问题描述
我写了个des加密程序，我把加解密分开了啊但是就出现了java.lang.NullPointerException，我把的代码附上第一个DESPlus/****/packagecom.des;importjava.security.*;importjavax.crypto.*;/***@authorzhanghu**/publicclassDESPlus{privatestaticStringstrDefaultKey="national";privateCipherencryptCipher=null;privateCipherdecryptCipher=null;/**将byte数组转换为表示16进制值的字符串，如：byte[]{8,18}转换为：0813，和publicstaticbyte[]hexStr2ByteArr(StringstrIn)互为可逆的转换过程@paramarrB需要转换的byte数组@return转换后的字符串@throwsException本方法不处理任何异常，所有异常全部抛出*/publicstaticStringbyteArr2HexStr(byte[]arrB)throwsException{intiLen=arrB.length;//每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍StringBuffersb=newStringBuffer(iLen*2);for(inti=0;i<iLen;i++){intintTmp=arrB[i];//把负数转换为正数while(intTmp<0){intTmp=intTmp+256;}//小于0F的数需要在前面补0if(intTmp<16){sb.append("0");}sb.append(Integer.toString(intTmp,16));}returnsb.toString();}/***将表示16进制值的字符串转换为byte数组，和publicstaticStringbyteArr2HexStr(byte[]arrB)*互为可逆的转换过程**@paramstrIn*需要转换的字符串*@return转换后的byte数组*@throwsException*本方法不处理任何异常，所有异常全部抛出*@author<ahref="mailto:leo841001@163.com">LiGuoQing</a>*/publicstaticbyte[]hexStr2ByteArr(StringstrIn)throwsException{byte[]arrB=strIn.getBytes();intiLen=arrB.length;//两个字符表示一个字节，所以字节数组长度是字符串长度除以2byte[]arrOut=newbyte[iLen/2];for(inti=0;i<iLen;i=i+2){StringstrTmp=newString(arrB,i,2);arrOut[i/2]=(byte)Integer.parseInt(strTmp,16);}returnarrOut;}/***默认构造方法，使用默认密钥**@throwsException*/publicDESPlus()throwsException{this(strDefaultKey);}/***指定密钥构造方法**@paramstrKey*指定的密钥*@throwsException*/publicDESPlus(StringstrKey)throwsException{Security.addProvider(newcom.sun.crypto.provider.SunJCE());Keykey=getKey(strKey.getBytes());encryptCipher=Cipher.getInstance("DES");encryptCipher.init(Cipher.ENCRYPT_MODE,key);decryptCipher=Cipher.getInstance("DES");decryptCipher.init(Cipher.DECRYPT_MODE,key);}/***加密字节数组**@paramarrB*需加密的字节数组*@return加密后的字节数组*@throwsException*/publicbyte[]encrypt(byte[]arrB)throwsException{returnencryptCipher.doFinal(arrB);}/***加密字符串**@paramstrIn*需加密的字符串*@return加密后的字符串*@throwsException*/publicStringencrypt(StringstrIn)throwsException{returnbyteArr2HexStr(encrypt(strIn.getBytes()));}/***解密字节数组*129.*@paramarrB130.*需解密的字节数组131.*@return解密后的字节数组132.*@throwsException133.*/publicbyte[]decrypt(byte[]arrB)throwsException{returndecryptCipher.doFinal(arrB);}/***解密字符串**@paramstrIn*需解密的字符串*@return解密后的字符串*@throwsException*/publicStringdecrypt(StringstrIn)throwsException{returnnewString(decrypt(hexStr2ByteArr(strIn)));}/***从指定字符串生成密钥，密钥所需的字节数组长度为8位不足8位时后面补0，超出8位只取前8位**@paramarrBTmp*构成该字符串的字节数组*@return生成的密钥*@throwsjava.lang.Exception*/privateKeygetKey(byte[]arrBTmp)throwsException{//创建一个空的8位字节数组（默认值为0）byte[]arrB=newbyte[8];//将原始字节数组转换为8位for(inti=0;i<arrBTmp.length&&i<arrB.length;i++){arrB[i]=arrBTmp[i];}//生成密钥Keykey=newjavax.crypto.spec.SecretKeySpec(arrB,"DES");returnkey;}}第二个是加密/****/packagecom.des;importjava.io.*;/***@authorzhanghu**/publicclassTest{publicstaticvoidmain(String[]args)throwsIOException{BufferedReaderreadStream=newBufferedReader(newInputStreamReader(System.in));System.out.print("请输入明文字符:");Stringinputstr=readStream.readLine();//TODOAuto-generatedmethodstubtry{Stringtest=inputstr;BufferedReaderreadStream1=newBufferedReader(newInputStreamReader(System.in));System.out.print("请输入密钥:");Stringinputstr1=readStream.readLine();DESPlusdes=newDESPlus(inputstr1);//System.out.println("加密前的字符："+test);System.out.println("加密后的字符："+des.encrypt(test));//System.out.println("解密后的字符："+des.decrypt(des.encrypt(test)));BufferedWriterwriteStream=newBufferedWriter(newFileWriter("d:\q.dat"));writeStream.write(des.encrypt(test));writeStream.close();}catch(Exceptione){//TODO:handleexceptione.printStackTrace();}}}第三个是解密/****/packagecom.des;importjava.io.*;/***@authorzhanghu**/publicclassTest1{publicstaticvoidmain(String[]args)throwsIOException{//TODOAuto-generatedmethodstubtry{BufferedReaderreadStream=newBufferedReader(newFileReader("d:\q.dat"));Stringins;while((ins=readStream.readLine())!=null)System.out.println(ins);Stringtest=ins;BufferedReaderreadStream1=newBufferedReader(newInputStreamReader(System.in));System.out.print("请输入密钥:");Stringinputstr1=readStream.readLine();DESPlusdes=newDESPlus(inputstr1);System.out.println("解密后的字符："+des.decrypt(test));}catch(Exceptione){//TODO:handleexceptione.printStackTrace();}}}
解决方案
解决方案二：
错误信息贴出来.
解决方案三：
5859b2abefc161f1请输入密钥:java.lang.NullPointerExceptionatcom.des.DESPlus.<init>(DESPlus.java:85)atcom.des.Test1.main(Test1.java:28)以上为错误信息