编辑线

Question

我试过这个代码，我在互联网

File file = new File("file.txt"); 
     BufferedReader reader = new BufferedReader(new FileReader(file)); 
     String line = "", oldtext = ""; 
     while((line = reader.readLine()) != null) 
      { 
      oldtext += line + "\n"; 

     } 
     reader.close(); 
     // replace a word in a file 
     //String newtext = oldtext.replaceAll("drink", "Love"); 

     //To replace a line in a file 
     String replace = JOptionPane.showInputDialog("Enter what to replace: "); 
     String toreplace = JOptionPane.showInputDialog("Enter where to replace: "); 
     String newtext = oldtext.replaceAll(replace, toreplace); 

     FileWriter writer = new FileWriter("file.txt"); 
     writer.append(newtext);writer.close(); 

发现，但我的不会这样的代码输出就可以了。这段代码的输出是这样的：

了unedit：

jojo moyes 
kim possible 
dexter laboratory 

编辑：当我进入 “玛丽” 编辑 “金”

jojo moyes 
mary possible 
dexter laboratoty 

但我的会是这样

jojo moyes 
kim possible 
dexter laboratoy 
mary possible 

我的寿命在编辑前已经注册。并且在寄存器中也有时间将它存储在文本文件中。而且，如果用户想要的信息进行编辑的东西，他进入（你的图片）

EDITED而来的编辑功能：这里是我的代码

public void Register_Edit_Info() throws IOException{ 
     FileWriter writeFile=new FileWriter("voters.txt", true); 
     BufferedWriter outFile=new BufferedWriter(writeFile); 
     File readFile=new File("voters.txt"); 
     BufferedReader read=new BufferedReader(new FileReader(readFile)); 

     String choice2; 
     String [] secondMenu = {"Register", "Edit", "Delete", "Back"}; 

     do{ 
      choice2=(String)JOptionPane.showInputDialog(null, "Please choose:", "Election 2765", 1, null, secondMenu, secondMenu[0]); 
      switch(choice2){ 
      case "Register": 
       String [] menuGender={"Male", "Female"}; 
       String [] menuStatus={"Single", "Married", "Widow(er)", "Legally separated"}; 

       do{ 
       age=Integer.parseInt(JOptionPane.showInputDialog("Age: ")); 
       while(age<18){ 
        JOptionPane.showMessageDialog(null, "Voter should be 18 or above"); 
        age=Integer.parseInt(JOptionPane.showInputDialog("Age: ")); 
       } 
       name=JOptionPane.showInputDialog("Full Name: "); 
       gender=(String)JOptionPane.showInputDialog(null, "Gender:", "Election 2765", 1, null, menuGender, menuGender[0]); 
       if(gender=="Male"){ 
        gender="Male"; 
       } 
       else{ 
        gender="Female"; 
       } 
       dBirth=JOptionPane.showInputDialog("Date of Birth: "); 
       pBirth=JOptionPane.showInputDialog("Place of Birth: "); 
       address=JOptionPane.showInputDialog("Address\n(Province, City/Municipality, Barangay, House No./Street: "); 
       status=(String)JOptionPane.showInputDialog(null, "Civil Status:", "Election 2765", 1, null, menuStatus, menuStatus[0]); 
       if(status=="Single"){ 
        status="Single"; 
       } 
       else if(status=="Married"){ 
        spouse=JOptionPane.showInputDialog("Spouse Name: "); 
        status="Married(Spouse: "+spouse+")"; 
       } 
       else if(status=="Widow(er)"){ 
        status="Widow(er)"; 
       } 
       else{ 
        status="Legally Separated"; 
       } 
       citizenship=JOptionPane.showInputDialog("Citizenship:"); 
       job=JOptionPane.showInputDialog("Profession/Occupation: "); 
       tin=JOptionPane.showInputDialog("Tin Number: "); 
       father=JOptionPane.showInputDialog("Father's Full Name: "); 
       mother=JOptionPane.showInputDialog("Mother's Full Name: "); 
       votersNumber++; 

       vNumber=Integer.toString(votersNumber); 

       outFile.append(vNumber+"/"+name+"/"+age+"/"+gender+"/"+dBirth+"/"+pBirth+"/"+address+"/"+status+"/"+citizenship+"/"+job+"/"+father+"/"+mother); 
       outFile.newLine(); 

       selectYN=JOptionPane.showInputDialog("You are now registered. Do you want to register more?\n[1]Yes [2]No"); 
       }while(!"2".equals(selectYN)); 

       break; 
      case "Edit": 
       vNumForEdit=JOptionPane.showInputDialog("Enter voters number: "); 
       String line=null, oldtext=""; 

       while((line=read.readLine())!=null){ 
        oldtext+=line+"\n"; 

        String [] info=line.split("/"); 
        if(info[0].matches(vNumForEdit)){ 
         String [] forEditMenu={"Name", "Age", "Gender", "Date of Birth", "Place of Birth", "Address", "Civil Status", "Citizenship", "Profession/Occupation", "Father's Name", "Mother's Name"}; 
         forEdit=(String)JOptionPane.showInputDialog(null, line+"\n\nPlease select what you want to edit", "National Election 2765", 1, null, forEditMenu, forEditMenu[0]); 
         switch(forEdit){ 
         case "Name": 
          oldName=JOptionPane.showInputDialog("Enter old name: "); 
          newName=JOptionPane.showInputDialog("Enter new name: "); 

          String newText = oldtext.replaceAll(oldName, newName); 
          outFile.append(newText);        
          break; 
         } 
        } 
       } 
      case "Delete": 
       break; 
      } 
     }while(choice2!="Back"); 
     read.close(); 
     outFile.close(); 
    } 

Answer 1

这个答案是对的第一部分的问题（编辑前）。

public static void main(String[] args) throws FileNotFoundException,IOException { 
     File file = new File("file.txt"); 
     BufferedReader reader = new BufferedReader(new FileReader(file)); 
     String line = "", oldtext = ""; 
     while((line = reader.readLine()) != null) 
      { 
      oldtext += line + "\n"; 

     } 
     reader.close(); 
     System.out.println(oldtext); 
     // replace a word in a file 
     //String newtext = oldtext.replaceAll("drink", "Love"); 

     //To replace a line in a file 
     String replace = JOptionPane.showInputDialog("Enter what to replace: "); 
     String toreplace = JOptionPane.showInputDialog("Enter where to replace: "); 
     String newtext = oldtext.replaceAll(replace, toreplace); 

     System.out.println(newtext); 
     java.io.FileWriter writer = new java.io.FileWriter("file1.txt"); 
     writer.write(newtext); 
     writer.close(); 
    } 

当第一次打开提示我写的“金”，并在那里更换，我写的“嫁”像这样的输出。我认为你的代码很好，除了不使用FileWriter的append()。您应该为FileWriter使用write()方法。

编辑： 使用不同的文件名（我不知道，如果读取和写入操作发生的同一文件）FileWriter和初始化，您可以使用

FileWriter writeFile=new FileWriter("voters1.txt"); 

让我知道问题是否解决。