JAVA 读取写入文件

读取  写入   复制 文件  
 
import java.io.*;
 
public class text6 {
    public static void main(String[] args) {
 
        long s1=System.nanoTime();
//        System.out.println(fiel_read("file\\a.txt"));   //读取文件
//
//        String str="abcdefg123456你好中国";
//        file_write("file2","/a.txt",str);   //写入文件
//
//        System.out.println(file_copy("file\\1.md","file\\2.md"));  //复制文件  原有文件  新文件
 
 
 
        //下面几个方法好用  已经封装好了
        String str="abcdefg123456你好中国";
        //file_write2("file","/e.txt",str); //写入文件
        file_write_coded("file","/m.txt",str,"GBK"); //带编码格式写入
        System.out.println(fiel_read_coded("file/m.txt","GBK"));  //带编码读取
        System.out.println(fiel_read2("file/m.txt"));  //读取
 
 
        long s2=System.nanoTime();
        System.out.println("耗时"+(s1-s2)/1E9+"秒");
 
    }
 
    public static String fiel_read2(String dirPath) {  //读取
        StringBuffer retstr = new StringBuffer();
        try (
                BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(dirPath))); //dirPath
        ){
            while (true) {
                String s = br.readLine();
                if (s == null) {break;}
                retstr.append(s);
            }
        }catch (Exception e){
            System.out.println(e.toString());
        }
        return retstr.toString();
    }
 
    public static String fiel_read_coded(String dirPath,String coded) {  //带编码读取
        if(coded==""){coded="UTF-8";}
        StringBuffer retstr = new StringBuffer();
        try (
                BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(dirPath),coded));
        ){
            while (true) {
                String s = br.readLine();
                if (s == null) {break;}
                retstr.append(s);
            }
        }catch (Exception e){
            System.out.println(e.toString());
        }
        return retstr.toString();
    }
 
    public static void file_write_coded(String dirPath,String name,String data,String coded) {  //写入文件带编码写入
        if(coded==""){coded="UTF-8";}
        File file = new File(dirPath);
        if (!file.exists() && !file.isDirectory()) {file.mkdirs();}
        try (
            FileOutputStream fos=new FileOutputStream(dirPath+name,true);
            OutputStreamWriter osw=new OutputStreamWriter(fos,coded);
            PrintWriter pw=new PrintWriter(osw);
        ){
            pw.write(data);
        }catch (Exception e){
            System.out.println(e.toString());
        }
    }
 
 
    public static void file_write2(String dirPath,String name,String data) {  //写入文件
        File file = new File(dirPath);
        if (!file.exists() && !file.isDirectory()) {file.mkdirs();}
        try (
             PrintWriter pw=new PrintWriter(new FileWriter(dirPath+name,true));
             ){
//            pw.print(5.5);
//            pw.println("一二三四五六");
//            pw.write("你好在吗？");
            pw.write(data);
        }catch (Exception e){
            System.out.println(e.toString());
        }
    }
 
 
 
 
 
 
    public static boolean file_copy(String file,String copyfile){  //复制文件  原有文件  新文件
        try (
                BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(copyfile));  //缓冲数据流  复制文件的路径
                BufferedInputStream  bis=new BufferedInputStream(new FileInputStream(file));  //缓冲数据流  被复制文件路径
        ){
            while (true){  //读取所有内容
//                int n=fis.read();
//                if(n==-1){break;}
//                fos.write(n);
                byte[] bs = new byte[1024];
                int n = bis.read(bs);
                if (n == -1) {break;}
                bos.write(bs);//将数组中的数据写入到目标文件
            }
            return true;
        }catch (Exception e){
            System.out.println(e.toString());
        }
        return false;
    }
 
    public static String fiel_read(String dirPath) {  //读取文件
        StringBuffer retstr = new StringBuffer();
        try (BufferedInputStream  bis=new BufferedInputStream(new FileInputStream(dirPath));  //缓冲数据流
        ) {
            while (true) {//利用read(byte[])+循环读取文件
                byte[] ss = new byte[1024];
                int n = bis.read(ss);
                if (n == -1) {
                    break;
                }
                for (int i = 0; i < n; i++) {
                    //System.out.println((char)ss[i]);
                    retstr.append((char) ss[i]);
                }
            }
            //fis.close();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
        return retstr.toString();
    }
 
    public static void file_write(String dirPath,String name,String data) {  //写入文件
        File file = new File(dirPath);
        if (!file.exists() && !file.isDirectory()) {file.mkdirs();}
 
        try (BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(dirPath+name,true));  //缓冲数据流
        ){
            bos.write(data.getBytes());
            //fos.close();
        }catch (Exception e){
            System.out.println(e.toString());
        }
    }
 
}