實現Spring零配置搭建
最近在爲去除配置文件做了一些研究,基於Spring 4 的一些特性將原來有配置的地方全部轉化成了基於註解的形式,發現Spring的強大不是一點點.
以下是對Spring的改造做了一些記錄:
Spring
註解介紹
-
@Configuration，用於表示這個類是一個配置類，用於配置Spring的相關信息 -
@EnableAspectJAutoProxy，啓用切面自動代理，用於AOP
等價於
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
-
@EnableTransactionManagement，啓用註解事務，即可以使用@Transactional註解來控制事務,具體實現
TransactionManagementConfigurer -> 等價於
<tx:annotation-driven transaction-manager="transactionManager"
proxy-target-class="true"></tx:annotation-driven>
-
@EnableCaching:啓用緩存實現,這裏是針對於Spring定義的緩存實現,具體實現類:CachingConfigurerSupport等價於
<cache:annotation-driven error-handler="defaultErrorCacheHandle" key-generator="defaultCacheKeyGenerator"/>
-
@ComponentScan，組件掃描，在basePackages指定的目錄下掃描被@Controller、@Service、@Component等註解註冊的組件 -
@Import，引入指定的配置類，我們引入了Spring容器配置類和數據源事務配置類 -
@PropertySource，加載指定的配置文件，配置文件內容會加載入Environment中等待調用
去除配置中的AOP動態代理
- xml
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
<!-- 多數據源切面類 -->
<bean id="manyDataSourceAspect" class="com.elab.core.aop.DataSourceAspect"/>
<!-- 多數據Aop配置 -->
<aop:config proxy-target-class="true">
<!-- 定義一個切入點表達式： 攔截哪些方法 -->
<aop:aspect ref="manyDataSourceAspect">
<aop:before method="before" pointcut="execution(* com.elab.ecrm.services..*.*(..))"> </aop:before>
<aop:after-returning pointcut="execution(* com.elab.ecrm.services..*.*(..))"
arg-names="point,retValue" returning="retValue" method="after"/>
</aop:aspect>
</aop:config>
- 註解
@Aspect
@EnableAspectJAutoProxy
@Configuration
public class DataSourceAopConfigBean {
@Bean
public DataSourceAspect getDataSourceAspect() {
DataSourceAspect catAspect = new DataSourceAspect();
return catAspect;
}
@Before(value = "execution(* com.elab.ecrm.services..*.*(..))")
public void dataSourceBefor(JoinPoint pjp) throws CoreException {
getDataSourceAspect().before(pjp);
}
}
去除配置中的數據源
其實這裏就和普通的bean定義沒什麼差別
<bean id="default" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
<property name="driverClassName" value="${default.driverClassName}"></property>
<property name="url" value="${default.url}"></property>
<property name="username" value="${default.username}"></property>
<property name="password" value="${default.password}"></property>
<property name="filters" value="${default.filters}"/>
<!-- 配置初始化大小、最小、最大 -->
<property name="initialSize" value="${default.initialSize}"/>
<property name="minIdle" value="${default.minIdle}"/>
</bean>
@EnableWebMvc
@PropertySource({"classpath:database.properties"})
@Configuration
public class DataSourceConfigBean {
@Autowired
private Environment env;
@Bean(name = "default")
public DataSource getDefaultDataSource() throws SQLException {
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(env.getProperty("default.driverClassName"));
dataSource.setUrl(env.getProperty("default.url"));
dataSource.setUsername(env.getProperty("default.username"));
dataSource.setPassword(env.getProperty("default.password"));
dataSource.setFilters(env.getProperty("default.filters"));
dataSource.setInitialSize(Integer.parseInt(env.getProperty("default.initialSize")));
dataSource.setMinIdle(Integer.parseInt(env.getProperty("default.minIdle")));
dataSource.setMaxActive(Integer.parseInt(env.getProperty("default.maxActive")));
return dataSource;
}
}
配置中的事務
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name = "dataSource" ref="default"/>
</bean>
<bean id="transactionManager" class="com.elab.ecrm.utils.DataSourceTransactionManager">
<property name="dataSource" ref="default"/>
</bean>
@EnableTransactionManagement
@Configuration
public class TransactionConfigBean implements TransactionManagementConfigurer {
@Qualifier("default")
@Autowired
private DataSource dataSource;
@Override
public PlatformTransactionManager annotationDrivenTransactionManager() {
return getDataSourceTransactionManager();
}
@Bean
public DataSourceTransactionManager getDataSourceTransactionManager() {
DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
transactionManager.setDataSource(dataSource);
return transactionManager;
}
@Bean
public JdbcTemplate getJDBCTemplate() {
JDBCTemplate jdbcTemplate = new JDBCTemplate();
return jdbcTemplate;
}
}
普通的Bean定義
<bean id="httpClientFactory"
class="org.springframework.http.client.SimpleClientHttpRequestFactory">
<property name="connectTimeout" value="120000"/>
<property name="readTimeout" value="120000"/>
</bean>
<!--RestTemplate-->
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
<constructor-arg ref="httpClientFactory"/>
</bean>
@Configuration
// 這裏默認只掃Spring相關的,去除Controller相關的
@ComponentScan(basePackages = {"com.*.*.*"}, excludeFilters = {
