Java中验证编码格式的一种方法

package forlittlecatty;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;

public class MainTest {

    public static void main(String[] args) {
        byte[] b1 = readByte(new File("./src/main/java/forlittlecatty/iso8859-1_en")); // 文件编码: ISO-8859-1 文件内容: "abc123!@#$%^&*()"
        byte[] b2 = readByte(new File("./src/main/java/forlittlecatty/utf-8_en_cn")); // 文件编码: UTF-8 文件内容: "abc123!@#$%^&*()小猫咪"
        byte[] b3 = readByte(new File("./src/main/java/forlittlecatty/gbk_en")); // 文件编码: GBK 文件内容: "abc123!@#$%^&*()"
        byte[] b4 = readByte(new File("./src/main/java/forlittlecatty/gbk_cn")); // 文件编码: GBK 文件内容: "小猫咪"
        System.out.println(isUTF8(b1)); // true
        System.out.println(isUTF8(b2)); // true
        System.out.println(isUTF8(b3)); // true
        System.out.println(isUTF8(b4)); // false
    }

    private static byte[] readByte(File file) {
        InputStream input = null;
        byte[] bytes = null;
        try {
            input = new FileInputStream(file);
            bytes = new byte[256];
            input.read(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                input.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return bytes;
    }

    private static boolean isUTF8(byte[] src) {
        byte[] tmp = null;
        try {
            tmp = new String(src, "UTF-8").getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return Arrays.equals(src, tmp);
    }
}