Java文件输入输出流（封装类）

Q1：第一个输入输出流封装类

package com.io1;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * 文件工具类
 */
public class FileUtil {
    /**
     * 读取文件内容
     *
     * @param is
     * @return
     */
    public static String readFile(InputStream is) {
        BufferedReader br = null;
        StringBuffer sb = new StringBuffer();
        try {
            br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            String readLine = null;
            while ((readLine = br.readLine()) != null) {
                sb.append(readLine+"
");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                br.close();
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
    /**
     * @description 写文件
     * @param args
     * @throws UnsupportedEncodingException
     * @throws IOException
     */
    public static boolean writeTxtFile(String content, File fileName, String encoding) {
        FileOutputStream o = null;
        boolean result=false;
        try {
            o = new FileOutputStream(fileName);
            o.write(content.getBytes(encoding));
            result=true;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (o != null) {
                try {
                    o.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return result;
    }
    public static String readFile(String path){
        File file07 = new File(path);
        InputStream is=null;
        try {
            is = new FileInputStream(file07);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return readFile(is);
    }
    
    /**
     * 判断指定的文件是否存在。
     *
     * @param fileName
     * @return
     */
    public static boolean isFileExist(String fileName) {
        return new File(fileName).isFile();
    }

    /**
     * 创建指定的目录。 如果指定的目录的父目录不存在则创建其目录书上所有需要的父目录。
     * 注意：可能会在返回false的时候创建部分父目录。
     *
     * @param file
     * @return
     */
    public static boolean makeDirectory(File file) {
        File parent = file.getParentFile();
        if (parent != null) {
            return parent.mkdirs();
        }
        return false;
    }

    /**
     * 返回文件的URL地址。
     *
     * @param file
     * @return
     * @throws MalformedURLException
     */
    public static URL getURL(File file) throws MalformedURLException {
        String fileURL = "file:/" + file.getAbsolutePath();
        URL url = new URL(fileURL);
        return url;
    }

    /**
     * 从文件路径得到文件名。
     *
     * @param filePath
     * @return
     */
    public static String getFileName(String filePath) {
        File file = new File(filePath);
        return file.getName();
    }

    /**
     * 从文件名得到文件绝对路径。
     *
     * @param fileName
     * @return
     */
    public static String getFilePath(String fileName) {
        File file = new File(fileName);
        return file.getAbsolutePath();
    }

    /**
     * 将DOS/Windows格式的路径转换为UNIX/Linux格式的路径。
     *
     * @param filePath
     * @return
     */
    public static String toUNIXpath(String filePath) {
        return filePath.replace("", "/");
    }

    /**
     * 从文件名得到UNIX风格的文件绝对路径。
     *
     * @param fileName
     * @return
     */
    public static String getUNIXfilePath(String fileName) {
        File file = new File(fileName);
        return toUNIXpath(file.getAbsolutePath());
    }

    /**
     * 得到文件后缀名
     *
     * @param fileName
     * @return
     */
    public static String getFileExt(String fileName) {
        int point = fileName.lastIndexOf('.');
        int length = fileName.length();
        if (point == -1 || point == length - 1) {
            return "";
        } else {
            return fileName.substring(point + 1, length);
        }
    }

    /**
     * 得到文件的名字部分。 实际上就是路径中的最后一个路径分隔符后的部分。
     *
     * @param fileName
     * @return
     */
    public static String getNamePart(String fileName) {
        int point = getPathLastIndex(fileName);
        int length = fileName.length();
        if (point == -1) {
            return fileName;
        } else if (point == length - 1) {
            int secondPoint = getPathLastIndex(fileName, point - 1);
            if (secondPoint == -1) {
                if (length == 1) {
                    return fileName;
                } else {
                    return fileName.substring(0, point);
                }
            } else {
                return fileName.substring(secondPoint + 1, point);
            }
        } else {
            return fileName.substring(point + 1);
        }
    }

