11.12 Spring開發環境以及第一個Spring程式

Spring開發環境搭建

Maven專案的porm.xml匯入Spring依賴

關鍵依賴：

Spring專案是基於Bean的程式設計，所以：

<dependencies>
    <!-- 測試相關依賴 -->
  <dependency>
       <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
    <version>7.1.0</version>
    <scope>test</scope>
  </dependency>
  
  <!-- 核心基礎依賴 -->
  <!--Spring核心容器Core-->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-core</artifactId>
     <version>5.0.2.RELEASE</version>
   </dependency>
  
  <!--Spring上下文依賴-->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-context</artifactId>
     <version>5.0.2.RELEASE</version>
   </dependency>
  
  <!--Spring的Bean依賴-->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-beans</artifactId>
     <version>5.0.2.RELEASE</version>
   </dependency>
  
  <!--Spring的M層-->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-expression</artifactId>
     <version>5.0.2.RELEASE</version>
   </dependency>
  
   <!--日誌相關-->
   <dependency>
     <groupId>commons-logging</groupId>
     <artifactId>commons-logging</artifactId>
     <version>1.2</version>
   </dependency>
   <dependency>
     <groupId>log4j</groupId>
     <artifactId>log4j</artifactId>
     <version>1.2.17</version>
   </dependency>
 </dependencies>
</dependencies>
 

依賴小結：

Spring相關：

• 核心Core依賴

• 上下文Context依賴

• 物件Bean依賴

• 表現層Expression依賴

例項搭建Spring專案

• 使用maven建立Spring專案

• 匯入相關依賴

• 建立Spring配置檔案

• 建立Java類

使用maven建立Spring專案

File--->project--->org.apache.maven下的webapp

匯入相關依賴：

<?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.junkingboy</groupId>
 <artifactId>SpringStudy</artifactId>
 <version>1.0-SNAPSHOT</version>
 <packaging>war</packaging>
​
 <name>SpringStudy Maven Webapp</name>
 <!-- FIXME change it to the project's website -->
 <url>http://www.example.com</url>
​
 <properties>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <maven.compiler.source>1.7</maven.compiler.source>
  <maven.compiler.target>1.7</maven.compiler.target>
 </properties>
​
 <dependencies>
  <!-- 測試相關依賴 -->
  <dependency>
   <groupId>junit</groupId>
   <artifactId>junit</artifactId>
   <version>4.11</version>
   <scope>test</scope>
  </dependency>
  <dependency>
   <groupId>org.testng</groupId>
   <artifactId>testng</artifactId>
   <version>7.4.0</version>
  </dependency>
​
  <!-- Spring核心依賴 -->
  <!--Spring底層Core-->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-core</artifactId>
   <version>5.2.3.RELEASE</version>
  </dependency>
​
  <!--Spring上下文依賴-->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context</artifactId>
   <version>5.2.3.RELEASE</version>
  </dependency>
​
  <!--Spring的Bean物件依賴-->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-beans</artifactId>
   <version>5.2.3.RELEASE</version>
  </dependency>
​
  <!--Spring的M層依賴-->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-expression</artifactId>
   <version>5.2.3.RELEASE</version>
  </dependency>
​
  <!--日誌相關依賴-->
  <dependency>
   <groupId>commons-logging</groupId>
   <artifactId>commons-logging</artifactId>
   <version>1.2</version>
  </dependency>
  <dependency>
   <groupId>log4j</groupId>
   <artifactId>log4j</artifactId>
   <version>1.2.17</version>
  </dependency>
 </dependencies>
​
 <build>
  <finalName>SpringStudy</finalName>
  <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
   <plugins>
    <plugin>
     <artifactId>maven-clean-plugin</artifactId>
     <version>3.1.0</version>
    </plugin>
    <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
    <plugin>
     <artifactId>maven-resources-plugin</artifactId>
     <version>3.0.2</version>
    </plugin>
    <plugin>
     <artifactId>maven-compiler-plugin</artifactId>
     <version>3.8.0</version>
    </plugin>
    <plugin>
     <artifactId>maven-surefire-plugin</artifactId>
     <version>2.22.1</version>
    </plugin>
    <plugin>
     <artifactId>maven-war-plugin</artifactId>
     <version>3.2.2</version>
    </plugin>
    <
 
plugin>
     <artifactId>maven-install-plugin</artifactId>
     <version>2.5.2</version>
    </plugin>
    <plugin>
     <artifactId>maven-deploy-plugin</artifactId>
     <version>2.8.2</version>
    </plugin>
   </plugins>
  </pluginManagement
 
>
 </build>
</project>

src下建立Spring的配置檔案Beans.xml：

<?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-3.0.xsd">
​
  <bean id="helloWorld" class="com.junkingboy.HelloWorld">
    <!-- 定義bean類的屬性和值 -->
    <property name="message" value="Hello World" />
  </bean>
</beans>

建立Beans.xml檔案中的bean類--->嚴格按照Spring檔案下的路徑去建立:

package com.junkingboy;
​
/**
 * @description:Spring的測試類
 * @data: 2021/11/15 11:11
 * @author: Lucifer
 */
public class HelloWorld {
  private String message;
​
  /* 提供get和set方法 */
  public String getMessage() {
    return message;
   }
​
  public void setMessage(String message) {
    this.message = message;
   }
}

作用：

• 給不同的Bean分配唯一的ID，並給相應的Bean屬性賦值

建立執行測試類：

MainApp.java

package com.junkingboy;
​
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
​
/**
 * @description:獲取Spring當中的Bean.xml配置檔案下的類和屬性資訊
 * @data: 2021/11/15 11:20
 * @author: Lucifer
 */
public class MainApp {
  public static void main(String[] args) {
    ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
    HelloWorld obj = (HelloWorld) context.getBean("helloWorld");
    System.out.println(obj.getMessage());
   }
}

整體呼叫過程：

• 面向介面程式設計，使用ClasspathXmlApplicationContext類載入Spring的配置檔案Beans.xml

• 使用ApplicationContext介面接收該物件

• 在通過介面接收的物件呼叫getBean()方法獲取Bean物件

• 呼叫Bean物件當中的方法