Spring注解--实现applicationContext.xml效果

 随着越来越多地使用Springboot敏捷开发，更多地使用注解配置Spring,而不是Spring的applicationContext.xml文件。

• Configuration注解： Spring解析为配置类，相当于spring配置文件
  
• Bean注解：容器注册Bean组件，默认id为方法名

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@Configuration public class AppConfig {      @Bean      public MyService myService() {         return new MyServiceImpl();      } }

等同于beans.xml文件

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<beans>     <bean id="myService" class="com.acme.services.MyServiceImpl"/> </beans>

1）applicationContext.xml文件-包扫描

@ComponentScans(value = {@ComponentScan(value = "com.self",excludeFilters = {
                @Filter(type = FilterType.ANNOTATION,classes = {Controller.class})
        })
})
@Configuration
public class RootConfig {
    
      //测试Bean
      @Bean
      public Person person() {
          return new Person("张励",22,"工程师");
      }
}

2）导入properties文件

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@PropertySource(value = {"classpath:person.properties"}) @Configuration public class MainConfigOfProperty {       @Bean     public Person person() {         return new Person();     } }

赋值

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public class Person {      @Value("${person.name}")//配置文件属性     private String name;   }

3）数据源

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@EnableTransactionManagement//开启基于注解的事务管理功能 @ComponentScan("com.self.ds") @Configuration public class TxConfig {           //数据源     @Bean     public DataSource dataSource() throws Exception{         ComboPooledDataSource dataSource = new ComboPooledDataSource();         dataSource.setUser("root");         dataSource.setPassword("000111");         dataSource.setDriverClass("com.mysql.jdbc.Driver");         dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/self");         return dataSource;     }                  @Bean     public JdbcTemplate jdbcTemplate() throws Exception{         JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource());         return jdbcTemplate;     }           //事务管理器     @Bean     public PlatformTransactionManager transactionManager() throws Exception{         return new DataSourceTransactionManager(dataSource());     }         }

　　

单元测试

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public class IOCTest {           AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);            @Test     public void test02() {         Object bean1 = applicationContext.getBean("person");         Object bean2 = applicationContext.getBean("person");         System.out.println( bean1 == bean2);     }           @Test     public void test01() {         Object bean = applicationContext.getBean("person01");         System.out.println("结果: " + bean);     }                 @Test     public void test() {         String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames();         for(String beanDef:beanDefinitionNames) {             System.out.println("输出: " + beanDef);         }               }   }

执行结果