Spring中IoC - 两种ApplicationContext加载Bean的配置

2023-08-23 11:27:22

说明：Spring IoC其实就是在Service的实现中定义了一些以来的策略类，这些策略类不是通过初始化、Setter、工厂方法来确定的。而是通过一个叫做上下文的(ApplicationContext)组建来加载进来的。这里介绍两种Context组建的构件过程

前提条件：在Gradle工程的build.gradle文件中引入对Spring framework 的支持

repositories {

    mavenCentral()

}

dependencies {

    compile group: 'org.springframework',name: 'spring-context', version: '4.1.5.RELEASE'

    compile group: 'org.springframework',name: 'spring-core', version: '4.1.5.RELEASE'

    testCompile group: 'junit', name: 'junit', version: '4.11'

}

第一种方式：通过ClassPathXmlApplicationContext加载xml配置文件

这里使用greenmail做测试邮件的例子来介绍：

1. 依赖管理

<?xml version="1.0" encoding="UTF-8"?>

<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.ygshen.mvnbook.account</groupId>

    <artifactId>account-service</artifactId>

    <version>1.0-SNAPSHOT</version>

    <dependencies>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context</artifactId>

            <version>4.3.3.RELEASE</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-beans</artifactId>

            <version>4.3.3.RELEASE</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-core</artifactId>

            <version>4.3.3.RELEASE</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context-support -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context-support</artifactId>

            <version>4.3.3.RELEASE</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.mail/mail -->

        <dependency>

            <groupId>javax.mail</groupId>

            <artifactId>mail</artifactId>

            <version>1.4.1</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/junit/junit -->

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.7</version>

            <scope>test</scope>

        </dependency>

        <!-- https://mvnrepository.com/artifact/com.icegreen/greenmail -->

        <dependency>

            <groupId>com.icegreen</groupId>

            <artifactId>greenmail</artifactId>

            <version>1.5.2</version>

            <scope>test</scope>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.apache.maven.plugins</groupId>

                <artifactId>maven-compiler-plugin</artifactId>

                <configuration>

                    <source>1.5</source>

                    <target>1.5</target>

                </configuration>

            </plugin>

        </plugins>

    </build>

</project>

2. 接口定义

public interface emailService {

    public void sendMail(String to, String subject,String htmlText) throws MessagingException;

}

3. 接口实现

public class emailServiceImp implements emailService{

      //这里有两个IOC的变量，后面将通过bean＋property的方式进行依赖管理

  private JavaMailSender javaMailSender;

    private String systemAccount;

／／ Get和Set时必须的

    public JavaMailSender getJavaMailSender() {

        return javaMailSender;

    }

    public void setJavaMailSender(JavaMailSender javaMailSender) {

        this.javaMailSender = javaMailSender;

    }

    public String getSystemAccount() {

        return systemAccount;

    }

    public void setSystemAccount(String systemAccount) {

        this.systemAccount = systemAccount;

    }

／／发送邮件主题函数，javamailsender是 spring的邮件类。这个mail sender就是发送邮件的smtp服务器。

／／ 如Gmail等，这里将在测试用例中使用greenemail代替他门

    public void sendMail(String to, String subject, String htmlText) throws MessagingException {

        MimeMessage message = javaMailSender.createMimeMessage();

        MimeMessageHelper helper = new MimeMessageHelper(message);

        helper.setFrom(systemAccount);

        helper.setTo(to);

        helper.setSubject(subject);

        helper.setText(htmlText);

        javaMailSender.send(message);

    }

}

4. Bean文件定义：

<?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.xsd">

<!--定义自动获取property配置-->

    <bean id="propertyConfigure" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

        <property name="location" value="classpath:service.properties"></property>

    </bean>
<!--定义java mail sender bean 对象，这个bean后边将作为依赖注入到service中-->

    <bean id="javaMailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">

        <property name="protocol" value="${email.protocol}"></property>

        <property name="port" value="${email.port}"></property>

        <property name="host" value="${email.host}"></property>

        <property name="username" value="${email.username}"></property>

        <property name="password" value="${email.password}"></property>

        <property name="javaMailProperties">

            <props>

                <prop key="mail.${email.protocol}.auth">${email.auth}</prop>

            </props>

        </property>

    </bean>

<!--真正负责发送邮件的类定义bean-->

    <bean id="accountService" class="com.ygshen.mvnbook.account.email.emailServiceImp">