    /**
     * 得到文件名中的父路径部分。 对两种路径分隔符都有效。 不存在时返回""。
     * 如果文件名是以路径分隔符结尾的则不考虑该分隔符，例如"/path/"返回""。
     *
     * @param fileName
     * @return
     */
    public static String getPathPart(String fileName) {
        int point = getPathLastIndex(fileName);
        int length = fileName.length();
        if (point == -1) {
            return "";
        } else if (point == length - 1) {
            int secondPoint = getPathLastIndex(fileName, point - 1);
            if (secondPoint == -1) {
                return "";
            } else {
                return fileName.substring(0, secondPoint);
            }
        } else {
            return fileName.substring(0, point);
        }
    }

    /**
     * 得到路径分隔符在文件路径中最后出现的位置。 对于DOS或者UNIX风格的分隔符都可以。
     *
     * @param fileName
     * @return
     */
    public static int getPathLastIndex(String fileName) {
        int point = fileName.lastIndexOf("/");
        if (point == -1) {
            point = fileName.lastIndexOf("");
        }
        return point;
    }

    /**
     * 得到路径分隔符在文件路径中指定位置前最后出现的位置。 对于DOS或者UNIX风格的分隔符都可以。
     *
     * @param fileName
     * @param fromIndex
     * @return
     */
    public static int getPathLastIndex(String fileName, int fromIndex) {
        int point = fileName.lastIndexOf("/", fromIndex);
        if (point == -1) {
            point = fileName.lastIndexOf("", fromIndex);
        }
        return point;
    }

    /**
     * 得到路径分隔符在文件路径中首次出现的位置。 对于DOS或者UNIX风格的分隔符都可以。
     *
     * @param fileName
     * @return
     */
    public static int getPathIndex(String fileName) {
        int point = fileName.indexOf("/");
        if (point == -1) {
            point = fileName.indexOf("");
        }
        return point;
    }

    /**
     * 得到路径分隔符在文件路径中指定位置后首次出现的位置。 对于DOS或者UNIX风格的分隔符都可以。
     *
     * @param fileName
     * @param fromIndex
     * @return
     */
    public static int getPathIndex(String fileName, int fromIndex) {
        int point = fileName.indexOf("/", fromIndex);
        if (point == -1) {
            point = fileName.indexOf("", fromIndex);
        }
        return point;
    }

    /**
     * 将文件名中的类型部分去掉。
     *
     * @param filename
     * @return
     */
    public static String removeFileExt(String filename) {
        int index = filename.lastIndexOf(".");
        if (index != -1) {
            return filename.substring(0, index);
        } else {
            return filename;
        }
    }

    /**
     * 得到相对路径。 文件名不是目录名的子节点时返回文件名。
     *
     * @param pathName
     * @param fileName
     * @return
     */
    public static String getSubpath(String pathName, String fileName) {
        int index = fileName.indexOf(pathName);
        if (index != -1) {
            return fileName.substring(index + pathName.length() + 1);
        } else {
            return fileName;
        }
    }

    /**
     * 删除一个文件。
     *
     * @param filename
     * @throws IOException
     */
    public static void deleteFile(String filename) throws IOException {
        File file = new File(filename);
        if (file.isDirectory()) {
            throw new IOException("IOException -> BadInputException: not a file.");
        }
        if (!file.exists()) {
            throw new IOException("IOException -> BadInputException: file is not exist.");
        }
        if (!file.delete()) {
            throw new IOException("Cannot delete file. filename = " + filename);
        }
    }

    /**
     * 删除文件夹及其下面的子文件夹
     *
     * @param dir
     * @throws IOException
     */
    public static void deleteDir(File dir) throws IOException {
        if (dir.isFile())
            throw new IOException("IOException -> BadInputException: not a directory.");
        File[] files = dir.listFiles();
        if (files != null) {
            for (int i = 0; i < files.length; i++) {
                File file = files[i];
                if (file.isFile()) {
                    file.delete();
                } else {
                    deleteDir(file);
                }
            }
        }
        dir.delete();
    }

