Java操作文件的常用方法

深碍√TFBOYSˉ_ 2022-03-25 03:14 319阅读 0赞

1.包含： 解压文件、读取文件内容、删除文件、删除文件夹、将图片转换成二进制与还原。

2.FileUtils.java:

import java.awt.image.BufferedImage;
    import java.io.BufferedReader;
    import java.io.ByteArrayInputStream;
    import java.io.ByteArrayOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.Enumeration;
    
    import javax.imageio.ImageIO;
    
    import org.apache.tools.zip.ZipEntry;
    import org.apache.tools.zip.ZipFile;
    import org.junit.Test;
    
    import sun.misc.BASE64Decoder;
    import sun.misc.BASE64Encoder;
    
    public class FileUtils {
    
    	private static BASE64Encoder encoder = new sun.misc.BASE64Encoder();
    	private static BASE64Decoder decoder = new sun.misc.BASE64Decoder();
    
    	public FileUtils() {
    	}
    
    	/**
    	 * @param sourcefiles
    	 *            源文件(服务器上的zip包存放地址)
    	 * @param decompreDirectory
    	 *            解压缩后文件存放的目录
    	 * @throws IOException
    	 *             IO异常
    	 */
    	public static void unzip(String sourcefiles, String decompreDirectory) throws IOException {
    		ZipFile readfile = null;
    		try {
    			readfile = new ZipFile(sourcefiles);
    			Enumeration<?> takeentrie = readfile.getEntries();
    			ZipEntry zipEntry = null;
    			File credirectory = new File(decompreDirectory);
    			credirectory.mkdirs();
    			while (takeentrie.hasMoreElements()) {
    				zipEntry = (ZipEntry) takeentrie.nextElement();
    				String entryName = zipEntry.getName();
    				InputStream in = null;
    				FileOutputStream out = null;
    				try {
    					if (zipEntry.isDirectory()) {
    						String name = zipEntry.getName();
    						name = name.substring(0, name.length() - 1);
    						File createDirectory = new File(decompreDirectory + File.separator + name);
    						createDirectory.mkdirs();
    					} else {
    						int index = entryName.lastIndexOf("\\");
    						if (index != -1) {
    							File createDirectory = new File(
    									decompreDirectory + File.separator + entryName.substring(0, index));
    							createDirectory.mkdirs();
    						}
    						index = entryName.lastIndexOf("/");
    						if (index != -1) {
    							File createDirectory = new File(
    									decompreDirectory + File.separator + entryName.substring(0, index));
    							createDirectory.mkdirs();
    						}
    						File unpackfile = new File(decompreDirectory + File.separator + zipEntry.getName());
    						in = readfile.getInputStream(zipEntry);
    						out = new FileOutputStream(unpackfile);
    						int c;
    						byte[] by = new byte[1024];
    						while ((c = in.read(by)) != -1) {
    							out.write(by, 0, c);
    						}
    						out.flush();
    					}
    				} catch (IOException ex) {
    					ex.printStackTrace();
    					throw new IOException("解压失败：" + ex.toString());
    				} finally {
    					if (in != null) {
    						try {
    							in.close();
    						} catch (IOException ex) {
    
    						}
    					}
    					if (out != null) {
    						try {
    							out.close();
    						} catch (IOException ex) {
    							ex.printStackTrace();
    						}
    					}
    					in = null;
    					out = null;
    				}
    
    			}
    		} catch (IOException ex) {
    			ex.printStackTrace();
    			throw new IOException("解压失败：" + ex.toString());
    		} finally {
    			if (readfile != null) {
    				try {
    					readfile.close();
    				} catch (IOException ex) {
    					ex.printStackTrace();
    					throw new IOException("解压失败：" + ex.toString());
    				}
    			}
    		}
    	}
    
    	/**
    	 * @param filePath
    	 * @param encode
    	 * @return 读取文件内容
    	 * @throws Exception
    	 */
    	public static String readFile(String filePath) {
    		return readFile(filePath, "utf-8");
    	}
    
    	/**
    	 * @param filePath
    	 * @param encode
    	 * @param limit
    	 * @return 读取文件内容
    	 * @throws Exception
    	 */
    	public static String readFile(String filePath, String encode) {
    		String result = "";
    		File file = new File(filePath);
    		FileInputStream inputStream = null;
    		InputStreamReader inputReader = null;
    		try {
    			inputStream = new FileInputStream(file);
    			inputReader = new InputStreamReader(inputStream, encode);
    			BufferedReader br = new BufferedReader(inputReader);
    			String str = "";
    			while ((str = br.readLine()) != null) {
    				result += str + "\n"; // TODO \n
    			}
    		} catch (Exception ex) {
    			ex.printStackTrace();
    		} finally {
    			try {
    				inputReader.close();
    				inputStream.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    		}
    		return result;
    	}
    
