string，stringbuffer，stringbuilder

string，stringbuffer，stringbuilder 效率。stringbuilder > stringbuffer > string

测试用例代码如下。

package cui.yao.nan.optional;

import java.util.Random;

/**
 * @Author: cuiyaonan2000@163.com
 * @Description: todo
 * @Date: Created at 2022-1-12  14:46
 */
public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {

        Random random = new Random(1000);
        long a = System.currentTimeMillis();
        String a1 = new String("a");
        for (int i = 0; i < 10000; i++) {
            a1 += random.nextFloat();
        }
        long b = System.currentTimeMillis();
        System.out.println("string:" + (b - a));
//        System.out.println(a1);

        long c = System.currentTimeMillis();
        StringBuffer c1 = new StringBuffer("a");
        for (int i = 0; i < 10000; i++) {
            c1.append(random.nextFloat());
        }
        long d = System.currentTimeMillis();
        System.out.println("stringbuffer:" + (d - c));
//        System.out.println(c1);

        long e = System.currentTimeMillis();
        StringBuilder e1 = new StringBuilder("a");
        for (int i = 0; i < 10000; i++) {
            e1.append(random.nextFloat());
        }
        long f = System.currentTimeMillis();
        System.out.println("stringbuild:" + (f - e));
//        System.out.println(e1);

    }
}

显示结果如下

string:1343
stringbuffer:16
stringbuild:0