深入学习Spring组件注册

50.Spring-Regist-Bean/pom.xml

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+<?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>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.1.0.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+    <groupId>cc.mrbird</groupId>
+    <artifactId>demo</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>demo</name>
+    <description>Demo project for Spring Boot</description>
+
+    <properties>
+        <java.version>1.8</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <optional>true</optional>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

50.Spring-Regist-Bean/src/main/java/cc/mrbird/DemoApplication.java

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+package cc.mrbird;
+
+import cc.mrbird.demo.config.WebConfig;
+import cc.mrbird.demo.service.CalculateService;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+import java.util.Arrays;
+
+@SpringBootApplication
+public class DemoApplication {
+
+    public static void main(String[] args) {
+        ConfigurableApplicationContext context1 = new SpringApplicationBuilder(DemoApplication.class)
+                .web(WebApplicationType.NONE)
+                .profiles("java7")
+                .run(args);
+
+        // 返回 IOC 容器，使用注解配置，传入配置类
+        ApplicationContext context = new AnnotationConfigApplicationContext(WebConfig.class);
+        System.out.println("容器创建完毕");
+
+        // User user = context.getBean(User.class);
+        // System.out.println(user);
+
+        // 查看 User 这个类在 Spring 容器中叫啥玩意
+        // String[] beanNames = context.getBeanNamesForType(User.class);
+        // Arrays.stream(beanNames).forEach(System.out::println);
+
+        // 查看基于注解的 IOC容器中所有组件名称
+        String[] beanNames = context.getBeanDefinitionNames();
+        Arrays.stream(beanNames).forEach(System.out::println);
+
+        // 组件的作用域
+        // Object user1 = context.getBean("user");
+        // Object user2 = context.getBean("user");
+        // System.out.println(user1 == user2);
+
+        // 测试懒加载
+        // Object user1 = context.getBean("user");
+        // Object user2 = context.getBean("user");
+
+        // 测试 Profile
+        CalculateService service = context1.getBean(CalculateService.class);
+        System.out.println("求合结果： " + service.sum(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
+
+        // FactoryBean测试
+        Object cherry = context.getBean("cherryFactoryBean");
+        System.out.println(cherry.getClass());
+
+        Object cherryFactoryBean = context.getBean("&cherryFactoryBean");
+        System.out.println(cherryFactoryBean.getClass());
+
+    }
+}
+

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/condition/MyCondition.java

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+package cc.mrbird.demo.condition;
+
+import org.springframework.context.annotation.Condition;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+
+/**
+ * @author MrBird
+ */
+public class MyCondition implements Condition {
+    @Override
+    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
+        String osName = context.getEnvironment().getProperty("os.name");
+        return osName != null && osName.contains("Windows");
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/config/WebConfig.java

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+package cc.mrbird.demo.config;
+
+import cc.mrbird.demo.condition.MyCondition;
+import cc.mrbird.demo.domain.Hello;
+import cc.mrbird.demo.domain.User;
+import cc.mrbird.demo.factory.CherryFactoryBean;
+import cc.mrbird.demo.filter.MyTypeFilter;
+import cc.mrbird.demo.register.MyImportBeanDefinitionRegistrar;
+import cc.mrbird.demo.selector.MyImportSelector;
+import lombok.Builder;
+import org.springframework.context.annotation.*;
+import org.springframework.context.annotation.ComponentScan.Filter;
+import org.springframework.stereotype.Controller;
+import org.springframework.stereotype.Repository;
+import org.springframework.stereotype.Service;
+
+/**
+ * @author MrBird
+ */
+@Configuration
+// @ComponentScan(value = "cc.mrbird.demo"
+        // , excludeFilters = {
+        //         @Filter(type = FilterType.ANNOTATION,
+        //                 classes = {Controller.class, Repository.class}),
+        //         @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = User.class)
+        //         @Filter(type = FilterType.CUSTOM, classes = MyTypeFilter.class)
+        // }
+        // includeFilters = {
+        //         @Filter(type = FilterType.ANNOTATION, classes = Service.class)
+        // }, useDefaultFilters = false
+// )
+@Import({Hello.class, MyImportSelector.class, MyImportBeanDefinitionRegistrar.class})
+public class WebConfig {
+
+    @Bean
+    // @Conditional(MyCondition.class)
+    // @Lazy
+    // @Scope("prototype")
+    public User user() {
+        System.out.println("往IOC容器中注册user bean");
+        return new User("mrbird", 18);
+    }
+
+    @Bean
+    public CherryFactoryBean cherryFactoryBean() {
+        return new CherryFactoryBean();
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/controller/UserController.java

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+package cc.mrbird.demo.controller;
+
+import org.springframework.stereotype.Controller;
+
+/**
+ * @author MrBird
+ */
+@Controller
+public class UserController {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/dao/UserMapper.java

