springboot学习23

email集成流：

@Data
// 使用了 @ConfigurationProperties 注解，可以在 application.yml 配置文件中配置
@ConfigurationProperties(prefix="springbootlearn.email")
@Component
public class EmailProperties {
    
    
    private String username;
    private String password;
    private String host;
    private String mailbox;
    private long pollRate = 60000; // 60秒轮询一次
    
    // 产生一个 IMAP URL
    public String getImapUrl() {
    
    
        return String.format("imaps://%s:%s@%s/%s",
             this.username, this.password, this.host, this.mailbox);
    }
}

在application.yml定义：

springbootlearn:
  email:
    host: imap.springbootlearndemo.com
    mailbox: INBOX
    username: demo-in-flow
    password: 123456
    poll-rate: 60000

Java DSL 配置：

@Configuration
public class OrderEmailIntegrationConfig {
    
    
    
    @Bean
    public IntegrationFlow orderEmailFlow(
        EmailProperties emailProps,
        // 将电子邮件转换为订单对象的转换器
        EmailToOrderTransformer emailToOrderTransformer,
        OrderSubmitMessageHandler orderSubmitHandler) {
    
    
        
        return IntegrationFlows
            .from(
              // IMAP 电子邮件入站信道适配器, IMP URL 来创建通道适配器
              Mail.imapInboundAdapter(emailProps.getImapUrl()), 
              e -> e.poller(
                  Pollers.fixedDelay(emailProps.getPollRate())))
            .transform(emailToOrderTransformer)
            // 处理程序接收一个订单对象，并将其提交到REST API
            .handle(orderSubmitHandler)
            .get();
    }
}

maven依赖：

<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-file</artifactId>
</dependency>

实现 Transformer 接口

// 继承AbstractMailMessageTransformer,实现 Transformer 接口
@Component
public class EmailToOrderTransformer extends AbstractMailMessageTransformer<Order> {
    
    
	// 从到来的消息中将邮件信息提取到
    @Override
    protected AbstractIntegrationMessageBuilder<Order>
        doTransform(Message mailMessage) throws Exception {
    
    
        Order myorder = processPayload(mailMessage);
        return MessageBuilder.withPayload(myorder);
    }
    // ... 
}

上面Order是自定义的类，如：

package spirngbootlearn.email;
import java.util.ArrayList;
import java.util.List;
import lombok.Data;
​
@Data
public class Order {
    
    
    private final String email;
    private List<Pen> pens = new ArrayList<>();
    
    public void addPen(Pen pen) {
    
    
        this.pens.add(pen);
    }
}

package spirngbootlearn.email;
import java.util.Map;
import org.springframework.integration.handler.GenericHandler;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
​
@Component
public class OrderSubmitMessageHandler
             implements GenericHandler<Order> {
    
    
    private RestTemplate rest;
    // ApiProperties 是为了避免在调用 postForObject() 方法时对 URL 进行硬编码。
    private ApiProperties apiProps;
    
    public OrderSubmitMessageHandler(
        ApiProperties apiProps, RestTemplate rest) {
    
    
        this.apiProps = apiProps;
        this.rest = rest;
    }
    
    @Override
    public Object handle(Order order, Map<String, Object> headers) {
    
    
        rest.postForObject(apiProps.getUrl(), order, String.class);
        return null;
    }
}

ApiProperties：

@Data
@ConfigurationProperties(prefix="spirngbootlearn.api")
@Component
public class ApiProperties {
    
    
    private String url;
}

在 application.yml：

spirngbootlearn:
  api:
    url: http://api.spirngbootlearndemo.com

maven加入依赖：使RestTemplate可用

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

这使得 RestTemplate 在 classpath 中可用，这也触发了 Spring MVC 的自动配置。作为一个独立的 Spring Integration 流，应用程序并不需要 Spring MVC，或是嵌入的Tomcat。
所以，在 application.yml 中禁用 Spring MVC 的自动配置：

spring:
  main:
    web-application-type: none  # 重写为 none，使SpringMVC和Tomcat不会自动配置

spring.main.web-application-type 属性可以被设置为 servlet、reactive 或是 none。