Spring JavaConfig
最近擼了一遍Spring action 4,發現裡面講的都不再使用xml檔案來配置spring,全都採用Java程式碼來配置.
用Java程式碼配置的話,感覺要比xml更便於維護,而且用程式碼肯定比xml更爽嘛
下面來一步步用JavaConfig搭一個Spring工程
那在用xml配置的時候,專案都是從載入web.xml檔案再掃描到各種spring-*.xml檔案
那不用xml檔案,專案從哪裡啟動呢?
那就要靠這個類了,AbstractAnnotationConfigDispatcherServletInitializer,這個就相當於web.xml啦,在這裡面可以配置上下文,DispatcherServlet,過濾器等等bean;
首先我們先建立一個類SpittrWebAppInitialzer
package com.fireyao;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
import javax.servlet.Filter;
public class SpittrWebAppInitialzer extends AbstractAnnotationConfigDispatcherServletInitializer {
/**
* 配置root上下文,如Jpa資料來源等等的配置
* @return
*/
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[]{RootConfig.class};
}
/**
* 配置dispatcher servlet
* @return
*/
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{WebConfig.class};
}
/**
* 將DispatcherServlet對映到 "/"
* 指定開始被servlet處理的url,配置從/開始
* @return
*/
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
/**
* 這裡註冊的所有過濾器,都會對映到DispatcherServlet
* 就是說這裡的過濾器過濾規則是 /*
* 所有的請求都會先到這裡註冊的過濾器中
*
* @return
*/
@Override
protected Filter[] getServletFilters() {
return new Filter[]{
new CharacterEncodingFilter("UTF-8", true)
};
}
}複製程式碼在SpittrWebAppInitialzer類裡面載入了RootConfig和WebConfig兩個配置類,
再建立這兩個類以及相關的配置(以下省略package和import)
RootConfig
/**
* 相當於applicationContext.xml
*/
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = {"com.fireyao.repository"},
entityManagerFactoryRef = "entityManagerFactory",
transactionManagerRef = "transactionManager")
@PropertySource(value = {"classpath:db.properties", "classpath:hibernate.properties", "classpath:app.properties"})
@ComponentScan(basePackages = "com.fireyao",
excludeFilters = {
@ComponentScan.Filter(
type = FilterType.ANNOTATION, value = EnableWebMvc.class
)})
@EnableAspectJAutoProxy(proxyTargetClass = true)
/**
* proxyTargetClass = true ==> 使用cglib代理
* proxyTargetClass = false(預設) ==> 使用JDK代理
*/
public class RootConfig {
@Value(value = "${db.driver:org.postgresql.Driver}")
private String DRIVERCLASSNAME;
@Value("${db.username}")
private String USERNAME;
@Value("${db.password}")
private String PASSWORD;
@Value("${db.jdbcURL}")
private String URL;
@Value("${hibernate.hbm2dll.create_namespaces}")
private String CREATE_NAMESPACES;
@Value("${hibernate.hbm2ddl.auto}")
private String HBM2DDL_AUTO;
@Value("${hibernate.show_sql}")
private String SHOW_SQL;
@Value("${hibernate.format_sql}")
private String FORMAT_SQL;
@Value("${hibernate.generate_statistics}")
private String GENERATE_STATISTICS;
/**
* 配置資料來源
*/
@Bean(name = "dataSource")
public DruidDataSource dataSource() {
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(DRIVERCLASSNAME);
dataSource.setUrl(URL);
dataSource.setUsername(USERNAME);
dataSource.setPassword(PASSWORD);
/* 配置初始化大小、最小、最大*/
dataSource.setInitialSize(5);
dataSource.setMinIdle(5);
dataSource.setMaxActive(20);
/* 配置獲取連線等待超時的時間*/
dataSource.setMaxWait(30000);
/*配置間隔多久才進行一次檢測，檢測需要關閉的空閒連線，單位是毫秒*/
dataSource.setTimeBetweenEvictionRunsMillis(60000);
/*配置一個連線在池中最小生存的時間，單位是毫秒*/
dataSource.setMinEvictableIdleTimeMillis(300000);
/*申請連線的時候檢測，如果空閒時間大於timeBetweenEvictionRunsMillis，執行validationQuery檢測連線是否有效*/
dataSource.setTestWhileIdle(true);
dataSource.setValidationQuery("select 1");
return dataSource;
}
@Bean
public HibernateJpaVendorAdapter hibernateJpaVendorAdapter() {
return new HibernateJpaVendorAdapter();
}
@Bean(name = "entityManagerFactory")
public LocalContainerEntityManagerFactoryBean entityManagerFactory(DruidDataSource dataSource,HibernateJpaVendorAdapter hibernateJpaVendorAdapter) {
