JAVA - 如何从 sqlite db 存储和读取 RSA 公钥
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JAVA - How to store and read an RSA public key from an sqlite db
提问by michele
i have to store a public key and a private one into a sqlite database. Actually i write the pubKey.getEncoded() into the database, and to recreate the pubkey i use the following code:
我必须将公钥和私钥存储到 sqlite 数据库中。实际上，我将 pubKey.getEncoded() 写入数据库，并使用以下代码重新创建公钥：
ResultSet result = stat.executeQuery("select publickey from cert where id='1'"); KeyFactory rsaKeyFac = KeyFactory.getInstance("RSA"); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(result.getBytes(1)); RSAPublicKey pubKey; pubKey = (RSAPublicKey) rsaKeyFac.generatePublic(keySpec);
ResultSet result = stat.executeQuery("select publickey from cert where id='1'"); KeyFactory rsaKeyFac = KeyFactory.getInstance("RSA"); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(result.getBytes(1)); RSAPublicKey pubKey; pubKey = (RSAPublicKey) rsaKeyFac.generatePublic(keySpec);
but it gives me the following error
但它给了我以下错误
Exception in thread "main" java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException: Detect premature EOF
线程“main”中的异常 java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException: 检测过早的 EOF
at this point :
这一点 ：
pubKey = (RSAPublicKey) rsaKeyFac.generatePublic(keySpec);
pubKey = (RSAPublicKey) rsaKeyFac.generatePublic(keySpec);
Anyone can help me?
任何人都可以帮助我吗？
Thank you in advance
先感谢您
回答by Romain Hippeau
If you look here: http://java.sun.com/docs/books/tutorial/jdbc/basics/retrieving.htmlyou will see how to properly retrieve from a DB. That is assuming you have a type of char(n) for your DB column.
如果您看这里：http: //java.sun.com/docs/books/tutorial/jdbc/basics/retrieving.html，您将看到如何从数据库中正确检索。那是假设您的 DB 列有一种 char(n) 类型。
ResultSet result = stat.executeQuery("select publickey from cert where id='1'");
while(result.next())
{
KeyFactory rsaKeyFac = KeyFactory.getInstance("RSA");
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(result.getString(1));
RSAPublicKey pubKey;
pubKey = (RSAPublicKey) rsaKeyFac.generatePublic(keySpec);
}
If the type is a BLOB or CLOB then you need to use a different mechanism. http://java.sun.com/j2se/1.5.0/docs/guide/jdbc/blob.html
如果类型是 BLOB 或 CLOB，那么您需要使用不同的机制。 http://java.sun.com/j2se/1.5.0/docs/guide/jdbc/blob.html
回答by Mike Baranczak
When you first get a ResultSet, the cursor points to the space beforethe first row of results. So you need to call next() on it before trying to retrieve the data.
You should make sure that the query actually succeeded.
当你第一次得到一个 ResultSet 时，光标指向第一行结果之前的空间。因此，您需要在尝试检索数据之前对其调用 next()。
您应该确保查询确实成功了。
