spring——依赖注入DI(spring-test方式)

骑猪看日落 2022-06-16 00:54 186阅读 0赞

# spring——依赖注入DI(spring-test方式) #

本文主要介绍如何实现spring 的依赖注入，并且浅显的讲述一下注入需要注意的事项。

1、创建一个maven项目

mvn archetype:generate -DarchetypeCatalog=internal

2、修改pom.xml，引入需要的依赖，首先spring-context，还是spring-test，最后还有junit。

<properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <springframework.version>4.3.7.RELEASE</springframework.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${springframework.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-test</artifactId>
                <version>${springframework.version}</version>
            </dependency>
    
        </dependencies>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                        <encoding>utf-8</encoding>
                    </configuration>
                </plugin>
                <plugin>
                    <artifactId>maven-assembly-plugin</artifactId>
                    <version>3.0.0</version>
                    <configuration>
                        <archive>
                            <manifest>
                                <mainClass>com.xueyoucto.xueyou.App</mainClass>
                            </manifest>
                        </archive>
                        <descriptorRefs>
                            <descriptorRef>jar-with-dependencies</descriptorRef>
                        </descriptorRefs>
                    </configuration>
                    <executions>
                        <execution>
                            <id>make-assembly</id> 
                            <phase>package</phase> 
                            <goals>
                                <goal>single</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </build>

3、添加类Person和Body

package com.xueyou.demo;
    
    import org.springframework.stereotype.Component;
    
    @Component
    public class Person {
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        private String name;
    
    }

package org.xueyou.demo;
    
    import org.springframework.stereotype.Component;
    
    @Component
    public class Body {
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        private int id;
    
    }

3、在配置类App中，添加ComponentScan。需要注意的是，这里需要指定扫描的包

package com.xueyou.demo;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    
    /**
     * Hello world!
     */
    @Configuration
    @ComponentScan(basePackages = {"org.xueyou.demo","com.xueyou.demo"})
    public class App {
        public static void main(String[] args) {
            System.out.println("Hello World!");
        }
    }

4、新建一个测试类

package com.xueyou.demo;
    
    import org.junit.Assert;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    import org.xueyou.demo.Body;
    
    
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = App.class)
    public class Springtest {
    
        @Autowired
        private Body body;
    
        @Autowired
        private Person person;
    
        @Test
        public void testBodyIsNull(){
            Assert.assertNotNull(body);
        }
    
        @Test
        public void testPersonIsNull(){
            Assert.assertNotNull(person);
        }
    
    
    }

5、运行测试类，结果如下：

![Center][]

6、从运行结果中我们能看到，Person类和Student类已经被依赖注入到spring中，spring能够使用这两个类了。

[Center]: /images/20220616/63a7279644a345598ed121888612d8c6.png