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+package cc.mrbird.demo.dao;
+
+import org.springframework.stereotype.Repository;
+
+/**
+ * @author MrBird
+ */
+@Repository
+public class UserMapper {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Apple.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Apple {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Banana.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Banana {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Cherry.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Cherry {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Hello.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Hello {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Strawberry.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Strawberry {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/User.java

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+package cc.mrbird.demo.domain;
+
+import lombok.*;
+import org.springframework.stereotype.Component;
+
+/**
+ * @author MrBird
+ */
+@ToString
+@AllArgsConstructor
+@NoArgsConstructor
+@Data
+// @Component
+public class User {
+    private String name;
+    private Integer age;
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/UserDetail.java

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+package cc.mrbird.demo.domain;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * @author MrBird
+ */
+// @Component
+public class UserDetail extends User {
+
+    private int sex;
+
+
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/domain/Watermelon.java

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+package cc.mrbird.demo.domain;
+
+/**
+ * @author MrBird
+ */
+public class Watermelon {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/factory/CherryFactoryBean.java

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+package cc.mrbird.demo.factory;
+
+import cc.mrbird.demo.domain.Cherry;
+import org.springframework.beans.factory.FactoryBean;
+
+/**
+ * @author MrBird
+ */
+public class CherryFactoryBean implements FactoryBean<Cherry> {
+    @Override
+    public Cherry getObject() {
+        return new Cherry();
+    }
+
+    @Override
+    public Class<?> getObjectType() {
+        return Cherry.class;
+    }
+
+    @Override
+    public boolean isSingleton() {
+        return false;
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/filter/MyTypeFilter.java

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+package cc.mrbird.demo.filter;
+
+import org.springframework.core.io.Resource;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.core.type.ClassMetadata;
+import org.springframework.core.type.classreading.MetadataReader;
+import org.springframework.core.type.classreading.MetadataReaderFactory;
+import org.springframework.core.type.filter.TypeFilter;
+import org.springframework.util.StringUtils;
+
+import java.io.IOException;
+
+/**
+ * @author MrBird
+ */
+public class MyTypeFilter implements TypeFilter {
+    @Override
+    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) {
+        // 获取当前正在扫描的类的注解信息
+        AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
+        // 获取当前正在扫描的类的类信息
+        ClassMetadata classMetadata = metadataReader.getClassMetadata();
+        // 获取当前正在扫描的类的路径等信息
+        Resource resource = metadataReader.getResource();
+
+        String className = classMetadata.getClassName();
+        return StringUtils.hasText("er");
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/register/MyImportBeanDefinitionRegistrar.java

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+package cc.mrbird.demo.register;
+
+import cc.mrbird.demo.domain.Strawberry;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * @author MrBird
+ */
+public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
+    @Override
+    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
+        final String beanName = "strawberry";
+        boolean contain = registry.containsBeanDefinition(beanName);
+        if (!contain) {
+            RootBeanDefinition rootBeanDefinition = new RootBeanDefinition(Strawberry.class);
+            registry.registerBeanDefinition(beanName, rootBeanDefinition);
+        }
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/selector/MyImportSelector.java

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+package cc.mrbird.demo.selector;
+
+import org.springframework.context.annotation.ImportSelector;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * @author MrBird
+ */
+public class MyImportSelector implements ImportSelector {
+
+    @Override
+    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
+        return new String[]{
+                "cc.mrbird.demo.domain.Apple",
+                "cc.mrbird.demo.domain.Banana",
+                "cc.mrbird.demo.domain.Watermelon"
+        };
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/service/CalculateService.java

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+package cc.mrbird.demo.service;
+
+/**
+ * @author MrBird
+ */
+public interface CalculateService {
+
+    Integer sum(Integer... value);
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/service/UserService.java

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+package cc.mrbird.demo.service;
+
+import org.springframework.stereotype.Service;
+
+/**
+ * @author MrBird
+ */
+@Service
+public class UserService {
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/service/impl/Java7CalculateServiceImpl.java

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+package cc.mrbird.demo.service.impl;
+
+import cc.mrbird.demo.service.CalculateService;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Service;
+
+/**
+ * @author MrBird
+ */
+@Service
+@Profile("java7")
+public class Java7CalculateServiceImpl implements CalculateService {
+
+    @Override
+    public Integer sum(Integer... value) {
+        System.out.println("Java 7环境下执行");
+        int result = 0;
+        for (int i = 0; i <= value.length; i++) {
+            result += i;
+        }
+        return result;
+    }
+}

50.Spring-Regist-Bean/src/main/java/cc/mrbird/demo/service/impl/Java8CalculateServiceImpl.java

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+package cc.mrbird.demo.service.impl;
+
+import cc.mrbird.demo.service.CalculateService;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Service;
+
+import java.util.Arrays;
+
+/**
+ * @author MrBird
+ */
+@Service
+@Profile("java8")
+public class Java8CalculateServiceImpl implements CalculateService {
+
+    @Override
+    public Integer sum(Integer... value) {
+        System.out.println("Java 8环境下执行");
+        return Arrays.stream(value).reduce(0, Integer::sum);
+    }
+}