InputStream读取文件到string后OutputStream到文件,按String和Bytes拷贝

2022-10-28 14:39:11

http://www.iteye.com/problems/72150

写了一段代码大体是 InputStream读取文件到string后OutputStream到文件
遇到的问题为TXT文件大小格式等都没有问题，但是PDF\RAR等格式的就无法打开了，重新生成的文件大小会比原文件小，代码如下。
package com.stream;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
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.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.util.Arrays;

public class bytearry {
// public static void main(String[] args) throws Exception{
//        String s = "中国";
//        ByteArrayOutputStream baos = new ByteArrayOutputStream();
//        DataOutputStream dos = new DataOutputStream(baos);
//        dos.writeUTF(s);
//        byte[] b = baos.toByteArray();
//        for(int i=0;i<b.length;i++){
//            System.out.println(Integer.toHexString(b[i]));
//        }
//        System.out.println(">>>"+new String(b,"UTF-8")+"<<<");
//        System.out.println("--------------------");
//        byte[] b2 = s.getBytes("UTF-8");
//        for(int i=0;i<b2.length;i++){
//            System.out.println(Integer.toHexString(b2[i]));
//        }
//    }

// public static void main(String[] args) throws IOException {
// String str = "Hello world!";
// // string转byte
// byte[] bs = str.getBytes();
// System.out.println(Arrays.toString(bs));
//
// // byte转string
// String str2 = new String(bs);
// System.out.println(str2);
//
// OutputStream os = new FileOutputStream("C://testCopy11.pdf"); //输出流
// FileInputStream fis = new FileInputStream("d://test.pdf"); //输入流
// //InputStreamReader
// Reader inputStreamReader = new InputStreamReader(fis);
// BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
//
// String ss = new String();
// String s;
// while((s = bufferedReader.readLine())!=null){
//           ss += s;
// }
// //System.out.println(ss);
//
// byte[] buf = new byte[255];
//
// buf = ss.getBytes();
//
//
//
//
//     int len = 0;
//     //while ((len = buf.length) != -1) {
//     // os.write(buf, 0, len);
//     os.write(buf);
//    // }
//
//     fis.close();
//     os.flush();
//     os.close();
//     //copy();
//
// }

public static void main(String[] args) throws IOException {
String str = "Hello world!";
// string转byte
byte[] bs = str.getBytes();
System.out.println(Arrays.toString(bs));

// byte转string
String str2 = new String(bs);
System.out.println(str2);

OutputStream os = new FileOutputStream("C://bytearry.java"); //输出流
FileInputStream fis = new FileInputStream("d://bytearry.java"); //输入流
//InputStreamReader
Reader inputStreamReader = new InputStreamReader(fis);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

String ss = new String();
String s;
while((s = bufferedReader.readLine())!=null){
          ss += s;
}
System.out.println(ss.length());

byte[] buf = new byte[255];

buf = loadAFileToStringDE2(new File("d://bytearry.java")).getBytes();
int len = 0;
    //while ((len = buf.length) != -1) {
    // os.write(buf, 0, len);
    os.write(buf);
   // }
    fis.close();
    os.flush();
    os.close();
    //copy();
    System.out.println(loadAFileToStringDE2(new File("d://bytearry.java")));

}
   public static String loadAFileToStringDE2(File f) throws IOException {
        long beginTime = System.currentTimeMillis();
        InputStream is = null;
        String ret = null;
        try {
            is = new FileInputStream(f) ;
            long contentLength = f.length();
            byte[] ba = new byte[(int)contentLength];
            is.read(ba);
            ret = new String(ba);
        } finally {
            if(is!=null) {try{is.close();} catch(Exception e){} }
        }
        long endTime = System.currentTimeMillis();
        System.out.println("方法2用时"+ (endTime-beginTime) + "ms");
        return ret;
    }

public static boolean copy() {
   try {
    OutputStream os = new FileOutputStream("C://test.pdf"); //输出流
    InputStream fis = new FileInputStream("d://test.pdf"); //输入流

    byte[] buf = new byte[255];
    int len = 0;
    while ((len = fis.read(buf)) != -1) {
    os.write(buf, 0, len);
    }

    fis.close();
    os.flush();
    os.close();

    return true;
   } catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    return false;
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    return false;
   }
}
}