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急！求一个简单Java程序实例，十分感谢！
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
class MyException extends Exception {
MyException(String message) {
System.out.println(message);
}
}
public class TDemo {
public static void main(String[] args) throws Exception {
File file = new File("d:\test.txt");
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(file));
String str;
while ((str = br.readLine()) != null) {
if (str == "error") {
throw new MyException("自定义异常");
}
System.out.println(str);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
用java设计一个简单的界面设计，越简单越好，谢谢
用java设计一个简单的界面可以参考如下实例：
import javax.swing.JFrame;//框架
import javax.swing.JPanel;//面板
import javax.swing.JButton;//按钮
import javax.swing.JLabel;//标签
import javax.swing.JTextField;//文本框
import java.awt.Font;//字体
import java.awt.Color;//颜色
import javax.swing.JPasswordField;//密码框
import java.awt.event.ActionListener;//事件监听
import java.awt.event.ActionEvent;//事件处理
import javax.swing.JOptionPane;//消息窗口public class UserLogIn extends JFrame{
public JPanel pnluser;
public JLabel lbluserLogIn;
public JLabel lbluserName;
public JLabel lbluserPWD;
public JTextField txtName;
public JPasswordField pwdPwd;
public JButton btnSub;
public JButton btnReset;
public UserLogIn(){
pnluser = new JPanel();
lbluserLogIn = new JLabel();
lbluserName = new JLabel();
lbluserPWD = new JLabel();
txtName = new JTextField();
pwdPwd = new JPasswordField();
btnSub = new JButton();
btnReset = new JButton();
userInit();
}
public void userInit(){
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置关闭框架的同时结束程序
this.setSize(300,200);//设置框架大小为长300,宽200
this.setResizable(false);//设置框架不可以改变大小
this.setTitle("用户登录");//设置框架标题
this.pnluser.setLayout(null);//设置面板布局管理
this.pnluser.setBackground(Color.cyan);//设置面板背景颜色
this.lbluserLogIn.setText("用户登录");//设置标签标题
this.lbluserLogIn.setFont(new Font("宋体",Font.BOLD | Font.ITALIC,14));//设置标签字体
this.lbluserLogIn.setForeground(Color.RED);//设置标签字体颜色
this.lbluserName.setText("用户名:");
this.lbluserPWD.setText("密 码:");
this.btnSub.setText("登录");
this.btnReset.setText("重置");
this.lbluserLogIn.setBounds(120,15,60,20);//设置标签x坐标120,y坐标15,长60,宽20
this.lbluserName.setBounds(50,55,60,20);
this.lbluserPWD.setBounds(50,85,60,25);
this.txtName.setBounds(110,55,120,20);
this.pwdPwd.setBounds(110,85,120,20);
this.btnSub.setBounds(85,120,60,20);
this.btnSub.addActionListener(new ActionListener()//匿名类实现ActionListener接口
{
public void actionPerformed(ActionEvent e){
btnsub_ActionEvent(e);
}
}
);
this.btnReset.setBounds(155,120,60,20);
this.btnReset.addActionListener(new ActionListener()//匿名类实现ActionListener接口
{
public void actionPerformed(ActionEvent e){
btnreset_ActionEvent(e);
}
}
);
this.pnluser.add(lbluserLogIn);//加载标签到面板
this.pnluser.add(lbluserName);
this.pnluser.add(lbluserPWD);
this.pnluser.add(txtName);
this.pnluser.add(pwdPwd);
this.pnluser.add(btnSub);
this.pnluser.add(btnReset);
this.add(pnluser);//加载面板到框架
this.setVisible(true);//设置框架可显
}
public void btnsub_ActionEvent(ActionEvent e){
String name = txtName.getText();
String pwd = String.valueOf(pwdPwd.getPassword());
if(name.equals("")){
JOptionPane.showMessageDialog(null,"账号不能为空","错误",JOptionPane.ERROR_MESSAGE);
return;
}else if (pwd.equals("")){
JOptionPane.showMessageDialog(null,"密码不能为空","错误",JOptionPane.ERROR_MESSAGE);
return;
}else if(true){
this.dispose();
}else{
JOptionPane.showMessageDialog(null,"账号或密码错误","错误",JOptionPane.ERROR_MESSAGE);
return;
}
}
public void btnreset_ActionEvent(ActionEvent e){
txtName.setText("");
pwdPwd.setText("");
}
public static void main(String[] args){
new UserLogIn();
}
}
用java编写一个简单例子，题目如下
package test;
public class Student {
private String name;
private String id;
private String clazz;
private int age;
private String address;
/**
* sayHello方法
*/
public void sayHello() {
System.out.println("学号为" + this.id + "的同学的具体信息如下：");
System.out.println("姓名：" + this.name);
System.out.println("班级：" + this.clazz);
System.out.println("年龄：" + this.age);
System.out.println("家庭住址：" + this.address);
}
/**
* 测试方法
*
* @param args
*/
public static void main(String[] args) {
// 第一问
Student student = new Student();
student.setAddress("百度知道");
student.setAge(1);
student.setClazz("一班");
student.setId("071251000");
student.setName("lsy605604013");
student.sayHello();
// 第二问
Student studentNew = new Student();
studentNew.setAddress("搜搜知道");
studentNew.setAge(2);
studentNew.setClazz("二班");
studentNew.setId("071251001");
studentNew.setName("lady");
if (student.getAge() studentNew.getAge())
studentNew.sayHello();
else if (student.getAge() studentNew.getAge())
student.sayHello();
else
System.out.println("两人一样大");
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getClazz() {
return clazz;
}
public void setClazz(String clazz) {
this.clazz = clazz;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
如何编写一个简单的java web前后端实例
你说的是一个完整的BS请求--响应模式，很多种方式都可以实现，
最简单的方法：写一个 form 表单，然后配置servlet ,提交数据到servlet,在servlet中实现你的逻辑如你保存数据库的操作，然后由servlet 转发到jsp 页面进行网页响应就可以了。ITjob的朋友跟我分享过的，发给你了不用谢~