25.打印流

字数 196阅读 11

打印流,打印数据的,打印流只能是输出流

PrintStream:字节打印流.

PrintWriter:字符打印流.

  • -对于PrintWriter来说,当启用自动刷新之后.
PrintWriter ps = new PrintWriter(new FileOutputStream(new File("file/abc.txt")),true);

PrinterStream,即使不close也会刷新 ,PrintWriter需要调用println或者printf或者format方法.便会立马刷新操作.或者close.

如果没有开启自动刷新,则需要手动刷新或者当缓冲区满的时候,再自动刷新,使用打印流作为输出流,此时的输出操作会特别简单.

因为在打印流中:

提供了print方法:打印不换行

提供了println方法:打印再换行

print和println方法可以支持打印/输出各种数据类型,记住void println(Object obj)既可.

示例代码
    public static void main(String[] args) throws Exception {

        test1();
        
        test2();
    }
    
    //字符打印流
    private static void test1() throws Exception {
        // TODO Auto-generated method stub
        PrintWriter writer = new PrintWriter(new File("target/abc.txt"));
        writer.print("no ");
        writer.print("pain ");
        writer.print("in ");
        writer.print("the ");
        writer.print("world ");
        writer.print("comes ");
        writer.print("near ");
        writer.print("to ");
        writer.print("this!");
        
        writer.close();
    }
    
    //字节打印流
    private static void test2() throws Exception {
        // TODO Auto-generated method stub
        PrintStream p = new PrintStream(new File("target/aaa.txt"));
        p.print("no ");
        p.print("pain ");
        p.print("in ");
        p.print("the ");
        p.print("world ");
        p.print("comes ");
        p.print("near ");
        p.print("to ");
        p.print("this!");
        
        //p.close();
    }

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