Question

java文本操作 删除文本中的某一行（或一个对象）

用java代码控制文本操作，
要求：具有增删改的功能
在修改时最好不要用以下方法
String s=文本内容;
然后change s的内容
最后将s写入文件，覆盖以前的内容。
asasas2002,我把多个对象存文本里面了，如何在文本删除其中一个对象,
问题解决，追加100

Answer 1

你说的不就是一个记事本吗，

//import java packages
import java.awt.*;
import java.awt.event.*;
import java.text.*;
import java.util.*;
import java.io.*;
import javax.swing.undo.*;
import javax.swing.border.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import java.awt.datatransfer.*;

public class Notepad extends JFrame implements ActionListener,DocumentListener{

//定义变量

//菜单
JMenu fileMenu,editMenu,formatMenu,viewMenu,helpMenu;

//"文件"的菜单项
JMenuItem fileMenu_New,fileMenu_Open,fileMenu_Save,fileMenu_SaveAs,fileMenu_PageSetup,fileMenu_Print,fileMenu_Exit;

//"编辑"的菜单项
JMenuItem editMenu_Undo,editMenu_Redo,editMenu_Cut,editMenu_Copy,editMenu_Paste,editMenu_Delete,editMenu_Find,editMenu_FindNext,editMenu_Replace,
editMenu_GoTo,editMenu_SelectAll,editMenu_TimeDate;

//"格式"的菜单项
JCheckBoxMenuItem formatMenu_LineWrap;
JMenu formatMenu_Color;
JMenuItem formatMenu_Font,formatMenu_Color_FgColor,formatMenu_Color_BgColor;

//"查看"的菜单项
JCheckBoxMenuItem viewMenu_Status;

//"帮助"的菜单项
JMenuItem helpMenu_HelpTopics,helpMenu_About;

//文本编辑区域
JTextArea editArea;

//状态栏标签
JLabel statusLabel;

//弹出菜单及菜单项
JPopupMenu popupMenu;
JMenuItem popupMenu_Undo,popupMenu_Redo,popupMenu_Cut,popupMenu_Copy,popupMenu_Paste,popupMenu_Delete,popupMenu_SelectAll;

//系统剪贴板
Toolkit toolKit=Toolkit.getDefaultToolkit();
Clipboard clipBoard=toolKit.getSystemClipboard();

//其它变量
boolean isNewFile=true; //是否新文件(未保存过的)
File currentFile; //当前文件名
String oldValue; //存放编辑区原来的内容，用于比较文本是否有改动
JButton fontOkButton; //字体设置里的"确定"按钮

//工具栏按钮
JButton newButton,openButton,saveButton,saveAsButton,printButton,undoButton,redoButton,
cutButton,copyButton,pasteButton,deleteButton,searchButton,timeButton,fontButton,
boldButton,italicButton,fgcolorButton,bgcolorButton,helpButton;

//创建撤消操作管理器
protected UndoManager undo = new UndoManager();
protected UndoableEditListener undoHandler = new UndoHandler();

//设置编辑区默认字体
protected Font defaultFont=new Font("宋体",Font.PLAIN,12);

//构造函数开始
public Notepad()
{
super("黄斌的记事本");

//获取容器
Container container=getContentPane();

//创建菜单条
JMenuBar menuBar = new JMenuBar();

//创建文件菜单及菜单项并注册事件监听
JMenu fileMenu = new JMenu("文件(F)", true);
fileMenu.setMnemonic('F');

fileMenu_New = new JMenuItem("新建(N)", 'N');
fileMenu_New.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N, InputEvent.CTRL_MASK));
fileMenu_New.addActionListener(this);

fileMenu_Open = new JMenuItem("打开(O)...", 'O');
fileMenu_Open.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O, InputEvent.CTRL_MASK));
fileMenu_Open.addActionListener(this);

fileMenu_Save = new JMenuItem("保存(S)", 'S');
fileMenu_Save.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, InputEvent.CTRL_MASK));
fileMenu_Save.addActionListener(this);

fileMenu_SaveAs = new JMenuItem("另存为(A)...", 'A');
fileMenu_SaveAs.addActionListener(this);

fileMenu_PageSetup = new JMenuItem("页面设置(U)...",'U');
fileMenu_PageSetup.addActionListener(this);

fileMenu_Print = new JMenuItem("打印(P)...", 'P');
fileMenu_Print.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_P, InputEvent.CTRL_MASK));
fileMenu_Print.addActionListener(this);

fileMenu_Exit = new JMenuItem("退出(X)",'X');
fileMenu_Exit.addActionListener(this);

