src/com/book/util/Util.java

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package com.book.util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.text.SimpleDateFormat;

public class Util {
	public static String encodeGB2312(String str){
		if(str == null || "".equals(str.trim()))
			return null;
		String s = null;
		try{
			s = new String(str.getBytes("iso_8859_1"),"gb2312");
		}catch(Exception e){
			e.printStackTrace();
		}
		return s;
	}
	
	public static float fineAmount(String str){
        Date    date    =    new    Date();
try{
		  SimpleDateFormat    formatDate    =    new    SimpleDateFormat("yyyy-MM-dd");   
		  date    =    formatDate.parse(str);

    	Calendar cl=Calendar.getInstance();  
        cl.setTime(date);  
        int year1=cl.get(Calendar.YEAR);  
        int day1= cl.get(Calendar.DAY_OF_YEAR );  
        
        Calendar c2=Calendar.getInstance();  
        int year2=c2.get(Calendar.YEAR);  
        int day2= c2.get(Calendar.DAY_OF_YEAR); 
        
        int day = (year2-year1)*365+(day2-day1);
        if(day > 0)
        	return Float.parseFloat(String.valueOf(day*0.5));  
        return 0;
}catch(Exception e){
	e.printStackTrace();
	return 0;
}
     
	}
	
	public static void main(String[] args) {
		Util a=new Util();
		System.out.println(a.fineAmount("2011-04-17"));
	}
}