    /**
     * 复制文件
     *
     * @param src
     * @param dst
     * @throws Exception
     */
    public static void copy(File src, File dst) throws Exception {
        int BUFFER_SIZE = 4096;
        InputStream in = null;
        OutputStream out = null;
        try {
            in = new BufferedInputStream(new FileInputStream(src), BUFFER_SIZE);
            out = new BufferedOutputStream(new FileOutputStream(dst), BUFFER_SIZE);
            byte[] buffer = new byte[BUFFER_SIZE];
            int len = 0;
            while ((len = in.read(buffer)) > 0) {
                out.write(buffer, 0, len);
            }
        } catch (Exception e) {
            throw e;
        } finally {
            if (null != in) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                in = null;
            }
            if (null != out) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                out = null;
            }
        }
    }

    /**
     * @复制文件，支持把源文件内容追加到目标文件末尾
     * @param src
     * @param dst
     * @param append
     * @throws Exception
     */
    public static void copy(File src, File dst, boolean append) throws Exception {
        int BUFFER_SIZE = 4096;
        InputStream in = null;
        OutputStream out = null;
        try {
            in = new BufferedInputStream(new FileInputStream(src), BUFFER_SIZE);
            out = new BufferedOutputStream(new FileOutputStream(dst, append), BUFFER_SIZE);
            byte[] buffer = new byte[BUFFER_SIZE];
            int len = 0;
            while ((len = in.read(buffer)) > 0) {
                out.write(buffer, 0, len);
            }
        } catch (Exception e) {
            throw e;
        } finally {
            if (null != in) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                in = null;
            }
            if (null != out) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                out = null;
            }
        }
    }
}

Q2：第二个输入输出流封装类

package com.io1;

import java.io.*;
import java.util.StringTokenizer;

public class FileUtil2 {

    private static String message;

    /**
     * 读取文本文件内容
     * 
     * @param filePathAndName
     *            带有完整绝对路径的文件名
     * @param encoding
     *            文本文件打开的编码方式
     * @return 返回文本文件的内容
     */
    public static String readTxt(String filePathAndName, String encoding) throws IOException {
        encoding = encoding.trim();
        StringBuffer str = new StringBuffer("");
        String st = "";
        try {
            FileInputStream fs = new FileInputStream(filePathAndName);
            InputStreamReader isr;
            if (encoding.equals("")) {
                isr = new InputStreamReader(fs);
            } else {
                isr = new InputStreamReader(fs, encoding);
            }
            BufferedReader br = new BufferedReader(isr);
            try {
                String data = "";
                while ((data = br.readLine()) != null) {
                    str.append(data + " ");
                }
            } catch (Exception e) {
                str.append(e.toString());
            }
            st = str.toString();
        } catch (IOException es) {
            st = "";
        }
        return st;
    }

    /**
     * @description 写文件
     * @param args
     * @throws UnsupportedEncodingException
     * @throws IOException
     */
    public static boolean writeTxtFile(String content, File fileName, String encoding) {
        FileOutputStream o = null;
        boolean result=false;
        try {
            o = new FileOutputStream(fileName,true);
            o.write(content.getBytes(encoding));
            result=true;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (o != null) {
                try {
                    o.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return result;
    }

    /**
     * 
     * @param content
     * @param fileName
     * @return
     */
    public static boolean writeTxtFile(String content,String fileName)
      {
         return   writeTxtFile(content,new File(fileName),"UTF-8");
      }

    /**
     * 新建目录
     * 
     * @param folderPath
     *            目录
     * @return 返回目录创建后的路径
     */
    public static String createFolder(String folderPath) {
        String txt = folderPath;
        try {
            java.io.File myFilePath = new java.io.File(txt);
            txt = folderPath;
            if (!myFilePath.exists()) {
                myFilePath.mkdir();
            }
        } catch (Exception e) {
            message = "创建目录操作出错";
        }
        return txt;
    }

    /**
     * 多级目录创建
     * 
     * @param folderPath
     *            准备要在本级目录下创建新目录的目录路径 例如 c:myf
     * @param paths
     *            无限级目录参数，各级目录以单数线区分 例如 a|b|c
     * @return 返回创建文件后的路径 例如 c:myfac
     */
    public static String createFolders(String folderPath, String paths) {
        String txts = folderPath;
        try {
            String txt;
            txts = folderPath;
            StringTokenizer st = new StringTokenizer(paths, "|");
            for (int i = 0; st.hasMoreTokens(); i++) {
                txt = st.nextToken().trim();
                if (txts.lastIndexOf("/") != -1) {
                    txts = createFolder(txts + txt);
                } else {
                    txts = createFolder(txts + txt + "/");
                }
            }
        } catch (Exception e) {
            message = "创建目录操作出错！";
        }
        return txts;
    }

