读取文件使用AES解密，不成功则退出java虚拟机

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import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
 
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
 
import sun.misc.BASE64Decoder;
 
public class FileRead {
 
    private final String ALGORITHM = "AES";
    private final String CIPHER = "AES/CBC/PKCS5Padding";
     
    public String fileRead(String projectName) throws Exception {
        String rtn = "fail";
        try {
            String jvmHome = System.getProperty("java.home");
            String tomcatHome = System.getProperty("catalina.home");
            String wsr = this.readFile("C:/Windows/System32", "webSystemRun");
            String sp = this.aesDecrypt(wsr, "idt"+projectName);
            String [] sinfo = sp.split("douhao");
            if ( !jvmHome.equals(sinfo[0]+"\\jre") ) {
                System.out.println("jvmHome error");
                System.exit(1);
            }
            if ( !tomcatHome.equals(sinfo[1]) ) {
                System.out.println("tomcatHome error");
                System.exit(1);
            }
            String timeLimit = this.readFile(sinfo[0]+"/jre/lib", "javafxrun");
            rtn = this.aesDecrypt(timeLimit, "idt"+projectName);
            if ( null == rtn ) {
                System.out.println("time limit error");
                System.exit(1);
            } else {
                try {
                    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
                    format.setLenient(false);
                    format.parse(rtn);
                } catch ( Exception e ) {
                    System.out.println("time limit error");
                    System.exit(1);
                }
            }
        } catch ( Exception e ) {
            e.printStackTrace();
            System.exit(1);
        }
        return rtn;
    }
 
    /**
    * 解密
    * @param strKey
    * @param content
    * @return
    * @throws Exception
    */
    private String decrypt(byte[] content,String strKey ) throws Exception {
        SecretKeySpec skeySpec = getKey(strKey);
        Cipher cipher = Cipher.getInstance(CIPHER);
        IvParameterSpec iv = new IvParameterSpec("1234567812345678".getBytes());
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
        byte[] original = cipher.doFinal(content);
        String originalString = new String(original);
        return originalString;
    }
     
    private SecretKeySpec getKey(String strKey) throws Exception {
        byte[] arrBTmp = strKey.getBytes();
        byte[] arrB = new byte[16]; // 创建一个空的16位字节数组（默认值为0）
        for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }
        SecretKeySpec skeySpec = new SecretKeySpec(arrB, ALGORITHM);
 
        return skeySpec;
    }
    /**
     * AES
     * 将base 64 code AES解密
     * @param encryptStr 待解密的base 64 code
     * @param decryptKey 解密密钥
     * @return 解密后的string
     * @throws Exception
     */
    private String aesDecrypt(String encryptStr, String decryptKey) throws Exception {
        return encryptStr.isEmpty() ? null : decrypt(base64Decode(encryptStr), decryptKey);
    }
 
    /**
     * base 64 decode
     * @param base64Code 待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception
     */
    private byte[] base64Decode(String base64Code) throws Exception{
        return base64Code.isEmpty() ? null : new BASE64Decoder().decodeBuffer(base64Code);
    }
     
    private String readFile(String filePath, String fileName) throws Exception {
        String rtn = "";
        byte[] data    = Files.readAllBytes(Paths.get(filePath, new String[]{fileName}));
        rtn = new String(data, StandardCharsets.UTF_8);
        return rtn;
    }
     
}
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