Sử dụng nhiều DataSource trong Spring MVC
Công ty Vĩnh Cửu tuyển dụng lập trình viên Java

1- Mục tiêu của tài liệu

Đôi khi bạn cần tạo một ứng dụng Web kết nối vào nhiều cơ sở dữ liệu khác nhau. Và thật tốt là bạn có thể làm điều đó dễ dàng trong Spring MVC.
Spring cung cấp cho bạn class AbstractRoutingDataSource, bạn cần viết một class mở rộng từ class này. Routing Datasource chứa một bản đồ (Map) các Datasource thực sự. Và nó sẽ quyết định DataSource nào sẽ được sử dụng tương ứng với mỗi request từ phía người dùng.
Routing Datasource cũng là một Datasource, nó là một Datasource đặc biệt.
Trong tài liệu này tôi mô phỏng một Website sử dụng 2 datasource. Mỗi datasource kết nối vào một Database khác nhau. Một database lưu trữ thông tin cho hệ thống Publisher (Nhà xuất bản) và một Database lưu trữ thông tin hệ thống Advertiser (Nhà quảng cáo).
Trong một số tình huống bạn cũng có thể xây dựng một website tin tức đa ngôn ngữ, bạn có thể tạo nhiều Database, mỗi database lưu trữ nội dung các bài viết của một ngôn ngữ cụ thể.

2- Chuẩn bị Database

Tôi sẽ tạo ra 2 cơ sở dữ liệu, một database dành cho hệ thống PUBLISHER (Nhà xuất bản) và một database dành cho hệ thống ADVERTISER (Nhà quảng cáo). Hai Database này có thể không cùng một loại. Bạn có thể sử dụng Oracle, MySQL hoặc SQL Server, ...
 

Database1:

Hệ thống database PUBLISHER có một bảng Publishers.
Database1 - (ORACLE)
-- Create table
create table PUBLISHERS
(
NAME VARCHAR2(50)
);

insert into publishers (NAME)
values ('publisher 1');

insert into publishers (NAME)
values ('publisher 2');

Commit;
Database1 - (MySQL or SQL Server)
-- Create table
create table PUBLISHERS
(
  NAME VARCHAR(50)
);

insert into publishers (NAME)
values ('publisher 1');

insert into publishers (NAME)
values ('publisher 2');

Database 2:

Hệ thống database ADVERTISER có một bảng Advertisers.
 
Database2 - (ORACLE)
-- Create table
create table ADVERTISERS
(
  NAME VARCHAR2(50)
);

insert into advertisers (NAME)
values ('Advertiser 1');

insert into advertisers (NAME)
values ('Advertiser 2');

Commit;
Database2 (MySQL or SQL Server)
-- Create table
create table ADVERTISERS
(
  NAME VARCHAR(50)
);

insert into advertisers (NAME)
values ('Advertiser 1');

insert into advertisers (NAME)
values ('Advertiser 2');

3- Tạo Maven Web App Project

4- Cấu hình web.xml & pom.xml

Sử dụng WebApp >= 3.
web.xml
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">
 
    <display-name>SpringMVCMultiDS Web Application</display-name>
 
</web-app>
Trong pom.xml tôi đã khai báo các thư viện JDBC cho cả 3 loại cơ sở dữ liệu Oracle, MySQLSQL Server.
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>org.o7planning</groupId>
  <artifactId>SpringMVCMultiDS</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>SpringMVCMultiDS Maven Webapp</name>
  <url>http://maven.apache.org</url>


    <repositories>
        <!-- Repository for ORACLE JDBC Driver -->
        <repository>
            <id>codelds</id>
            <url>https://code.lds.org/nexus/content/groups/main-repo</url>
        </repository>
    </repositories>

    <dependencies>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- Servlet API -->
        <!-- http://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- Jstl for jsp page -->
        <!-- http://mvnrepository.com/artifact/javax.servlet/jstl -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>


        <!-- JSP API -->
        <!-- http://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
            <scope>provided</scope>
        </dependency>

        <!-- Spring dependencies -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>

        <!-- http://mvnrepository.com/artifact/org.springframework/spring-web -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>

