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Java 文件io流

程序员文章站 2024-01-21 18:39:58
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package fileInputStream;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.Buffer;
import java.nio.CharBuffer;

public class FileInputStreamTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		
//		testFileMethod("D:\\workspace\\datafile","jjn.txt");
		
//		lsFile("D:\\workspace\\1");
		
		File file = new File("D:\\workspace\\datafile","jjn.txt");
		String str = "我是一只小小小鸟,飞呀飞呀,飞不高!!";
		writeFile(file, str);
		readFile(file);
		testFileMethod("D:\\workspace\\datafile","jjn.txt");

	}
	
	/**
	 * 创建File文件
	 * @param parent 父路径字符串
	 * @param fileName	子路径字符串,文件名
	 */
	public static void createFile(String parent,String fileName) {
		File f = new File(parent,fileName);
		if(!f.exists()) {
			try {
//				创建文件
				f.createNewFile();
				System.out.println("文件被创建");
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	/**
	 * 删除文件
	 * @param parent  父路径字符串
	 * @param fileName 子路径字符串,文件名
	 */
	public static void deleteFile(String parent,String fileName){
		File f = new File(parent,fileName);
		if(f.exists()) {
				f.delete();
				System.out.println("文件被删除");
		}
	}


	
	public static void testFileMethod(String parent,String fileName) {
		File file = new File(parent,fileName);
		
//		test exists()方法
		boolean file_exists = file.exists();
		System.out.println("file exists:"+file_exists);
		
		if(!file_exists) {
			try {
				file.createNewFile();
				System.out.println("文件被创建");
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}else {
//			test getName()方法
			String fileNmae = file.getName();
			System.out.println("fileName:"+fileName);
			
//			test canRead()方法
			boolean flage = file.canRead();
			System.out.println(fileName+"can read :"+flage);

//			test canWrite()方法
			flage = file.canWrite();
			System.out.println(fileName+"can write :"+flage);

//			test length()方法  返回值为字节长度
			long length = file.length();
			System.out.println("file length :"+length);
			
//			test getAbsolutePath()方法
			String path = file.getAbsolutePath();
			System.out.println("absolute path:"+path);
			
//			test getParent()方法
			String parentPath = file.getParent();
			System.out.println("parent path:"+parentPath);
			
			flage = file.isFile();
			System.out.println(fileNmae+" is file :"+flage);
			
			flage = file.isDirectory();
			System.out.println(fileNmae+" is directory :"+flage);
			
			flage = file.isHidden();
			System.out.println(fileNmae+" is hidden :"+flage);

			long modifieTime = file.lastModified();
			System.out.println(fileNmae+" last modified time :"+modifieTime);
			
		}
		
	}
	
	/**
	 * 边路path目录下的所有文件
	 * @param path 文件路径
	 */
	public static void lsFile(String path) {
		File file = new File(path);
		
		if(file.exists()) {
			if(file.isFile())
			{
				//是文件
				System.out.println(file.getAbsolutePath());
				return;
			}
			if(file.isDirectory()) {
				String[] files=file.list();
				for(int i=0;i<files.length;i++)
				{
					lsFile(file.getAbsolutePath()+File.separatorChar+files[i]);
				}
			}		
		}else {
			System.out.println("路径不存在");
		}
		

	}

	/**
	 * 写文件
	 * @param file File对象
	 * @param bt	byte[] 要写入的数据
	 */
	public static void writeFile(File file,String str) {
		

		try {
//													在文件的文末增加新内容
				FileWriter fw = new FileWriter(file,true);
				BufferedWriter buwt = new BufferedWriter(fw);
				buwt.write(str);
				buwt.write("\n");
				buwt.close();
				fw.close();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
				
			}

		
	}
	
	/**
	 *读文件
	 * @param file File对象
	 */
	public static void readFile(File file) {
		try {
			FileReader fr = new FileReader(file);
			BufferedReader bufr = new BufferedReader(fr);
			String str= null;
			int i = 0;
			
			while(null != (str = bufr.readLine())) {
				i++;
				System.out.println("第"+i+"行:"+str);
			}
			
			System.out.println("文件大小:"+file.length()+"字节");
			bufr.close();
			fr.close();
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			
		}
	}
	
	
}