IO--FileReader和FileWriter

FileReader

從文件中讀取消息

package Inputoutputcopy;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

/*
 * 文件字符輸入流
 * 
 */
public class fileread {

	public static void main(String[] args) {
		
		//創建源
		File file = new File("dest.txt");
		
		//選擇流
		Reader read =  null;
		
		try {
			read=  new FileReader(file);
			
			char[] ch = new char[1024];
			
			int len =-1;//接受長度
			 
			while((len=read.read(ch))!=-1) {
				//字符數組到字符串
				String str = new String(ch,0,len);
				
				System.out.println(str);
			}
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			if(read!=null) {
				try {
					read.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		
		
	}

}

FileWriter

往文件中寫入消息

package Inputoutputcopy;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;

public class filewritw {

	public static void main(String[] args) {
		
		//創建源
		File file = new File("dest.txt");
		
		//選擇流
		Writer writer = null;
		
		try {
			//操作
			writer = new FileWriter(file);
			
			//方法一
			String str = "josephus is so handsome";
			char[] ch= str.toCharArray();//字符串--》字符數粗
			writer.write(ch,0,ch.length);
			writer.flush();
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			if(writer!=null) {
				try {
					writer.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		
	}

}

其中註釋方法一的地方還可以改爲
直接

writer(String)

//方法二
String str = "josephus is so handsome yes";
writer.write(str,0,str.length());
writer.flush();//刷新流 刷新之後再close

最後一個方法三

append

append的優點是可以直接通過writer對象調用，而且還可以連續調用
如：

writer.append("josephus is ").append("very ").append("handsome!");
writer.flush();//刷新不能少