java8 .map是什么意思，java8的stream().mapToInt()什么意思
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关于java~ setActionMap 是什么
yout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.Date;
import java.util.StringTokenizer;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JToggleButton;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
/**
*<p>Title: Swing日历</p>
*<p>Description:操作日期</p>
*@author duxu2004
*@version 1.0.1
*/
class JCalendar extends JPanel{
//动态表示年月日
private int year=0;
private int month=0;
private int day=0;
//主面板
private JPanel Main= new JPanel();
//日面板
private JPanel jPanelDay= new JPanel();
//月面板
private JPanel jPanelMonth= new JPanel();
//年的输入位置
private JTextField Year= new JTextField();
//月的输入位置
private JTextField Month= new JTextField();
//减少月份
private JButton MonthDown= new JButton();
//增加月份
private JButton MonthUp= new JButton();
private JPanel jPanelButton= new JPanel();
//减少年份
private JButton YearDown= new JButton();
//增加年份
private JButton YearUp= new JButton();
//显示日期的位置
private JLabel Out= new JLabel();
//中国时区，以后可以从这里扩展可以设置时区的功能
private Locale l=Locale.CHINESE;
//主日历
private GregorianCalendar cal=new GregorianCalendar(l);
//星期面板
private JPanel weekPanel=new JPanel();
//天按钮组
private JToggleButton[] days=new JToggleButton[42];
//天面板
private JPanel Days= new JPanel();
//标示
private JLabel jLabel1= new JLabel();
private JLabel jLabel2= new JLabel();
private JLabel jLabel3= new JLabel();
private JLabel jLabel4= new JLabel();
private JLabel jLabel5= new JLabel();
private JLabel jLabel6= new JLabel();
private JLabel jLabel7= new JLabel();
//当前选择的天数按钮
private JToggleButton cur=null;
//月份天数数组，用来取得当月有多少天
// 1 2 3 4 5 6 7 8 9 10 11 12
private int[] mm=;
//空日期构造函数
public JCalendar(){
try{
jbInit();
}
catch(Exception e){
e.printStackTrace();
}
}
//带日期设置的构造函数
public JCalendar(int year, int month, int day){
cal.set(year, month, day);
try{
jbInit();
}
catch(Exception e){
e.printStackTrace();
}
}
//带日历输入的构造函数
public JCalendar(GregorianCalendar calendar){
cal=calendar;
try{
jbInit();
}
catch(Exception e){
e.printStackTrace();
}
}
//带日期输入的构造函数
public JCalendar(Date date){
cal.setTime(date);
try{
jbInit();
}
catch(Exception e){
e.printStackTrace();
}
}
//初始化组件
private void jbInit() throws Exception{
//初始化年、月、日
iniCalender();
this.setLayout(new BorderLayout());
this.setBorder(BorderFactory.createRaisedBevelBorder());
this.setMaximumSize(new Dimension(200, 200));
this.setMinimumSize(new Dimension(200, 200));
this.setPreferredSize(new Dimension(200, 200));
Main.setLayout(new BorderLayout());
Main.setBackground(SystemColor.info);
Main.setBorder(null);
Out.setBackground(Color.lightGray);
Out.setHorizontalAlignment(SwingConstants.CENTER);
Out.setMaximumSize(new Dimension(100, 19));
Out.setMinimumSize(new Dimension(100, 19));
Out.setPreferredSize(new Dimension(100, 19));
jLabel1.setForeground(Color.red);
jLabel1.setHorizontalAlignment(SwingConstants.CENTER);
jLabel1.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel1.setText("日");
jLabel2.setForeground(Color.blue);
jLabel2.setHorizontalAlignment(SwingConstants.CENTER);
jLabel2.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel2.setText("六");
jLabel3.setHorizontalAlignment(SwingConstants.CENTER);
jLabel3.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel3.setText("五");
