测试String——StringBuffer——StringBulider的速度

package comnf147Package;

import java.util.ArrayList;
import java.util.List;

public class String_Test {
    public static void main(String[] args) {
        long n = 1000000;
        long startTime=System.currentTimeMillis();
        List<Thread> thread = new ArrayList();
        {
            StringBuffer sb=new StringBuffer();
            thread=new ArrayList<>();
            for (int i = 0; i < n ; i++) {
                Thread t=new Thread();
                thread.add(t);
                sb.append(".");
            }
            long endTime=System.currentTimeMillis();

            System.out.println("Buffer"+(endTime - startTime)/1000.0+"ms");
        }
        {
            StringBuilder sb=new StringBuilder();
            thread=new ArrayList<>();
            for (int i = 0; i < n ; i++) {
                Thread t=new Thread();
                thread.add(t);
                sb.append(".");
            }
            long endTime=System.currentTimeMillis();

            System.out.println("Builder"+(endTime - startTime)/1000.0+"ms");
        }
        {
           String str;
            thread=new ArrayList<>();
            for (int i = 0; i < n ; i++) {
                Thread t=new Thread();
                thread.add(t);
             str=i+".";
            }
            long endTime=System.currentTimeMillis();
            System.out.println("String"+(endTime - startTime)/1000.0+"ms");
        }
    }
}