spring配置：xml配置和java注解配置对比
虽然spring早就推出java注解的方式配置框架，由于习惯了看xml所以一直没有去学习，然而最近需要学习springboot，为了平滑过渡，先被迫研究一下注解配置方式。
这里展示3种spring配置文件，来对比xml配置和java注解配置的区别，分别是spring\mvc\shiro的配置
先说总结：
对比2种配置方式会发现xml方法更繁琐（xml那恶心的头部约束），拿shiro来说，配完spring-shiro.xml，往往还需要在mvc.xml中开启代理，启用aop，然后在web.xml中启动shiro的Filter
而纯java配置只需一个类就能搞定，并且个人觉得可以更直观的看出bean的构造和依赖情况，又不依赖xsd文件
所以貌似java配置方法越来越流行，而xml的方式逐渐在被替代
话说回来现在springboot项目里似乎都已经放弃xml，要学习springboot的童鞋还是先习惯java配置方法吧（boot的配置还要高级，还要简单，感觉还是要先从基础的学起，免得直接看高级的一脸懵逼）
一、 spring配置
1、传统的spring.xml配置
2、基于注解的java类配置方式：
import org.apache.commons.dbcp2.BasicDataSource;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@ComponentScan("com.demo")//启动spring扫描
@PropertySource(value = {"classpath:jdbc.properties"}, ignoreResourceNotFound = true)//找不到配置文件则抛出异常
@EnableTransactionManagement//启动事务
public class SpringConfig {
@Value("${jdbc.username}")
private String username;
@Value("${jdbc.password}")
private String password;
//数据源
@Bean
public BasicDataSource basicDataSource() {
BasicDataSource dataSource = new BasicDataSource();
dataSource.setDriverClassName("com.mysql.jdbc.Driver");
dataSource.setUrl("jdbc:mysql:///test?useSSL=false&useUnicode=true&characterEncoding=UTF-8");
dataSource.setUsername(username);
dataSource.setPassword(password);
return dataSource;
}
//session工厂
@Bean
public SqlSessionFactoryBean sqlSessionFactoryBean(BasicDataSource dataSource) throws IOException {
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dataSource);
// mapper location
PathMatchingResourcePatternResolver pathResolver = new PathMatchingResourcePatternResolver();
factoryBean.setMapperLocations(pathResolver.getResources("classpath*:com/demo/**/*-mapper.xml"));
// config file
factoryBean.setConfigLocation(new ClassPathResource("mybatis.xml"));
return factoryBean;
}
//mapper扫描
@Bean
public MapperScannerConfigurer mapperScannerConfigurer() {
MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
mapperScannerConfigurer.setBasePackage("com.demo.dao");
mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactoryBean");
return mapperScannerConfigurer;
}
//事务配置
@Bean
public PlatformTransactionManager transactionManager(BasicDataSource dataSource) {
DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
dataSourceTransactionManager.setDataSource(dataSource);
return dataSourceTransactionManager;
}
}说明：
2个配置文件内里都定义了数据源、mybatis的session工厂以及启用@Transantional的事务
第一份是xml配置方法（这里忽略了web.xml），第二份是基于注解的纯java配置方法
接下来看看mvc的配置：
二、spring-mvc配置
1、xml配置方法
然后是配置web.xml：
org.springframework.web.context.ContextLoaderListener
mvc
org.springframework.web.servlet.DispatcherServlet
contextConfigLocation
classpath:mvc.xml
mvc
/
2、java注解方式
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
@Configuration
@EnableWebMvc//启动springMVC注解驱动 等价于xml 配置中的再配个启动类（相当于web.xml中配置ContextLoadListener）
继承了AbstractAnnotationConfigDispatcherServletInitializer的AppInitalizer的作用就类似web.xml中的ContextLoadListener，并且会在web项目运行初始化被自动发现并加载，这就是java config的魅力所在了，不管在哪里声明了配置了，只要继承了AbstractAnnotationConfigDispatcherServletInitializer，它就可以被自动加载。
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class WebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class[] getRootConfigClasses() {
return new Class[]{RootConfig.class};//非SpringMVC上下文配置类，不需要就return null
}
@Override
protected Class[] getServletConfigClasses() {
return new Class[]{WebMvcConfig.class};//SpringMVC上下文配置类
}
@Override
protected String[] getServletMappings() {
return new String[]{"/"};//dispatcher映射路径，一个string的列表，这里处理所有请求
}
//相当于web.xml中的
//
// mvc
// /
//
}RootConfig，不需要的话在上面 WebAppInitializer 的 getRootConfigClasses() 里直接return null即可
可以参考官方文档：
https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#spring-web
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@Configuration
@ComponentScan(basePackages="com.ssm",excludeFilters={
@ComponentScan.Filter(type= FilterType.ANNOTATION,value=EnableWebMvc.class)
})
public class RootConfig {
//RootConfig.class的内容如下，它可以放在和AppInitializer同个目录下，主要用来配置spring的bean，这里只关注web项目的实现，所以暂时没有具体内容
}
三、shiro配置
1、shiro.xml
/static/** = anon
/login = authc
/test = testAuth
如果需要使用注解，还需要在mvc.xml中加入如下代码
最后还要在web.xml中配置如下，启动shiro的Filter
shiroFilter
org.springframework.web.filter.DelegatingFilterProxy
