如何在另一个类中解析args？

I have an issue about parsing args. I have a write method which is in WriteToFile class like this:

我有一个关于解析args的问题。我有一个WriteToFile类的write方法,如下所示:

public class WriteToFile {  

    public void write (String text){
        try{
            FileWriter writer = new FileWriter("output.txt",true);
            BufferedWriter write = new BufferedWriter(writer);

            write.write(text);
            write.newLine();
            write.close();
        }
        catch (Exception error){
            error.printStackTrace();
        }
    }

public class A {

    WriteToFile write = new WriteToFile();
    write.write(something);

}

public class B {

    WriteToFile write = new WriteToFile();
    write.write(something);

}

We need to change "output.txt" to args[1]. Normally adding one more argument to method is the solution but allowed only 3 line code changes. I tried to add a set method but write method used by multiple classes so it takes more than 3 lines to fix it. I tried to extend main class to get into scope, didn't work. Is there any way to do it?

我们需要将“output.txt”更改为args [1]。通常向方法添加一个参数是解决方案,但只允许3行代码更改。我尝试添加一个set方法但是写了多个类使用的方法,所以修复它需要3行以上。我试图扩展主类进入范围,没有工作。有什么办法吗?

3 个解决方案

#1

1) create new public field in the WriteToFile class (fileName)

1)在WriteToFile类(fileName)中创建新的公共字段

2) from main myWriter.fileName = args[1]

2)来自main myWriter.fileName = args [1]

3) FileWriter writer = new FileWriter(fileName, true);

3)FileWriter writer = new FileWriter(fileName,true);

// no change to the method signature called 100 times

//没有更改方法签名调用100次

Edit

If you are constructing many instances of WriteToFile all over the place, then use a static field in Main

如果要在整个地方构建WriteToFile的许多实例,那么在Main中使用静态字段

1) In Main public static String fileName;

1)在Main public static String fileName中;

2) from main Main.fileName = args[1]

2)来自main Main.fileName = args [1]

3) FileWriter writer = new FileWriter(Main.fileName, true);

3)FileWriter writer = new FileWriter(Main.fileName,true);

#2

Adding a parameter and using it when you call the method would only take three changes:

在调用方法时添加参数并使用它只需要进行三处更改:

// Change 1 - add a fileName parameter to the method
public void write (String text, String fileName) { 
    try{
        FileWriter writer = new FileWriter(fileName, true); // Change 2 - use it
        BufferedWriter write = new BufferedWriter(writer);

        write.write(text);
        write.newLine();
        write.close();
    }
    catch (Exception error){
        error.printStackTrace();
    }
}

// Change 3 - in the main method that calls this one, pass args[1]:
myWriter.write("someText", args[1]);

#3

public void write (String text, String filename) // 1
{
   FileWriter writer = new FileWriter(filename,true); // 2
   ...

In your main, do this while calling.

在你的主要部分,在打电话时这样做。

new WriteToFile().write(text, args[1]); // 3

These are exactly 3 line changes as shown by comments.

这些正好是3行更改,如注释所示。

#1