Java I/O 教程（九） FileWriter和FileReader

FileWriter

Java FileWriter 用于往文件中写入字符数据。
不像FileOutputStream类，你无需转换字符串成字节数组，因为它提供了直接写字符串的方法。

类定义

public class FileWriter
extends OutputStreamWriter

构造函数

FileWriter(File file)

Constructs a FileWriter object given a File object.

FileWriter(File file, boolean append)

Constructs a FileWriter object given a File object.

FileWriter(FileDescriptor fd)

Constructs a FileWriter object associated with a file descriptor.

FileWriter(String fileName)

Constructs a FileWriter object given a file name.

FileWriter(String fileName, boolean append)

Constructs a FileWriter object given a file name with a boolean indicating whether or not to append the data written.

方法

• Methods inherited from class java.io.OutputStreamWriter

  close, flush, getEncoding, write, write, write

• Methods inherited from class java.io.Writer

  append, append, append, write, write

请参考：OutputStreamWriter

例子

package com.dylan.io;

import java.io.FileWriter;

/**
 * @author xusucheng
 * @create 2018-01-07
 **/
public class FileWriterExample {
    public static void main(String args[]){
        try{
            FileWriter fw=new FileWriter("D:\\testout.txt");
            fw.write("Welcome to java.io.");
            fw.close();
        }catch(Exception e){System.out.println(e);}
        System.out.println("Success...");
    }
}

FileReader

Java FileReader 用于从文件中读取数据。返回字符数据。

类定义

public class FileReader
extends InputStreamReader

构造函数

FileReader(File file)

Creates a new   FileReader, given the   File  to read from.

FileReader(FileDescriptor fd)

Creates a new   FileReader, given the   FileDescriptor  to read from.

FileReader(String fileName)

Creates a new   FileReader, given the name of the file to read from.

方法

• Methods inherited from class java.io.InputStreamReader

  close, getEncoding, read, read, ready

• Methods inherited from class java.io.Reader

  mark, markSupported, read, read, reset, skip

具体请参考：InputStreamReader

例子

package com.dylan.io;

import java.io.FileReader;

/**
 * @author xusucheng
 * @create 2018-01-07
 **/
public class FileReaderExample {
    public static void main(String args[])throws Exception{
        FileReader fr=new FileReader("D:\\testout.txt");
        int i;
        while((i=fr.read())!=-1)
            System.out.print((char)i);
        fr.close();
    }
}