测试StringBuffer与StringBuilder的效率

悠悠 2024-04-17 23:15 27阅读 0赞

**相同点**:都是长度可变的字符串,两者基本操作相同

**两者主要区别在于:**

1.StringBuffer是线程安全的,StringBuilder是线程不安全的

2.StringBuffer从jdk1.0就存在,StringBuilder是在jdk5.0后才出现

**StringBuilder相较与StringBuffer有速度优势,所以多数情况下建议使用StringBuilder  
然而应用程序要求线程安全的情况下,则必须使用StringBuffer类**

代码演示:

//StringBuilder线程不安全
    public class StringBuilderDemo {
    	public static void main(String[] args) {
    		long beginTime = System.currentTimeMillis();//开始计时
    		StringBuilder builder = new StringBuilder();
    		for(int i=0;i<80000000;i++) {
    			builder.append(i);
    		}
    		long endtime = System.currentTimeMillis();//结束计时
    		System.out.println("StringBuilder所用时间:"+(endtime-beginTime));
    	}
    }

结果:![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW9qeF8_size_16_color_FFFFFF_t_70]

//StringBuffer线程安全
    public class StringBufferDemo {
    	public static void main(String[] args) {
    		long beginTime1 = System.currentTimeMillis();//开始计时
    		StringBuffer buffer = new StringBuffer();
    		for(int i=0;i<80000000;i++) {
    			buffer.append(i);
    		}
    		long endtime1 = System.currentTimeMillis();//结束计时
    		System.out.println("StringBuffer所用时间:"+(endtime1-beginTime1));
    	}
    }

结果:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW9qeF8_size_16_color_FFFFFF_t_70 1]  
由此可见,StringBuilder确实是会比StringBuffer速度更快一些

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW9qeF8_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/87638a257715462e99d0f1f746893512.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW9qeF8_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/81ba3e67f1d94616bdfed2eb80b0b8b4.png