Question

我有以下代码用Java编辑我的.txt文件：

public static void editInfo() throws IOException
    {

        Scanner inFile2 = new Scanner( new FileReader ("FileOut.txt")); 

        int id_number = Integer.parseInt(JOptionPane.showInputDialog(
                "Enter Id number to be searched: "));   


        String copy = "";

        while (inFile2.hasNext())
            {   
            int idnumber = inFile2.nextInt();  
            String firstname = inFile2.next();
            String lastname = inFile2.next();
            if (id_number == idnumber)
            {
                firstname = JOptionPane.showInputDialog("Enter First Name : ");
                lastname = JOptionPane.showInputDialog("Enter Last Name : ");
                copy += idnumber + " " + firstname + " " + lastname + "\n";  
             } 
            else
            {
            copy += idnumber + " " + firstname + " " + lastname + "\n";
            }   
        }
        add(copy);  //Method that writes a string into the 
        JOptionPane.showMessageDialog(null, "Information Successfully updated" , "edit information" , JOptionPane.INFORMATION_MESSAGE);
          inFile2.close();
    }

我的问题是，还有其他更简单的方法可以在java中编辑文件吗？

Answer 1

以下是如何使用新的Java 7文件API（嗯，新... Java 8现在出来，所以这不是新的）：

// Read all lines from source file
final Path source = Paths.get("/path/to/source.txt");
final List<String> lines = Files.readAllLines(source, StandardCharsets.UTF_8);

// Ask for necessary information

// Update relevant line
boolean found;
int idnumber;
String line;
Scanner scanner;
for (int index = 0; index < lines.size(); index++) {
    line = lines.get(index);
    scanner = new Scanner(line);
    idnumber = scanner.nextInt();
    if (idnumber != id_number) // not the good line
        continue;
    found = true;
    firstname = JOptionPane.showInputDialog("Enter First Name : ");
    lastname = JOptionPane.showInputDialog("Enter Last Name : ");
    lines.set(index, String.format("%d %s %s", idnumber, firstname, lastname);
    break; // no need to go further
}

if (!found) {
    JOptionPane.showMessageDialog(null, "Index not found" , "oops" ,
        JOptionPane.WARNING_MESSAGE);
    return;
}

//Create a temporary file to write the modified contents
final Path tmpfile = Files.createTempFile("temp", ".txt");
try (
    final BufferedWriter writer = Files.newBufferedWriter(tmpfile,
        StandardCharsets.UTF_8);
) {
    for (final String line: lines) {
        writer.write(line);
        writer.newLine();
    }
}

// Rename to original file
Files.move(tmpfile, source, StandardCopyOption.REPLACE_EXISTING);
JOptionPane.showMessageDialog(null, "Information Successfully updated" ,
    "edit information" , JOptionPane.INFORMATION_MESSAGE);

Java：如何编辑文件

1 个答案: