StoredProcedure

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2023-12-01

org.springframework.jdbc.core.StoredProcedure类是RDBMS存储过程的对象抽象的超类。这个类是抽象的，并且子类将提供一个类型化的调用方法，该方法委托给提供的execute（java.lang.Object ...）方法。继承的SQL属性是RDBMS中存储过程的名称。

Class 声明 (Class Declaration)

以下是org.springframework.jdbc.core.StoredProcedure类的声明 -

public abstract class StoredProcedure
   extends SqlCall

下面的示例将演示如何使用Spring StoredProcedure调用存储过程。我们将通过调用存储过程来读取学生表中的一个可用记录。我们将通过身份证并收到学生记录。

语法 (Syntax)

class StudentProcedure extends StoredProcedure{
   public StudentProcedure(DataSource dataSource, String procedureName){
      super(dataSource,procedureName);
      declareParameter(new SqlParameter("in_id", Types.INTEGER));
      declareParameter(new SqlOutParameter("out_name", Types.VARCHAR));
      declareParameter(new SqlOutParameter("out_age", Types.INTEGER));
      compile();
   }
   public Student execute(Integer id){
      Map<String, Object> out = super.execute(id);
      Student student = new Student();
      student.setId(id);
      student.setName((String) out.get("out_name"));
      student.setAge((Integer) out.get("out_age"));
      return student;  	
   }
}

Where,

StoredProcedure - StoredProcedure对象，表示存储过程。
StudentProcedure - StudentProcedure对象扩展StoredProcedure以声明输入，输出变量和映射结果到Student对象。
student - 学生对象。

为了理解与Spring JDBC相关的上述概念，让我们编写一个调用存储过程的示例。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。

步	描述
1	更新在Spring JDBC - First Application章节下创建的项目Student 。
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StudentDAO.java 。

package cn.xnip;
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 cn.xnip;
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 cn.xnip;
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StudentJDBCTemplate.java的实现类文件StudentJDBCTemplate.java 。

package cn.xnip;
import java.sql.Types;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.SqlOutParameter;
import org.springframework.jdbc.core.SqlParameter;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.jdbc.object.StoredProcedure;
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) {    
      StudentProcedure studentProcedure = new StudentProcedure(dataSource, "getRecord");
      return studentProcedure.execute(id);      
   }    
}
class StudentProcedure extends StoredProcedure{
   public StudentProcedure(DataSource dataSource, String procedureName) {
      super(dataSource,procedureName);
      declareParameter(new SqlParameter("in_id", Types.INTEGER));
      declareParameter(new SqlOutParameter("out_name", Types.VARCHAR));
      declareParameter(new SqlOutParameter("out_age", Types.INTEGER));
      compile();
   }
   public Student execute(Integer id){
      Map<String, Object> out = super.execute(id);
      Student student = new Student();
      student.setId(id);
      student.setName((String) out.get("out_name"));
      student.setAge((Integer) out.get("out_age"));
      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存储过程中声明的参数名称的名称相匹配非常重要。 execute方法接受IN参数并返回一个Map，该Map包含由存储过程中指定的名称键入的任何out参数。

以下是MainApp.java文件的内容。

package cn.xnip;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.xnip.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() );
      System.out.println(", Age : " + student.getAge()); 
   }
}

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 = "cn.xnip.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。如果您的应用程序一切正常，它将打印以下消息。

ID : 1, Name : Zara, Age : 10