java中的folder怎么用

1. java中的folder怎么用

可以。比如第一级建为a 想在里面建b文件夹的话可以：右击新建 -> 文件夹名字为a.b

2. java里面新建folder是用来保存什么的啊

用来保存文件的啊，各种各样的文件的啊，这个是文件夹的意思啊，文件夹不是保存文件的么？？楼主为何有此一问呢？？难道没有用过电脑么

3. java注册登录

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class HelloWorld extends JPanel {
 static final int WIDTH = 300;
 static final int HEIGHT = 150;
 JFrame mainJFrame;
 JTextField nameinput, passwordinput;
 JButton ok, cancel;

 public void add(Component c, GridBagConstraints constraints, int x, int y,
   int w, int h) {
  constraints.gridx = x;
  constraints.gridy = y;
  constraints.gridwidth = w;
  constraints.gridheight = h;
  add(c, constraints);
 }

 public HelloWorld() {
  mainJFrame = new JFrame();
  mainJFrame.setTitle("欢迎进入java世界");
  setLayout(new GridBagLayout());
  mainJFrame.add(this, BorderLayout.WEST);
  mainJFrame.setSize(WIDTH, HEIGHT);
  Toolkit kit = Toolkit.getDefaultToolkit();
  Dimension screenSize = kit.getScreenSize();
  int width = screenSize.width;
  int height = screenSize.height;
  int x = (width - WIDTH) / 2;
  int y = (height - HEIGHT) / 2;
  mainJFrame.setLocation(x, y);
  // final JPasswordField passwordinput=new JPasswordField(15);
  nameinput = new JTextField(15);
  passwordinput = new JTextField(15);
  JButton ok = new JButton("登录");
  // ok.setActionCommand("pp");
  SS s = new SS();
  ok.addActionListener(s);
  JButton cancel = new JButton("取消");
  cancel.addActionListener(s);
  JLabel title = new JLabel("欢迎进入java世界");
  JLabel name = new JLabel("用户名");
  JLabel password = new JLabel("密    码");
  GridBagConstraints constraints = new GridBagConstraints();
  constraints.fill = GridBagConstraints.NONE;
  constraints.anchor = GridBagConstraints.EAST;
  constraints.weightx = 3;
  constraints.weighty = 4;
  add(title, constraints, 0, 0, 4, 1);
  add(name, constraints, 0, 1, 1, 1);
  add(password, constraints, 0, 2, 1, 1);
  add(nameinput, constraints, 2, 1, 1, 1);
  add(passwordinput, constraints, 2, 2, 1, 1);
  add(ok, constraints, 1, 3, 1, 1);
  add(cancel, constraints, 2, 3, 1, 1);
  mainJFrame.setVisible(true);
  mainJFrame.setResizable(false);
  mainJFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

 public static void main(String[] args) {
  new HelloWorld();
 }

 class SS implements ActionListener {
  public void actionPerformed(ActionEvent e) {
   String st = e.getActionCommand();

   System.out.println(st);
   System.out.println(e.getSource());
   if (st.equals("登录")) {
    String nametext = nameinput.getText();
    String passwordtext = passwordinput.getText();
    String str = new String(passwordtext);
    boolean x = (nametext.equals("admin"));
    boolean y = (str.equals("123456"));
    boolean z = (x && y);
    if (z == true) {
     mainJFrame.dispose();
     JOptionPane.showMessageDialog(new HelloWorld(), "输入正确!");
     mainJFrame.setVisible(false);
    } else {
     nameinput.setText(" ");
     passwordinput.setText(" ");
     JOptionPane.showMessageDialog(new HelloWorld(), "密码有误!");
    }
   } else if (st.equals("取消")) {
    nameinput.setText(" ");
    passwordinput.setText(" ");
   }
  }
 }

}


特别简单的一个，账号admin密码123456

4. matlab 2009a 激活出错java.io.IOException: Could not get shell folder ID list该怎么解决？

不要点 那个browse  直接输入path  如 D:\MATLAB\R2009a\
这样就可以了  以后遇到同样问题就直接输入路径就行

5. java中的方法书写格式

返回值类型，方法中必须return一个Connection对象

6. 用java填写代码

public class test {
 public static void main(String[] args) {
  String path="c:\\java\\jsp\\A.java"; 
  int position = path.indexOf(path.split("\\\\")[path.split("\\\\").length-1]);
  String fileName = path.split("\\\\")[path.split("\\\\").length-1];
  System.out.println("position="+position+"         fileName="+fileName);
 }
}

