关于Spring两种注入方式的小例子

朱雀 2022-04-03 02:15 244阅读 0赞

1.Spring注入方式主要分两种：设值注入、构造注入，我们将一一举例

2.创建项目：

（1）.创建一个maven项目：

如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 1][]

（2）.打开pom.xml放入spring依赖：

<dependencies>  
        <dependency>  
            <groupId>junit</groupId>  
            <artifactId>junit</artifactId>  
            <version>4.12</version>  
            <scope>test</scope>  
        </dependency>  
        <dependency>  
            <groupId>log4j</groupId>  
            <artifactId>log4j</artifactId>  
            <version>1.2.17</version>  
        </dependency>

<dependency>  
            <groupId>javax.servlet</groupId>  
            <artifactId>servlet-api</artifactId>  
            <version>2.5</version>  
            <scope>provided</scope>  
        </dependency>  
        <dependency>  
            <groupId>javax.servlet.jsp</groupId>  
            <artifactId>javax.servlet.jsp-api</artifactId>  
            <version>2.3.1</version>  
            <scope>provided</scope>  
        </dependency>  
        <dependency>  
            <groupId>javax.servlet.jsp.jstl</groupId>  
            <artifactId>javax.servlet.jsp.jstl-api</artifactId>  
            <version>1.2.1</version>  
        </dependency>  
        <dependency>  
            <groupId>javax.ws.rs</groupId>  
            <artifactId>javax.ws.rs-api</artifactId>  
            <version>2.0</version>  
        </dependency>  
        <dependency>  
            <groupId>javax.websocket</groupId>  
            <artifactId>javax.websocket-api</artifactId>  
            <version>1.0</version>  
        </dependency>  
        <dependency>  
            <groupId>javax.annotation</groupId>  
            <artifactId>javax.annotation-api</artifactId>  
            <version>1.2</version>  
        </dependency>  
        <dependency>  
            <groupId>javax.transaction</groupId>  
            <artifactId>javax.transaction-api</artifactId>  
            <version>1.2</version>  
        </dependency>

<dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-context</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-orm</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-oxm</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-jdbc</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-tx</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-web</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-webmvc</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-aop</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-test</artifactId>  
        </dependency>

<dependency>  
            <groupId>org.codehaus.castor</groupId>  
            <artifactId>castor-xml</artifactId>  
            <version>1.4.1</version>  
        </dependency>

<dependency>  
            <groupId>com.fasterxml.jackson.core</groupId>  
            <artifactId>jackson-databind</artifactId>  
            <version>2.9.4</version>  
        </dependency>  
          
              
              
              
          
          
        <dependency>  
            <groupId>org.aspectj</groupId>  
            <artifactId>aspectjweaver</artifactId>  
            <version>1.8.13</version>  
        </dependency>

<dependency>  
            <groupId>commons-fileupload</groupId>  
            <artifactId>commons-fileupload</artifactId>  
            <version>1.3.3</version>  
        </dependency>

<dependency>  
            <groupId>mysql</groupId>  
            <artifactId>mysql-connector-java</artifactId>  
            <version>$\{mysql.version\}</version>  
        </dependency>  
          
          
        <dependency>  
            <groupId>com.alibaba</groupId>  
            <artifactId>druid</artifactId>  
            <version>1.1.9</version>  
        </dependency>

<dependency>  
            <groupId>org.mybatis</groupId>  
            <artifactId>mybatis</artifactId>  
            <version>3.4.6</version>  
        </dependency>  
        <dependency>  
            <groupId>org.mybatis</groupId>  
            <artifactId>mybatis-spring</artifactId>  
            <version>1.3.2</version>  
        </dependency>  
          
        <dependency>  
            <groupId>org.mybatis.generator</groupId>  
            <artifactId>mybatis-generator-core</artifactId>  
            <version>1.3.6</version>  
            <scope>compile</scope>  
            <optional>true</optional>  
        </dependency>

<dependency>  
            <groupId>com.alibaba</groupId>  
            <artifactId>fastjson</artifactId>  
            <version>1.2.47</version>  
        </dependency>

</dependencies>

3.使用设值注入方式：

（1）创建Dao类，作为数据持久层接口，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 2][]

（2）创建DaoImpl做数据持久层的实现类，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 3][]

（3）创建事务层Service类，里面包含需要装配的dao属性，注意需要set方法，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 4][]

（4）修改xml配置文件，在容器中进行依赖注入，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 5][]

（5）.编写测试类Test，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 6][]

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 7][]

（6）总结：

可以看出service里面的dao属性并没有进行赋值，就可以调用里面的方法，说明IOC容器已经成功注入了

4.使用构造注入方式：

（1）创建Dao类，作为数据持久层接口，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 2][]

（2）创建DaoImpl做数据持久层的实现类，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 3][]

（3）创建事务层Service类，里面包含需要装配的dao属性，这次需要构造方法，而不是set方法，这是这连个方法的区别，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 8][]

（4）修改xml配置文件，在容器中进行依赖注入，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 9][]

（5）.编写测试类Test，如图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 6][]

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3Mjg0Nzk4_size_16_color_FFFFFF_t_70 7][]

（6）总结：

可以看出service里面的dao属性并没有进行赋值，就可以调用里面的方法，说明IOC容器已经成功注入了，这是使用构造注入的方式

5.以上就是IOC容器依赖注入的两种方式，关于spring的一些问题，大家可以在评论区讨论

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