急！！怎样读取JTextArea里内容，对其加密后在输回JTextArea 解决的马上给分
这里有一个通过输入文件进行加密解密再输出文件保存的例子，我想把它改成从JTextArea里读取字符串加密后再输出到JTextArea怎么改
import java.io.*;
import java.security.*;
import javax.crypto.*;
/**
使用方法:
java RSATest -genkey public private
java RSATest -encrypt plaintext encrypted public
java RSATest -decrypt encrypted decrypted private
*/
public class RSATest
{
public static void main(String[] args)
{
try
{
if (args[0].equals( "-genkey "))//产生密钥对
{
KeyPairGenerator pairgen = KeyPairGenerator.getInstance( "RSA ");
SecureRandom random = new SecureRandom();
pairgen.initialize(KEYSIZE, random);
KeyPair keyPair = pairgen.generateKeyPair();
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(args[1]));
out.writeObject(keyPair.getPublic());
out.close();
out = new ObjectOutputStream(new FileOutputStream(args[2]));
out.writeObject(keyPair.getPrivate());
out.close();
}
else if (args[0].equals( "-encrypt "))//加密
{
KeyGenerator keygen = KeyGenerator.getInstance( "AES ");
SecureRandom random = new SecureRandom();
keygen.init(random);
SecretKey key = keygen.generateKey();
// wrap with RSA public key
ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
Key publicKey = (Key) keyIn.readObject();
keyIn.close();
Cipher cipher = Cipher.getInstance( "RSA ");
cipher.init(Cipher.WRAP_MODE, publicKey);
byte[] wrappedKey = cipher.wrap(key);
DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
out.writeInt(wrappedKey.length);
out.write(wrappedKey);
InputStream in = new FileInputStream(args[1]);
cipher = Cipher.getInstance( "AES ");
cipher.init(Cipher.ENCRYPT_MODE, key);
crypt(in, out, cipher);
in.close();
out.close();
}
else//解密
{
DataInputStream in = new DataInputStream(new FileInputStream(args[1]));
int length = in.readInt();
byte[] wrappedKey = new byte[length];
in.read(wrappedKey, 0, length);
// unwrap with RSA private key
ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
Key privateKey = (Key) keyIn.readObject();
keyIn.close();
Cipher cipher = Cipher.getInstance( "RSA ");
cipher.init(Cipher.UNWRAP_MODE, privateKey);
Key key = cipher.unwrap(wrappedKey, "AES ", Cipher.SECRET_KEY);
OutputStream out = new FileOutputStream(args[2]);
cipher = Cipher.getInstance( "AES ");
cipher.init(Cipher.DECRYPT_MODE, key);
crypt(in, out, cipher);
in.close();
out.close();
}
}
catch (IOException e)
{
e.printStackTrace();
}
catch (GeneralSecurityException e)
{
e.printStackTrace();
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
}
public static void crypt(InputStream in, OutputStream out,
Cipher cipher) throws IOException, GeneralSecurityException//加密方法
{
int blockSize = cipher.getBlockSize();
int outputSize = cipher.getOutputSize(blockSize);
byte[] inBytes = new byte[blockSize];
byte[] outBytes = new byte[outputSize];
int inLength = 0;
boolean more = true;
while (more)
{
inLength = in.read(inBytes);
if (inLength == blockSize)
{
int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
out.write(outBytes, 0, outLength);
}
else more = false;
}
if (inLength > 0)
outBytes = cipher.doFinal(inBytes, 0, inLength);
else
outBytes = cipher.doFinal();
out.write(outBytes);
}
private static final int KEYSIZE = 512;
}
[解决办法]
从JTextArea读取String：JTextArea.getText();
输出String到JTextArea: JTextArea.replaceRange(String str, int start, int end);或者使用
public void setText(String t)，查看一下帮助，应该差不多了。
http://www.java2s.com/Code/Java/Swing-JFC/Replacetextintextarea.htm这个例子有点用。
[解决办法]
关键是getText()后怎么办
这个是AES和RSA混和加密，加密使用字节流形式
用RSA加密AES密钥，用RSA加密消息 再将加密的AES密钥和加密消息包装起来的 下面部分是像out流写入密钥
DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
out.writeInt(wrappedKey.length);//向流中写入加密后密钥长度
out.write(wrappedKey);//加密后密钥长度
而解密时还要分离加密的AES密钥和加密消息，用RSA解密加密的AES密钥，再用AES密钥解密消息
上面源程序已用文件形式实现,关键是getText()得到字符串怎么实现上面的过程