format.format(rs.getTimestamp("birth"))
//将字串符转换成日期类型java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); java.util.Date date = format.parse("1981-10-25 10:20:25");
//在数据库中将字符串转成日期存入数据库birth=to_date(?,'YYYY-MM-DD HH24:MI:SS')
//发送SQL语句，执行存储过程java.sql.CallableStatement cs = con.prepareCall("{call addAge}")
//更新时使用数据库的系统时间（sysdate）"update student set birth=sysdate"
//IO的几种常用通信方法---------------采用对象方式进行传输数据-------------------------java.io.BufferedReader in = new java.io.BufferedReader( new java.io.InputStreamReader(socket.getInputStream()//System.in));
java.io.PrintWriter out = new java.io.PrintWriter( new java.io.OutputStreamWriter(new java.io.BufferedOutputStream( socket.getOutputStream())));
java.io.ObjectOutputStream out = new java.io.ObjectOutputStream( new java.io.BufferedOutputStream(new java.io.FileOutputStream("t.dat")));out.writeObject(s); out.flush(); out.close();java.io.ObjectInputStream in = new java.io.ObjectInputStream( new java.io.BufferedInputStream(new java.io.FileInputStream("t.dat"))); Student ss = (Student)in.readObject();
--------------------------------------------------------------//给按钮添加事件 按钮触发数字自动滚动
this.button.addActionListener( new java.awt.event.ActionListener(){ public void actionPerformed(java.awt.event.ActionEvent e){ new Thread(){ public void run(){ while(true){ String s=txt.getText(); char c=s.charAt(s.length()-1); String cs=s.substring(0,s.length()-1); txt.setText(c+cs); try{ Thread.sleep(1000); }catch(Exception y){} } } }.start(); } });
----------------------------------------
另一种添加事件的方法button1.addActionListener( new CalculationListener());
//在剪切时候，它在一个内部类class CalculationListener implements java.awt.event.ActionListener{ public void actionPerformed(java.awt.event.ActionEvent e){ javax.swing.JButton button = (javax.swing.JButton)e.getSource(); calc.calculate(button.getText()); }}
-----------------------------------------启动线程的几种方法..----------------------------
R1 r = new R1(); R1 w = new R1(); Thread t = new Thread(r); Thread q = new Thread(w); t.start(); q.start();
new Thread(new W(socket)).start();
class R1 implements Runnable{ public void run(){ }}-----------------------------------Thread1 t1 =new Thread1();t1.start();
class Thread1 extends Thread{ public void run(){ }}
命名线程：//Thread t2 = new Thread(new Thread3(10),"线程名")得到线程序号：System.out.println (t2.getPriority());
applet框架-----------------------------public class TestApplet extends javax.swing.JApplet{ public void init(){ super.init(); }
}
//设置窗口关闭时自动退出this.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
------------------------------------------在lesson中有一个鼠标事件还没有看通，有点复杂(day16)
//给按钮添加事件的一种方法 //按钮调用 button.addActionListener(new count2()); //事件类继承监听器 class count2 implements java.awt.event.ActionListener{ public void actionPerformed(java.awt.event.ActionEvent e){ counter(); } } //方法与其分开 public void counter(){ String s = jt1.getText(); String m = jt2.getText(); int n = Integer.parseInt(m); int u = Integer.parseInt(s); int w = n+u; jt3.setText(""+w); }
//为了代码与窗体进行分开合作工作，因此将方法嵌入窗体中(“你中用我 我中有你”)如：LotteryFunction lf = new LotteryFunction(this);
LotteryFunction 为功能类
将this作为工功能类构造的参数可很方便的在窗体显示计算结果
------------------------------------------------------------------------------
如面板上有多个控件时，可用以下方法将其加入面板中class MyPanel extends javax.swing.JPanel{ javax.swing.JTextField[] texts = new javax.swing.JTextField[7]; MyPanel(){ this.setLayout(new java.awt.GridLayout(1,7,3,3)); for(int i=0;i<texts.length;i++){ texts[i] = new javax.swing.JTextField(); texts[i].setBackground(java.awt.Color.green); this.add(texts[i]); } }}