    /**
     * 新建文件
     * 
     * @param filePathAndName
     *            文本文件完整绝对路径及文件名
     * @param fileContent
     *            文本文件内容
     * @return
     */
    public static void createFile(String filePathAndName, String fileContent) {

        try {
            String filePath = filePathAndName;
            filePath = filePath.toString();
            File myFilePath = new File(filePath);
            if (!myFilePath.exists()) {
                myFilePath.createNewFile();
            }
            FileWriter resultFile = new FileWriter(myFilePath);
            PrintWriter myFile = new PrintWriter(resultFile);
            String strContent = fileContent;
            myFile.println(strContent);
            myFile.close();
            resultFile.close();
        } catch (Exception e) {
            message = "创建文件操作出错";
        }
    }

    /**
     * 有编码方式的文件创建
     * 
     * @param filePathAndName
     *            文本文件完整绝对路径及文件名
     * @param fileContent
     *            文本文件内容
     * @param encoding
     *            编码方式 例如 GBK 或者 UTF-8
     * @return
     */
    public static void createFile(String filePathAndName, String fileContent, String encoding) {

        try {
            String filePath = filePathAndName;
            filePath = filePath.toString();
            File myFilePath = new File(filePath);
            if (!myFilePath.exists()) {
                myFilePath.createNewFile();
            }
            PrintWriter myFile = new PrintWriter(myFilePath, encoding);
            String strContent = fileContent;
            myFile.println(strContent);
            myFile.close();
        } catch (Exception e) {
            message = "创建文件操作出错";
        }
    }

    /**
     * 删除文件
     * 
     * @param filePathAndName
     *            文本文件完整绝对路径及文件名
     * @return Boolean 成功删除返回true遭遇异常返回false
     */
    public static boolean delFile(String filePathAndName) {
        boolean bea = false;
        try {
            String filePath = filePathAndName;
            File myDelFile = new File(filePath);
            if (myDelFile.exists()) {
                myDelFile.delete();
                bea = true;
            } else {
                bea = false;
                message = (filePathAndName + "删除文件操作出错");
            }
        } catch (Exception e) {
            message = e.toString();
        }
        return bea;
    }

    /**
     * 删除文件夹
     * 
     * @param folderPath
     *            文件夹完整绝对路径
     * @return
     */
    public static void delFolder(String folderPath) {
        try {
            delAllFile(folderPath); // 删除完里面所有内容
            String filePath = folderPath;
            filePath = filePath.toString();
            java.io.File myFilePath = new java.io.File(filePath);
            myFilePath.delete(); // 删除空文件夹
        } catch (Exception e) {
            message = ("删除文件夹操作出错");
        }
    }

    /**
     * 删除指定文件夹下所有文件
     * 
     * @param path
     *            文件夹完整绝对路径
     * @return
     * @return
     */
    public static boolean delAllFile(String path) {
        boolean bea = false;
        File file = new File(path);
        if (!file.exists()) {
            return bea;
        }
        if (!file.isDirectory()) {
            return bea;
        }
        String[] tempList = file.list();
        File temp = null;
        for (int i = 0; i < tempList.length; i++) {
            if (path.endsWith(File.separator)) {
                temp = new File(path + tempList[i]);
            } else {
                temp = new File(path + File.separator + tempList[i]);
            }
            if (temp.isFile()) {
                temp.delete();
            }
            if (temp.isDirectory()) {
                delAllFile(path + "/" + tempList[i]);// 先删除文件夹里面的文件
                delFolder(path + "/" + tempList[i]);// 再删除空文件夹
                bea = true;
            }
        }
        return bea;
    }

