java获取文件编码格式
时间: 2023-10-07 21:12:45 浏览: 42
可以使用Java的StandardCharsets类来获取文件编码格式,代码如下:
``` java
import java.io.*;
public class FileEncodingChecker {
public static void main(String[] args) {
File file = new File("file.txt");
String encoding = getFileEncoding(file);
System.out.println("File encoding: " + encoding);
}
public static String getFileEncoding(File file) {
String encoding = null;
try {
FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis);
byte[] bytes = new byte[4096];
bis.mark(4096);
int read = bis.read(bytes);
bis.reset();
bis.close();
fis.close();
encoding = getFileEncoding(bytes);
} catch (Exception e) {
e.printStackTrace();
}
return encoding;
}
public static String getFileEncoding(byte[] bytes) {
String encoding = null;
if (bytes[0] == (byte) 0xFF && bytes[1] == (byte) 0xFE) {
encoding = "UTF-16LE";
} else if (bytes[0] == (byte) 0xFE && bytes[1] == (byte) 0xFF) {
encoding = "UTF-16BE";
} else if (bytes[0] == (byte) 0xEF && bytes[1] == (byte) 0xBB && bytes[2] == (byte) 0xBF) {
encoding = "UTF-8";
} else {
int i = 0;
int utf8Bytes = 0;
int nonAsciiBytes = 0;
while (i < bytes.length) {
byte b = bytes[i];
if ((b & 0b10000000) == 0b00000000) {
i += 1;
} else if ((b & 0b11100000) == 0b11000000) {
if (i + 1 < bytes.length && (bytes[i + 1] & 0b11000000) == 0b10000000) {
utf8Bytes += 2;
i += 2;
} else {
nonAsciiBytes += 1;
i += 1;
}
} else if ((b & 0b11110000) == 0b11100000) {
if (i + 2 < bytes.length && (bytes[i + 1] & 0b11000000) == 0b10000000 && (bytes[i + 2] & 0b11000000) == 0b10000000) {
utf8Bytes += 3;
i += 3;
} else {
nonAsciiBytes += 1;
i += 1;
}
} else if ((b & 0b11111000) == 0b11110000) {
if (i + 3 < bytes.length && (bytes[i + 1] & 0b11000000) == 0b10000000 && (bytes[i + 2] & 0b11000000) == 0b10000000 && (bytes[i + 3] & 0b11000000) == 0b10000000) {
utf8Bytes += 4;
i += 4;
} else {
nonAsciiBytes += 1;
i += 1;
}
} else {
nonAsciiBytes += 1;
i += 1;
}
}
if (nonAsciiBytes == 0) {
encoding = "ASCII";
} else if (nonAsciiBytes == 1 && utf8Bytes == 0) {
encoding = "ISO8859_1";
} else if (nonAsciiBytes == 1 && utf8Bytes == 1) {
encoding = "WINDOWS_1252";
} else if (nonAsciiBytes == 1 && utf8Bytes > 1) {
encoding = "UTF-8";
} else if (nonAsciiBytes > 1 && utf8Bytes == 0) {
encoding = "ISO8859_1";
} else if (nonAsciiBytes > 1 && utf8Bytes == nonAsciiBytes * 2) {
encoding = "UTF-16LE";
} else if (nonAsciiBytes > 1 && utf8Bytes == nonAsciiBytes * 3) {
encoding = "UTF-8";
} else {
encoding = "UNKNOWN";
}
}
return encoding;
}
}
```
在这个示例中,`getFileEncoding`方法接受一个文件对象并返回文件的编码格式。它首先读取文件的前4096个字节,然后将指针重置到文件的开头。然后,它调用`getFileEncoding`方法来检查字节的编码格式。对于UTF-16LE和UTF-16BE编码,它检查前两个字节来确定编码。对于UTF-8编码,它检查前三个字节。对于其他编码,它采用一种启发式方法来检测字节中的非ASCII字符数量并推断编码。
相关推荐
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)