    	/**
    	 * @param filePath
    	 * @return 删除文件
    	 */
    	public static boolean delFile(String filePath) {
    		boolean flag = false;
    		File file = new File(filePath);
    		if (file.isFile() && file.exists()) {
    			flag = file.delete();
    		}
    		return flag;
    	}
    
    	/**
    	 * @param dir
    	 * @return 删除文件夹
    	 */
    	public static boolean deleteDir(File dir) {
    		if (dir.isDirectory()) {
    			String[] children = dir.list();
    			// 递归删除目录中的子目录下
    			for (int i = 0; i < children.length; i++) {
    				boolean success = deleteDir(new File(dir, children[i]));
    				if (!success) {
    					return false;
    				}
    			}
    		}
    		// 目录此时为空，可以删除
    		return dir.delete();
    	}
    
    	/**
    	 * 将图片转换成二进制
    	 * @return
    	 */
    	public static String getImageBinary(File file) {
    		String fileName = file.getName();
    		// System.out.println(fileName + " " + fileName.substring(fileName.indexOf(".")+1, fileName.length()));
    		
    		BufferedImage bi;
    		try {
    			bi = ImageIO.read(file);
    			ByteArrayOutputStream baos = new ByteArrayOutputStream();
    			ImageIO.write(bi, fileName.substring(fileName.indexOf(".")+1, fileName.length()), baos); // 经测试转换的图片是格式这里就什么格式，否则会失真
    			byte[] bytes = baos.toByteArray();
    
    			return encoder.encodeBuffer(bytes).trim();
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    		return null;
    	}
    
    	/**
    	 * @param base64String
    	 * @param savePath
    	 * @param type
    	 * 将二进制转换为图片
    	 */
    	public static void base64StringToImage(String base64String, String savePath) {
    		try {
    			byte[] bytes1 = decoder.decodeBuffer(base64String);
    
    			ByteArrayInputStream bais = new ByteArrayInputStream(bytes1);
    			BufferedImage bi1 = ImageIO.read(bais);
    			File w2 = new File(savePath);// File w2 = new File("e://QQ.jpg") 可以是jpg,png,gif格式
    			// TODO jpg
    			ImageIO.write(bi1, savePath.substring(savePath.indexOf(".")+1, savePath.length()), w2);// 不管输出什么格式图片，此处不需改动  
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    
    	// 解压 zip
    	public static void main(String[] args) {
    		try {
    			unzip("D:/workplace/Producer/files/20190116.zip",
    					"D:/workplace/Producer/files/abc");
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    
    	// 读取内容
    	@Test
    	public void test01() {
    		System.out.println(
    				readFile("D:/workplace/Producer/files/20190116/1547449028337.txt"));
    	}
    
    	// 删除文件夹
    	@Test
    	public void test02() throws IOException {
    		unzip("D:/workplace/Producer/files/20190116.zip",
    				"D:/workplace/Producer/files/");
    		deleteDir(new File("D:/workplace/Producer/files/20190116"));
    	}
    
    	// 文件属性
    	@Test
    	public void test03() throws IOException {
    		File file = new File("D:/workplace/Producer/files/20190116.zip");
    		System.out.println(file.getAbsolutePath());
    		System.out.println(file.getCanonicalPath());
    		System.out.println(file.getPath());
    		System.out.println(file.getTotalSpace());
    		System.out.println(file.getFreeSpace());
    		System.out.println(file.getUsableSpace());
    
    		System.out.println(file.getParent());
    	}
    	
    	// 图片处理
    	@Test
    	public void test04() {
    		String photo = getImageBinary(new File("D:/workplace/Producer/files/714b348d35e1e1ec3d5c769c8bbdb727__1.jpg"));	
    		System.out.println(photo);
    		
    		base64StringToImage(photo, "D:/workplace/Producer/files/20190114/a.jpg");
    	}
    	
    	@Test
    	public void test05() {
    		String str = "abc\ndef\nghi";
    		String str_[] = str.split("\n");
    		System.out.println( str_.length + " " + str_[0] + "," + str_[1] + "," + str_[2] );
    	}
    	
    }