java 计算前6个月月份

package com.web.controller;

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

import javax.servlet.http.HttpServletRequest;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;


public class TestDate {

	public static String getLast12Months(int i) {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
		Calendar c = Calendar.getInstance();
		c.setTime(new Date());
		c.add(Calendar.MONTH, -i);
		Date m = c.getTime();
		return sdf.format(m);
	}
	
	public static void main(String[] args) throws Exception {
	
		
		Calendar c = Calendar.getInstance();
		c.add(Calendar.MONTH, -4);
		StringBuilder sb = new StringBuilder();
		sb.append(c.get(Calendar.YEAR)).append(c.get(Calendar.MONTH));
		String before_six = sb.toString();
		ArrayList<String> result = new ArrayList<String>();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");// 格式化为年月
		Calendar min = Calendar.getInstance();
		Calendar max = Calendar.getInstance();
		min.setTime(sdf.parse(before_six));
		min.set(min.get(Calendar.YEAR), min.get(Calendar.MONTH), 1);
		max.setTime(sdf.parse(sdf.format(new Date())));
		max.set(max.get(Calendar.YEAR), max.get(Calendar.MONTH), 2);
		Calendar curr = min;
		while (curr.before(max)) {
			result.add(sdf.format(curr.getTime()));
			curr.add(Calendar.MONTH, 1);
		}
		System.out.println(result);
		//倒序
		Collections.reverse(result);
		System.out.println(result);

	}
}