------------------------------------------------------------排序的代码：
static int t;int[] r ={8,9,7,6,5,4,3};for(int i=0;i<r.length;i++){ for(int j=1;j<r.length-i;j++){ if(r[j]<r[j-1]){ t=r[j]; r[j]=r[j-1]; r[j-1]=t; } }}
--------------------------
如何给文件进行锁定
public static void lock()throws Exception{ java.io.FileOutputStream out = new java.io.FileOutputStream("c://TestIO.txt",true); java.nio.channels.FileChannel f = out.getChannel(); java.nio.channels.FileLock lock = f.tryLock(); if (lock!=null){ System.out.println ("正在锁定"); Thread.sleep(100000); System.out.println ("解除完毕"); lock.release(); } }
------------------------------java.nio 如何进行文件传输的
java.io.FileInputStream in = new java.io.FileInputStream("TestNIO.java"); java.nio.channels.FileChannel ch = in.getChannel(); java.nio.ByteBuffer buff = java.nio.ByteBuffer.allocate(1024); while((ch.read(buff))!=-1){ buff.flip(); java.nio.charset.Charset ca = java.nio.charset.Charset.forName("gb2312"); //对缓存进行编码设置后，再进行解析 java.nio.CharBuffer cb = ca.decode(buff); System.out.println (cb); buff.clear(); }
---------------文件传输public static void copyfile()throws Exception{ java.io.FileInputStream in = new java.io.FileInputStream("TestNIO.java"); java.nio.channels.FileChannel ch = in.getChannel(); java.io.FileOutputStream out = new java.io.FileOutputStream("c://TestIO.java"); java.nio.channels.FileChannel outch = out.getChannel(); java.nio.ByteBuffer buff = java.nio.ByteBuffer.allocate(32); while((ch.read(buff))!=-1){ buff.flip(); outch.write(buff); buff.clear(); } in.close(); out.close(); }-------------------------------？？？关于java.nio.buff中的一些缓冲区的管理代码还没有看懂？？
几种IO通信方法1---------java.io.BufferedInputStream in =new java.io.BufferedInputStream( new java.io.FileInputStream("TestIO.java")); java.io.BufferedOutputStream out =new java.io.BufferedOutputStream( new java.io.FileOutputStream("c://t.txt"));
byte[] b =new byte[32]; int len= 0 ; while((len=in.read(b))!=-1){ out.write(b,0,len); } out.flush(); in.close(); out.close();
2-----------
java.io.FileReader f =new java.io.FileReader("c://t.txt"); char[] c = new char[32]; int len=0; while((len=f.read(c))!=-1){ System.out.println (new String(c,0,len)); } f.close();
3------------------java.io.BufferedReader r= new java.io.BufferedReader(new java.io.FileReader("TestIO.java")); java.io.PrintWriter w= new java.io.PrintWriter(new java.io.BufferedWriter(new java.io.FileWriter("c://t.txt"))); String line=null; while((line =r.readLine())!=null){ w.println(line); } w.flush(); r.close(); w.close();
4-----------------------java.io.PrintWriter p = new java.io.PrintWriter(new java.io.BufferedWriter( //是否在文件后进行追加数据（true） new java.io.FileWriter("c://t.txt",true))); p.print("12"); p.flush();
5------------------------java.io.FileOutputStream out = new java.io.FileOutputStream("c://t.txt"); java.io.OutputStreamWriter write = new java.io.OutputStreamWriter(out,"UTF-8"); write.write("2222222222"); write.close();5---------------------------从控制台读取数据java.io.BufferedReader r = new java.io.BufferedReader( new java.io.InputStreamReader(System.in)); String s=r.readLine(); System.out.println (s);
6-------------------------------向文件写入数字int i = 0; java.io.DataOutputStream out =new java.io.DataOutputStream( new java.io.BufferedOutputStream(new java.io.FileOutputStream("c://t.txt"))); out.writeInt(1); out.writeChar('a'); out.writeInt(2); out.writeChar('b'); //out.writeInt(4); out.flush(); out.close(); java.io.DataInputStream in =new java.io.DataInputStream( new java.io.BufferedInputStream(new java.io.FileInputStream("c://t.txt"))); while(i!=-1){ System.out.println (i=in.readInt()); //System.out.println (in.readDouble()); System.out.println (in.readChar()); }
