PreparedStatement in
时间: 2023-11-27 09:54:16 浏览: 28
Java is a feature of JDBC (Java Database Connectivity) that allows developers to execute SQL statements with parameters. It is used to pre-compile and cache SQL statements that are frequently executed, improving performance and preventing SQL injection attacks.
A PreparedStatement object is created by calling the prepareStatement() method of a Connection object. It takes a SQL query as a string parameter, with placeholders for the parameters. For example:
```
String sql = "SELECT * FROM employees WHERE age > ?";
PreparedStatement ps = conn.prepareStatement(sql);
```
In this example, the "?" is a placeholder for the parameter that will be passed in when the statement is executed.
To set the parameter value, you can call one of the set methods on the PreparedStatement object, passing in the index of the parameter and the value. For example:
```
ps.setInt(1, 30);
```
This sets the value of the first parameter to 30.
To execute the statement, you can call the execute() method on the PreparedStatement object. For example:
```
ResultSet rs = ps.executeQuery();
```
This executes the query and returns a ResultSet object containing the results.
Overall, using PreparedStatement in Java can help improve performance and security when working with databases.