//创建编辑菜单及菜单项并注册事件监听
JMenu editMenu = new JMenu("编辑(E)", true);
editMenu.setMnemonic('E');
editMenu.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e){
checkMenuItemEnabled();//设置剪切、复制、粘贴、删除等功能的可用性
}
}
);

editMenu_Undo = new JMenuItem("撤消(U)",'U');
editMenu_Undo.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Z, InputEvent.CTRL_MASK));
editMenu_Undo.addActionListener(this);
editMenu_Undo.setEnabled(false);

editMenu_Redo = new JMenuItem("重做(R)",'R');
editMenu_Redo.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Y,InputEvent.CTRL_MASK));
editMenu_Redo.addActionListener(this);
editMenu_Redo.setEnabled(false);

editMenu_Cut = new JMenuItem("剪切(T)",'T');
editMenu_Cut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X, InputEvent.CTRL_MASK));
editMenu_Cut.addActionListener(this);

editMenu_Copy = new JMenuItem("复制(C)",'C');
editMenu_Copy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.CTRL_MASK));
editMenu_Copy.addActionListener(this);

editMenu_Paste = new JMenuItem("粘贴(P)",'P');
editMenu_Paste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V, InputEvent.CTRL_MASK));
editMenu_Paste.addActionListener(this);

editMenu_Delete = new JMenuItem("删除(L)",'L');
editMenu_Delete.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0));
editMenu_Delete.addActionListener(this);

editMenu_Find = new JMenuItem("查找(F)...",'F');
editMenu_Find.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F, InputEvent.CTRL_MASK));
editMenu_Find.addActionListener(this);

editMenu_FindNext = new JMenuItem("查找下一个(N)",'N');
editMenu_FindNext.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F3,0));
editMenu_FindNext.addActionListener(this);

editMenu_Replace = new JMenuItem("替换(R)...",'R');
editMenu_Replace.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_H, InputEvent.CTRL_MASK));
editMenu_Replace.addActionListener(this);

editMenu_GoTo = new JMenuItem("转到(G)...",'G');
editMenu_GoTo.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_G, InputEvent.CTRL_MASK));
editMenu_GoTo.addActionListener(this);

editMenu_SelectAll = new JMenuItem("全选",'A');
editMenu_SelectAll.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_A, InputEvent.CTRL_MASK));
editMenu_SelectAll.addActionListener(this);

editMenu_TimeDate = new JMenuItem("时间/日期(D)",'D');
editMenu_TimeDate.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F5,0));
editMenu_TimeDate.addActionListener(this);

//创建格式菜单及菜单项并注册事件监听
JMenu formatMenu = new JMenu("格式(O)", true);
formatMenu.setMnemonic('O');

formatMenu_LineWrap = new JCheckBoxMenuItem("自动换行(W)");
formatMenu_LineWrap.setMnemonic('W');
formatMenu_LineWrap.setState(true);
formatMenu_LineWrap.addActionListener(this);

formatMenu_Font = new JMenuItem("字体(F)...",'F');
formatMenu_Font.addActionListener(this);

formatMenu_Color = new JMenu("设置颜色");
formatMenu_Color_FgColor=new JMenuItem("字体颜色");
formatMenu_Color_FgColor.addActionListener(this);
formatMenu_Color_BgColor=new JMenuItem("背景颜色");
formatMenu_Color_BgColor.addActionListener(this);

//创建查看菜单及菜单项并注册事件监听
JMenu viewMenu = new JMenu("查看(V)", true);
viewMenu.setMnemonic('V');

viewMenu_Status = new JCheckBoxMenuItem("状态栏(S)");
viewMenu_Status.setMnemonic('S');
viewMenu_Status.setState(true);
viewMenu_Status.addActionListener(this);

