最近在学习java的Swing编程，用java参照课本写了个字符串替换的程序，把代码贴出来与大家分享，如有不妥之处，还望指正。

text.java文件

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class text extends JFrame implements ActionListener{
	private JTextArea tarea;
	private JTextField tfObj1,tfObj2;
	private JButton btnFind;
	private JButton btnReplace;
	private JButton btnExit;
	private JPanel pObj1,pObj2,pObj3,pObj4,pObj5;
	private JLabel labObj1,labObj2,labObj3;
	boolean boolObj=false;
	JDialog diaObj;
	JLabel textLab;
	JButton butObj2=new JButton("OK");
	public text(){
		setTitle("文本的替换与查找");
		setSize(500,200);
		setVisible(true);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		
		tarea = new JTextArea();
		JScrollPane scroller = new JScrollPane(tarea);
		tfObj1=new JTextField();
		tfObj2=new JTextField();
		
		btnFind=new JButton("Find");
		btnReplace=new JButton("Replace");
		btnExit=new JButton("Exit");
		
		labObj1=new JLabel("文本区域(从光标处开始查找):");
		labObj2=new JLabel("待查找或替换前的字符串:");
		labObj3=new JLabel("替换后的字符串");
		
		pObj1=new JPanel();
		pObj2=new JPanel();
		pObj3=new JPanel();
		pObj4=new JPanel();
		pObj5=new JPanel();
		pObj1.setLayout(new BorderLayout());
		pObj1.add("North", labObj1);
		pObj1.add("Center", scroller);
		
		pObj2.setLayout(new BorderLayout());
		pObj2.add("North",labObj2);
		pObj2.add("Center", tfObj1);
		
		pObj3.setLayout(new BorderLayout());
		pObj3.add("North", labObj3);
		pObj3.add("Center", tfObj2);
		
		pObj4.setLayout(new GridLayout(1,3));
		pObj4.add(btnFind);
		pObj4.add(btnReplace);//面板pObj4用于控制Find、Replace和Exit按钮的相对位置
		pObj4.add(btnExit);
		
		pObj5.setLayout(new GridLayout(3,1));
		pObj5.add(pObj2);
		pObj5.add(pObj3);
		pObj5.add(pObj4);
		
		setLayout(new GridLayout(1,2));
		add(pObj1);
		add(pObj5);
		
		validate();//确保组件有有效的布局
		
		btnFind.addActionListener(this);
		btnReplace.addActionListener(this);
		btnReplace.addActionListener(this);
		
		diaObj=new JDialog(this);
		diaObj.setLayout(new FlowLayout(FlowLayout.CENTER,40,40));
		textLab=new JLabel("");
		diaObj.add(textLab);
		diaObj.add(butObj2);
		butObj2.addActionListener(this);//创建一个对话框，当用户单击Find或Replace按钮后，
		diaObj.setSize(200, 200);       //显示一个呈现结果信息的对话框，对话框上有一个Label组件
										//和一个OK按钮，Label组件用于显示查找或替换字符串的次数
	}
	public void actionPerformed(ActionEvent e){
		JButton butObj=(JButton)(e.getSource());//获得事件源按钮
		if(butObj.getLabel()=="Exit"){
			System.exit(0);
		}
		if(butObj.getLabel()=="OK"){
			diaObj.setVisible(false);
		}
		if(butObj.getLabel()=="Find"||butObj.getLabel()=="Replace"){
			String str1=tarea.getText();
			String str2=tfObj1.getText();
			
			int matchNum=0;//存放字符串匹配词数，初值为0
			//int cursorPos=tarea.getCaretPosition();从光标开始的地方统计
			int cursorPos=0;
			matchFun classObj=new matchFun();
			if(butObj.getLabel()=="Find"){
				//System.out.println("Find:"+str1);
				
				
				
				matchNum=classObj.strFind(str1,str2,cursorPos);
				textLab.setText("共找到"+matchNum+"处");
				diaObj.show();//显示查找结果对话框
			}
			if(butObj.getLabel()=="Replace"){
				String str3=tfObj2.getText();
				matchNum = classObj.strReplace(str1,str2,str3,cursorPos);
				textLab.setText("共替换到"+matchNum+"处");
				diaObj.show();
				StringBuffer taText=classObj.repStr;
				tarea.setText(taText.toString());
			}
		}
	}
}

matchFun.java文件

/*类matchFun用于处理有关字符串查找和替换的算法*/
public class matchFun {
	StringBuffer repStr;
	public int strFind(String s1,String s2,int pos){
		//用于实现字符串的查找，返回匹配的次数
		int i,j,k=0;
		i=pos;
		j=0;
		//变量i和j分别表示主串和模式串中当前字符串的位置，
		//k表示匹配次数，pos代表主串中开始比较的位置
		while(i<s1.length()&&j<s2.length()){
			if(s1.charAt(i)==s2.charAt(j)){
				++i;++j;
				if(j==s2.length()){
					k=k+1;
					i=i-j+1;
					j=0;
				}
			}
			else{
				i=i-j+1;
				j=0;
			}
		}
		return k;
	}
	public int strReplace(String s1,String s2,String s3,int pos){
		int i,j,k=0;
		i=pos;
		j=0;
		repStr=new StringBuffer(s1);
		while(i<repStr.length()&&j<s2.length()){
			if(repStr.charAt(i)==s2.charAt(j)){
				++i;++j;
				if(j==s2.length()){
					k=k+1;
					
					repStr.replace(i-j, i, s3);
					j=0;//将j进行重新赋值开始比较
				}
			}
			else{
				i=i-j+1;
				j=0;
			}
		}
		System.out.println("返回的k="+k);
		return k;
	}	
}

TextFindReplace.java主程序

public class TextFindReplace {
	public static void main(String[] args){
		new text();
	}
}

运行后为

点击Replace,程序变为（其中“我”改变为了“你”）

文字替换程序