spring

1.spring容器

@component注解解释

使用该注解标记的类会被spring自动创建对象，不用使用new关键字

@componentScan

使用该注解标记的类会搜索有component注解的类

applicationcontext 是spring的容器 使用它的实现类AnnotationConfigApplicationContext用于向容器中添加数据

实例代码

package hello; import org.springframework.stereotype.Component; /** * @author GuoZhaoning */ @Component public class MessageService { public MessageService() { super(); System.out.println("MessageService..."); } /** * * 消息服务 * @return */ public String getMessage(){ return "hello world"; } } package hello; import org.springframework.stereotype.Component; /** * @author GuoZhaoning */ @Component public class MessagePrinter { public MessagePrinter() { super(); System.out.println("MessagePrinter..."); } private MessageService messageService; public void setMessageService(MessageService messageService) { this.messageService = messageService; } public void printMessage() { System.out.println(messageService.getMessage()); } } package hello; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.support.ClassPathXmlApplicationContext; /** * @author GuoZhaoning */ @ComponentScan public class ApplicationSpring { public static void main(String[] args) { System.out.println("ApplicationSpring"); ApplicationContext applicationContext = new AnnotationConfigApplicationContext(ApplicationSpring.class); } }

2.获取容器中的对象

使用getbean方法

实例代码

MessageService messageService = applicationContext.getBean(MessageService.class); MessagePrinter messagePrinter = applicationContext.getBean(MessagePrinter.class); System.out.println(messageService); System.out.println(messagePrinter);

3.管理对象之间的关联关系

使用@autowired注解，自动调用注解下的方法

实例代码

private MessageService messageService; @Autowired public void setMessageService(MessageService messageService) { this.messageService = messageService; } MessagePrinter messagePrinter = applicationContext.getBean(MessagePrinter.class); // MessageService messageService = applicationContext.getBean(MessageService.class); // System.out.println(messageService); // System.out.println(messagePrinter); // messagePrinter.setMessageService(messageService); messagePrinter.printMessage();

4.xml配置

对象工厂

代码示例

<?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.xsd"> <bean id="service" class="ServiceMessage"></bean> <bean id="printer" class="ServicePrinter"> <property name="serviceMessage" ref="service"></property> </bean> </beans> public class ApplicationSpringXml { public static void main(String[] args) { System.out.println("applicationXml"); ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); //通过id获取，对应xml文件中的id值 ServicePrinter printer = (ServicePrinter) context.getBean("printer"); //通过class获取 ServicePrinter printer1 = context.getBean(ServicePrinter.class); printer.getMessage(); } }

5.加入log4j日志文件

加入依赖

<dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency>

加入log4j配置文件

log4j.rootCategory=INFO, stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%p - %m%n log4j.category.org.springframework.beans.factory=DEBUG

6.idea的config配置

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-ViYs4yle-1593879079741)(C:\Users\GuoZhaoning\AppData\Roaming\Typora\typora-user-images\image-20200522203118839.png)]

关联作用，能给出更多的提示

7. 装配bean的三种方式

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-0cpj29GY-1593879079746)(C:\Users\GuoZhaoning\AppData\Roaming\Typora\typora-user-images\image-20200522203402830.png)]

自动装配就是三个注解的使用component，autowired，componentScan，以及ApplicationContext context = new AnnotationConfigApplicationContext(App.class);

有时候没有主类，没有地方放componentScan注解，需要进行解耦，方法单独创建一个lei，进行组件的扫描及配置。

配置类

@Configuration @ComponentScan public class ApplConfig { }

主类修改

public class App { public static void main(String[] args) { ApplicationContext context = new AnnotationConfigApplicationContext(ApplConfig.class); CDPlayer player = context.getBean(CDPlayer.class); player.player(); } }

注解

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-MfH3DXyI-1593879079749)(C:\Users\GuoZhaoning\AppData\Roaming\Typora\typora-user-images\image-20200522210153418.png)]

8.加入junit单元测试

配置依赖

<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.13</version> <scope>test</scope> </dependency>

正常测试

9.使用spring单元测试

配置依赖

<dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>4.3.13.RELEASE</version> </dependency>

测试类

@RunWith(SpringJUnit4ClassRunner.class)//配置上下文环境 @ContextConfiguration(classes = ApplConfig.class)//配置需要测试的配置类 public class AppTest { @Autowired//进行注入，相当于set方法 private CDPlayer player; @Test public void testPlay(){ player.player(); } }

10.autowired注解的使用场景

1.构造函数可以使用

@Autowired public CDPlayer(CompactDisc compactDisc, Power power) { this.compactDisc = compactDisc; this.power = power; System.out.println("CDPlayer的多参数构造函数"); }

2.成员直接使用