Java操作文件的常用方法-蒲公英云

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] );
    }
}