        <property name="javaMailSender" ref="javaMailSender"></property>

        <property name="systemAccount" value="${email.systemAccount}"></property>

    </bean>

</beans>

5. Property 文件

email.protocol=smtps
email.host=smtp.gmail.com
email.port=465
email.username=shenyuangong@gmail.com
email.password=111111
email.auth=true
email.systemAccount=ygshen@163.com

初始化javamailsender的配置文件。 main／Resources目录下。注意这个配置文件将在test／resource中重新定义目的是模拟测试

6. 测试代码：

package com.ygshen.mvnbook.account;

import com.icegreen.greenmail.util.GreenMail;

import com.icegreen.greenmail.util.ServerSetup;

import com.ygshen.mvnbook.account.email.emailService;

import org.junit.After;

import org.junit.Assert;

import org.junit.Before;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import javax.mail.Message;

import javax.mail.MessagingException;

/**

 * Created by ygshen on 16/10/31.

 */

／／这里需要注意junit的测试文件必须以Test结尾 否则 mvn clean test 的时候将没有办法获取到测试用例

public class emailServiceTest {

／／这里初始化一个本地的greenmail作为测试邮箱服务器

private GreenMail mail;

    @Before

    public void startMailBox(){

        mail = new GreenMail(new ServerSetup(12000,null,"smtp"));

        mail.setUser("shenyuangong@gmail.com", "123456");

        mail.start();

    }

    @Test

    public void sendMail() throws MessagingException {

        ApplicationContext context = new ClassPathXmlApplicationContext("account-service.xml");

／／ 这里将初始化发送邮件的service，而service所依赖的javamailsender初始化所配置的邮箱服务器和start中 定义的port、protocol也是一样的。 在测试test/resources中定义。这里greenmail起到模拟gmail服务器的能力

        emailService service = (emailService)context.getBean("accountService");

        service.sendMail("test2@163.com","Test Subject","<h1>test</h1>");

        mail.waitForIncomingEmail(2000,1);

        Message[] msgs = mail.getReceivedMessages();

        Assert.assertEquals(1,msgs.length);

    }

    @After

    public void closeMail(){

        mail.stop();

    }

}

7. 测试用的Properties文件

email.protocol=smtp
email.host=localhost
email.port=12000
＃ 注意这里的邮箱登陆的帐号要和Greenmail中 setUser使用的相同才行。
email.username=shenyuangong@gmail.com
email.password=123456
email.auth=true
email.systemAccount=ygshen@163.com

第二种方式：AnnotationConfigApplicationContext类加载JavaClass File的配置文件

配置文件JavaClass如下：

@Configuration：表示这是一个配置文件

@Bean: 表示这是一个Bean（名字为方法名），将来他要用来与Service中的@Autowired属性配对，注意配对的时候是根据返回类型来对应的，也就是说所有的Service中但凡有@Autowired的属性，他们都是从这个配置文件中拿到的。

@Configuration

public class ApplicationContextConfiguration {

    @Bean

    public AccountRepoisitory accountRepoisitory() {

        return new AccountRepositoryImp();

    }

    @Bean

    public TransactionService transactionService() {

        return new TransactionServiceImp();

    }

    @Bean

    public TransferService transferService() {

        return new TransferServiceImp();

    }

}

再来看一下使用@AutoWired的Service类。这个AutoWired将与上面配置文件中的@Bean结成一对儿

public class TransactionServiceImp implements TransactionService {

    @Autowired

    public  AccountRepoisitory accountRepoisitory;

    @Override

    public void NewTransaction(String accountId1, String accountId2, double money) {

        Account account1=accountRepoisitory.GetAccountByAccountId(accountId1);

        Account account2=accountRepoisitory.GetAccountByAccountId(accountId2);

        Transaction transaction=new Transaction(){ };

        transaction.fromAccount=account1;

        transaction.toAccount=account2;

        transaction.moneyTransfered=money;

        transaction.transactionDate= Calendar.getInstance().getTime();

        BankFactory.Transactions.add(transaction);

    }

}

最后来看Main函数是如何将配置文件与Service文件结合在一起的。很简单

  ApplicationContext context=

                new AnnotationConfigApplicationContext(

                        com.ctrip.configuration.ApplicationContextConfiguration.class

                );

// 接下来我们就可以使用任何Service中定义的方法了

AccountRepoisitory accountRepoisitory=context.getBean("accountRepoisitory",
        AccountRepositoryImp.class);

TransactionService transactionService=context.getBean("transactionService",
        TransactionServiceImp.class);

TransferService transferService=context.getBean("transferService",
        TransferServiceImp.class
        );
transferService.Transfer("1","2",234);

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