//创建帮助菜单及菜单项并注册事件监听
JMenu helpMenu = new JMenu("帮助(H)", true);
helpMenu.setMnemonic('H');

helpMenu_HelpTopics = new JMenuItem("帮助主题(H)",'H');
helpMenu_HelpTopics.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_F1,0));
helpMenu_HelpTopics.addActionListener(this);

helpMenu_About = new JMenuItem("关于记事本(A)",'A');
helpMenu_About.addActionListener(this);

//向菜单条添加"文件"菜单及菜单项
menuBar.add(fileMenu);
fileMenu.add(fileMenu_New);
fileMenu.add(fileMenu_Open);
fileMenu.add(fileMenu_Save);
fileMenu.add(fileMenu_SaveAs);
fileMenu.addSeparator(); //分隔线
fileMenu.add(fileMenu_PageSetup);
fileMenu.add(fileMenu_Print);
fileMenu.addSeparator(); //分隔线
fileMenu.add(fileMenu_Exit);

//向菜单条添加"编辑"菜单及菜单项
menuBar.add(editMenu);
editMenu.add(editMenu_Undo);
editMenu.add(editMenu_Redo);
editMenu.addSeparator(); //分隔线
editMenu.add(editMenu_Cut);
editMenu.add(editMenu_Copy);
editMenu.add(editMenu_Paste);
editMenu.add(editMenu_Delete);
editMenu.addSeparator(); //分隔线
editMenu.add(editMenu_Find);
editMenu.add(editMenu_FindNext);
editMenu.add(editMenu_Replace);
editMenu.add(editMenu_GoTo);
editMenu.addSeparator(); //分隔线
editMenu.add(editMenu_SelectAll);
editMenu.add(editMenu_TimeDate);

//向菜单条添加"格式"菜单及菜单项
menuBar.add(formatMenu);
formatMenu.add(formatMenu_LineWrap);
formatMenu.add(formatMenu_Font);
formatMenu.addSeparator();
formatMenu.add(formatMenu_Color);
formatMenu_Color.add(formatMenu_Color_FgColor);
formatMenu_Color.add(formatMenu_Color_BgColor);

//向菜单条添加"查看"菜单及菜单项
menuBar.add(viewMenu);
viewMenu.add(viewMenu_Status);

//向菜单条添加"帮助"菜单及菜单项
menuBar.add(helpMenu);
helpMenu.add(helpMenu_HelpTopics);
helpMenu.addSeparator();
helpMenu.add(helpMenu_About);

//向窗口添加菜单条
this.setJMenuBar(menuBar);

//创建文本编辑区并添加滚动条
editArea=new JTextArea(20,50);
JScrollPane scroller=new JScrollPane(editArea);
scroller.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
container.add(scroller,BorderLayout.CENTER);//向容器添加文本编辑区
editArea.setWrapStyleWord(true); //设置单词在一行不足容纳时换行
editArea.setLineWrap(true); //设置文本编辑区自动换行默认为true,即会"自动换行"
editArea.setFont(defaultFont); //设置编辑区默认字体
editArea.setBackground(Color.white); //设置编辑区默认背景色
editArea.setForeground(Color.black); //设置编辑区默认前景色
oldValue=editArea.getText(); //获取原文本编辑区的内容

//编辑区注册事件监听
editArea.getDocument().addUndoableEditListener(undoHandler);
editArea.getDocument().addDocumentListener(this);

//创建右键弹出菜单
popupMenu=new JPopupMenu();
popupMenu_Undo=new JMenuItem("撤消(U)",'U');
popupMenu_Redo=new JMenuItem("重做(R)",'R');
popupMenu_Cut =new JMenuItem("剪切(T)",'T');
popupMenu_Copy=new JMenuItem("复制(C)",'C');
popupMenu_Paste=new JMenuItem("粘贴(P)",'P');
popupMenu_Delete=new JMenuItem("删除(D)",'D');
popupMenu_SelectAll=new JMenuItem("全选(A)",'A');

popupMenu_Undo.setEnabled(false); //撤消选项初始设为不可用
popupMenu_Redo.setEnabled(false); //重做选项初始设为不可用