jLabel4.setHorizontalAlignment(SwingConstants.CENTER);
jLabel4.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel4.setText("四");
jLabel5.setHorizontalAlignment(SwingConstants.CENTER);
jLabel5.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel5.setText("三");
jLabel6.setBorder(null);
jLabel6.setHorizontalAlignment(SwingConstants.CENTER);
jLabel6.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel6.setText("二");
jLabel7.setBackground(Color.lightGray);
jLabel7.setForeground(Color.black);
jLabel7.setBorder(null);
jLabel7.setHorizontalAlignment(SwingConstants.CENTER);
jLabel7.setHorizontalTextPosition(SwingConstants.CENTER);
jLabel7.setText("一");
weekPanel.setBackground(UIManager.getColor("InternalFrame.activeTitleGradient"));
weekPanel.setBorder(BorderFactory.createEtchedBorder());
weekPanel.setLayout(new GridLayout(1,7));
weekPanel.add(jLabel1, null);
weekPanel.add(jLabel7, null);
weekPanel.add(jLabel6, null);
weekPanel.add(jLabel5, null);
weekPanel.add(jLabel4, null);
weekPanel.add(jLabel3, null);
weekPanel.add(jLabel2, null);
MonthUp.setAlignmentX((float) 0.0);
MonthUp.setActionMap(null);
jPanelMonth.setBackground(SystemColor.info);
jPanelMonth.setLayout(new BorderLayout());
jPanelMonth.setBorder(BorderFactory.createEtchedBorder());
Month.setBorder(null);
Month.setHorizontalAlignment(SwingConstants.CENTER);
Month.addMouseListener(new java.awt.event.MouseAdapter(){
public void mouseClicked(MouseEvent e){
Month_mouseClicked(e);
}
});
Month.addKeyListener(new java.awt.event.KeyAdapter(){
public void keyPressed(KeyEvent e){
Month_keyPressed(e);
}
});
MonthDown.setBorder(null);
MonthDown.setText("\u25C4");
MonthDown.addActionListener(new java.awt.event.ActionListener(){
public void actionPerformed(ActionEvent e){
MonthDown_actionPerformed(e);
}
});
MonthUp.setBorder(null);
MonthUp.setText("\u25BA");
MonthUp.addActionListener(new java.awt.event.ActionListener(){
public void actionPerformed(ActionEvent e){
MonthUp_actionPerformed(e);
}
});
jPanelButton.setLayout(null);
jPanelButton.setBorder(null);
jPanelButton.addComponentListener(new java.awt.event.ComponentAdapter(){
public void componentResized(java.awt.event.ComponentEvent evt){
jPanelButtonComponentResized(evt);
}
});
Year.setBorder(BorderFactory.createEtchedBorder());
Year.setMaximumSize(new Dimension(80, 25));
Year.setMinimumSize(new Dimension(80, 25));
Year.setPreferredSize(new Dimension(80, 25));
Year.setHorizontalAlignment(SwingConstants.CENTER);
Year.addMouseListener(new java.awt.event.MouseAdapter(){
public void mouseClicked(MouseEvent e){
Year_mouseClicked(e);
}
});
Year.addKeyListener(new java.awt.event.KeyAdapter(){
public void keyPressed(KeyEvent e){
Year_keyPressed(e);
}
});
YearDown.setBorder(null);
YearDown.setMaximumSize(new Dimension(16, 16));
YearDown.setMinimumSize(new Dimension(16, 16));
YearDown.setPreferredSize(new Dimension(16, 16));
YearDown.setSize(new Dimension(16, 16));
YearDown.setText("▼");
YearDown.addActionListener(new java.awt.event.ActionListener(){
public void actionPerformed(ActionEvent e){
YearDown_actionPerformed(e);
}
});
YearUp.setBorder(null);
YearUp.setMaximumSize(new Dimension(16, 16));
YearUp.setMinimumSize(new Dimension(16, 16));
YearUp.setPreferredSize(new Dimension(16, 16));
YearUp.setSize(new Dimension(16, 16));
YearUp.setText("▲");
