疯狂Java练习题 实现一个按字符来截取字符串的方法

//处理请求
String request = in.readLine();
StringTokenizer st = new StringTokenizer(request);
String method = st.nextToken();
String url = st.nextToken();

import java.io.*;
/**
* Description:
* <br/>Program Name:实现一个按字符来截取字符串的方法
* <br/>Date:2013/11/13
* @author Peter Pan
* @version 1.0
*/

public class InterceptString
{
//这是截取字符串的方法
public String intercept(String str, int first, int last)
{
String result = "";
int num = str.length();
//遍历字符串，生成新语句
for(int i = first; i < num && i < last ; i++)
{
result += str.charAt(i);
}
return result;
}

public static void main(String[] args)  throws IOException
{

//读入语句
System.out.println("请输入语句：");
BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
String str = null;
str = read.readLine();

//读入截取位置
System.out.println("请截取新语句开始和结束位置：如1,3");
String position =null;
position = read.readLine();
String [] postr = position.split(",");
int i = Integer.parseInt(postr[0]);
int j = Integer.parseInt(postr[1]);

//显示新语句
InterceptString icepts = new InterceptString();
System.out.println("截取后语句：" + icepts.intercept(str , i, j));

//关闭缓存
read.close();
}
}