实现Spring零配置搭建
最近在为去除配置文件做了一些研究,基于Spring 4 的一些特性将原来有配置的地方全部转化成了基于注解的形式,发现Spring的强大不是一点点.
以下是对Spring的改造做了一些记录:
Spring
注解介绍
-
@Configuration，用于表示这个类是一个配置类，用于配置Spring的相关信息 -
@EnableAspectJAutoProxy，启用切面自动代理，用于AOP
等价于
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
-
@EnableTransactionManagement，启用注解事务，即可以使用@Transactional注解来控制事务,具体实现
TransactionManagementConfigurer -> 等价于
<tx:annotation-driven transaction-manager="transactionManager"
proxy-target-class="true"></tx:annotation-driven>
-
@EnableCaching:启用缓存实现,这里是针对于Spring定义的缓存实现,具体实现类:CachingConfigurerSupport等价于
<cache:annotation-driven error-handler="defaultErrorCacheHandle" key-generator="defaultCacheKeyGenerator"/>
-
@ComponentScan，组件扫描，在basePackages指定的目录下扫描被@Controller、@Service、@Component等注解注册的组件 -
@Import，引入指定的配置类，我们引入了Spring容器配置类和数据源事务配置类 -
@PropertySource，加载指定的配置文件，配置文件内容会加载入Environment中等待调用
去除配置中的AOP动态代理
- xml
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
<!-- 多数据源切面类 -->
<bean id="manyDataSourceAspect" class="com.elab.core.aop.DataSourceAspect"/>
<!-- 多数据Aop配置 -->
<aop:config proxy-target-class="true">
<!-- 定义一个切入点表达式： 拦截哪些方法 -->
<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>
- 注解
@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);
}
}
去除配置中的数据源
其实这里就和普通的bean定义没什么差别
<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;
}
}
配置中的事务
<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定义
<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
// 这里默认只扫Spring相关的,去除Controller相关的
@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;
}
}
缓存替代
基于Spring的缓存接口做替换
<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
注解介绍
-
@EnableWebMvc: 开启SpringMVC的支持，注册了这个方法并且实现了WebMvcConfigurerAdapter类的话,就拥有相当SpingMVC配置文件中的所有属性了
image.png
将这个类注册到容器时,会触发一个DelegatingWebMvcConfiguration委托类的注册的setConfigurers方法
@Autowired(required = false)
public void setConfigurers(List<WebMvcConfigurer> configurers) {
if (configurers == null || configurers.isEmpty()) {
return;
}
this.configurers.addWebMvcConfigurers(configurers);
}
这个方法会将所有实现WebMvcConfigurer接口的方法全部注册进来,WebMvcConfigurerAdapter已经实现了接口
image.png
所以重写过的所有方法都会被触发注册
拦截器
<mvc:interceptors>
<!-- 使用bean定义一个Interceptor，直接定义在mvc:interceptors根下面的Interceptor将拦截所有的请求 -->
<mvc:interceptor>
<mvc:mapping path="/**"/>
<!-- 需排除拦截的地址 -->
<mvc:exclude-mapping path="/"/>
<!-- 定义在mvc:interceptor下面的表示是对特定的请求才进行拦截的 -->
<bean class="com.demo.log.asepct.TimeInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
这里只需要根据业务实现从WebMvcConfigurerAdapter重写自己需要的方法即可
@Configuration
@EnableWebMvc
// 这里只扫描和MVC相关的注解,为了和Spring容器区分开
@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
从前Spring和SpringMVC的启动入口 , 由于Spring 4是基于Servlet 3.0以上实现的 , 所以Spring提供了SpringServletContainerInitializer这个类可以做为一个入口类.
<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>
改成编程方式
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();
// 这里一般配置扫描类
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);
}
}
以上代码可以总结出来:
- spring 将配置文件和编程方式做了共同的实现,稍微复杂的配置例如
<cache:annotation-driven />
<aop:aspectj-autoproxy />
<tx:annotation-driven />
Spring也通过编程方式去指定了具体的实现类,这个可以从注解类中的注释了解到
- 启动方面基于Servlet 3去实现的,也能通过接口方式启动应用
由于代码中贴入的时候有一些去除,可能会导致阅读收到影响,这只是提供一些更改思路,可以照着这个来.基本上应该是OK的。
项目可以部署到tomcat中,无需纠结..