YearUp.addActionListener(new java.awt.event.ActionListener(){
public void actionPerformed(ActionEvent e){
YearUp_actionPerformed(e);
}
});
jPanelDay.setLayout(new BorderLayout());
Days.setLayout(new GridLayout(6,7));
Days.setBackground(SystemColor.info);
for(int i=0;i<42;i++){
days[i]=new JToggleButton();
days[i].setBorder(null);
days[i].setBackground(SystemColor.info);
days[i].setHorizontalAlignment(SwingConstants.CENTER);
days[i].setHorizontalTextPosition(SwingConstants.CENTER);
//days[i].setSize(l,l);
days[i].addActionListener(new java.awt.event.ActionListener(){
public void actionPerformed(ActionEvent e){
day=Integer.parseInt(((JToggleButton)e.getSource()).getText());
showDate();
showDays();
}
});
Days.add(days[i]);
}
this.add(Main, BorderLayout.NORTH);
this.add(jPanelDay, BorderLayout.CENTER);
this.add(jPanelMonth, BorderLayout.SOUTH);
Main.add(Year, BorderLayout.CENTER);
Main.add(Out, BorderLayout.WEST);
Main.add(jPanelButton, BorderLayout.EAST);
jPanelButton.add(YearUp);
jPanelButton.add(YearDown);
jPanelDay.add(weekPanel,BorderLayout.NORTH);
jPanelDay.add(Days, BorderLayout.CENTER);
jPanelMonth.add(Month, BorderLayout.CENTER);
jPanelMonth.add(MonthDown, BorderLayout.WEST);
jPanelMonth.add(MonthUp, BorderLayout.EAST);
showMonth();
showYear();
showDate();
showDays();
}
//自定义重画年选择面板
void jPanelButtonComponentResized(java.awt.event.ComponentEvent evt){
YearUp.setLocation(0,0);
YearDown.setLocation(0,YearUp.getHeight());
jPanelButton.setSize(YearUp.getWidth(),YearUp.getHeight()*2);
jPanelButton.setPreferredSize(new Dimension(YearUp.getWidth(),YearUp.getHeight()*2));
jPanelButton.updateUI();
}
//测试用
public static void main(String[] args){
JFrame f=new JFrame();
f.setContentPane(new JCalendar());
f.pack();
//f.setResizable(false);
f.show();
}
//增加年份
void YearUp_actionPerformed(ActionEvent e){
year++;
showYear();
showDate();
showDays();
}
//减少年份
void YearDown_actionPerformed(ActionEvent e){
year--;
showYear();
showDate();
showDays();
}
//减少月份
void MonthDown_actionPerformed(ActionEvent e){
month--;
if(month<0){
month= 11;
year--;
showYear();
}
showMonth();
showDate();
showDays();
}
//增加月份
void MonthUp_actionPerformed(ActionEvent e){
month++;
if(month==12){
month=0;
year++;
showYear();
}
showMonth();
showDate();
showDays();
}
//初始化年月日
void iniCalender(){
year=cal.get(Calendar.YEAR);
month=cal.get(Calendar.MONTH);
day=cal.get(Calendar.DAY_OF_MONTH);
}
//刷新月份
void showMonth(){
Month.setText(Integer.toString(month+1)+"月");
}
//刷新年份
void showYear(){
Year.setText(Integer.toString(year)+"年");
}
//刷新日期
void showDate(){
Out.setText(Integer.toString(year)+"-"+Integer.toString(month+1)+"-"+Integer.toString(day));
}
//重画天数选择面板
void showDays(){
cal.set(year,month,1);
int firstDayOfWeek= cal.get(Calendar.DAY_OF_WEEK);
int n=mm[month];
if(cal.isLeapYear(year)&&month==1) n++;
int i=0;
for(;i<firstDayOfWeek-1;i++){
days[i].setEnabled(false);
days[i].setSelected(false);
days[i].setText("");
}
int d=1;
for(;d<=n;d++){
days[i].setText(Integer.toString(d));
days[i].setEnabled(true);
if(d==day) days[i].setSelected(true);
else days[i].setSelected(false);;
i++;
}
for(;i<42;i++){
days[i].setEnabled(false);
days[i].setSelected(false);
days[i].setText("");
}
}
//单击年份面板选择整个年份字符串
void SelectionYear(){
Year.setSelectionStart(0);
Year.setSelectionEnd(Year.getText().length());
}
//单击月份面板选择整个月份字符串
