对字符串的操作

package controller;

import java.util.ArrayList;

public class Mytest {

  /**
   * 将集合变为集合中的数据变成字符串输出，并以','好分隔，且最后一个没有逗号
   * @param args
   */
  public static void main(String[] args) {
    ArrayList<String> list = new ArrayList<String>();
    list.add("1");
    list.add("2");
    list.add("3");
    /* String[] array=new String[list.size()];
     list.toArray(array);
    for (int i = 0; i < array.length; i++) {
      System.out.print(array[i]);
    }*/
    StringBuffer buffer=new StringBuffer();
    for (String str  : list) {
      buffer.append(str +",");
    }
        String substring = buffer.substring(0,buffer.length()-1);
     System.out.println(substring.toString());
     //以‘，’分隔拆分再输出
     String[] split = substring.toString().split(",");
     for (int i = 0; i < split.length; i++) {
      String string = split[i];
      System.out.println(string);
    }
     
     test.test2();
  }
  
  
  /**
   * 将集合转换为数组输出
   * @author Administrator
   *
   */
  static class test{
    public static  void  test2(){
      ArrayList<String> arrayList = new ArrayList<String>();
      arrayList.add("1");
      arrayList.add("2");
      arrayList.add("3");
      String[] list=new String[arrayList.size()];
      arrayList.toArray(list);
      for (int i = 0; i < list.length; i++) {
        String string = list[i];
        System.out.print(string);
      } 
    }
  }
}