以下是使用CallableStatement
以及MySQL存储过程:getEmpName()
的示例 -
确保已经在EMP
数据库中创建了getEmpName()
存储过程,可以使用MySQL查询来创建 -
DELIMITER $$
DROP PROCEDURE IF EXISTS `EMP`.`getEmpName` $$
CREATE PROCEDURE `EMP`.`getEmpName`
(IN EMP_ID INT, OUT EMP_FIRST VARCHAR(255))
BEGIN
SELECT first INTO EMP_FIRST
FROM Employees
WHERE ID = EMP_ID;
END $$
DELIMITER ;
查询emp
数据库的所有存储过程,如下语句 -
mysql> select `name` from mysql.proc where db = 'emp' and `type` = 'PROCEDURE';
+------------+
| name |
+------------+
| getEmpName |
+------------+
1 row in set (0.00 sec)
此示例代码是基于前面章节中完成的环境和数据库设置编写的。复制以下示例代码到JDBCCallableStatement.java
中编译,并运行如下 -
//STEP 1. Import required packages
import java.sql.*;
public class JDBCCallableStatement {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/EMP";
// Database credentials
static final String USER = "root";
static final String PASS = "123456";
public static void main(String[] args) {
Connection conn = null;
CallableStatement stmt = null;
try{
//STEP 2: Register JDBC driver
Class.forName("com.mysql.jdbc.Driver");
//STEP 3: Open a connection
System.out.println("Connecting to database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
//STEP 4: Execute a query
System.out.println("Creating statement...");
String sql = "{call getEmpName (?, ?)}";
stmt = conn.prepareCall(sql);
//Bind IN parameter first, then bind OUT parameter
int empID = 102;
stmt.setInt(1, empID); // This would set ID as 102
// Because second parameter is OUT so register it
stmt.registerOutParameter(2, java.sql.Types.VARCHAR);
//Use execute method to run stored procedure.
System.out.println("Executing stored procedure..." );
stmt.execute();
//Retrieve employee name with getXXX method
String empName = stmt.getString(2);
System.out.println("Emp Name with ID:" +
empID + " is " + empName);
stmt.close();
conn.close();
}catch(SQLException se){
//Handle errors for JDBC
se.printStackTrace();
}catch(Exception e){
//Handle errors for Class.forName
e.printStackTrace();
}finally{
//finally block used to close resources
try{
if(stmt!=null)
stmt.close();
}catch(SQLException se2){
}// nothing we can do
try{
if(conn!=null)
conn.close();
}catch(SQLException se){
se.printStackTrace();
}//end finally try
}//end try
System.out.println("Goodbye!");
}//end main
}//end JDBCExample
现在编译上面例子中的代码,如下 -
F:\worksp\jdbc>
F:\worksp\jdbc>javac -Djava.ext.dirs=F:\worksp\jdbc\libs JDBCCallableStatement.java
运行JDBCCallableStatement
时,会产生以下结果 -
F:\worksp\jdbc>java -Djava.ext.dirs=F:\worksp\jdbc\libs JDBCCallableStatement
Connecting to database...
Wed May 31 03:49:50 CST 2017 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Creating statement...
Executing stored procedure...
Emp Name with ID:102 is Xueyou
Goodbye!
F:\worksp\jdbc>