String.valueOf和字符串直接相加的性能比较

/**
* 测试StringValueOf
* 2015年3月20日   wenzibin1    新建
*/
public static void testStringValueOf() {
long t = System.currentTimeMillis();
for (int i = 0; i < 1000000; i++) {
String s0 = String.valueOf(11);
}
System.out.println("耗时" + (System.currentTimeMillis() - t));

t = System.currentTimeMillis();
for (int i = 0; i < 1000000; i++) {
String s = "" + 11;
}
System.out.println("耗时" + (System.currentTimeMillis() - t));

String str = "";
t = System.currentTimeMillis();
for (int i = 0; i < 1000000; i++) {
String s = str + 11;
}
System.out.println("耗时" + (System.currentTimeMillis() - t));
}