Jdbc 出站通道介面卡 - xml 配置

在 Spring Integration Reference Docuement 中 ，它說：

出站通道介面卡是入站的反向：它的作用是處理訊息並使用它來執行 SQL 查詢。預設情況下，訊息有效負載和標頭可用作查詢的輸入引數…

• Java 程式碼

  public class OutboundApplication {
      static class Book {
          String title;
          double price;
  
          Book(String title, double price) {
              this.title = title;
              this.price = price;
          }
  
          public double getPrice() {
              return price;
          }
  
          public String getTitle() {
              return title;
          }
  
      }
  
      static class Producer {
          public Book produce() {
              return IntStream.range(0, 3)
                      .mapToObj(i -> new Book("book" + i, i * 10))
                      .collect(Collectors.toList())
                      .get(new Random().nextInt(3));
          }
      }
  
      public static void main(String[] args) {
          new ClassPathXmlApplicationContext(
                  "classpath:spring/integration/stackoverflow/jdbc/jdbc-outbound.xml");
      }
  }
  

• xml 配置檔案

  <?xml version="1.0" encoding="UTF-8"?>
  <beans xmlns="http://www.springframework.org/schema/beans"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns:jdbc="http://www.springframework.org/schema/jdbc"
         xmlns:int="http://www.springframework.org/schema/integration"
         xmlns:int-jdbc="http://www.springframework.org/schema/integration/jdbc"
         xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/jdbc
         http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
         http://www.springframework.org/schema/integration
         http://www.springframework.org/schema/integration/spring-integration.xsd
         http://www.springframework.org/schema/integration/jdbc
         http://www.springframework.org/schema/integration/jdbc/spring-integration-jdbc.xsd">
      <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
          <property name="url" value="jdbc:h2:tcp://localhost/~/booksystem"/>
          <property name="username" value="sa"/>
          <property name="password" value=""/>
          <property name="driverClassName" value="org.h2.Driver"/>
      </bean>
      <jdbc:initialize-database>
          <jdbc:script location="classpath:spring/integration/stackoverflow/jdbc/schema.sql"/>
      </jdbc:initialize-database>
      <int:channel id="channel"/>
      <int:inbound-channel-adapter channel="channel" method="produce" >
          <bean class="spring.integration.stackoverflow.jdbc.OutboundApplication$Producer"/>
          <int:poller fixed-rate="1000"/>
      </int:inbound-channel-adapter>
      <int-jdbc:outbound-channel-adapter id="jdbcOutbound"
                                         channel="channel"
                                         data-source="dataSource"
                                         sql-parameter-source-factory="sqlParameterSource"
                                         query="INSERT INTO BOOKS(TITLE, PRICE) VALUES(:title, :price)"/>
      <bean id="sqlParameterSource"   class="org.springframework.integration.jdbc.ExpressionEvaluatingSqlParameterSourceFactory">
          <property name="parameterExpressions">
              <map>
                  <entry key="title" value="payload.title"/>
                  <entry key="price" value="payload.price"/>
              </map>
          </property>
      </bean>
  </beans>
  

• schema.sql 檔案

  DROP TABLE IF EXISTS BOOKS;
  CREATE TABLE BOOKS (
    TITLE VARCHAR(20) NOT NULL,
    PRICE DOUBLE      NOT NULL
  );
  

• 你可以觀察 BOOKS 表，並可以看到插入的記錄。或者你可以寫一個 int-jdbc:inbound-channel-adapter 來計算 BOOKS 表，你會發現計數值不斷增長。

• 摘要：

  • inbound：一個通用的入站介面卡，用於將 Book 物件作為訊息有效負載並將其傳送到通道 channel。
  • channel：用於傳遞資訊。
  • jdbcOutbound：一個 jdbc 出站介面卡，它接收帶有 Book 型別的訊息，然後使用像 payload.title 和 payload.price 這樣的 SpEL 通過 sqlParameterSource bean 準備查詢引數:title 和:price，從而獲得訊息有效負載的標題和價格。