        <!-- http://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>


        <!-- http://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>

        <!-- http://mvnrepository.com/artifact/org.springframework/spring-tx -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>
 

        <!-- Commons DataSources -->
        <!-- https://mvnrepository.com/artifact/commons-dbcp/commons-dbcp -->
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.4</version>
        </dependency>


        <!-- MySQL JDBC driver -->
        <!-- http://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>6.0.4</version>
        </dependency>

        <!-- Oracle JDBC driver -->
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc6</artifactId>
            <version>11.2.0.3</version>
        </dependency>

        <!-- SQLServer JDBC driver (JTDS) -->
        <!-- http://mvnrepository.com/artifact/net.sourceforge.jtds/jtds -->
        <dependency>
            <groupId>net.sourceforge.jtds</groupId>
            <artifactId>jtds</artifactId>
            <version>1.3.1</version>
        </dependency>


    </dependencies>


    <build>
        <finalName>SpringMVCMultiDS</finalName>
        <plugins>
       
            <!-- Config: Maven Tomcat Plugin -->
            <!-- http://mvnrepository.com/artifact/org.apache.tomcat.maven/tomcat7-maven-plugin -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <!-- Config: contextPath and Port (Default - /SpringMVCMultiDS,8080) -->
                <!--
                <configuration>
                    <path>/</path>
                    <port>8899</port>
                </configuration>
                -->   
            </plugin>
        </plugins>
    </build>   

</project>

5- Cấu hình Spring MVC

SpringWebAppInitializer.java
package org.o7planning.springmvcmultids.config;

import javax.servlet.FilterRegistration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.DispatcherServlet;

public class SpringWebAppInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
        appContext.register(ApplicationContextConfig.class);

        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("SpringDispatcher",
                new DispatcherServlet(appContext));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");       
        // 
        dispatcher.setInitParameter("contextClass", appContext.getClass().getName());

        servletContext.addListener(new ContextLoaderListener(appContext));

        // UTF8 Charactor Filter.
        FilterRegistration.Dynamic fr = servletContext.addFilter("encodingFilter", CharacterEncodingFilter.class);

        fr.setInitParameter("encoding", "UTF-8");
        fr.setInitParameter("forceEncoding", "true");
        fr.addMappingForUrlPatterns(null, true, "/*");
    }

}
Trong WebMvcConfig bạn cần đăng ký DataSourceInterceptor, interceptor này phân tích URL của request gửi đến để quyết định Datasource nào sẽ được sử dụng.
WebMvcConfig.java
package org.o7planning.springmvcmultids.config;

import org.o7planning.springmvcmultids.interceptor.DataSourceIntercetor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
@EnableWebMvc
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        // Default..
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    //
    @Override
    public void addInterceptors(InterceptorRegistry registry) {

        registry.addInterceptor(new DataSourceIntercetor())//
                .addPathPatterns("/publisher/*", "/advertiser/*");
    }

}
ApplicationContextConfig.java
package org.o7planning.springmvcmultids.config;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSource;
import org.o7planning.springmvcmultids.routing.MyRoutingDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.context.annotation.PropertySources;
import org.springframework.core.env.Environment;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@ComponentScan("org.o7planning.springmvcmultids.*")

@EnableTransactionManagement

// Load to Environment.
@PropertySources({ @PropertySource("classpath:ds/datasource-cfg.properties") })

public class ApplicationContextConfig {
 

   // Lưu trữ các giá thuộc tính load bởi @PropertySource.
   @Autowired
   private Environment env;

   @Bean(name = "viewResolver")
   public InternalResourceViewResolver getViewResolver() {
       InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();

       viewResolver.setPrefix("/WEB-INF/pages/");
       viewResolver.setSuffix(".jsp");

       return viewResolver;
   }

   // Returns Routing DataSource (MyRoutingDataSource)
   @Autowired
   @Bean(name = "dataSource")
   public DataSource getDataSource(DataSource dataSource1, DataSource dataSource2) {

       System.out.println("## Create DataSource from dataSource1 & dataSource2");

       MyRoutingDataSource dataSource = new MyRoutingDataSource();

