全面了解java byte数组与文件读写_JAVA教程

全面了解java byte数组与文件读写

2020-06-06 14:06jingxian JAVA教程

下面小编就为大家带来一篇全面了解java byte数组与文件读写。小编觉得挺不错的，现在就分享给大家，也给大家做个参考。一起跟随小编过来看看吧

全面了解java byte数组与文件读写

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									import java.io.ByteArrayOutputStream;

									import java.io.File;

									import java.io.FileInputStream;

									import java.io.FileOutputStream;

									import java.io.IOException;

									public class FileHelper {

									<span style="white-space:pre">  </span>//第一种获取文件内容方式

									  public byte[] getContent(String filePath) throws IOException {

									    File file = new File(filePath);

									    long fileSize = file.length();

									    if (fileSize > Integer.MAX_VALUE) {

									      System.out.println("file too big...");

									      return null;

									    }

									    FileInputStream fi = new FileInputStream(file);

									    byte[] buffer = new byte[(int) fileSize];

									    int offset = 0;

									    int numRead = 0;

									    while (offset < buffer.length

									    && (numRead = fi.read(buffer, offset, buffer.length - offset)) >= 0) {

									      offset += numRead;

									    }

									    // 确保所有数据均被读取

									    if (offset != buffer.length) {

									      throw new IOException("Could not completely read file "

									          + file.getName());

									    }

									    fi.close();

									    return buffer;

									  }

									  //第二种获取文件内容方式

									  public byte[] getContent2(String filePath) throws IOException

									  {

									    FileInputStream in=new FileInputStream(filePath);

									    ByteArrayOutputStream out=new ByteArrayOutputStream(1024);

									    System.out.println("bytes available:"+in.available());

									    byte[] temp=new byte[1024];

									    int size=0;

									    while((size=in.read(temp))!=-1)

									    {

									      out.write(temp,0,size);

									    }

									    in.close();

									    byte[] bytes=out.toByteArray();

									    System.out.println("bytes size got is:"+bytes.length);

									    return bytes;

									  }

									    //将byte数组写入文件

									  public void createFile(String path, byte[] content) throws IOException {

									    FileOutputStream fos = new FileOutputStream(path);

									    fos.write(content);

									    fos.close();

									  }

									}