targetFilterLifecycle
true
shiroFilter
/*
2、java方式：
import org.apache.shiro.authc.credential.HashedCredentialsMatcher;
import org.apache.shiro.cache.ehcache.EhCacheManager;
import org.apache.shiro.spring.LifecycleBeanPostProcessor;
import org.apache.shiro.spring.security.interceptor.AuthorizationAttributeSourceAdvisor;
import org.apache.shiro.spring.web.ShiroFilterFactoryBean;
import org.apache.shiro.web.mgt.DefaultWebSecurityManager;
import org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
@Configuration
public class ShiroConfig {
//在springboot中利用FilterRegistrationBean注册delegatingFilterProxy来启动shiro
// @Bean
// public FilterRegistrationBean delegatingFilterProxy(){
// FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
// DelegatingFilterProxy proxy = new DelegatingFilterProxy();
// proxy.setTargetFilterLifecycle(true);
// proxy.setTargetBeanName("shiroFilter");
// filterRegistrationBean.setFilter(proxy);
// return filterRegistrationBean;
// }
@Bean("shiroFilter")
public ShiroFilterFactoryBean factory(DefaultWebSecurityManager securityManager) {
ShiroFilterFactoryBean factoryBean = new ShiroFilterFactoryBean();
factoryBean.setSecurityManager(securityManager);
factoryBean.setLoginUrl("/login");
factoryBean.setSuccessUrl("/user");
factoryBean.setUnauthorizedUrl("/fail");
//自定义Filter（视需求而定）
Map filters = factoryBean.getFilters();//等号后面也可以直接new LinkedHashMap();
filters.put("testAuth", new YourFilter());
factoryBean.setFilters(filters);
//自定义url规则
// http://shiro.apache.org/web.html#urls-
Map filterChainDefinitions = new LinkedHashMap<>();
filterChainDefinitions.put("/login", "authc");
filterChainDefinitions.put("/test", "testAuth");
filterChainDefinitions.put("/static/**", "anon");
factoryBean.setFilterChainDefinitionMap(filterChainDefinitions);
return factoryBean;
}
@Bean("securityManager")
public DefaultWebSecurityManager getManager() {
DefaultWebSecurityManager manager = new DefaultWebSecurityManager();
manager.setRealm(myShiroRealm());
// manager.setCacheManager(ehCacheManager());//注入缓存管理器,看需求
/*
* 关闭shiro自带的session，详情见文档
* http://shiro.apache.org/session-management.html#SessionManagement-StatelessApplications%28Sessionless%29
*/
// DefaultSubjectDAO subjectDAO = new DefaultSubjectDAO();
// DefaultSessionStorageEvaluator defaultSessionStorageEvaluator = new DefaultSessionStorageEvaluator();
// defaultSessionStorageEvaluator.setSessionStorageEnabled(false);
// subjectDAO.setSessionStorageEvaluator(defaultSessionStorageEvaluator);
// manager.setSubjectDAO(subjectDAO);
return manager;
}
@Bean
public MyShiroRealm myShiroRealm() {
MyShiroRealm myShiroRealm = new MyShiroRealm();
myShiroRealm.setCredentialsMatcher(credentialsMatcher());
return myShiroRealm;
}
@Bean("credentialsMatcher")
public HashedCredentialsMatcher credentialsMatcher() {
HashedCredentialsMatcher credentialsMatcher = new HashedCredentialsMatcher();
credentialsMatcher.setHashAlgorithmName("md5");
credentialsMatcher.setHashIterations(5);
return credentialsMatcher;
}
/**
* 下面的代码是添加注解支持
*/
@Bean
@DependsOn("lifecycleBeanPostProcessor")
public DefaultAdvisorAutoProxyCreator defaultAdvisorAutoProxyCreator() {
DefaultAdvisorAutoProxyCreator defaultAdvisorAutoProxyCreator = new DefaultAdvisorAutoProxyCreator();
// 强制使用cglib，防止重复代理和可能引起代理出错的问题
// https://zhuanlan.zhihu.com/p/29161098
defaultAdvisorAutoProxyCreator.setProxyTargetClass(true);
return defaultAdvisorAutoProxyCreator;
}
@Bean("lifecycleBeanPostProcessor")
public LifecycleBeanPostProcessor lifecycleBeanPostProcessor() {
return new LifecycleBeanPostProcessor();
}
/**
* 开启shiro aop注解支持. 使用代理方式; 所以需要开启代码支持;
*/
@Bean
public AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor(DefaultWebSecurityManager securityManager) {
AuthorizationAttributeSourceAdvisor advisor = new AuthorizationAttributeSourceAdvisor();
advisor.setSecurityManager(securityManager);
return advisor;
}
// @Bean
// public EhCacheManager ehCacheManager() {
// EhCacheManager cacheManager = new EhCacheManager();
//// cacheManager.setCacheManagerConfigFile("classpath:ehcache.xml");
// return cacheManager;
// }
} 没有FilterRegistrationBean的话web.xml那段代码不能少，还得配置（暂时还没找到不通过FilterRegistrationBean注册
DelegatingFilterProxy来启动Filter的方法）