       Map<Object, Object> dsMap = new HashMap<Object, Object>();
       dsMap.put("PUBLISHER_DS", dataSource1);
       dsMap.put("ADVERTISER_DS", dataSource2);

       dataSource.setTargetDataSources(dsMap);

       return dataSource;
   }

   @Bean(name = "dataSource1")
   public DataSource getDataSource1() throws SQLException {
       BasicDataSource dataSource = new BasicDataSource();

       // See: datasouce-cfg.properties
       dataSource.setDriverClassName(env.getProperty("ds.database-driver1"));
       dataSource.setUrl(env.getProperty("ds.url1"));
       dataSource.setUsername(env.getProperty("ds.username1"));
       dataSource.setPassword(env.getProperty("ds.password1"));

       System.out.println("## getDataSource1: " + dataSource);
       return dataSource;
   }

   @Bean(name = "dataSource2")
   public DataSource getDataSource2() throws SQLException {
       BasicDataSource dataSource = new BasicDataSource();

       // See: datasouce-cfg.properties
       dataSource.setDriverClassName(env.getProperty("ds.database-driver2"));
       dataSource.setUrl(env.getProperty("ds.url2"));
       dataSource.setUsername(env.getProperty("ds.username2"));
       dataSource.setPassword(env.getProperty("ds.password2"));

       System.out.println("## getDataSource2: " + dataSource);

       return dataSource;
   }

   @Autowired
   @Bean(name = "transactionManager")
   public DataSourceTransactionManager getTransactionManager(DataSource dataSource) {
       DataSourceTransactionManager txManager = new DataSourceTransactionManager();

       txManager.setDataSource(dataSource);

       return txManager;
   }

}
Thông tin các Database được cấu hình tại file ds/datasource-cfg.xml, và được đọc bởi class ApplicationContextConfig.
ds/datasource-cfg.properties (ORACLE + ORACLE)


# DataSource (PUBLISHER System).

ds.database-driver1=oracle.jdbc.driver.OracleDriver
ds.url1=jdbc:oracle:thin:@localhost:1521:db12c
ds.username1=publisher
ds.password1=12345


# DataSource (ADVERTISER System).

ds.database-driver2=oracle.jdbc.driver.OracleDriver
ds.url2=jdbc:oracle:thin:@localhost:1521:db12c
ds.username2=advertiser
ds.password2=12345
ds/datasource-cfg.properties (MySQL + MySQL)

# DataSource (PUBLISHER System).

ds.database-driver1=com.mysql.jdbc.Driver
ds.url1=jdbc:mysql://localhost:3306/publisher
ds.username1=root
ds.password1=12345



# DataSource (ADVERTISER System).

ds.database-driver2=com.mysql.jdbc.Driver
ds.url2=jdbc:mysql://localhost:3306/advertiser
ds.username2=root
ds.password2=12345
ds/datasource-cfg.properties (SQL Server + SQL Server)

# DataSource  (PUBLISHER System).

ds.database-driver1=net.sourceforge.jtds.jdbc.Driver
ds.url1=jdbc:jtds:sqlserver://localhost:1433/simplehr;instance=SQLEXPRESS
ds.username1=publisher
ds.password1=12345


# DataSource  (ADVERTISER System).

ds.database-driver2=net.sourceforge.jtds.jdbc.Driver
ds.url2=jdbc:jtds:sqlserver://localhost:1433/simplehr;instance=SQLEXPRESS
ds.username2=advertiser
ds.password2=12345

6- Model, Interceptor, Routing, Controller ...

