将指纹模板保存到数据库 mysql - java
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Save a fingerprint template into a database mysql - java
提问by rave
I am developing a project with the sdk fingerprint of Griaule , and as a start I'm creating a program without a GUI that allows the user to scan his fingerprint and store it in a mysql database already created earlier. I'm here to ask you a hand with regard to storing the fingerprint in the database. In the program I created, I captured the fingerprint, I extracted the template from the fingerprint through a function I call extract () . After that I should call another function , enroll (), which allows me to save the fingerprint in a database. Even looking at the SDK examples I did not understand how it works, can someone help me? thanks in advance! :)
我正在使用 Griaule 的 sdk 指纹开发一个项目，作为开始，我正在创建一个没有 GUI 的程序，该程序允许用户扫描他的指纹并将其存储在之前已经创建的 mysql 数据库中。我在这里请教您将指纹存储在数据库中的问题。在我创建的程序中，我捕获了指纹，我通过一个我调用的函数从指纹中提取了模板 extract() 。之后我应该调用另一个函数 enroll()，它允许我将指纹保存在数据库中。即使查看 SDK 示例我也不明白它是如何工作的，有人可以帮助我吗？提前致谢！:)
public void enroll() {
try {
//Inserts the template on the database
enrollStmt.setBinaryStream(1,new ByteArrayInputStream(template.getData()), template.getData().length);
enrollStmt.executeUpdate();
//Picks the ID generated for it.
ResultSet rs = insertedIdStmt.executeQuery();
rs.next();
ui.writeLog("Fingerprint enrolled with id = "+Integer.toString(rs.getInt(1)));
} catch (SQLException e) {
ui.writeLog("Error enrolling template");
}
}
采纳答案by Hirak
It is saving the finger print data as BLOB in the database. Blob (Binary Large Object) is nothing but a byte array representation of information, mainly used to store images etc in database. In your case, the fingerprint information is being stored.
它将指纹数据保存为数据库中的 BLOB。Blob（Binary Large Object）只不过是信息的字节数组表示，主要用于在数据库中存储图像等。在您的情况下，正在存储指纹信息。
enrollStmt.setBinaryStream(1,new ByteArrayInputStream(template.getData()), template.getData().length);
In this line, the bytearrayinputstream is created using the data in the template object. template.getData is giving you the byte[] representation of the fingerprint information. Then the byte[] is getting saved in database, by
在这一行中，bytearrayinputstream 是使用模板对象中的数据创建的。template.getData 为您提供了指纹信息的 byte[] 表示。然后字节 [] 被保存在数据库中，通过
enrollStmt.executeUpdate();
enrollStmt.executeUpdate();
Whereas, the following query gives you the id for the data stored, for your use.
而以下查询为您提供了存储数据的 id，供您使用。
ResultSet rs = insertedIdStmt.executeQuery();
回答by rave
Ok thank you very much Hirak , so I open a new connection with a function I created called initdb () , structured as follows:
好的，非常感谢 Hirak，所以我用我创建的一个名为 initdb () 的函数打开了一个新连接，结构如下：
private void initDB() {
try {
//Loads the JDBC driver.
Class.forName("com.mysql.jdbc.Driver").newInstance();
/**Connection to the Database.*/
Connection db;
String user = "root";
String password = "";
// connect to a memory database
db = DriverManager.getConnection("jdbc:mysql://localhost:3306/impronte?user=" + user + "&password=" + password);
Statement stm = (Statement) db.createStatement();
//Creates the statements that will be executed on the database,
enrollStmt = db.prepareStatement("INSERT INTO persona(template) values(?)");
insertedIdStmt = db.prepareStatement("SELECT MAX(ID) FROM persona");
} catch (Exception e) {
System.out.println("Error connecting to the database.");
System.out.println(e.getMessage());
}
}
and inside the enroll function this code, but nevertheless gives me the error("Error enrolling template"):
并在注册函数中使用此代码，但仍然给了我错误（“错误注册模板”）：
public void enroll ( Template template ) throws GrFingerJavaException {
try {
//Inserts the template on the database
enrollStmt.setBinaryStream(1,new ByteArrayInputStream(template.getData()), template.getData().length);
enrollStmt.executeUpdate();
//Picks the ID generated for it.
ResultSet rs = insertedIdStmt.executeQuery();
rs.next();
System.out.println("Fingerprint enrolled with id = "+Integer.toString(rs.getInt(1)));
System.out.println("Fingerprint enrolled");
} catch (SQLException e) {
System.out.println("Error enrolling template");
}
}
回答by michaelprime_
You need to set the templateto the template class of the sdk you are using before calling the binaryStream, see what I meant: Line 6 if I'm correct.
template在调用 binaryStream 之前，您需要将 设置为您正在使用的 sdk 的模板类，看看我的意思：第 6 行，如果我是正确的。
public void enroll ( Template template ) throws GrFingerJavaException {
try {
//Inserts the template on the database
Template temp = template;
if(temp != null){
byte[] b = temp.serialize();
enrollStmt.setBytes(1, b);
}
enrollStmt.executeUpdate();
//Picks the ID generated for it.
ResultSet rs = insertedIdStmt.executeQuery();
rs.next();
System.out.println("Fingerprint enrolled with id = "+Integer.toString(rs.getInt(1)));
System.out.println("Fingerprint enrolled");
} catch (SQLException e) {
System.out.println("Error enrolling template");
}
}
}
