你还要指定一输出对象呀,不然怎么知道你要输出到哪里?Constructor Summary
PrintStream(OutputStream out)
Create a new print stream.
PrintStream(OutputStream out, boolean autoFlush)
Create a new print stream.
PrintStream(OutputStream out, boolean autoFlush, String encoding)
Create a new print stream.
PrintStream(OutputStream out)
Create a new print stream.
PrintStream(OutputStream out, boolean autoFlush)
Create a new print stream.
PrintStream(OutputStream out, boolean autoFlush, String encoding)
Create a new print stream.
PrintStream p = new PrintStream((new FileOutputStream(filename)));