DataSourceIntercetor là một interceptor, nó dựa trên URL của request gửi tới để quyết định xem Datasource nào sẽ được sử dụng.
DataSourceIntercetor.java
package org.o7planning.springmvcmultids.interceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class DataSourceIntercetor extends HandlerInterceptorAdapter {

    // Request:

    // /publisher/list
    // /advertiser/list
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {

        String contextPath = request.getServletContext().getContextPath();

        // /SpringMVCMultiDS/publisher
        String prefixPublisher = contextPath + "/publisher";
       
        // /SpringMVCMultiDS/advertiser
        String prefixAdvertiser = contextPath + "/advertiser";

        // /SpringMVCMultiDS/publisher/dashboard
        // /SpringMVCMultiDS/advertiser/dashboard
       
        String uri = request.getRequestURI();
        System.out.println("URI:"+ uri);
       
        if(uri.startsWith(prefixPublisher)) {
            request.setAttribute("keyDS", "PUBLISHER_DS");
        }
       
        else if(uri.startsWith(prefixAdvertiser)) {
            request.setAttribute("keyDS", "ADVERTISER_DS");
        }

        return true;
    }

}
MyRoutingDataSource là một DataSource, nó chứa một bản đồ (Map) giữa các khóa và các Datasource thực sự.
MyRoutingDataSource.java
package org.o7planning.springmvcmultids.routing;

import javax.servlet.http.HttpServletRequest;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

 
// Đây là một DataSource.
public class MyRoutingDataSource extends AbstractRoutingDataSource {

   @Override
   protected Object determineCurrentLookupKey() {

       HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
               .getRequest();
 
       // Xem thêm: DataSourceInterceptor
       String keyDS = (String) request.getAttribute("keyDS");

       System.out.println("KeyDS=" + keyDS);

       if (keyDS == null) {
           keyDS = "PUBLISHER_DS";
       }

       return keyDS;
   }

}
DataDAO là class tiện ích, truy vấn dữ liệu từ Database.
DataDAO.java
package org.o7planning.springmvcmultids.dao;

import java.util.List;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

@Repository
public class DataDAO extends JdbcDaoSupport {

    @Autowired
    public DataDAO(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    public List<String> queryPublishers() {
        String sql = "Select name from Publishers";

        List<String> list = this.getJdbcTemplate().queryForList(sql, String.class);
        return list;
    }

    public List<String> queryAdvertisers() {
        String sql = "Select name from Advertisers";

        List<String> list = this.getJdbcTemplate().queryForList(sql, String.class);
        return list;
    }
   
}
MainController.java
package org.o7planning.springmvcmultids.controller;

import java.sql.SQLException;
import java.util.List;

import org.o7planning.springmvcmultids.dao.DataDAO;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class MainController {

    @Autowired
    private DataDAO dataDAO;

    @RequestMapping(value = { "/advertiser/list" }, method = RequestMethod.GET)
    public String advertiser(Model model) throws SQLException {

        List<String> list = dataDAO.queryAdvertisers();
        model.addAttribute("advertisers", list);

        return "advertiser";
    }

    @RequestMapping(value = { "/publisher/list" }, method = RequestMethod.GET)
    public String publisher(Model model) throws SQLException {

        List<String> list = dataDAO.queryPublishers();
        model.addAttribute("publishers", list);

        return "publisher";
    }

}

7- Views

/WEB-INF/pages/advertiser.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Advertiser</title>
</head>
<body>
<div style="border:1px solid #ccc;text-align:right;padding:5px;">
   <a href="${pageContext.request.contextPath}/publisher/list">Publisher List</a>
   &nbsp;&nbsp;
   <a href="${pageContext.request.contextPath}/advertiser/list">Advertiser List</a>
</div>

<h1>Advertiser Page</h1>

<c:forEach var="item" items="${advertisers}" varStatus="status">

  ${item}  <br/>
 
</c:forEach>


</body>
</html>
/WEB-INF/pages/publisher.jsp
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Advertiser</title>
</head>
<body>
<div style="border:1px solid #ccc;text-align:right;padding:5px;">
   <a href="${pageContext.request.contextPath}/publisher/list">Publisher List</a>
   &nbsp;&nbsp;
   <a href="${pageContext.request.contextPath}/advertiser/list">Advertiser List</a>
</div>

<h1>Publisher Page</h1>

<c:forEach var="item" items="${publishers}" varStatus="status">

  ${item}  <br/>
 
</c:forEach>

</body>
</html>

8- Cấu hình chạy ứng dụng

  • Name: Run SpringMVCMultiDS
  • Base Directory: ${workspace_loc:/SpringMVCMultiDS}
  • Goals: tomcat7:run