以下示例将演示如何使用Spring JDBC删除查询.我们将删除学生表中的一个可用记录.
String deleteQuery = "delete from Student where id = ?"; jdbcTemplateObject.update(deleteQuery, id);
其中,
deleteQuery : 删除查询以删除具有占位符的学生.
jdbcTemplateObject : StudentJDBCTemplate对象删除数据库中的student对象.
为了理解上面提到的与Spring JDBC相关的概念,让我们编写一个例子这将删除一个查询.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<a href章节下创建的项目学生 ="https://img01.yuandaxia.cn/Content/img/tutorials/springjdbc/springjdbc_first_application.htm"> Spring JDBC - 第一个应用程序 . |
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 * all the records from the Student table. */ public List<Student> listStudents(); /** * This is the method to be used to delete * a record from the Student table corresponding * to a passed student id. */ public void delete(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; 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 List<Student> listStudents() { String SQL = "select * from Student"; List <Student> students = jdbcTemplateObject.query(SQL, new StudentMapper()); return students; } public void delete(Integer id){ String SQL = "delete from Student where id = ?"; jdbcTemplateObject.update(SQL, id); System.out.println("Deleted Record with ID = " + id ); return; } }
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.IT屋.StudentJDBCTemplate; public class MainApp { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml"); StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate)context.getBean("studentJDBCTemplate"); System.out.println("----Delete Record with ID = 2 -----" ); studentJDBCTemplate.delete(2); System.out.println("------Listing Multiple Records--------" ); List<Student> students = studentJDBCTemplate.listStudents(); for (Student record : students) { System.out.print("ID : " + record.getId() ); System.out.print(", Name : " + record.getName() ); System.out.println(", Age : " + record.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"> <! - 数据源初始化 - > < 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> <! - studentJDBCTemplate bean的定义 - > < 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.如果您的应用程序一切正常,它将打印以下消息.
----Updating Record with ID = 2 ----- Updated Record with ID = 2 ----Listing Record with ID = 2 ----- ID : 2, Name : Nuha, Age : 20