String StringBuffer StringBuilder 性能比较

最新推荐文章于 2024-06-02 22:05:12 发布

原创最新推荐文章于 2024-06-02 22:05:12 发布 · 253 阅读

CC 4.0 BY-SA版权

本文通过实验对比了在Java中使用String、StringBuffer和StringBuilder进行字符串拼接的性能。结果显示，StringBuilder（线程不安全）的性能最优，其次是StringBuffer（线程安全），而传统的String拼接方式效率最低。

for (int k = 0 ; k < 10; k++){
    long start = System.nanoTime();
    String str="";

    for (int j = 0; j <100;j++){
        for (int i = 0; i < 100;i++){
            str = str+String.valueOf(i);
        }
    }

    long end = System.nanoTime();

    Log.d(TAG,"str k:"+k+"cost:"+(end - start)/1000000);
}

for (int k = 0 ; k < 10; k++){
    long start = System.nanoTime();
    StringBuffer sb = new StringBuffer();

    for (int j = 0; j <100;j++){
        for (int i = 0; i < 100;i++){
            sb.append(String.valueOf(i))  ;
        }
    }

    long end = System.nanoTime();

    Log.d(TAG,"StringBuffer k:"+k+"cost:"+(end - start)/1000000);
}

for (int k = 0 ; k < 10; k++){
    long start = System.nanoTime();
    StringBuilder sb = new StringBuilder();

    for (int j = 0; j <100;j++){
        for (int i = 0; i < 100;i++){
            sb.append(String.valueOf(i))  ;
        }
    }

    long end = System.nanoTime();

    Log.d(TAG,"StringBuilder k:"+k+"cost:"+(end - start)/1000000);
}

str k:0cost:1241
str k:1cost:1200
str k:2cost:1211
str k:3cost:1234
str k:4cost:1207
str k:5cost:1204
str k:6cost:1210
str k:7cost:1220
str k:8cost:1206
str k:9cost:1210
StringBuffer k:0cost:3
StringBuffer k:1cost:1
StringBuffer k:2cost:2
StringBuffer k:3cost:1
StringBuffer k:4cost:1
StringBuffer k:5cost:1
StringBuffer k:6cost:1
StringBuffer k:7cost:2
StringBuffer k:8cost:1
StringBuffer k:9cost:1
StringBuilder k:0cost:1
StringBuilder k:1cost:1
StringBuilder k:2cost:1
StringBuilder k:3cost:2
StringBuilder k:4cost:1
StringBuilder k:5cost:1
StringBuilder k:6cost:1
StringBuilder k:7cost:1
StringBuilder k:8cost:2
StringBuilder k:9cost:2