Spring JDBC查詢數(shù)據(jù)

以下示例將展示如何使用Spring jdbc進(jìn)行查詢數(shù)據(jù)記錄，將從student表中查詢記錄。

語法：

String selectQuery = "select * from student";
List <Student> students = jdbcTemplateObject.query(selectQuery, new StudentMapper());

在上面語法中 -

• selectQuery - 選擇查詢學(xué)生數(shù)據(jù)記錄。
• jdbcTemplateObject - StudentJDBCTemplate 對(duì)象將 Student 對(duì)象插入到數(shù)據(jù)庫中。
• StudentMapper - StudentMapper是一個(gè)RowMapper對(duì)象，用于將每個(gè)獲取的記錄映射到Student對(duì)象。

創(chuàng)建項(xiàng)目

要了解上面提到的Spring JDBC相關(guān)的概念，這里創(chuàng)建一個(gè)項(xiàng)目用來演示如何從Student表讀取數(shù)據(jù)的示例。使用Eclipse IDE，并按照以下步驟創(chuàng)建一個(gè)名稱為：ReadQuery 的Spring應(yīng)用程序項(xiàng)目。

步驟說明

1. 參考第一個(gè)Spring JDBC項(xiàng)目來創(chuàng)建一個(gè)Maven項(xiàng)目 - http://www.yiibai.com/springjdbc/first_application.html
2. 更新bean配置并運(yùn)行應(yīng)用程序。

完整的項(xiàng)目結(jié)構(gòu)如下所示 -

文件 : pom.xml 的內(nèi)容 -

<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.yiibai</groupId>
    <artifactId>ReadQuery</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <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>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.40</version>
        </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>

以下是數(shù)據(jù)訪問對(duì)象接口文件：StudentDAO.java的代碼內(nèi)容：

package com.yiibai;

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();
}

以下是文件：Student.java的代碼內(nèi)容：

package com.yiibai;

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;
    }
}

以下是文件：StudentMapper.java的代碼內(nèi)容：

package com.yiibai;

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;
    }
}

以下是實(shí)現(xiàn)類文件:StudentJDBCTemplate.java，它實(shí)現(xiàn)了接口StudentDAO.java：
以下是文件：StudentJDBCTemplate.java的代碼內(nèi)容：

package com.yiibai;

import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;

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 insertQuery = "insert into Student (name, age) values (?, ?)";

        jdbcTemplateObject.update(insertQuery, 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;
    }

    public Student getStudent(Integer id) {
        // TODO Auto-generated method stub
        return null;
    }
}

以下是程序執(zhí)行入口文件：MainApp.java的代碼內(nèi)容：

package com.yiibai;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.StudentJDBCTemplate;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
             new ClassPathXmlApplicationContext("application-beans.xml");

      StudentJDBCTemplate studentJDBCTemplate = 
      (StudentJDBCTemplate)context.getBean("studentJDBCTemplate");

      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Bean和數(shù)據(jù)庫配置文件：application-beans.xml的代碼內(nèi)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?characterEncoding=utf8&useSSL=true" />
        <property name="username" value="root" />
        <property name="password" value="123456" />
    </bean>

    <!-- Definition for studentJDBCTemplate bean -->
    <bean id="studentJDBCTemplate" class="com.yiibai.StudentJDBCTemplate">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

注意： application-beans.xml 文件的位置是：{workspace}/fistapp/src/main/java 目錄，如果放置錯(cuò)了，程序可能會(huì)因?yàn)檎也坏酱伺渲梦募鲥e(cuò)。

完成創(chuàng)建源代碼和bean和數(shù)據(jù)庫連接信息的文件配置后，運(yùn)行應(yīng)用程序。這里先簡單說明一下運(yùn)行的步驟，在項(xiàng)目名稱(ReadQuery)上點(diǎn)擊右鍵，在彈出的菜單中選擇：【Run As】-> 【Maven test】

在運(yùn)行測(cè)試成功后，應(yīng)該會(huì)輸出類似以下內(nèi)容(含有 BUILD SUCCESS 的信息) 。
接下來，點(diǎn)擊類文件：MainApp.java 選擇【Run As】->【Java Application】，如果應(yīng)用程序一切正常，這將打印以下消息：

信息: Loaded JDBC driver: com.mysql.jdbc.Driver
------Listing Multiple Records--------
ID : 1, Name : Maxsu, Age : 19
ID : 2, Name : Minsu, Age : 23
ID : 3, Name : Allen, Age : 27
ID : 4, Name : Maxsu, Age : 19
ID : 5, Name : Minsu, Age : 23
ID : 6, Name : Allen, Age : 27
ID : 7, Name : Maxsu, Age : 19
ID : 8, Name : Minsu, Age : 23
ID : 9, Name : Allen, Age : 27