Spring JDBC 示例
阿新 • • 發佈:2021-12-30
Spring JDBC 示例
想要理解帶有 jdbc 模板類的 Spring JDBC 框架的相關概念,讓我們編寫一個簡單的示例,來實現下述 Student 表的所有 CRUD 操作。
CREATE TABLE Student( ID INT NOT NULL AUTO_INCREMENT, NAME VARCHAR(20) NOT NULL, AGE INT NOT NULL, PRIMARY KEY (ID) );
在繼續之前,讓我們適當地使用 Eclipse IDE 並按照如下所示的步驟建立一個 Spring 應用程式:
步驟 | 描述 |
---|---|
1 | 建立一個名為SpringExample的專案,並在建立的專案中的src |
2 | 使用Add External JARs選項新增必需的 Spring 庫,解釋見Spring Hello World Example章節。 |
3 | 在專案中新增 Spring JDBC 指定的最新的庫mysql-connector-java.jar,org.springframework.jdbc.jar和org.springframework.transaction.jar。如果這些庫不存在,你可以下載它們。 |
4 | 建立 DAO 介面StudentDAO並列出所有必需的方法。儘管這一步不是必需的而且你可以直接編寫StudentJDBCTemplate |
5 | 在com.tutorialspoint包下建立其他的必需的 Java 類Student,StudentMapper,StudentJDBCTemplate和MainApp。 |
6 | 確保你已經在 TEST 資料庫中建立了Student表。並確保你的 MySQL 伺服器執行正常,且你可以使用給出的使用者名稱和密碼讀/寫訪問資料庫。 |
7 | 在src資料夾下建立 Beans 配置檔案Beans.xml。 |
8 | 最後一步是建立所有的 Java 檔案和 Bean 配置檔案的內容並按照如下所示的方法執行應用程式。 |
以下是資料訪問物件介面檔案StudentDAO.java
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 create
* a record in the Student table.
*/
public void create(String name, 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);
/**
* 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);
/**
* This is the method to be used to update
* a record into the Student table.
*/
public void update(Integer id, Integer age);
}
下面是Student.java檔案的內容:
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檔案的內容:
package com.tutorialspoint;
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;
}
}
下面是為定義的 DAO 介面 StudentDAO 的實現類檔案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 create(String name, Integer age) {
String SQL = "insert into Student (name, age) values (?, ?)";
jdbcTemplateObject.update( SQL, name, age);
System.out.println("Created Record Name = " + name + " Age = " + age);
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;
}
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;
}
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;
}
}
以下是MainApp.java檔案的內容:
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("------Records Creation--------" );
studentJDBCTemplate.create("Zara", 11);
studentJDBCTemplate.create("Nuha", 2);
studentJDBCTemplate.create("Ayan", 15);
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());
}
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());
}
}
下述是配置檔案Beans.xml的內容:
<?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="password"/>
</bean>
<!-- Definition for studentJDBCTemplate bean -->
<bean id="studentJDBCTemplate"
class="com.tutorialspoint.StudentJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
當你完成建立源和 bean 配置檔案後,執行應用程式。如果你的應用程式一切執行順利的話,將會輸出如下所示的訊息:
------Records Creation--------
Created Record Name = Zara Age = 11
Created Record Name = Nuha Age = 2
Created Record Name = Ayan Age = 15
------Listing Multiple Records--------
ID : 1, Name : Zara, Age : 11
ID : 2, Name : Nuha, Age : 2
ID : 3, Name : Ayan, Age : 15
----Updating Record with ID = 2 -----
Updated Record with ID = 2
----Listing Record with ID = 2 -----
ID : 2, Name : Nuha, Age : 20
你可以嘗試自己刪除在我的例子中我沒有用到的操作,但是現在你有一個基於 Spring JDBC 框架的工作應用程式,你可以根據你的專案需求來擴充套件這個框架,新增複雜的功能。還有其他方法來訪問你使用NamedParameterJdbcTemplate和SimpleJdbcTemplate類的資料庫,所以如果你有興趣學習這些類的話,那麼你可以檢視 Spring 框架的參考手冊。