java中把字符串“20110101”转换为字符串"2011-01-01"的技巧

import java.text.ParseException;
import java.text.SimpleDateFormat;

public static void main(String[] args) {
  String str = "20110101";
  SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
  SimpleDateFormat format1 = new SimpleDateFormat("yyyyMMdd");
    try {
      System.out.println(format1.format(format.parse(str)));
    } catch (ParseException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
 }

输出结果为2011-01-01