7. 用JAVA做一个网页（注册页）

新用户注册


function refreshImage(){
    document.getElementById("image").src = "image.jsp";
}
function checkInput(){
    var f = document.forms[0];
    var usernamePatrn = /^[a-zA-Z]{4,12}$/;
 if(!usernamePatrn.exec(f.username.value)){
     alert("输入用户名不合法，请重新输入!");
  f.username.select;
  f.username.focus();
  return false;
 }
 var passwordPatrn = /^(\w){6,12}$/;
 if(!passwordPatrn.exec(f.password.value)){
     alert("密码不符合要求，请重新输入!");
  f.passowrd.focus();
  return false;
 }
 if(f.password.value != f.passwordverify.value){
     alert("两次密码输入不一样，请重新输入!");
  f.password.focus();
  return false;
 }
 document.getElementById("info").innerHTML = "正在处理。。。请等待。。。";
 send_request("get","private/register1.jsp?userName="+f.username.value+"&password="+f.password.value+
      "&checkCode="+f.check.value,null,"text",callback);
}
function callback(){
    if(http_request.readyState == 4){
     if(http_request.status == 200){
      var result = http_request.responseText;
   if(result == 1){
         alert("注册成功！点击确定后进入主界面!");
      window.location="mainPage.html";
   }
   else alert(result);
  }
  else{
      alert("页面异常");
   alert(http_request.status);
  }
 }
}







    用户名:
 
 (2-12字符, 必须全为英文字母)



    


    密码:
 (4-12字符)


    密码确认:
 (4-12字符)


    
 


    请输入验证码:
 


    
 





ajax的
下面是image.jsp

 
<%! 

Color getRandColor(Random random,int fc,int bc) 
{ 
if(fc>255) fc=255; 
if(bc>255) bc=255; 
int r=fc+random.nextInt(bc-fc); 
int g=fc+random.nextInt(bc-fc); 
int b=fc+random.nextInt(bc-fc); 
return new Color(r,g,b); 
} 
%> 
<% 
response.setHeader("Pragma","No-cache"); 
response.setHeader("Cache-Control","no-cache"); 
response.setDateHeader("Expires", 0); 


// 设置图片的长宽 
int width=176, height=30; 
//设置备选汉字，剔除一些不雅的汉字 
String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927"+
"\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77"+
"\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341"+
"\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9"+

"\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0"+

"\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769"+

"\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21"+

"\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8"+

"\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374"+

"\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66"+

"\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76"+

"\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5"+

"\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0"+

"\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6"+

"\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868"+

"\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2"+

"\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317"+

"\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408"+

"\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3"+

"\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54"+

"\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5"+

"\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6"; 
//备选汉字的长度 
int length = base.length(); 


//创建内存图像 
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 
// 获取图形上下文 
Graphics g = image.getGraphics(); 


//创建随机类的实例 
Random random = new Random(); 


// 设定图像背景色(因为是做背景，所以偏淡) 
g.setColor(getRandColor(random,200,250)); 
g.fillRect(0, 0, width, height); 


//备选字体 
String[] fontTypes = {"\u5b8b\u4f53","\u65b0\u5b8b\u4f53","\u9ed1\u4f53","\u6977\u4f53","\u96b6\u4e66"}; 
int fontTypesLength = fontTypes.length; 


//在图片背景上增加噪点  
g.setColor(getRandColor(random,160,200)); 
g.setFont(new Font("Times New Roman",Font.PLAIN,14)); 
for (int i=0;i<6;i++) 
{ 
g.drawString("*********************************************",0,5*(i+2)); 
} 




//取随机产生的认证码(6个汉字) 


//保存生成的汉字字符串  
String sRand=""; 
for (int i=0;i<4;i++) 
{ 
int start = random.nextInt(length); 
String rand=base.substring(start,start+1); 
sRand+=rand; 

//设置字体的颜色 
g.setColor(getRandColor(random,10,150)); 
//设置字体 
g.setFont(new Font(fontTypes[random.nextInt(fontTypesLength)],Font.BOLD,18 + random.nextInt(6))); 
//将此汉字画到图片上 
g.drawString(rand,24*i+ 10 + random.nextInt(8),24); 
} 


session.setAttribute("rand",sRand); 


g.dispose(); 


ImageIO.write(image, "JPEG", response.getOutputStream()); 

%>

8. 想用java做个网站的自动注册，谁知道怎么写，都用哪些类和方法

先采纳，我帮你做