Java字符生成器简单例子
public class Jerque {
/**
* 比较一般情况下的字符串生成器,和String-Builder所耗的时间
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String str = “”;
long startTime1 = System.currentTimeMillis();
for (int i =0; i<10000; i++)
{
str = str +i;
}
long endTime1 = System.currentTimeMillis();
long time1 = endTime1 – startTime1;
System.out.println(“字符串1消耗时间:”+ time1);
StringBuilder builder = new StringBuilder(“”);
long startTime2 = System.currentTimeMillis();
for (int i=0;i<10000;i++)
{
builder.append(i);
}
long endTime2 = System.currentTimeMillis();
long time2 = endTime2 – startTime2;
System.out.println(“字符串2消耗时间:” + time2);
}
}
字符串1消耗时间:1210
字符串2消耗时间:3
总结:
1. 用JAVA自带的字符序列String-Builder类,无疑大大提高了效率。
2. 此类常用的方法如下:
a. append(content)方法
b. insert(int offset,arg)方法
StringBuilder b = new StringBuilder(“Hello”);
b.insert(5,”World!”);
System.out.println(b.tostring());
c.