java日历学习 package Test4; import java.util.Scanner; import java.util.GregorianCalendar; import java.util.Calendar; public class Rili { final static String blank=" "; final static String border=" | "; public static void PrintWeek() { String [] week={"周日","周一","周二","周三","周四","周五","周六"}; for(int i=0;i<3;i++) { for(String element:week) { System.out.printf(" %s"+" ",element); } if(i<2) System.out.print(border); else System.out.println(blank); } } public static void PrintFestival(GregorianCalendar day,int month) { for(int i=7;i>=1;i--) { day.add(Calendar.DAY_OF_MONTH,-i); int monthday=day.get(Calendar.DAY_OF_MONTH); if(month-1==day.get(Calendar.MONTH)) {if(month==1&&monthday==1) System.out.print("元旦节"); else if (month==4&&monthday==1) System.out.print("愚人节"); else if (month==5&&monthday==1) System.out.print("劳动节"); else if (month==3&&monthday==8) System.out.print("妇女节"); else if (month==6&&monthday==1) System.out.print("儿童节"); else if (month==7&&monthday==1) System.out.print("建党节"); else if (month==8&&monthday==1) System.out.print("建军节"); else if (month==9&&monthday==10) System.out.print("教师节"); else if (month==10&&monthday==1) System.out.print("国庆节"); else if (month==11&&monthday==11) System.out.print("双十一"); else if (month==12&&monthday==25) System.out.print("圣诞节"); else System.out.print(blank); } else System.out.print(blank); day.add(Calendar.DAY_OF_MONTH,i); } } public static void PrintBorderLine(String symbol1,String symbol2,String symbol3) { for(int j=1;j<4;j++) { for(int k=1;k<8;k++) System.out.print(symbol1); if(j<3) System.out.print(symbol2); else System.out.println(symbol3); } } public static void PrintLine(GregorianCalendar day,int m,int month,int year) { int week = day.get(Calendar.DAY_OF_WEEK); GregorianCalendar today = new GregorianCalendar (); if(m==1) { for(int i=0;i<week-1;i++) System.out.print(blank); for(int i=0;i<=7-week;i++) { if(day==today) System.out.printf("%4d* ",day.get(Calendar.DAY_OF_MONTH)); else System.out.printf("%4d ",day.get(Calendar.DAY_OF_MONTH)); day.add(Calendar.DAY_OF_MONTH,1); } } if(m>=2&&m<=4) { for(int i=1;i<=7;i++) { if(year==today.get(Calendar.YEAR)&&month==today.get(Calendar.MONTH)&&today.get(Calendar.DAY_OF_MONTH)==day.get(Calendar.DAY_OF_MONTH)) System.out.printf("%4d* ",day.get(Calendar.DAY_OF_MONTH)); else System.out.printf("%4d ",day.get(Calendar.DAY_OF_MONTH)); day.add(Calendar.DAY_OF_MONTH,1); } } if(m>=5) { for(int i=1;i<=7;i++) { if(month==day.get(Calendar.MONTH)) { if(year==today.get(Calendar.YEAR)&&month==today.get(Calendar.MONTH)&&today.get(Calendar.DAY_OF_MONTH)==day.get(Calendar.DAY_OF_MONTH)) System.out.printf("%4d* ",day.get(Calendar.DAY_OF_MONTH)); else System.out.printf("%4d ",day.get(Calendar.DAY_OF_MONTH)); } else System.out.print(blank); day.add(Calendar.DAY_OF_MONTH,1); } } } public static void printmonth(int month) { for(int i=1;i<=3;i++) System.out.print(blank); if(month==1) System.out.print("*一月*"); else if (month==2) System.out.print("*二月*"); else if (month==3) System.out.print("*三月*"); else if (month==4) System.out.print("*四月*"); else if (month==5) System.out.print("*五月*"); else if (month==6) System.out.print("*六月*"); else if (month==7) System.out.print("*七月*"); else if (month==8) System.out.print("*八月*"); else if (month==9) System.out.print("*九月*"); else if (month==10) System.out.print("*十月*"); else if (month==11) System.out.print("*十一*"); else if (month==12) System.out.print("*十二*"); for(int i=1;i<=3;i++) System.out.print(blank); } public static void main(String[] args) { Scanner in = new Scanner(System.in); System.out.println("请输入四位年份..."); int year = in.nextInt(); System.out.println(""); System.out.println(""); for (int i=1;i<=10;i++) System.out.print(blank); System.out.printf("***%4d年日历如下***",year); System.out.println(""); System.out.println(""); for(int i=1;i<=4;i++) { PrintWeek(); PrintBorderLine(blank," | ",blank); GregorianCalendar day1 = new GregorianCalendar(year,3*i-3,1); GregorianCalendar day2 = new GregorianCalendar(year,3*i-2,1); GregorianCalendar day3 = new GregorianCalendar(year,3*i-1,1); for(int m=1;m<=6;m++) { PrintLine(day1,m,3*i-3,year); System.out.print(border); PrintLine(day2,m,3*i-2,year); System.out.print(border); PrintLine(day3,m,3*i-1,year); System.out.println(blank); PrintFestival(day1,3*i-2); System.out.print(border); PrintFestival(day2,3*i-1); System.out.print(border); PrintFestival(day3,3*i); System.out.println(blank); PrintBorderLine(blank," | ",blank); } printmonth(3*i-2); System.out.print(border); printmonth(3*i-1); System.out.print(border); printmonth(3*i); System.out.println(blank); PrintBorderLine("------","--+---",blank); if(i<4) PrintBorderLine(blank," | ",blank); } } }

Java Test 简易记事本package Test; import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.io.IOException; import java.io.RandomAccessFile; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.nio.channels.FileChannel; import java.nio.channels.FileLock; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.nio.charset.CharsetEncoder; public class Jishiben implements ActionListener { private Frame frame; private FileDialog fd_load; private FileDialog fd_save; private TextArea ta; private String file=""; private MenuItem save; private RandomAccessFile raf; private FileChannel fci; private FileLock flock; private CharsetEncoder encoder; private CharsetDecoder decoder; public static void main(String[] args) { new Jishiben().init(); } public void init(){ frame=new Frame("我的笔记本"); MenuBar mb=new MenuBar(); Menu file=new Menu("file"); Menu help=new Menu("help"); MenuItem open=new MenuItem("open"); save=new MenuItem("save"); save.setEnabled(false); file.add(open); file.add(save); mb.add(file); mb.add(help); frame.setMenuBar(mb); ta=new TextArea(); frame.add(ta,"Center"); open.addActionListener(this); save.addActionListener(this); frame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); frame.setSize(600,400); frame.setLocation(300,100); frame.setVisible(true); fd_load=new FileDialog(frame,"打开文件",FileDialog.LOAD); fd_save=new FileDialog(frame,"保存文件",FileDialog.SAVE); Charset charset=Charset.forName(System.getProperty("file.encoding")); encoder= charset.newEncoder(); decoder= charset.newDecoder(); } public void actionPerformed(ActionEvent e){ String s=e.getActionCommand(); if (s.equals("open")){ fd_load.setVisible(true); String d=fd_load.getDirectory(); String f=fd_load.getFile(); if ((d!=null)&&(f!