//格式化日期为指定的格式
java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
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_VALUE
Short.MAX_VALUE
-----------------------------------
//在一常量池中引用的是同一地址
q="sss";
w="sss";