7---------------------------------未看懂的代码？？？？？？？？？？？？java.io.RandomAccessFile r = new java.io.RandomAccessFile("c://t.txt","r"); System.out.println (r.readInt()); r.seek(0); System.out.println (r.readInt()); r.seek(r.length()-8); System.out.println (r.readDouble()); r.seek(r.length()-11); System.out.println (r.readUTF());
//压缩解压文件的代码--还未看
public static void ZipFile()throws Exception{ java.io.BufferedInputStream b = new java.io.BufferedInputStream( new java.io.FileInputStream("c://t.txt")); java.util.zip.ZipOutputStream z = new java.util.zip.ZipOutputStream( new java.io.BufferedOutputStream(new java.io.BufferedOutputStream( new java.io.FileOutputStream("c://t.zip")))); z.putNextEntry(new java.util.zip.ZipEntry("test.txt")); byte[] t = new byte[32]; int len = 0; while((len=b.read(t))!=-1){ z.write(t,0,len);//z.write(t); } z.flush(); b.close(); z.close(); }
----------public static void unzip()throws Exception{ java.util.zip.ZipFile zip = new java.util.zip.ZipFile("c://t.zip"); java.util.Enumeration enu = zip.entries(); while(enu.hasMoreElements()){ java.util.zip.ZipEntry entry = (java.util.zip.ZipEntry)enu.nextElement(); java.io.InputStream in = zip.getInputStream(entry); java.io.BufferedOutputStream out = new java.io.BufferedOutputStream( new java.io.FileOutputStream("c://test.txt"/*+entry.getName()*/)); byte[] b = new byte[32]; int len =0; while((len=in.read(b))!=-1){ out.write(b,0,len); } } }
------------------从控制台向文件输入数据
java.io.BufferedReader in = new java.io.BufferedReader(new java.io.InputStreamReader(System.in)); java.io.PrintStream out =new java.io.PrintStream(new java.io.BufferedOutputStream(new java.io.FileOutputStream("test.log"))); // System.setErr(out);//可以使输入转向 // System.setOut(out);//可以使输入转向 while(true){ out.println(in.readLine()); out.flush();
---------------------添加多的一个“/”表示转义符java.io.File f2 = new java.io.File("c://test//a//b//c");
实现文件类型的过滤方法-------1
String[] list = f2.list(); System.out.println (java.util.Arrays.asList(list)); list = f2.list( new java.io.FilenameFilter(){ public boolean accept(java.io.File dir,String name){ return name.endsWith(".java"); } } );
----------------------------2( 多个过滤方式)String[] list = f2.list(); list =f2.list( new java.io.FilenameFilter(){ public boolean accept(java.io.File dir,String names){ boolean java= names.endsWith(".java"); boolean txt = names.endsWith(".txt"); return java || txt; } } );
//String[] list = f2.list();java.util.Arrays.asList(list)将数组转成ArrayList
--------------------------------------------------删除有文件的目录实用代码
public static void delDir(java.io.File dir){ if(dir.isFile()){ dir.delete(); }else{ java.io.File[] fis = dir.listFiles(); for(int i=0;i<fis.length;i++){ delDir(fis[i]); } dir.delete(); }}------------------------------------------------------计算文件夹大小代码
System.out.println ("文件大小 "+s/1024+" kB"+" = "+(float)s/1024/1024+"M");
public static double len(java.io.File dir){ double s=0,len=0; if(dir.isFile()){ s=dir.length(); }else{ java.io.File[] file = dir.listFiles(); for(int i=0;i<file.length;i++){ len+=len(file[i]); } } return len+s; }
--------------------------------------------------------几种集合类的使用
java.util.ArraryList list=new java.util.ArraryList(); list.add("abc"); list.size(); list.iterator();