=null)){ String destfile=d+f; if (destfile.equals(file)){ return; }else { this.closeFile(); file=destfile; this.loadFile(); } } }else if (s.equals("save")){ this.saveFile(); } } private void saveFile() { String content= ta.getText(); try{ CharBuffer cb=CharBuffer.wrap(content.toCharArray()); ByteBuffer bb=encoder.encode(cb); raf.setLength(0); fci.write(bb); fci.force(true); }catch (IOException e){ e.printStackTrace(); } } private void loadFile() { try{ raf=new RandomAccessFile(file,"rw"); fci=raf.getChannel(); flock=fci.tryLock(); if (flock==null){ ta.setText(""); JOptionPane.showMessageDialog(null,"文件正在使用中喔","错误提示",JOptionPane.ERROR_MESSAGE); file=""; raf.close(); raf=null; }else { int length=(int)fci.size(); ByteBuffer bb=ByteBuffer.allocate(length); fci.read(bb); bb.flip(); CharBuffer cb=decoder.decode(bb); ta.setText(cb.toString()); frame.setTitle("我的笔记本"+file); save.setEnabled(true); } }catch(IOException e){ e.printStackTrace(); } } private void closeFile() { try{ if (flock!=null){ flock.release(); } if (raf!=null){ raf.close(); } file=""; frame.setTitle("我的记事本"); save.setEnabled(false); }catch(IOException e){ e.printStackTrace(); } } }

Java初学Method 01package method; public class Test1 { //main方法 public static void main(String[] args) { //实际参数：实际调用传递给他的参数 int sum = add(1, 2); System.out.println(sum); //test(); } //加法 //形式参数，用来定义作用的 public static int add(int a,int b){ return a+b; } public static void test(){ for (int i = 0; i <= 1000; i++) { if (i%5==0){ System.out.print(i+"\t"); } if (i%(5*3)==0){ System.out.println(); } } } }02

Java初学Struct Breakpackage struct; public class BreakTest1 { public static void main(String[] args) { int i=0; while (i<100){ i++; System.out.println(i); if (i==30){ break; } } System.out.println("123"); }; }Continuepackage struct; public class ContinueTest1 { public static void main(String[] args) { int i=0; while (i<100){ i++; if (i%10==0){ System.out.println(); continue; } System.out.print(i); } /* Break在任何循环语句的主体部分，均可用break控制循环的流程。 break用于强行退出循环，不执行循环中剩余的语句。（break语句也在switch语句中使用） continue语句用在循环语句体中，用于终止某次循环过程，即跳过循环体中尚未执行的语句，接着进行下一次是否执行循环的判定。 */ } }DoWhile 01package struct; public class DoWhileTest1 { public static void main(String[] args) { int i=0; int sum=0; do { sum=sum+i; i++; }while (i<=100); System.out.println(sum); System.out.println(i); } }DoWhile 02package struct; public class DoWhileTest2 { public static void main(String[] args) { int a=0; while (a<0){ System.out.println(a); a++; } System.out.println("============================="); do { System.out.println(a); a++; }while (a<0); System.out.println("a的值："+a); } }For 01package struct; public class ForTest1 { public static void main(String[] args) { int a=1;//初始化条件 while (a<=100){//条件判断 System.out.println(a);//循环体 a+=2;//迭代 a+=2→a=a+2 } System.out.println("while循环结束！"); //初始化值//条件判断//迭代 for (int i=1;i<=100;i++){ System.out.println(i); } System.out.println("for循环结束！"); /* 关于For循环有以下几点说明： 最先执行初始化步骤。可以声明一种类型，但可初始化一个或多个循环控制变量，也可以是空语句。 然后，检测布尔表达式的值，如果为true，循环体被执行。如果为false，循环终止，开始执行循环体后面的语句。 执行一次循环后，更新循环控制变量（迭代因子控制循环变量的增减）。 再次检测布尔表达式。循环执行上面的过程。 */ //死循环 for (; ; ) { } } }For 02package struct; public class ForTest2 { public static void main(String[] args) { //练习1：计算0到100之间的奇数和偶数的和 int oddsum=0; int evensum=0; int a=0,b=0; for (int i = 0; i <=100; i++) { if(i%2!