First Application

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2023-12-01

要了解与JDBC模板类相关的Spring JDBC框架的概念,让我们编写一个简单的示例,它将在以下Student表上实现Insert和Read操作。

CREATE TABLE Student(
   ID   INT NOT NULL AUTO_INCREMENT,
   NAME VARCHAR(20) NOT NULL,
   AGE  INT NOT NULL,
   PRIMARY KEY (ID)
);

让我们继续编写一个简单的基于控制台的Spring JDBC Application,它将演示JDBC概念。

创建项目

让我们打开命令控制台,转到C:\MVN目录并执行以下mvn命令。

C:\MVN>mvn archetype:generate -DgroupId = cn.xnip -DartifactId = Student
   -DarchetypeArtifactId = maven-archetype-quickstart -DinteractiveMode = false

Maven将开始处理并将创建完整的Java应用程序项目结构。

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources
@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources
@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom --
-
[INFO] Generating project in Batch mode
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.jar
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.jar (5 KB at 1.1 KB/s
ec)
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/ma
ven-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.pom
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/archetypes/mav
en-archetype-quickstart/1.0/maven-archetype-quickstart-1.0.pom (703 B at 1.2 KB/
sec)
[INFO] -------------------------------------------------------------------------
---
[INFO] Using following parameters for creating project from Old (1.x) Archetype:
 maven-archetype-quickstart:1.0
[INFO] -------------------------------------------------------------------------
---
[INFO] Parameter: groupId, Value: cn.xnip
[INFO] Parameter: packageName, Value: cn.xnip
[INFO] Parameter: package, Value: cn.xnip
[INFO] Parameter: artifactId, Value: Student
[INFO] Parameter: basedir, Value: C:\MVN
[INFO] Parameter: version, Value: 1.0-SNAPSHOT
[INFO] project created from Old (1.x) Archetype in dir: C:\MVN\Student
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:17 min
[INFO] Finished at: 2017-02-19T21:11:14+05:30
[INFO] Final Memory: 15M/114M
[INFO] ------------------------------------------------------------------------

现在转到C:/ MVN目录。 您将看到一个名为student的Java应用程序项目(在artifactId中指定)。 更新POM.xml以包含Spring JDBC依赖项。 添加Student.java,StudentMapper.java,MainApp.java,StudentDAO.java和StudentJDBCTemplate.java文件。

的pom.xml

<project xmlns = "http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>cn.xnip</groupId>
   <artifactId>Student</artifactId>
   <packaging>jar</packaging>
   <version>1.0-SNAPSHOT</version>
   <name>Student</name>
   <url>http://maven.apache.org</url>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-jdbc</artifactId>
         <version>4.1.0.RELEASE</version>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>4.1.4.RELEASE</version>
      </dependency>
   </dependencies>
</project>

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 create
      * a record in the Student table.
   */
   public void create(String name, Integer age);
   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();
}

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.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 List<Student> listStudents() {
      String SQL = "select * from Student";
      List <Student> students = jdbcTemplateObject.query(SQL, new StudentMapper());
      return students;
   }
}

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");
      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());
      }  
   }
}

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。

------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