使用Java在终端中替换两行 [英] Replacing two lines in the terminal using Java

问题描述

我知道如何使用Java通过替换上一行来将终端中的输出包含在一行中.例如:

I know how to use Java to have output in the terminal be contained in one line by replacing the previous line. For example:

System.out.print("old line");
Thread.sleep(3000);
System.out.print("\rnew line");

但是如果我有两行输出并且我想都替换掉

But what if I have two lines of output and I want both replaced

/* array must have length divisible by 2 */
public void doPrinting(String[] array) {
    for(int i = 0; i < array.length / 2; i++) {
        System.out.println(array[i*2]);
        System.out.println(array[i*2+1]);
        Thread.sleep(3000);
        //I imagine some fancy ascii crypticness shall go here?
    }

因此，如果我呼叫doPrinting(new String[]{"Old1", "Old2", "New1", "New2"})，则在Mac终端中应该看起来像这样:

So, if I call doPrinting(new String[]{"Old1", "Old2", "New1", "New2"}), this should look like, in the Mac terminal:

MyName$ java MyClass
Old1
Old2

然后暂停3秒钟，然后看起来像

and then pause for 3 seconds, and then look like

MyName$ java MyClass
New1
New2

我该怎么做?我在Mac OS上，并且正在通过终端运行Java主方法.理想的答案是添加代码以修改上面的doPrinting方法.

How can I do this? I'm on Mac OS and am running my Java main method through the terminal. The ideal answer would add code to modify the doPrinting method above.

更新:从下面回答一个之后，我尝试了此操作:

UPDATE: After one answer from below, I tried this:

String ANSI_CSI = "\\x1b[";
String[] array = {"old1","old2","new1","new2"};
System.out.print("\n\n");
for(int i = 0; i < array.length / 2; i++) {
    System.out.print(ANSI_CSI + "2A"); // Up 2
    System.out.print(ANSI_CSI + "K");  // Clear
    System.out.println(array[i*2]);
    System.out.print(ANSI_CSI + "K");  // Clear
    System.out.println(array[i*2+1]);
    Thread.sleep(3000);
 }

但这只是在终端上给我的输出

but that just gives me this output in the terminal

MyName$ MyClass


\x1b[2A\x1b[Kold1
\x1b[Kold2
\x1b[2A\x1b[Knew1
\x1b[Knew2

推荐答案

您将要使用 ANSI转义代码.

在这里，您可能会对向上移动光标"(CSI-A)和擦除行"(CSI-K)感兴趣.

Here, you'll probably be interested in "Move Cursor Up" (CSI-A) and "Erase line" (CSI-K).

// outside code
public static final String ANSI_CSI = "\x1b[";
// inside code
System.out.println("First line of text");
System.out.println("[  5/365]");
System.out.print(ANSI_CSI + "2A"); // up 2 lines
System.out.println("Different first line of text");
System.out.println("[ 11/365)");
System.out.print(ANSI_CSI + "A"); // up line
System.out.print(ANSI_CSI + "2K"); // erase all of line
System.out.print(ANSI_CSI + "A"); // up line
System.out.print(ANSI_CSI + "K"); // erase after cursor
System.out.println("Line one");
System.out.println("[240/365]");

如果要循环执行此操作(为简便起见，省略了System.out):

If you want to do this in a loop (System.out has been omitted for brevity):

// Init to safe state
print("\n\n");
for (loop conditions here) {
  print(ANSI_CSI + "2A"); // Up 2
  print(ANSI_CSI + "K");  // Clear
  println(text_a);        // Print + newline
  print(ANSI_CSI + "K");  // Clear
  println(text_b);        // Print + newline
  Thread.sleep(3000);     // Wait
}

请注意，您将需要使用支持这些功能的终端.查看Wikipedia文章以获取更多信息.如果它说某个代码在"ANSI.SYS"下具有不同的行为，则适用于默认的Windows命令提示符.

Note that you're going to need to use a terminal that supports these. Check the Wikipedia article for more information. If it says that a certain code has different behavior under "ANSI.SYS", then that applies to the default Windows command prompt.

我对Mac没有任何经验，因此您的体验可能会因不同的终端而异.

I don't have any experience with Macs, so your experience may vary with different terminals.

大多数备用终端和UNIX终端(gnome-terminal，PuTTY)更全面地支持这些代码(请参阅有关xterm的完全RGB支持的注释).

Most alternate and UNIX terminals (gnome-terminal, PuTTY) support these codes more fully (see the notes about xterm's full RGB support).

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