Java 根据年月和周获取日期 java根据日期获取星期几

private String getWeek(String date) {
        String[] arr=date.split("-");
       Calendar calendar = Calendar.getInstance();//获得一个日历
        calendar.set( Integer.parseInt(arr[0]),Integer.parseInt(arr[1])-1, Integer.parseInt(arr[2]));//设置当前时间,月份是从0月开始计算
        int number = calendar.get(Calendar.DAY_OF_WEEK);//星期表示1-7，是从星期日开始，   
        String [] str = {"","星期日","星期一","星期二","星期三","星期四","星期五","星期六",};
        return str[number];
    }