📅 最后修改于: 2020-11-11 06:04:00 🧑 作者: Mango
以下示例将演示如何使用Spring JDBC更新查询。我们将更新学生表中的可用记录。
String updateQuery = "update Student set age = ? where id = ?";
jdbcTemplateObject.update(updateQuery, age, id);
哪里，
updateQuery-更新查询以使用占位符更新学生。
jdbcTemplateObject -StudentJDBCTemplate对象，用于更新数据库中的学生对象。
为了理解与Spring JDBC相关的上述概念，让我们编写一个示例来更新查询。为了编写示例，让我们准备好一个可以运行的Eclipse IDE，并使用以下步骤创建一个Spring应用程序。
| Step | Description |
|---|---|
| 1 | Update the project Student created under chapter Spring JDBC – First Application. |
| 2 | Update the bean configuration and run the application as explained below. |
以下是数据访问对象接口文件StudentDAO.java的内容。
package com.tutorialspoint;
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 update
* a record into the Student table.
*/
public void update(Integer id, Integer age);
/**
* 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.tutorialspoint;
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.tutorialspoint;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
public class StudentMapper implements RowMapper {
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;
}
}
以下是已定义的DAO接口StudentDAO的实现类文件StudentJDBCTemplate.java 。
package com.tutorialspoint;
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 void update(Integer id, Integer age){
String SQL = "update Student set age = ? where id = ?";
jdbcTemplateObject.update(SQL, age, id);
System.out.println("Updated Record with ID = " + id );
return;
}
public Student getStudent(Integer id) {
String SQL = "select * from Student where id = ?";
Student student = jdbcTemplateObject.queryForObject(
SQL, new Object[]{id}, new StudentMapper());
return student;
}
}
以下是MainApp.java文件的内容。
package com.tutorialspoint;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.tutorialspoint.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("----Updating Record with ID = 2 -----" );
studentJDBCTemplate.update(2, 20);
System.out.println("----Listing Record with ID = 2 -----" );
Student student = studentJDBCTemplate.getStudent(2);
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 。
完成创建源和Bean配置文件后，让我们运行该应用程序。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