java 对比目标时间与系统时间 ，得出是否今天、昨天
首先用到2个类 ，一个是Date ，一个是Calendar

代码如下

// 将传入时间与当前时间进行对比，是否今天昨天private String getTime(Date date) {String todySDF = "今天 HH:mm";String yesterDaySDF = "昨天 HH:mm";String otherSDF = "M月d日 HH:mm";SimpleDateFormat sfd = null;String time = "";Calendar dateCalendar = Calendar.getInstance();dateCalendar.setTime(date);Date now = new Date();Calendar targetCalendar = Calendar.getInstance();targetCalendar.setTime(now);targetCalendar.set(Calendar.HOUR_OF_DAY, 0);targetCalendar.set(Calendar.MINUTE, 0);if (dateCalendar.after(targetCalendar)) {sfd = new SimpleDateFormat(todySDF);time = sfd.format(date);return time;} else {targetCalendar.add(Calendar.DATE, -1);if (dateCalendar.after(targetCalendar)) {sfd = new SimpleDateFormat(yesterDaySDF);time = sfd.format(date);return time;}}sfd = new SimpleDateFormat(otherSDF);time = sfd.format(date);return time;}

注意地方 24小时制 String todySDF = "今天 HH:mm";12小时制为小写 "hh:mm";
同样targetCalendar.set(Calendar.HOUR, 0);为12小时制