将控制台输出重定向到 Java 中的字符串 [英] Redirect console output to string in Java
问题描述
我有一个方法,它的返回类型是void
,它直接在控制台上打印.
I have one method whose return type is void
and it prints directly on console.
但是我需要一个字符串中的输出,以便我可以处理它.
However I need that output in a String so that I can work on it.
由于我无法对返回类型为 void
的方法进行任何更改,因此我必须将该输出重定向到字符串.
As I can't make any changes to the method with return type void
I have to redirect that output to a String.
如何在 Java 中重定向它?
How can I redirect it in Java?
推荐答案
如果函数正在打印到 System.out
,您可以使用 System.setOut
捕获该输出code> 方法将 System.out
更改为您提供的 PrintStream
.如果您创建一个连接到 ByteArrayOutputStream
的 PrintStream
,那么您可以将输出捕获为 String
.
If the function is printing to System.out
, you can capture that output by using the System.setOut
method to change System.out
to go to a PrintStream
provided by you. If you create a PrintStream
connected to a ByteArrayOutputStream
, then you can capture the output as a String
.
示例:
// Create a stream to hold the output
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PrintStream ps = new PrintStream(baos);
// IMPORTANT: Save the old System.out!
PrintStream old = System.out;
// Tell Java to use your special stream
System.setOut(ps);
// Print some output: goes to your special stream
System.out.println("Foofoofoo!");
// Put things back
System.out.flush();
System.setOut(old);
// Show what happened
System.out.println("Here: " + baos.toString());
这个程序只打印一行:
Here: Foofoofoo!
这篇关于将控制台输出重定向到 Java 中的字符串的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!