Here you can find the source of getDayOfWeek(Date date, int day)
public static Date getDayOfWeek(Date date, int day)
//package com.java2s; /**/*from w w w. ja va 2 s . c o m*/ * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; public class Main { public static Date getDayOfWeek(Date date, int day) { Calendar c = new GregorianCalendar(); c.setFirstDayOfWeek(Calendar.MONDAY); c.setTime(date); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + day - 1); return c.getTime(); } public static int getDayOfWeek(Date date) { Calendar calendar = Calendar.getInstance(); calendar.setTime(date); int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK) - 1; if (dayOfWeek < 0) dayOfWeek = 0; return dayOfWeek; } public static Date getFirstDayOfWeek(Date date) { Calendar c = new GregorianCalendar(); c.setFirstDayOfWeek(Calendar.MONDAY); c.setTime(date); c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); return c.getTime(); } }