//向右键菜单添加菜单项和分隔符
popupMenu.add(popupMenu_Undo);
popupMenu.add(popupMenu_Redo);
popupMenu.addSeparator();
popupMenu.add(popupMenu_Cut);
popupMenu.add(popupMenu_Copy);
popupMenu.add(popupMenu_Paste);
popupMenu.add(popupMenu_Delete);
popupMenu.addSeparator();
popupMenu.add(popupMenu_SelectAll);

//右键菜单注册事件
popupMenu_Undo.addActionListener(this);
popupMenu_Redo.addActionListener(this);
popupMenu_Cut.addActionListener(this);
popupMenu_Copy.addActionListener(this);
popupMenu_Paste.addActionListener(this);
popupMenu_Delete.addActionListener(this);
popupMenu_SelectAll.addActionListener(this);

//文本编辑区注册右键菜单事件
editArea.addMouseListener(
new MouseAdapter(){
public void mousePressed(MouseEvent e)
{
checkForTriggerEvent(e);
}

public void mouseReleased(MouseEvent e)
{
checkForTriggerEvent(e);
}

private void checkForTriggerEvent(MouseEvent e)
{
if(e.isPopupTrigger())
popupMenu.show(e.getComponent(),e.getX(),e.getY());
checkMenuItemEnabled(); //设置剪切、复制、粘贴、删除等功能的可用性
editArea.requestFocus(); //编辑区获取焦点
}

});

//创建工具栏
JPanel toolBar=new JPanel();
toolBar.setLayout(new FlowLayout(FlowLayout.LEFT));

Icon newIcon=new ImageIcon("Icons/new.gif");
Icon openIcon=new ImageIcon("Icons/open.gif");
Icon saveIcon=new ImageIcon("Icons/save.gif");
Icon saveAsIcon=new ImageIcon("Icons/saveas.gif");
Icon printIcon=new ImageIcon("Icons/print.gif");
Icon undoIcon=new ImageIcon("Icons/undo.gif");
Icon redoIcon=new ImageIcon("Icons/redo.gif");
Icon cutIcon=new ImageIcon("Icons/cut.gif");
Icon copyIcon=new ImageIcon("Icons/copy.gif");
Icon pasteIcon=new ImageIcon("Icons/paste.gif");
Icon deleteIcon=new ImageIcon("Icons/delete.gif");
Icon searchIcon=new ImageIcon("Icons/search.gif");
Icon timeIcon=new ImageIcon("Icons/time.gif");
Icon fontIcon=new ImageIcon("Icons/font.gif");
Icon boldIcon=new ImageIcon("Icons/bold.gif");
Icon italicIcon=new ImageIcon("Icons/italic.gif");
Icon bgcolorIcon=new ImageIcon("Icons/bgcolor.gif");
Icon fgcolorIcon=new ImageIcon("Icons/fgcolor.gif");
Icon helpIcon=new ImageIcon("Icons/help.gif");

newButton= new JButton(newIcon);
openButton=new JButton(openIcon);
saveButton= new JButton(saveIcon);
saveAsButton=new JButton(saveAsIcon);
printButton=new JButton(printIcon);
undoButton=new JButton(undoIcon);
undoButton.setEnabled(false);
redoButton=new JButton(redoIcon);
redoButton.setEnabled(false);
cutButton=new JButton(cutIcon);
cutButton.setEnabled(false);
copyButton=new JButton(copyIcon);
copyButton.setEnabled(false);
pasteButton=new JButton(pasteIcon);
pasteButton.setEnabled(false);
deleteButton=new JButton(deleteIcon);
deleteButton.setEnabled(false);
searchButton=new JButton(searchIcon);
timeButton=new JButton(timeIcon);
fontButton=new JButton(fontIcon);
boldButton=new JButton(boldIcon);
italicButton=new JButton(italicIcon);
fgcolorButton=new JButton(fgcolorIcon);
bgcolorButton=new JButton(bgcolorIcon);
helpButton=new JButton(helpIcon);

