Spring DataSource JNDI与Tomcat示例
欢迎来到Spring DataSource JNDI Tomcat示例教程。之前我们学习了如何使用Spring JDBC集成来实现数据库操作。然而，大多数企业应用程序都部署在诸如Tomcat、JBoss等的Servlet容器中。
春季数据源
我们知道，使用JNDI的数据源是实现连接池和获取容器实现优势的首选方式。今天我们将看看如何配置一个Spring Web应用程序来使用Tomcat提供的JNDI连接。对于我的示例，我将使用MySQL数据库服务器并创建一个带有一些行的简单表。我们将创建一个Spring Rest Web服务，它将返回包含该表中所有数据列表的JSON响应。
数据库设置 (Databases configuration)
CREATE TABLE `Employee` (
`id` int(11) unsigned NOT NULL,
`name` varchar(20) DEFAULT NULL,
`role` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `Employee` (`id`, `name`, `role`)
VALUES
(1, 'Pankaj', 'CEO'),
(2, 'David', 'Manager');
commit;
春季数据源MVC项目
在Spring Tool Suite中创建一个Spring MVC项目，这样我们的Spring应用程序的骨架代码就准备好了。一旦我们完成实现，我们的项目结构将如下图所示。
Spring JDBC和Jackson依赖
我们将不得不将Spring JDBC、Jackson和MySQL数据库驱动程序添加为pom.xml文件中的依赖项。我的最终pom.xml文件如下所示。
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.Olivia.spring</groupId>
<artifactId>SpringDataSource</artifactId>
<name>SpringDataSource</name>
<packaging>war</packaging>
<version>1.0.0-BUILD-SNAPSHOT</version>
<properties>
<java-version>1.6</java-version>
<org.springframework-version>4.0.2.RELEASE</org.springframework-version>
<org.aspectj-version>1.7.4</org.aspectj-version>
<org.slf4j-version>1.7.5</org.slf4j-version>
<jackson.databind-version>2.2.3</jackson.databind-version>
</properties>
<dependencies>
<!-- Spring JDBC Support -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${org.springframework-version}</version>
</dependency>
<!-- MySQL Driver -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.0.5</version>
</dependency>
<!-- Jackson -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.databind-version}</version>
</dependency>
<!-- Spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${org.springframework-version}</version>
<exclusions>
<!-- Exclude Commons Logging in favor of SLF4j -->
<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${org.springframework-version}</version>
</dependency>
<!-- AspectJ -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${org.aspectj-version}</version>
</dependency>
<!-- Logging -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${org.slf4j-version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.15</version>
<exclusions>
<exclusion>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
</exclusion>
<exclusion>
<groupId>javax.jms</groupId>
<artifactId>jms</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jdmk</groupId>
<artifactId>jmxtools</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jmx</groupId>
<artifactId>jmxri</artifactId>
</exclusion>
</exclusions>
<scope>runtime</scope>
</dependency>
<!-- @Inject -->
<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>
<!-- Servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- Test -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.7</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<additionalProjectnatures>
<projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
</additionalProjectnatures>
<additionalBuildcommands>
<buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
</additionalBuildcommands>
<downloadSources>true</downloadSources>
<downloadJavadocs>true</downloadJavadocs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<compilerArgument>-Xlint:all</compilerArgument>
<showWarnings>true</showWarnings>
<showDeprecation>true</showDeprecation>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<configuration>
<mainClass>org.test.int1.Main</mainClass>
</configuration>
</plugin>
</plugins>
</build>
</project>
如果您对Spring Restful的了解还不熟悉，请阅读Spring Restful Webservice示例。
模型类
我们的员工对象是根据员工表设计的，具体形式如下。
package com.Olivia.spring.jdbc.model;
import java.io.Serializable;
public class Employee implements Serializable{
private static final long serialVersionUID = -7788619177798333712L;
private int id;
private String name;
private String role;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
}
春季控制器类
我们简单的控制器类如下所示。
package com.Olivia.spring.jdbc.controller;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.Olivia.spring.jdbc.model.Employee;
/**
* Handles requests for the Employee JDBC Service.
