IO流--標準步驟+文件字節流

標準步驟

1.創建源
2.選擇流
3.操作
4.釋放

package Input;

/*
 * 標準步驟
 * 1.創建源
 * 2.選擇流
 * 3.操作
 * 4.釋放
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class input1 {

	public static void main(String[] args) {

		File s = new File("abc.txt");// 1.創建源

		InputStream is = null;

		int t;
		try {
			is = new FileInputStream(s);// 2.選擇流
			while ((t = is.read()) != -1) {// 3.操作
				System.out.println((char) t);
			}
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (is != null) {
				try {
					is.close();// 4.釋放
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
}

文件字節流

FileInputStream

瞭解read的三種用法

package Input;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class fileinputstream {

	public static void main(String[] args) {
		
		File s = new File("abc.txt");
		
		InputStream is = null;
		
		try {
			is = new FileInputStream(s);
			
			byte[] flush = new byte [1024];//緩衝容器
			int len = -1;
			while((len=is.read(flush))!=-1) {
				
				//字節數組----》字符串 ：(解碼)
				String str = new String(flush,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(is!=null) {
				try {
					is.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
}

FileOutputStream

package Input;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class fileoutstream {

	public static void main(String[] args) {
	
		File dest = new File("dest.txt");
		
		OutputStream os = null;
		
		try {
			os = new FileOutputStream(dest);
			
			String str  = "Josephus is very handsome";
			byte[] by = str.getBytes();//字符串--》字節數組（編碼）
			os.write(by,0,by.length);
			os.flush();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			if(os!=null) {
				try {
					os.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}

	}

}

這裏只是修改文本內容，不能進行添加

把這個boolean的參數設置爲true就表示在文本後面添加內容

入門代碼多寫幾遍達到熟練（3~10遍）