封装文件读取、写入，文件拷贝与文件夹拷贝

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封装类：

import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;/* * 封装文件读取、写入，拷贝与文件夹的拷贝 */public class FileUtil {    //读取文件    public static String readfile(File src,File dest) {        return readfile(src.getAbsoluteFile(),dest.getAbsoluteFile());    }    public static String readfile(String src,String dest) {        String retString = "";        //1、建立关联        File file = new File(src);        //2、选择流        InputStream stream = null;        try {            stream = new FileInputStream(file);            //3、确定一次读取字节大小            byte[] size = new byte[1024];            int len = 0;//每次读取字节数            //4、循环读取            while(-1!=(len = stream.read(size))){//读取失败返回-1                String info = new String(size,0,len);                retString += info;                if(null!=dest){                    writefile(dest,size);                }            }        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }finally{            if(stream!=null){                try {                    stream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return retString;    }    //写出文件    public static void writefile(String dest,String str) {        writefile(dest,str.getBytes());    }    public static void writefile(String dest,byte[] size) {        File file = new File(dest);        if(!file.exists()){            try {                file.createNewFile();            } catch (IOException e) {                e.printStackTrace();            }        }        OutputStream stream = null;        try {            stream = new FileOutputStream(file,true);            //字符串转字符数组            stream.write(size,0,size.length);            stream.flush();//强制刷新出去        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }finally{            if(null!=stream){                try {                    stream.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }    //拷贝文件    public static void copyFile(File src,File dest) {        copyFile(src.getAbsoluteFile(),dest.getAbsoluteFile());    }    public static void copyFile(String src,String dest) {        readfile(src, dest);    }    //拷贝文件夹    public static void copyDir(String src,String dest) {        File srcData = new File(src);        File desData = null;        if(srcData.isDirectory()){            desData = new File(dest,srcData.getName());        }        copyDirdetails(srcData,desData);    }    private static void copyDirdetails(File src,File dest) {        if(src.isFile()){//文件            CopyFile.copyFile(src.getAbsolutePath(), dest.getAbsolutePath());        }else{            if(src.isDirectory()){//文件夹                //确保目标文件夹存在                dest.mkdirs();                //获取下一级目录|文件                for(File sub:src.listFiles()){                    copyDirdetails(sub,new File(dest,sub.getName()));                }            }        }    }}

测试类：

public class FileUtiltest {    public static void main(String[] args) {        FileUtil.copyFile("E:/test.txt", "D:/a.txt");        System.out.println(FileUtil.readfile("E:/test.txt", null));        FileUtil.writefile("E:/d.txt", "my name is hu cheng peng.");        FileUtil.copyDir("D:/JAVA/Workspaces/MyEclipse 8.6/SloarModel", "E:/");    }}

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