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  • 文件操作二

    一、             字符输入流

    Reader:字符输入流。示例代码如下:

    import java.io.File;

    import java.io.FileReader;

    import java.io.Reader;

    public class ReaderDemo {

       /**

        * @param args

        * @throws Exception 

        */

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

         // TODO Auto-generated method stub

         File file=new File("c:"+File.separator+"hi.txt");

         Reader r=new FileReader(file);

         char[] c=new char[(int) file.length()];

         int len=r.read(c);

         System.out.println(new String(c,0,len));

         r.close();

       }

    }

    二、BufferedReader操作流:
    InputStreamReader:字节输入变为字符流

    OutputStreamWriter:字符的输出流变为字节的输出流

    使用BufferedReader完成键盘输入:

    import java.io.BufferedReader;

    import java.io.InputStreamReader;

    public class BufferedReaderDemo {

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

         // TODO Auto-generated method stub

         BufferedReader buf=null;

         System.out.println("输入内容:");

         buf=new BufferedReader(new InputStreamReader(System.in));

         System.out.println(buf.readLine());

       }

    }

    三、             打印流:

    打印流分为:PrintReader和PrintWriter。

    使用PrintStream示例

    import java.io.File;

    import java.io.FileOutputStream;

    import java.io.PrintStream;

    public class PrintWriterDemo {

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

         // TODO Auto-generated method stub

         File file=new File("c:"+File.separator+"hi.txt");

         PrintStream pr=new PrintStream(new FileOutputStream(file),true);

         pr.print("\r\nhello");

         pr.print("\r\nworld");

         pr.close();

       }

    }

    示例代码二:

    import java.io.PrintStream;

    public class PrintWriterDemo2 {

       /**

        * @param args

        * @throws Exception 

        */

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

         // TODO Auto-generated method stub

         PrintStream pr=new PrintStream(System.out);

         pr.print("\r\nhello");

         pr.print("\r\nworld");

         pr.close();

       }

    }

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  • 原文地址:https://www.cnblogs.com/itfenqing/p/4429545.html
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