void SelectionMonth(){
Month.setSelectionStart(0);
Month.setSelectionEnd(Month.getText().length());
}
//月份面板响应鼠标单击事件
void Month_mouseClicked(MouseEvent e){
//SelectionMonth();
inputMonth();
}
//检验输入的月份
void inputMonth(){
String s;
if(Month.getText().endsWith("月"))
{
s=Month.getText().substring(0,Month.getText().length()-1);
}
else s=Month.getText();
month=Integer.parseInt(s)-1;
this.showMe();
}
//月份面板键盘敲击事件响应
void Month_keyPressed(KeyEvent e){
if(e.getKeyChar()==10)
inputMonth();
}
//年份面板响应鼠标单击事件
void Year_mouseClicked(MouseEvent e){
//SelectionYear();
inputYear();
}
//年份键盘敲击事件响应
void Year_keyPressed(KeyEvent e){
//System.out.print(new Integer(e.getKeyChar()).byteValue());
if(e.getKeyChar()==10)
inputYear();
}
//检验输入的年份字符串
void inputYear(){
String s;
if(Year.getText().endsWith("年"))
{
s=Year.getText().substring(0,Year.getText().length()-1);
}
else s=Year.getText();
year=Integer.parseInt(s);
this.showMe();
}
//以字符串形式返回日期,yyyy-mm-dd
public String getDate()
//以字符串形式输入日期,yyyy-mm-dd
public void setDate(String date){
if(date!=null){
StringTokenizer f= new StringTokenizer(date,"-");
if(f.hasMoreTokens())
year= Integer.parseInt(f.nextToken());
if(f.hasMoreTokens())
month= Integer.parseInt(f.nextToken());
if(f.hasMoreTokens())
day= Integer.parseInt(f.nextToken());
cal.set(year,month,day);
}
this.showMe();
}
//以日期对象形式输入日期
public void setTime(Date date){
cal.setTime(date);
this.iniCalender();
this.showMe();
}
//返回日期对象
public Date getTime()
//返回当前的日
public int getDay(){
return day;
}
//设置当前的日
public void setDay(int day){
this.day= day;
cal.set(this.year,this.month,this.day);
this.showMe();
}
//设置当前的年
public void setYear(int year){
this.year= year;
cal.set(this.year,this.month,this.day);
this.showMe();
}
//返回当前的年
public int getYear(){
return year;
}
//返回当前的月
public int getMonth(){
return month;
}
//设置当前的月
public void setMonth(int month){
this.month= month;
cal.set(this.year,this.month,this.day);
this.showMe();
}
//刷新
public void showMe(){
this.showDays();
this.showMonth();
this.showYear();
this.showDate();
}
}
public class TestJCalendar{
public static void main(String[] args){
JFrame f=new JFrame();
f.setContentPane(new JCalendar());
f.pack();
//f.setResizable(false);
f.show();
}
}
java8的stream().mapToInt()什么意思
Stream（流）是一个来自数据源的元素队列并支持聚合操作
<strong元素队列< strong="">元素是特定类型的对象，形成一个队列。 Java中的Stream并不会存储元素，而是按需计算。
数据源流的来源。可以是集合，数组，I/O channel，产生器generator等。
聚合操作类似SQL语句一样的操作，比如filter, map, reduce, find, match, sorted等。
可以试试这个输出什么：
String[] strarr={"abc","defg","vwxyz"};
int iSum= Arrays.stream(strarr)
.mapToInt(s-> s.length())
.sum();
System.out.println("长度和:"+iSum);
扩展资料：
Java还包括一个类的扩展集合，分别组成各种程序包（Package），用户可以在自己的程序中使用。例如，Java提供产生图形用户接口部件的类（java.awt包），这里awt是抽象窗口工具集（abstract windowing toolkit）的缩写，处理输入输出的类（java.io包）和支持网络功能的类（java.net包）。
参考资料来源：百度百科-Java
HashMap是什么东西
HashMap，中文名哈希映射，HashMap是一个用于存储Key-Value键值对的集合，每一个键值对也叫做Entry。这些个键值对（Entry）分散存储在一个数组当中，这个数组就是HashMap的主干。HashMap数组每一个元素的初始值都是Null。
HashMap是基于哈希表的 Map接口的实现。此实现提供所有可选的映射操作，并允许使用 null值和 null键。（除了非同步和允许使用 null之外，HashMap类与 Hashtable大致相同。）此类不保证映射的顺序，特别是它不保证该顺序恒久不变。
扩展资料：
因为HashMap的长度是有限的，当插入的Entry越来越多时，再完美的Hash函数也难免会出现index冲突的情况。
HashMap数组的每一个元素不止是一个Entry对象，也是一个链表的头节点。每一个Entry对象通过Next指针指向它的下一个Entry节点。当新来的Entry映射到冲突的数组位置时，只需要插入到对应的链表即可。
参考资料来源：
百度百科-Hashmap
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