import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

//设置界面框架
public class text1_1 {
public static void main(String[] args) {
Win win = new Win();
win.setTitle("四则运算");
win.setBounds(0,0,500,200);
}
}

//设置界面
class Win extends JFrame{
Win(){
setLayout(null);
Container con = getContentPane();//设置底层容器
con.setBackground(Color.blue);
init();
setBounds(10,10,460,360);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void init(){
JButton button1 = new JButton("加法题目");
JTextArea textshow1 = new JTextArea();
JButton button2 = new JButton("减法题目");
JTextArea textshow2 = new JTextArea();
JButton button3 = new JButton("乘法题目");
JTextArea textshow3 = new JTextArea();
JButton button4 = new JButton("除法题目");
JTextArea textshow4 = new JTextArea();
JButton button6 = new JButton("重置");
textshow1.setFont(new Font("楷体",Font.BOLD,20));//修改字体样式
textshow2.setFont(new Font("楷体",Font.BOLD,20));
textshow3.setFont(new Font("楷体",Font.BOLD,20));
textshow4.setFont(new Font("楷体",Font.BOLD,20));
Listen listen = new Listen();
listen.setJTextArea1(textshow1);
listen.setJTextArea2(textshow2);
listen.setJTextArea3(textshow3);
listen.setJTextArea4(textshow4);
button1.addActionListener(listen);
button2.addActionListener(listen);
button3.addActionListener(listen);
button4.addActionListener(listen);
button6.addActionListener(listen);
button1.setBounds(10,10,100,25);
textshow1.setBounds(110,10,200,25);
button2.setBounds(10,40,100,25);
textshow2.setBounds(110,40,200,25);
button3.setBounds(10,70,100,25);
textshow3.setBounds(110,70,200,25);
button4.setBounds(10,100,100,25);
textshow4.setBounds(110,100,200,25);
button6.setBounds(350,50,100,25);
add(button1);
add(textshow1);
add(button2);
add(textshow2);
add(button3);
add(textshow3);
add(button4);
add(textshow4);
add(button6);
}
}

//设置监视器
class Listen implements ActionListener{
JTextArea textshow1;
JTextArea textshow2;
JTextArea textshow3;
JTextArea textshow4;
int numberOne;
int numberTwo;
public void setJTextArea1(JTextArea textshow1) 
{
this.textshow1 = textshow1;
}
public void setJTextArea2(JTextArea textshow2) 
{
this.textshow2 = textshow2;
}
public void setJTextArea3(JTextArea textshow3) 
{
this.textshow3 = textshow3;
}
public void setJTextArea4(JTextArea textshow4) 
{
this.textshow4 = textshow4;
}
public void setnumberOne(int numberOne)
{
this.numberOne = numberOne;
}
public void setnumberTwo(int numberTwo)
{
this.numberTwo = numberTwo;
}

public void actionPerformed(ActionEvent e) {
String str = e.getActionCommand();
if(str.equals("加法题目"))
{
numberOne = (int)(Math.random()*100);
numberTwo = (int)(Math.random()*100);
setnumberOne(numberOne);
setnumberTwo(numberTwo);
int sum1 = numberOne + numberTwo;
textshow1.append(numberOne+"+"+numberTwo+"="+sum1);
}
if(str.equals("减法题目"))
{
numberOne = (int)(Math.random()*100);
numberTwo = (int)(Math.random()*100);
setnumberOne(numberOne);
setnumberTwo(numberTwo);
int sum2 = numberOne - numberTwo;
textshow2.append(numberOne+"-"+numberTwo+"="+sum2);
}
if(str.equals("乘法题目"))
{
numberOne = (int)(Math.random()*100);
numberTwo = (int)(Math.random()*100);
setnumberOne(numberOne);
setnumberTwo(numberTwo);
int sum3 = numberOne * numberTwo;
textshow3.append(numberOne+"*"+numberTwo+"="+sum3);
}
if(str.equals("除法题目"))
{
numberOne = (int)(Math.random()*100);
numberTwo = (int)(Math.random()*100);
setnumberOne(numberOne);
setnumberTwo(numberTwo);
float sum4 =(float) numberOne / numberTwo;
textshow4.append(numberOne+"/"+numberTwo+"="+sum4);
}
if(str.equals("重置")){
textshow1.setText("");
textshow2.setText("");
textshow3.setText("");
textshow4.setText("");
}
}
}

　　以下是代码运行界面：

 其中界面颜色、按钮参数等可在代码中修改；通过点击加法/减法/乘法/除法题目，可以实现自动出题，点击重置则可以清除已有题目。