以下示例将演示如何使用Spring JDBC调用存储的函数.我们将通过调用存储函数来读取学生表中的一个可用记录.我们将传递一个id并收到学生姓名.
SimpleJdbcCall jdbcCall = new SimpleJdbcCall(dataSource).withFunctionName("get_student_name"); SqlParameterSource in = new MapSqlParameterSource().addValue("in_id", id); String name = jdbcCall.executeFunction(String.class, in); Student student = new Student(); student.setId(id); student.setName(name);
其中,
in : SqlParameterSource对象将参数传递给存储的函数.
jdbcCall : SimpleJdbcCall对象表示存储的函数.
jdbcTemplateObject : StudentJDBCTemplate对象从数据库调用存储函数.
学生 : 学生对象.
SimpleJdbcCall 类可用于使用IN参数调用存储函数并返回值.您可以在使用任何RDBMS(如Apache Derby,DB2,MySQL,Microsoft SQL Server,Oracle和Sybase)时使用此方法.
要了解该方法,请考虑以下MySQL存储过程,它接收学生ID并返回相应学生的姓名.因此,让我们使用MySQL命令提示符在您的TEST数据库中创建此存储函数 :
DELIMITER $$ DROP FUNCTION IF EXISTS `TEST`.`get_student_name` $$ CREATE FUNCTION `get_student_name` (in_id INTEGER) RETURNS varchar(200) BEGIN DECLARE out_name VARCHAR(200); SELECT name INTO out_name FROM Student where id = in_id; RETURN out_name; DELIMITER ;
为了理解上面提到的与Spring JDBC相关的概念,让我们编写一个调用存储函数的例子.要编写我们的示例,让我们使用一个可用的Eclipse IDE并使用以下步骤创建一个Spring应用程序.
Step | 描述 |
---|---|
1 | 更新在章节下创建的项目学生 Spring JDBC - First Application . |
2 | 更新bean配置并运行应用程序,如下所述. |
以下是数据访问对象接口文件的内容 StudentDAO.java .
package com.it1352; import java.util.List; import javax.sql.DataSource; public interface StudentDAO { /** * This is the method to be used to initialize * database resources ie. connection. */ public void setDataSource(DataSource ds); /** * This is the method to be used to list down * a record from the Student table corresponding * to a passed student id. */ public Student getStudent(Integer id); }
以下是 Student.java 文件的内容.
package com.it1352; public class Student { private Integer age; private String name; private Integer id; public void setAge(Integer age) { this.age = age; } public Integer getAge() { return age; } public void setName(String name) { this.name = name; } public String getName() { return name; } public void setId(Integer id) { this.id = id; } public Integer getId() { return id; } }
以下是 StudentMapper.java 文件的内容.
package com.it1352; import java.sql.ResultSet; import java.sql.SQLException; import org.springframework.jdbc.core.RowMapper; public class StudentMapper implements RowMapper<Student> { public Student mapRow(ResultSet rs, int rowNum) throws SQLException { Student student = new Student(); student.setId(rs.getInt("id")); student.setName(rs.getString("name")); student.setAge(rs.getInt("age")); return student; } }
以下是定义的DAO接口StudentDAO的实现类文件 StudentJDBCTemplate.java .
package com.it1352; import java.util.List; import javax.sql.DataSource; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.namedparam.MapSqlParameterSource; import org.springframework.jdbc.core.namedparam.SqlParameterSource; import org.springframework.jdbc.core.simple.SimpleJdbcCall; public class StudentJDBCTemplate implements StudentDAO { private DataSource dataSource; private JdbcTemplate jdbcTemplateObject; public void setDataSource(DataSource dataSource) { this.dataSource = dataSource; this.jdbcTemplateObject = new JdbcTemplate(dataSource); } public Student getStudent(Integer id) { SimpleJdbcCall jdbcCall = new SimpleJdbcCall(dataSource).withFunctionName("get_student_name"); SqlParameterSource in = new MapSqlParameterSource().addValue("in_id", id); String name = jdbcCall.executeFunction(String.class, in); Student student = new Student(); student.setId(id); student.setName(name); return student; } }
为执行调用而编写的代码涉及创建包含IN参数的SqlParameterSource.将为输入值提供的名称与在存储函数中声明的参数名称的名称相匹配非常重要. executeFunction方法接受IN参数并返回存储函数中指定的String.
以下是 MainApp.java 文件的内容
package com.it1352; import java.util.List; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.it1352.StudentJDBCTemplate; public class MainApp { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml"); StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate)context.getBean("studentJDBCTemplate"); Student student = studentJDBCTemplate.getStudent(1); System.out.print("ID : " + student.getId() ); System.out.print(", Name : " + student.getName() ); } }
以下是配置文件 Beans.xml .
<?xml version = "1.0" encoding = "UTF-8"?> <beans xmlns = "http://www.springframework.org/schema/beans" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation = "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd "> <!-- Initialization for data source --> <bean id = "dataSource" class = "org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name = "driverClassName" value = "com.mysql.jdbc.Driver"/> <property name = "url" value = "jdbc:mysql://localhost:3306/TEST"/> <property name = "username" value = "root"/> <property name = "password" value = "admin"/> </bean> <!-- Definition for studentJDBCTemplate bean --> <bean id = "studentJDBCTemplate" class = "com.it1352.StudentJDBCTemplate"> <property name = "dataSource" ref = "dataSource" /> </bean> </beans>
完成源和bean配置文件的创建后,让我们运行应用程序.如果你的申请一切正常,它将打印以下信息.
ID : 1, Name : Zara