java.util.HashSet set = new java.util.HashSet(); for(int i=0;i<10;i++){ set.add("abc"+i); } java.util.Iterator it = set.iterator(); while(it.hasNext()){ System.out.println (it.next()); } java.util.HashMap map = new java.util.HashMap(); map.put(new Integer(1),"002"); map.put(new Integer(4),"001"); System.out.println (map.get(new Integer(1))); System.out.println (map.get(new Integer(4))); java.util.Set keys = map.keySet();//返回一个SET集合 it=keys.iterator(); while(it.hasNext()){ Object o = it.next(); System.out.println (o+":"+map.get(o)); }-------------系统属性的操作
java.util.Properties p = new java.util.Properties(); FileInputStream f = new FileInputStream("c://a.properties"); p.load(f); System.out.println (p.get("test.author")); System.out.println (p.get("test.version")); p.setProperty("test.author","llldiadsfsa"); p.setProperty("test.address","meimei"); p.setProperty("test.version","10.0"); java.io.FileOutputStream out = new FileOutputStream("c://a.properties"); p.save(out,"ruanwei"); //p.store(out,"test"); out.close();---------------------------------------------------------------未懂代码：以后再看？？？？ String str1 = args[0]; String str2 = args[1]; if("int".equals(System.getProperty("precition"))){ int i1 = Integer.parseInt(str1); int i2 = Integer.parseInt(str2); System.out.println ("i1"+"/"+"i2"+"="+divide(i1,i2)); }else if("double".equals(System.getProperty("precition"))){ double d1 = Double.parseDouble(str1); double d2 = Double.parseDouble(str2); System.out.println ("d1"+"/"+"d2"+"="+divide(d1,d2)); }else if("你好".equals(System.getProperty("precition"))){ System.out.println ("你好"); } } public static int divide(int i1,int i2){ return i1/i2; } public static double divide(double d1,double d2){ return d1/d2; }---------------------------------------------------------------------------------猜数字游戏代码class GuessGame{ public static void main(String[] args){ outer: while(true){ int num =1 + (int)(Math.random()*100); int num1=20 ; System.out.println ("输入数字"+num); inner: while(num!=num1){ java.io.BufferedReader in = new java.io.BufferedReader( new java.io.InputStreamReader(System.in));
try{ num1 = Integer.parseInt(in.readLine()); if(num1>100 || num1<1){ throw new java.lang.NumberFormatException(); } }catch(java.io.IOException e){ System.out.println ("io error"+e); }catch(java.lang.NumberFormatException e2){ System.out.println ("请输入正确的数字[1-100]"); continue ; } if(num>num1){ System.out.println ("is too small"); }else if(num<num1){ System.out.println ("is too large"); }else{ System.out.println ("ok"); System.out.print ("还玩么? (y/n)"); try{ if("y".equalsIgnoreCase(in.readLine())){ continue outer; } }catch(java.io.IOException e){} break outer; } }
} } }---------------------------------------------------------------------从随机数据取出与输入相等的数据
static char[] getText(String s){ int w = s.length(); char[] cc =new char[w]; int index=0; while(true){ char c = (char)(Math.random()*65536); if(c==s.charAt(index)){ cc[index]=c; index++; if (index>=w){ break; } } } return cc; }-----------------------------------------------------------------------多维数组的赋值------
int[][] in= new int[5][]; in[0] = new int[]{0,1,2,3}; in[1] = new int[]{1,2};--------------------------------------------------------覆盖垃圾收集方法public void finalize(){ System.out.println ("000");}-----------------------------------------------------移位）
3>>1 正数移位 0011---》 0001 为1(正数移位在前面加0)-3>>1 负数移位 1011 -》1100--》1101 移位得 1110 --》1101--》1010 为-2（负数移位在前面加1）-3>>>1 （这种移位以后再看？？？？？？？？？？？？？？？未懂）-
-----------描述注释文档----------------javadoc -d 文件绝对路径 -author -version private/public/protected
/** * *描述学生信息 *@author 阮卫 *@version 1.1 *@docroot e:/lesson/day02/indexz */
/***无参数据构造函数*/
/*** 有参数据构造函数*@param n 表示姓名*/
/***方法说明*/-----------------------------------------------Integer.MIN_VALUEShort.MAX_VALUE-----------------------------------//在一常量池中引用的是同一地址 q="sss"; w="sss";
