本文目录一览：
- 急！求一个简单Java程序实例，十分感谢！
- 用java设计一个简单的界面设计，越简单越好，谢谢
- 用java编写一个简单例子，题目如下
- [如何编写一个简单的java web前后端实例](#如何编写一个简单的java web前后端实例)
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;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JTextField;
import java.awt.Font;
import java.awt.Color;
import javax.swing.JPasswordField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JOptionPane;
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);
this.setSize(300, 200);
this.setResizable(false);
this.setTitle("用户登录");
this.pnluser.setLayout(null);
this.pnluser.setBackground(Color.cyan);
this.lbluserLogIn.setText("用户登录");
this.lbluserLogIn.setFont(new Font("宋体", Font.BOLD | Font.ITALIC, 14));
this.lbluserLogIn.setForeground(Color.RED);
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);
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() {
public void actionPerformed(ActionEvent e) {
btnsub_ActionEvent(e);
}
});
this.btnReset.setBounds(155, 120, 60, 20);
this.btnReset.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btnreset_ActionEvent(e);
}
});
this.pnluser.add(lbluserLogIn);
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);
this.setVisible(true);
}
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~
