Spring -- 杂记

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Spring -- 杂记

一、Bean 的初始化过程前后执行的方法：<两种实现方式>

public class MyBeanInit01 {

   public MyBeanInit01() {
       System.out.println("MyBeanInit01 -- 构造方法执行...");
   }

   public void init() {
       System.out.println("MyBeanInit01 -- init方法执行...");
   }

   public void distory() {
       System.out.println("MyBeanInit01 -- distory方法执行...");
   }
}

public class MyBeanInit2 {

   public MyBeanInit2() {
       System.out.println("MyBeanInit2 -- 构造方法执行...");
   }

   @PostConstruct //构造函数执行完之后执行
   public void init() {
       System.out.println("MyBeanInit2 -- init方法执行...");
   }

   @PreDestroy //Bean销毁之后执行
   public void distory() {
       System.out.println("MyBeanInit2 -- distory方法执行...");
   }
}

//测试

@Configuration
public class BeanConfig {

   // init -- 构造函数执行之后执行
   @Bean(initMethod="init",destroyMethod="distory")
   public MyBeanInit01 myBeanInit01() {
       return new MyBeanInit01();
   }

   @Bean
   public MyBeanInit2 myBeanInit2() {
       return new MyBeanInit2();
   }
}

二、Spring Aware

1、BeanNameAware : 获得容器中Bean的名称；

2、ResourceLoaderAware ：获得资源加载器，可以获得外部资源文件。

示例：必须重载两个set方法。

@Service
public class UserService implements BeanNameAware,ResourceLoaderAware{

   private String beanName;

   private ResourceLoader loader;

   @Override
   public void setResourceLoader(ResourceLoader resourceLoader) {
       this.loader = resourceLoader;
   }

   @Override
   public void setBeanName(String name) {
       this.beanName = name;
   }

   public String myAware() throws IOException {
       System.out.println("当前 Bean的name为：=="+beanName);
       Resource resource = loader.getResource("classpath:myProperties.properties");
       InputStream is = resource.getInputStream();
       String result = IOUtils.toString(is);
       return result;
   }

}

三、Spring 单元测试

@Configuration
public class TestConfig{

   @Bean
   @Profile("dev")
   public TestBean devTestBean(){
       return new TestBean("from development profile");
   }

   @Bean
   @Profile("prod")
   public TestBean prodTestBean(){
       return new TestBean("from production profile");
   }
}

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {TestConfig.class})
@ActiveProfiles("prod")
public class DemoBeanIntegrationTests{
@Autowired
private TestBean testBean

   @Test
   public void prodBeanShouldInject(){
       String expected = "from production profile";
       String actual = testBean.getContent();
       Assert.assertEquals(expected,actual);
   }
}

四、计划任务

1、配置类上加 @EnableScheduling -- 开启任务支持；

2、执行计划任务的方法上加 @Scheduled（包括：cron、fixDelay、fixRate等）。

五、添加拦截器：

1、普通的 Bean 实现 HanlderInterceptor 接口或者继承 HandlerInterceptorAdapter 类来自定义拦截器。

@Component
public class InterceptorService extends HandlerInterceptorAdapter{

   @Override //在请求发生前执行
   public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
           throws Exception {
       Long startTime = System.currentTimeMillis();
       request.setAttribute("startTime", startTime);
       return true;
   }

   @Override //在请求完成后执行
   public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
           ModelAndView modelAndView) throws Exception {
       Long startTime = (Long) request.getAttribute("startTime");
       request.removeAttribute("startTime");
       Long endTime = System.currentTimeMillis();
       request.setAttribute("handlingTime", endTime - startTime);
       System.out.println("本次请求耗时为： "+(endTime - startTime)+" 毫秒。");
   }
}

2、MVC的配置类中重写 addInterceptors 方法

/**
* @EnableWebMvc -- 启用SpringMVC的组件
* 相当于 xml配置文件的 <mvc:annotation-driven>
* 1、启用组件扫描
* @author fmr
*/
@Configuration
@ComponentScan("com")
@EnableWebMvc
public class DispatcherConfig extends WebMvcConfigurerAdapter {

   /**
   * 2、配置视图解析器
   * @return
   */
   @Bean
   public InternalResourceViewResolver internalResourceViewResolver() {
       InternalResourceViewResolver internalResourceViewResolver = new InternalResourceViewResolver();
       internalResourceViewResolver.setViewClass(JstlView.class);
       internalResourceViewResolver.setPrefix("/WEB-INF/jsp/");
       internalResourceViewResolver.setSuffix(".jsp");
       return internalResourceViewResolver;
   }

   /**
   * 设置统一错误处理要跳转的视图
   * @return
   */
   @Bean
   public SimpleMappingExceptionResolver simpleMappingExceptionResolver() {
       SimpleMappingExceptionResolver simpleMappingExceptionResolver = new SimpleMappingExceptionResolver();
       Properties properties = new Properties();
       properties.getProperty("java.lang.Exception", "error");
       simpleMappingExceptionResolver.setExceptionMappings(properties);
       return simpleMappingExceptionResolver;
   }

   /**
   * 3、添加静态资源
   * @param registry
   */
   @Override
   public void addResourceHandlers(ResourceHandlerRegistry registry) {
       registry.addResourceHandler("/view/**")
               .addResourceLocations("/view/", "classpath:/view/")
               .setCachePeriod(360000);
   }

4、自定义拦截器

@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new InterceptorService());
}

}

六、文件上传的配置类

@Bean
   public MultipartResolver multipartResolver() {
       CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
       multipartResolver.setMaxUploadSize(1000000);
       return multipartResolver;
   }

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