*/
@Controller
public class EmployeeController {
private static final Logger logger = LoggerFactory.getLogger(EmployeeController.class);
@Autowired
@Qualifier("dbDataSource")
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
@RequestMapping(value = "/rest/emps", method = RequestMethod.GET)
public @ResponseBody List<Employee> getAllEmployees() {
logger.info("Start getAllEmployees.");
List<Employee> empList = new ArrayList<Employee>();
//JDBC Code - Start
String query = "select id, name, role from Employee";
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
List<Map<String,Object>> empRows = jdbcTemplate.queryForList(query);
for(Map<String,Object> empRow : empRows){
Employee emp = new Employee();
emp.setId(Integer.parseInt(String.valueOf(empRow.get("id"))));
emp.setName(String.valueOf(empRow.get("name")));
emp.setRole(String.valueOf(empRow.get("role")));
empList.add(emp);
}
return empList;
}
}
控制器类的重点有以下几点：
- DataSource will be wired by Spring Bean configuration with name dbDataSource.
- We are using JdbcTemplate to avoid common errors such as resource leak and remove JDBC boiler plate code.
- URI to retrieve the list of Employee will be https://{host}:{port}/SpringDataSource/rest/emps
- We are using @ResponseBody to send the list of Employee objects as response, Spring will take care of converting it to JSON.
春天的豆子配置
我们可以通过两种方式进行JNDI查找并将其连接到控制器数据源，我的Spring Bean配置文件包含这两种方式，但其中一种被注释了。您可以在这两种方式之间进行切换，响应将是相同的。
-
- 使用jee命名空间标记执行JNDI查找并将其配置为Spring Bean。在这种情况下，我们还需要包括jee命名空间和模式定义。
- 通过传递JNDI上下文名称创建一个类型为org.springframework.jndi.JndiObjectFactoryBean的Bean。对于此配置，jndiName是一个必需的参数。
我的Spring Bean配置文件看起来如下所示。
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="https://www.springframework.org/schema/mvc"
xmlns:jee="https://www.springframework.org/schema/jee"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xmlns:beans="https://www.springframework.org/schema/beans"
xmlns:context="https://www.springframework.org/schema/context"
xsi:schemaLocation="https://www.springframework.org/schema/jee https://www.springframework.org/schema/jee/spring-jee.xsd
https://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd
https://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
https://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<!-- DispatcherServlet Context: defines this servlet's request-processing
infrastructure -->
<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />
<!-- Handles HTTP GET requests for /resources/** by efficiently serving
up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />
<!-- Resolves views selected for rendering by @Controllers to .jsp resources
in the /WEB-INF/views directory -->
<beans:bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<beans:property name="prefix" value="/WEB-INF/views/" />
<beans:property name="suffix" value=".jsp" />
</beans:bean>
<!-- Configure to plugin JSON as request and response in method handler -->
<beans:bean
class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<beans:property name="messageConverters">
<beans:list>
<beans:ref bean="jsonMessageConverter" />
</beans:list>
</beans:property>
</beans:bean>
<!-- Configure bean to convert JSON to POJO and vice versa -->
<beans:bean id="jsonMessageConverter"
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
</beans:bean>
<!-- Create DataSource Bean -->
<beans:bean id="dbDataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<beans:property name="jndiName" value="java:comp/env/jdbc/MyLocalDB"/>
</beans:bean>
<!-- using JEE namespace for lookup -->
<!--
<jee:jndi-lookup id="dbDataSource" jndi-name="jdbc/MyLocalDB"
expected-type="javax.sql.DataSource" />
-->
<context:component-scan base-package="com.Olivia.spring.jdbc.controller" />
</beans:beans>
Tomcat数据源JNDI配置
既然我们已经完成了项目，最后一步是在Tomcat容器中进行JNDI配置，创建JNDI资源。
<Resource name="jdbc/TestDB"
global="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/TestDB"
username="scdev"
password="scdev123"
maxActive="100"
maxIdle="20"
minIdle="5"
maxWait="10000"/>
将上述配置添加到server.xml文件的GlobalNamingResources部分。
<ResourceLink name="jdbc/MyLocalDB"
global="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource" />
我们还需要创建资源链接以使用应用程序中的JNDI配置，在服务器的context.xml文件中添加是最好的方法。请注意，ResourceLink的名称应与我们在应用程序中使用的JNDI上下文名称相匹配。还要确保MySQL jar文件存在于tomcat lib目录中，否则tomcat将无法创建MySQL数据库连接池。
运行Spring DataSource JNDI示例项目
我们的项目和服务器配置已经完成，我们准备好进行测试了。将项目导出为WAR文件，并放置在tomcat部署目录中。 Rest调用的JSON响应如下图所示。关于Spring与servlet容器JNDI上下文的整合就只有这些了，从下面的链接下载示例项目，并自行尝试来学习更多。
下载 Spring DataSource JNDI 项目