    /**
     * 复制单个文件
     * 
     * @param oldPathFile
     *            准备复制的文件源
     * @param newPathFile
     *            拷贝到新绝对路径带文件名
     * @return
     */
    public static void copyFile(String oldPathFile, String newPathFile) {
        try {
            int bytesum = 0;
            int byteread = 0;
            File oldfile = new File(oldPathFile);
            if (oldfile.exists()) { // 文件存在时
                InputStream inStream = new FileInputStream(oldPathFile); // 读入原文件
                FileOutputStream fs = new FileOutputStream(newPathFile);
                byte[] buffer = new byte[1444];
                while ((byteread = inStream.read(buffer)) != -1) {
                    bytesum += byteread; // 字节数 文件大小
                    System.out.println(bytesum);
                    fs.write(buffer, 0, byteread);
                }
                inStream.close();
            }
        } catch (Exception e) {
            message = ("复制单个文件操作出错");
        }
    }

    /**
     * 复制整个文件夹的内容
     * 
     * @param oldPath
     *            准备拷贝的目录
     * @param newPath
     *            指定绝对路径的新目录
     * @return
     */
    public static void copyFolder(String oldPath, String newPath) {
        try {
            new File(newPath).mkdirs(); // 如果文件夹不存在 则建立新文件夹
            File a = new File(oldPath);
            String[] file = a.list();
            File temp = null;
            for (int i = 0; i < file.length; i++) {
                if (oldPath.endsWith(File.separator)) {
                    temp = new File(oldPath + file[i]);
                } else {
                    temp = new File(oldPath + File.separator + file[i]);
                }
                if (temp.isFile()) {
                    FileInputStream input = new FileInputStream(temp);
                    FileOutputStream output = new FileOutputStream(newPath + "/" + (temp.getName()).toString());
                    byte[] b = new byte[1024 * 5];
                    int len;
                    while ((len = input.read(b)) != -1) {
                        output.write(b, 0, len);
                    }
                    output.flush();
                    output.close();
                    input.close();
                }
                if (temp.isDirectory()) {// 如果是子文件夹
                    copyFolder(oldPath + "/" + file[i], newPath + "/" + file[i]);
                }
            }
        } catch (Exception e) {
            message = "复制整个文件夹内容操作出错";
        }
    }

    /**
     * 移动文件
     * 
     * @param oldPath
     * @param newPath
     * @return
     */
    public static void moveFile(String oldPath, String newPath) {
        copyFile(oldPath, newPath);
        delFile(oldPath);
    }

    /**
     * 移动目录
     * 
     * @param oldPath
     * @param newPath
     * @return
     */
    public static void moveFolder(String oldPath, String newPath) {
        copyFolder(oldPath, newPath);
        delFolder(oldPath);
    }

    /**
     * 得到错误信息
     */
    public static String getMessage() {
        return message;
    }
}

提示:以上两个封装类都可以，有些不同，下面有一些使用方法，大家可以根据下面例子好好理解

package com.io1;

import java.io.File;
import java.util.Date;

public class FileUtilText {

    public static void main(String[] args) throws Exception{
        // TODO Auto-generated method stub
        String path = "e:" + File.separator + "file07.txt";
        String path2 = "e:" + File.separator + "file08.txt";
        File f=new File("e:"+File.separator+"file07.txt");
        File f2=new File("e:"+File.separator+"file08.txt");
        /*if (FileUtil2.writeTxtFile("当前时间："+new Date().toString(), path)) {
               System.out.println(FileUtil.readFile(path));
            System.out.println(FileUtil2.readTxt(path, "UTF-8"));
        }*/
        /*FileUtil2.writeTxtFile("沙发阿三发射点发顺丰", f, "utf-8");
          System.out.println(FileUtil2.readTxt(path, "utf-8"));
          System.out.println(FileUtil.getPathPart(path));
          FileUtil.copy(f, f2, true);*/
        //FileUtil.deleteFile(path2);
        System.out.println(FileUtil.readFile(path));
        FileUtil.writeTxtFile("fas的发生", f, "utf-8");
    }

}

大家可以根据例子然后自己把封装类都给用一便，这样就会熟悉