=0){//奇数 oddsum+=i;//oddsum=oddsum+i a=i; }else{//偶数 evensum+=i; b=i; } } System.out.println("奇数的和："+oddsum); System.out.println("偶数的和："+evensum); System.out.println(a); System.out.println(b); } }For 03package struct; public class ForTest3 { public static void main(String[] args) { //练习2：用while或for循环输出1-1000之间能被5整除的数，并且每行输出3个 for (int i = 0; i <= 1000; i++) { if(i%5==0){ System.out.print(i+"\t"); } if (i%(5*3)==0){ System.out.println(); //System.out.print("\n"); } } //println 输出完会换行 //print 输出完不会换行 } }For 04package struct; public class ForTest4 { public static void main(String[] args) { //练习3：打印九九乘法表 /* */ for (int j = 1; j <= 9; j++) { for (int i = 1; i <= j; i++) { System.out.print(j+"*"+i+"="+(j*i)+"\t"); } System.out.println(); } } }For 05package struct; public class ForTest5 { public static void main(String[] args) { int [] numbers={10,20,30,40,50};//定义数组 for (int i = 0; i < 5; i++) { System.out.println(numbers[i]); } System.out.println("================"); //遍历数组的元素 for (int x:numbers){ System.out.println(x); } } }If 01package struct; import java.awt.image.SampleModel; import java.util.Scanner; public class IfTest1 { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.println("请输入内容："); String s = scanner.nextLine(); //equals:判断字符串是否相等 if(s.equals("Hello")){ System.out.println(s); } System.out.println("End"); scanner.close(); } }If 02package struct; import java.util.Scanner; public class IfTest2 { public static void main(String[] args) { //考试分数大于60就是及格，小于60分就是不及格。 Scanner scanner=new Scanner(System.in); System.out.println("请输入成绩："); int score = scanner.nextInt(); if (score>=60){ System.out.println("及格"); }else{ System.out.println("不及格"); } scanner.close(); } }If 03package struct; import java.util.Scanner; public class IfTest3 { public static void main(String[] args) { //考试分数大于60分就是及格，小于60分就不及格 Scanner scanner=new Scanner(System.in); /** * if语句至多有一个else语句，else语句在所有的else if语句之后 * if语句可以有若干个else if语句，他们必须在else语句之前 * 一旦其中一个else if语句检测为true，其他的else if以及else语句都将跳过执行。 */ System.out.println("请输入成绩:"); int score=scanner.nextInt(); if (score==100){ System.out.println("恭喜满分"); }else if (score<100&&score>=90){ System.out.println("A级"); }else if (score<90&&score>=80){ System.out.println("B级"); }else if (score<80&&score>=70){ System.out.println("C级"); }else if (score<70&&score>=60){ System.out.println("D级"); }else if (score<60&&score>=0){ System.out.println("不及格"); }else { System.out.println("成绩不合法"); } scanner.close(); } }Labelpackage struct; public class LabelTest { public static void main(String[] args) { //打印101-105之间所有的质数(只有能被1和它本身能整除的数) int count=0; outer:for(int i=101;i<150;i++){ for (int j=2;j<i/2;j++){ if (i%j==0){ continue outer; } } System.out.print(i+" "); } } }Shunxupackage struct; public class ShunXuTest1 { public static void main(String[] args) { System.out.println("Hello1"); System.out.println("Hello2"); System.out.println("Hello3"); System.out.println("Hello4"); System.out.println("Hello5"); } }Switch 01package struct; import jdk.swing.interop.SwingInterOpUtils; import java.util.Scanner; public class SwitchTest1 { public static void main(String[] args) { //case穿透 没有break会往下执行后面的case //switch 匹配一个具体的值 char grade='C'; switch (grade){ case 'A': System.out.println("优秀"); break;//可选 case 'B': System.out.println("良好"); break;//可选 case 'C': System.out.println("及格"); break;//可选 case 'D': System.out.println("再接再厉"); break;//可选 case 'E': System.out.println("挂科"); break;//可选 default: System.out.println("未知等级"); } } }Switch 