@ComponentScan.Filter(type = FilterType.ANNOTATION, value = {Controller.class})
})
public class BeanConfig {
@Bean
public ClientHttpRequestFactory getClientHttpRequestFactory() {
SimpleClientHttpRequestFactory simpleClientHttpRequestFactory = new SimpleClientHttpRequestFactory();
simpleClientHttpRequestFactory.setConnectTimeout(120000);
simpleClientHttpRequestFactory.setReadTimeout(120000);
return simpleClientHttpRequestFactory;
}
@Bean
public RestTemplate getRestTemplate() {
RestTemplate restTemplate = new RestTemplate(getClientHttpRequestFactory());
return restTemplate;
}
}
緩存替代
基於Spring的緩存接口做替換
<cache:annotation-driven error-handler="defaultErrorCacheHandle" key-generator="defaultCacheKeyGenerator"/>
@EnableCaching
@Configuration
public class RedisBeanConfig extends CachingConfigurerSupport {
@Value("${domain}")
private String domain;
@Autowired
private org.springframework.core.env.Environment env;
@Override
public KeyGenerator keyGenerator() {
return getDefaultCacheKeyGenerator();
}
@Override
public CacheErrorHandler errorHandler() {
return getErrorCacheHandle();
}
@Override
public CacheManager cacheManager() {
return getCompositeCacheManager();
}
}
SpringMVC
註解介紹
-
@EnableWebMvc: 開啓SpringMVC的支持，註冊了這個方法並且實現了WebMvcConfigurerAdapter類的話,就擁有相當SpingMVC配置文件中的所有屬性了
image.png
將這個類註冊到容器時,會觸發一個DelegatingWebMvcConfiguration委託類的註冊的setConfigurers方法
@Autowired(required = false)
public void setConfigurers(List<WebMvcConfigurer> configurers) {
if (configurers == null || configurers.isEmpty()) {
return;
}
this.configurers.addWebMvcConfigurers(configurers);
}
這個方法會將所有實現WebMvcConfigurer接口的方法全部註冊進來,WebMvcConfigurerAdapter已經實現了接口
image.png
所以重寫過的所有方法都會被觸發註冊
攔截器
<mvc:interceptors>
<!-- 使用bean定義一個Interceptor，直接定義在mvc:interceptors根下面的Interceptor將攔截所有的請求 -->
<mvc:interceptor>
<mvc:mapping path="/**"/>
<!-- 需排除攔截的地址 -->
<mvc:exclude-mapping path="/"/>
<!-- 定義在mvc:interceptor下面的表示是對特定的請求才進行攔截的 -->
<bean class="com.demo.log.asepct.TimeInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
這裏只需要根據業務實現從WebMvcConfigurerAdapter重寫自己需要的方法即可
@Configuration
@EnableWebMvc
// 這裏只掃描和MVC相關的註解,爲了和Spring容器區分開
@ComponentScan(basePackages = {"com.elab.ecrm.controllers"}, includeFilters = {
@ComponentScan.Filter(type = FilterType.ANNOTATION, value = {Controller.class})
})
public class MvcConfigBean extends WebMvcConfigurerAdapter {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(getTimeHandlerInterceptor())
.addPathPatterns("/**")
.excludePathPatterns("/");
}
public HandlerInterceptor getTimeHandlerInterceptor() {
return new TimeInterceptor();
}
}
web.xml
從前Spring和SpringMVC的啓動入口 , 由於Spring 4是基於Servlet 3.0以上實現的 , 所以Spring提供了SpringServletContainerInitializer這個類可以做爲一個入口類.
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
classpath:applicationContext-datasource.xml
</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>=
</servlet>
改成編程方式
public class WebInitializer implements WebApplicationInitializer {
private Logger logger = LoggerFactory.getLogger(WebInitializer.class);
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
logger.info("begin init web application.");
long startTime = System.currentTimeMillis();
CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
characterEncodingFilter.setEncoding("UTF-8");
//配置Spring
AnnotationConfigWebApplicationContext springContext = new AnnotationConfigWebApplicationContext();
// 這裏一般配置掃描類
springContext.register(BeanConfig.class);
//添加linstener
servletContext.addListener(new ContextLoaderListener(springContext));
//添加servlet
ServletRegistration.Dynamic dispatcher = servletContext.addServlet(
"dispatcher", new DispatcherServlet(springContext));
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("/");
//添加filter
// LoggerFilter loggerFilter = new LoggerFilter();
// FilterRegistration.Dynamic logFilterRegistration=container.addFilter("requestResponseLogFilter", loggerFilter);
// logFilterRegistration.addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST, DispatcherType.ASYNC), false, "/*");
javax.servlet.FilterRegistration.Dynamic filter = servletContext.addFilter("encoding", characterEncodingFilter);
long time = System.currentTimeMillis() - startTime;
logger.info("init web application success. start count time : " + time);
}
}
以上代碼可以總結出來:
- spring 將配置文件和編程方式做了共同的實現,稍微複雜的配置例如
<cache:annotation-driven />
<aop:aspectj-autoproxy />
<tx:annotation-driven />
Spring也通過編程方式去指定了具體的實現類,這個可以從註解類中的註釋瞭解到
- 啓動方面基於Servlet 3去實現的,也能通過接口方式啓動應用
由於代碼中貼入的時候有一些去除,可能會導致閱讀收到影響,這只是提供一些更改思路,可以照着這個來.基本上應該是OK的。
項目可以部署到tomcat中,無需糾結..