How to call MySQL stored procedure in Java

In the MySQL database, stored procedures have high flexibility and reusability, and are often used to optimize complex database operations and improve database performance. Java programs often need to call stored procedures in MySQL. This article will introduce the specific implementation of how Java calls stored procedures in MySQL.

1. Create a stored procedure

First you need to create a stored procedure in the MySQL database. Stored procedures can be created through the command line or MySQL graphical tools (such as Navicat).

The following is a simple stored procedure example, which can find all table names in the specified library:

CREATE PROCEDURE `GetAllTableNames`(IN dbName VARCHAR(100))
BEGIN
    SELECT table_name
    FROM information_schema.tables
    WHERE table_schema = dbName;
END

2. Java calls the stored procedure

Usage The process of Java calling MySQL stored procedures is actually calling the stored procedure related methods of JDBC (Java Database Connection) API. The specific steps for Java to call MySQL stored procedures will be introduced in detail below.

1. Import MySQL JDBC driver package

Java programs need to use the MySQL JDBC driver package. You can download the corresponding version of the MySQL Connector/J driver package from the MySQL official website, and then Add it to the CLASSPATH of the Java project.

2. Get the database connection

The steps to use JDBC to connect to the MySQL database in Java are the same as ordinary database connections. You need to load the driver first, and then obtain the database connection.

Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");

3. Creating a CallableStatement object

The core step of calling a stored procedure in Java is to create a CallableStatement object and call the execute method of the stored procedure. CallableStatement is a subclass of PreparedStatement and is used to execute statements with input parameters or output parameters or both. Stored procedures usually have input parameters or output parameters or both.

Before creating a CallableStatement object, you need to prepare the parameter list of the stored procedure. For example, for the above stored procedure example, the dbName parameter needs to be passed in, and the CallableStatement object can be obtained through this code:

CallableStatement callableStatement = conn.prepareCall("{call GetAllTableNames(?)}");
callableStatement.setString(1, "test");

It should be noted that the setXX() method of CallableStatement is similar to the usage of PreparedStatement. Use To set the input parameters of the stored procedure.

4. Call the execute method to execute the stored procedure

After completing the parameter transfer and preparation of the CallableStatement object, you can call the execute method to execute the SQL statement. For stored procedures, you can call one of three methods: execute(), executeQuery(), or executeUpdate(), depending on the specific implementation of the stored procedure.

After executing the stored procedure, the result set needs to be saved to the ResultSet object for subsequent processing.

ResultSet rs = callableStatement.executeQuery();
while (rs.next()) {
    System.out.println(rs.getString(1));
}

The complete sample code for Java to call MySQL stored procedures is as follows:

Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");

CallableStatement callableStatement = conn.prepareCall("{call GetAllTableNames(?)}");
callableStatement.setString(1, "test");

ResultSet rs = callableStatement.executeQuery();
while (rs.next()) {
    System.out.println(rs.getString(1));
}

rs.close();
callableStatement.close();
conn.close();

3. Summary

This article introduces the specific steps for Java to call MySQL stored procedures, including creating storage Procedure, import the MySQL JDBC driver package, obtain the database connection, create the CallableStatement object, and call the execute method to execute the stored procedure.

Java calling MySQL stored procedures can help Java developers improve the efficiency and performance of database operations. According to specific needs, the implementation of stored procedures can be flexibly adjusted to obtain better results.

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