编辑文本文件中的行

Question

我已经尝试过我在互联网上找到的这段代码

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();

但我的不会像这段代码那样输出。 这段代码的输出是这样的：

未编辑：

jojo moyes
kim possible
dexter laboratory

已编辑：当我输入“mary”来编辑“kim”时

jojo moyes
mary possible
dexter laboratoty

但我的会是这样

jojo moyes
kim possible
dexter laboratoy
mary possible

我的tho在编辑之前注册过。 并且在寄存器中还有时间在文本文件中存储一些东西。 如果用户想要编辑他输入的信息中的某些内容（你得到图片），就会有编辑功能

编辑：这是我的代码

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

此答案适用于您问题的第一部分。（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();
    }

当第一次提示打开时，我写“kim”和替换位置，我写“marry”和这样的输出。 我认为您的代码很好，只是不要对 FileWriter 使用append() 。 你应该对 FileWriter 使用write()方法。

编辑：使用不同的文件名（我不知道是否对同一文件进行读写操作。）用于FileWriter和初始化，您可以使用

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

如果问题得到解决，请告诉我。