newButton.setPreferredSize(new Dimension(22,22));
openButton.setPreferredSize(new Dimension(22,22));
saveButton.setPreferredSize(new Dimension(22,22));
saveAsButton.setPreferredSize(new Dimension(22,22));
printButton.setPreferredSize(new Dimension(22,22));
undoButton.setPreferredSize(new Dimension(22,22));
redoButton.setPreferredSize(new Dimension(22,22));
cutButton.setPreferredSize(new Dimension(22,22));
copyButton.setPreferredSize(new Dimension(22,22));
pasteButton.setPreferredSize(new Dimension(22,22));
deleteButton.setPreferredSize(new Dimension(22,22));
searchButton.setPreferredSize(new Dimension(22,22));
timeButton.setPreferredSize(new Dimension(22,22));
fontButton.setPreferredSize(new Dimension(22,22));
boldButton.setPreferredSize(new Dimension(22,22));
italicButton.setPreferredSize(new Dimension(22,22));
fgcolorButton.setPreferredSize(new Dimension(22,22));
bgcolorButton.setPreferredSize(new Dimension(22,22));
helpButton.setPreferredSize(new Dimension(22,22));

//注册工具栏按钮事件
newButton.addActionListener(this);
openButton.addActionListener(this);
saveButton.addActionListener(this);
saveAsButton.addActionListener(this);
printButton.addActionListener(this);
undoButton.addActionListener(this);
redoButton.addActionListener(this);
cutButton.addActionListener(this);
copyButton.addActionListener(this);
pasteButton.addActionListener(this);
deleteButton.addActionListener(this);
searchButton.addActionListener(this);
timeButton.addActionListener(this);
fontButton.addActionListener(this);
boldButton.addActionListener(this);
italicButton.addActionListener(this);
fgcolorButton.addActionListener(this);
bgcolorButton.addActionListener(this);
helpButton.addActionListener(this);

Answer 2

多个对象是什么对象？
计事本里只能存文字列吧，
把你存的那段代码拿出来，或者把你存的操作说一下

主要思想是，打开这个文件，把这个文件的内容读取到一个Vector里面，
然后再对文本内容进行改变，改变好的放在Vector2里面。最后把Vector2的内容输出到同一个文件里。
附上代码：
/*
* JiShiBen.java
*
*
*删除文本中的某一行（或一个对象）
*要求：具有增删改的功能
*在修改时最好不要用以下方法
*String s=文本内容;
*然后change s的内容
*最后将s写入文件，覆盖以前的内容。
*
*
*/
package FileXml;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Vector;

/**
* @author songml
*
*/
public class JiShiBen {

/**
* @param args
*/
public static void main(String args[]){
File f_obj1;

String path1 = "";
path1 = "D:\\1.txt" ;

String outPath = path1;

f_obj1 = new File (path1);
if (!f_obj1.exists()) {
System.out.println("SourceFile \"" + path1 + "\" is not exist!");
return;
}
BufferedReader br;
try{
br = new BufferedReader(new FileReader(path1));
String s = "";
String s2 = "";
int intCountNo = 0;
Vector vector = new Vector();
Vector vector2 = new Vector();

while((s=br.readLine())!= null) {
vector.add(s);
}
for (int i = 0; i < vector.size(); i++) {
s = (String)vector.get(i);
System.out.println(s);
if (isExsit("1",s)) {
vector2.add(s.replaceAll("1", "2"));
System.out.println(s);
} else {
vector2.add(s);
}

}
PrintWriter pw = new PrintWriter(new FileWriter(outPath));
for (int i = 0; i < vector2.size(); i++) {
s2 = (String)vector2.get(i);
intCountNo++;
pw.println(s2);
pw.flush();
}
System.out.println("OK! Number is :"+intCountNo);
System.out.println("OutPath is :"+outPath);

}catch(IOException e){
System.out.println("File Create Error!");
}
}

/**
* @param str
* @param s
* @return isExsit
*/
public static boolean isExsit (String str,String s) {
boolean Flg =false;
if (s.indexOf(str) != -1) {
Flg = true;
}
return Flg;
}

}

Answer 3

对文本文件进行操作,可以直接追加一行.但无法直接删除其中一行!!!!
无论JAVA还是其它语言都不行!!!
只能把文本内容读入内存,修改后再全部保存,覆盖原来的内容...

Answer 4

搜索一个开源的记事本看看～