1. Requirements description, implementation details:
Parsing 2 files \ case10 \ binary hexadecimal file, which contains a string and 1 image, the data file format for the length of the string data (2 bytes) + + image data string content length (4 bytes) + image data, the data length are data bytes, in the high string for UTF - 8 encoding, please parsing, output string content, image file is saved as a files \ case10 \ test png.
2. Implementation code:
package com.igen.case10;
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.net.URISyntaxException;
/**
*
* @ClassName Case10
* @Description TODO
*
* @author wjggwm
* @data 2017 years 2 month 7 day In the morning 11:46:25
*/
public class Case10 {
static final String fileName = "/test.png";
static final String filePath = "D:/files/case10";
static final String sourceFileName = "binary";
public static void main(String[] args) {
try {
readFile(Case10.class.getResource(sourceFileName).toURI().getPath());
} catch (URISyntaxException e) {
e.printStackTrace();
}
}
/**
*
* @Description parsing 2 A binary file
* @param sourceFileName
*
* @author wjggwm
* @data 2017 years 2 month 7 day In the morning 11:47:12
*/
public static void readFile(String sourceFileName) {
InputStream in = null;
try {
in = new FileInputStream(sourceFileName);
// Reads the length bytes of string data
byte[] txtLenByte = new byte[2];
in.read(txtLenByte);
int txtlen = byte2ToUnsignedShort(txtLenByte, 0);
// Read string byte
byte[] txtByte = new byte[txtlen];
in.read(txtByte);
// The string for UTF-8 coding
String txt = new String(txtByte, "UTF-8");
// Output string
System.out.println(txt);
// Read the length of image data
byte[] imgLenByte = new byte[4];
in.read(imgLenByte);
int imgLen = byte4ToInt(imgLenByte, 0);
// Read image data
byte[] img = new byte[imgLen];
in.read(img);
// Generate image files
saveToImgByBytes(filePath, fileName, img);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
*
* @Description Writes the bytes to the file
* @param imgName
* @param imgByte
*
* @author wjggwm
* @data 2017 years 2 month 7 day In the morning 11:07:45
*/
public static void saveToImgByBytes(String filePath, String imgName, byte[] imgByte) {
try {
File dic = new File(filePath);
if (!dic.exists()) {
dic.mkdirs();
}
File image = new File(filePath + imgName);
if (!image.exists()) {
image.createNewFile();
}
FileOutputStream fos = new FileOutputStream(image);
fos.write(imgByte);
fos.flush();
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
*
* @Description byte Array converted to unsigned short The integer
* @param bytes
* @param off
* @return
*
* @author wjggwm
* @data 2017 years 2 month 7 day In the morning 11:05:58
*/
public static int byte2ToUnsignedShort(byte[] bytes, int off) {
// Note that the higher order is at the back, the big and small end
int low = bytes[off];
int high = bytes[off + 1];
return (high << 8 & 0xFF00) | (low & 0xFF);
}
/**
*
* @Description byte Array to int The integer
* @param bytes
* @param off
* @return
*
* @author wjggwm
* @data 2017 years 2 month 7 day In the morning 11:07:23
*/
public static int byte4ToInt(byte[] bytes, int off) {
// Note that the higher order is at the back, the big and small end
int b3 = bytes[off] & 0xFF;
int b2 = bytes[off + 1] & 0xFF;
int b1 = bytes[off + 2] & 0xFF;
int b0 = bytes[off + 3] & 0xFF;
return (b0 << 24) | (b1 << 16) | (b2 << 8) | b3;
}
}