Question

String id = filedda.getText();
String pass= filedda1.getText();
try {
    File inputFile = new File("E:/yoo.txt");
    File tempfile = new File("E:/mytempfile.txt");

    BufferedReader reader = new BufferedReader(new FileReader(inputFile));
    BufferedWriter writer = new BufferedWriter(new FileWriter(tempfile));

    String CurrentLine;

    while((CurrentLine = reader.readLine())!=null){
        if(CurrentLine.contains(id+pass)){
            CurrentLine= CurrentLine.replace(id+pass, "");

        }
        writer.write(CurrentLine);
        reader.close();
        writer.close();


        inputFile.delete();
        tempfile.renameTo(inputFile);
    }
} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

我想要它做的是：它将从文件中删除id + pass的字符串。

如果情景如此，它正在正确地进行，

abc
cde

我的id+pass= cde

文件输出：abc

但是如果是id+pass= abc，那么整个文件输出就变成什么了。

Answer 1

您应该只在while循环后关闭文件：

while(){
//...
}
reader.close();
writer.close();

Answer 2

您正在提前关闭文件。在这附近：

   }
        reader.close();
        writer.close();

} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();

此外，如果您正在使用Swing，请确保其EDT安全。

Answer 3

创建FileWriter时，您应该提供true作为参数，以表明您希望附加数据。 Shown here.

e.g：

BufferedWriter writer = new BufferedWriter(new FileWriter(tempfile, true));

如果我理解你的问题。

Answer 4

试试这段代码：

String id = filedda.getText();
        String pass= filedda1.getText();
        try {
            File inputFile = new File("E:/yoo.txt");
            File tempfile = new File("E:/mytempfile.txt");

            BufferedReader reader = new BufferedReader(new FileReader(inputFile));
            BufferedWriter writer = new BufferedWriter(new FileWriter(tempfile));

            String CurrentLine;

            while((CurrentLine = reader.readLine())!=null){
                if(CurrentLine.contains(id+pass)){
                    CurrentLine= CurrentLine.replace(id+pass, "");

                }

            }
                writer.write(CurrentLine);
                reader.close();
                writer.close();


                inputFile.delete();
                tempfile.renameTo(inputFile);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

难以从Java中删除文本文件中的行

4 个答案: