FileWriter

Java FileWriter 用於往檔案中寫入字元資料。
不像FileOutputStream類，你無需轉換字串成位元組陣列，因為它提供了直接寫字串的方法。

類定義

public class FileWriter
extends OutputStreamWriter

建構函式

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

請參考：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 用於從檔案中讀取資料。返回字元資料。

類定義

public class FileReader
extends InputStreamReader

建構函式

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

具體請參考：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();
    }
}