了解Spring set依赖注入

2024年5月6日 互联网

  1. 新建一个java项目，不是动态Web项目；就是一个简单的java项目；

  2. 创建domain模型 User.java

    public class User {private int id;private String username;private String password;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

  3. 创建lib文件夹，导入下列包，全选右键->”Build Path”->”add …”

  4. 创建上下文环境配置文件ApplicationContext.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/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsd"><bean id="userManager" class="cn.com.xalead.spring.UserManager"><property name="driverCalss"><value>jdbc.msyql.Driver</value></property><property name="username"><value>root</value></property><property name="password"><value>root</value></property><property name="url"><value>jdbc:mysql://localhost:3306</value></property></bean><!-- manager变量是UserAction类中的变量，引用上面的userManager"Bean"来注入其中 --><bean id="userAction" class="cn.com.xalead.spring.UserAction"><property name="manager" ref="userManager" /></bean></beans>

  5. 创建一个UserManager类，模拟对User对象的操作；
    变量username, password, url, driveclass是模仿jdbc连接（没有具体实现连接，只是利用变量实现依赖注入的赋值操作）；

    public class UserManager {private String username;private String password;private String url;private String driverCalss;public void setUsername(String username) {this.username = username;}public void setPassword(String password) {this.password = password;}public void setUrl(String url) {this.url = url;}public void setDriverCalss(String driverCalss) {this.driverCalss = driverCalss;}public void add(User user){System.out.println(username);System.out.println("执行添加User对象的操作!");}
}

  6. 创建一个UserAction类，类似MVC三层架构中的controller

    import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;public class UserAction{private UserManager manager = null;public void setManager(UserManager manager) {this.manager = manager;}public String execute(){User user = new User();manager.add(user);return "success";}
}

  7. 测试

    import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class MainClass {public static void main(String[] args) {BeanFactory factory = new ClassPathXmlApplicationContext("applicationContext.xml");
//      BeanFactory factory = new ClassPathXmlApplicationContext("app*.xml");UserAction ua = (UserAction)factory.getBean("userAction");System.out.println(ua.execute());}}

    测试结果：

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