 100000; i++) {
            s3.append(s1);
        }
        double end1 = System.currentTimeMillis();
        System.out.println("StringBuffer拼接时间：" + (end1 - start1));
    }

}