02package struct; public class SwitchTest2 { public static void main(String[] args) { String name="mango2"; //JDK7的新特性，表达式结果可以是字符串!!! //字符串的本质还是数字 //反编译 java---class(字节码文件)----反编译（IDEA） switch(name){ case "mango1": System.out.println("mango1"); break; case "mango2": System.out.println("mango2"); break; default: System.out.println("都不是"); } } }While 01package struct; public class WhileTest1 { public static void main(String[] args) { //输出1~100 int i=0; while (i<100){ i++; System.out.println(i); } } }While 02package struct; public class WhileTest2 { public static void main(String[] args) { //死循环 while (true){ //等待客户端连接 //定时检查 //。。。。 } } }While 03package struct; public class WhileTest3 { public static void main(String[] args) { //计算1+2+3+...+100=? int i=0; int sum=0; while (i<=100){ sum=sum+i; i++; } System.out.println(sum); System.out.println(i); } }Test1 (打印三角形)package struct; public class Test1 { public static void main(String[] args) { //打印三角形 5行 for (int i = 1; i <= 5; i++) { for (int j = 5; j >=i ; j--) { System.out.print(" "); } for (int j = 1; j <=i ; j++) { System.out.print("*"); } for (int j = 1; j <i ; j++) { System.out.print("*"); } System.out.println(); } } }

Java初学Scanner 01package scanner; import java.util.Scanner; public class Test1 { public static void main(String[] args) { //创建一个扫描对象，用于接收键盘数据 Scanner scanner = new Scanner(System.in); System.out.println("使用next方式接受："); //判断用户有没有输入字符串 if(scanner.hasNext()){ String str=scanner.next();//有空格就断了 以空格为结束符 System.out.println("输入的内容为："+str); } //凡是属于IO流的类，如果不关闭会一直占用资源，要养成好习惯，用完就关掉 scanner.close(); } }02package scanner; import java.util.Scanner; public class Test2 { public static void main(String[] args) { //从键盘接收数据 Scanner scanner = new Scanner(System.in); System.out.println("使用nextLine方式接受："); //判断是否还有输入 if(scanner.hasNextLine()){ String str = scanner.nextLine();//有空格也没关系，以回车为结束符 System.out.println("输入的内容为："+str); } scanner.close(); } }03package scanner; import java.util.Scanner; public class Test3 { public static void main(String[] args) { //从键盘接收数据 Scanner scanner = new Scanner(System.in); System.out.println("请输入数据："); String str = scanner.nextLine(); System.out.println("输入的内容为："+str); scanner.close(); } }04package scanner; import java.util.Scanner; public class Test4 { public static void main(String[] args) { Scanner scanner=new Scanner(System.in); //从键盘接收数据 int i=0; float f=0.0f; System.out.println("请输入整数："); //如果。。。那么。。。 if (scanner.hasNextInt()){ i=scanner.nextInt(); System.out.println("整数数据："+i); } else{ System.out.println("输入的不是整数数据："+i); } System.out.println("请输入小数："); //如果。。。那么。。。 if (scanner.hasNextFloat()){ f=scanner.nextFloat(); System.out.println("小数数据："+f); } else{ System.out.println("输入的不是小数数据："+f); } scanner.close(); } }05package scanner; import java.util.Scanner; public class Test5 { public static void main(String[] args) { //我们可以输入多个数字，并求其总和与平均数，每输入一个数字用回车确认，通过输入非数字来结束输入并输出执行结果 Scanner scanner = new Scanner(System.in); //和 double sum=0; //计算输入了多少个数字 int m=0; System.out.println("请输入数据："); //通过循环判断是否还有输入，并在里面对每一次进行求和和统计 while (scanner.hasNextDouble()) { double x = scanner.nextDouble(); m=m+1;//m++ sum=sum+x; System.out.println("你输入了第"+m+"个输入，然后当前结果sum="+sum); } System.out.println(m+"个数的和为"+sum); System.out.println(m+"个数的平均值是"+(sum/m)); scanner.close(); } }