Android中几种字符串拼接的效率比较

废话不多说，直接上代码

		long n = 10000;

		long start1 = System.currentTimeMillis();
		String s1 = new String("hello");
		for (long i = 0; i < n; i++)
		{
			s1 += "拼接--";
		}
		long end1 = System.currentTimeMillis();
		long time1 = end1 - start1;
		System.out.println("用String+=拼接字符串的时间:" + time1);

		long start2 = System.currentTimeMillis();
		String s2 = new String("hello");
		for (long i = 0; i < n; i++)
		{
			s2 = s2 + "拼接--";
		}
		long end2 = System.currentTimeMillis();
		long time2 = end2 - start2;
		System.out.println("用String=String+拼接字符串的时间" + time2);

		long start3 = System.currentTimeMillis();
		String s3 = new String("hello");
		for (long i = 0; i < n; i++)
		{
			s3 = s3.concat("拼接--");
		}
		long end3 = System.currentTimeMillis();
		long time3 = end3 - start3;
		System.out.println("用String.concat拼接字符串的时间" + time3);

		long start4 = System.currentTimeMillis();
		StringBuffer s4 = new StringBuffer("hello");
		for (long i = 0; i < n; i++)
		{
			s4.append("拼接--");
		}
		long end4 = System.currentTimeMillis();
		long time4 = end4 - start4;
		System.out.println("用StringBuffer.append拼接字符串的时间" + time4);

		long start5 = System.currentTimeMillis();
		StringBuilder s5 = new StringBuilder("hello");
		for (long i = 0; i < n; i++)
		{
			s5.append("拼接--");
		}
		long end5 = System.currentTimeMillis();
		long time5 = end5 - start5;
		System.out.println("用StringBuilder.append拼接字符串的时间" + time5);

在Android机上的实测结果为：

06-08 22:06:23.650: I/System.out(28027): 用String+=拼接字符串的时间:3295
06-08 22:06:27.080: I/System.out(28027): 用String=String+拼接字符串的时间3429
06-08 22:06:30.280: I/System.out(28027): 用String.concat拼接字符串的时间3208
06-08 22:06:30.320: I/System.out(28027): 用StringBuffer.append拼接字符串的时间27
06-08 22:06:30.320: I/System.out(28027): 用StringBuilder.append拼接字符串的时间8

以上数据仅在一台Android 4.1.2版手机上做了测试，不够充分，数据仅供参考。