LocalContainerEntityManagerFactoryBean entityManagerFactory = new LocalContainerEntityManagerFactoryBean();
entityManagerFactory.setDataSource(dataSource);
entityManagerFactory.setJpaVendorAdapter(hibernateJpaVendorAdapter);
entityManagerFactory.setPackagesToScan("com.fireyao.domain");
/*指定JPA屬性；如Hibernate中指定是否顯示SQL的是否顯示、方言等*/
Map<String, Object> jpaProp = new HashMap();
jpaProp.put("hibernate.dialect", new PostgisDialect());
jpaProp.put("hibernate.hbm2ddl.auto", HBM2DDL_AUTO);
jpaProp.put("hibernate.show_sql", SHOW_SQL);
jpaProp.put("hibernate.generate_statistics", GENERATE_STATISTICS);
jpaProp.put("hibernate.format_sql", FORMAT_SQL);
jpaProp.put("hibernate.hbm2dll.create_namespaces", CREATE_NAMESPACES);
entityManagerFactory.setJpaPropertyMap(jpaProp);
return entityManagerFactory;
}
/**
* 事務管理器
*
* @param entityManagerFactory
* @return
*/
@Bean(name = "transactionManager")
public JpaTransactionManager transactionManager(LocalContainerEntityManagerFactoryBean entityManagerFactory) {
return new JpaTransactionManager(entityManagerFactory.getObject());
}
}複製程式碼WebConfig
/**
* 相當於springmvc-servlet.xml
*/
@Configuration
@EnableWebMvc//啟用spring mvc
@ComponentScan(basePackages = "com.fireyao.controller") //啟用元件掃描
public class WebConfig extends WebMvcConfigurerAdapter {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
//處理中文亂碼問題
List<MediaType> fastMediaTypes = new ArrayList<>();
fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
fastConverter.setSupportedMediaTypes(fastMediaTypes);
fastConverter.setFastJsonConfig(fastJsonConfig);
converters.add(fastConverter);
}
/**
* Thymeleaf檢視解析器
*
* @param springTemplateEngine
* @return
*/
@Bean
public ThymeleafViewResolver viewResolver(SpringTemplateEngine springTemplateEngine) {
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
viewResolver.setTemplateEngine(springTemplateEngine);
viewResolver.setCharacterEncoding("utf-8");
return viewResolver;
}
/**
* 模版引擎
*
* @param iTemplateResolver
* @return
*/
@Bean
public SpringTemplateEngine templateEngine(ITemplateResolver iTemplateResolver) {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(iTemplateResolver);
return templateEngine;
}
/**
* Thymeleaf3.0之後
* Thymeleaf模版解析器
*
* @return
*/
@Bean
public ITemplateResolver iTemplateResolver() {
SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
templateResolver.setTemplateMode("HTML5");
templateResolver.setPrefix("/WEB-INF/templates/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode("HTML");
templateResolver.setCharacterEncoding("utf-8");
templateResolver.setCacheable(false);
return templateResolver;
}
/**
* Thymeleaf3.0之前
* Thymeleaf模版解析器
* @return
*/
/* @Bean
public TemplateResolver templateResolver() {
TemplateResolver resolver = new ServletContextTemplateResolver();
resolver.setPrefix("/WEB-INF/VIEWS/");
resolver.setSuffix(".html");
resolver.setTemplateMode("HTML5");
resolver.setCacheable(false);
return resolver;
}*/
/**
* 配置靜態資源的處理
* 要求DispatcherServlet將對靜態資源的請求轉發到Servlet容器中預設的Servlet上
* 而不是使用DispatcherServlet本身來處理此類請求。
*
* @param configurer
*/
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
/**
* 配置檢視解析器
* ==> JSP檢視
*
* @return
*/
/*@Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix("/WEB-INF/views/");
resolver.setSuffix(".jsp");
resolver.setExposeContextBeansAsAttributes(true);
return resolver;
}*/
}複製程式碼@Configuration 標註為配置類
@EnableTransactionManagement註解開啟註解式事務的支援。
@EnableJpaRepositories註解開啟對Spring Data JPA Repostory的支援
@PropertySource 掃面db.properties等配置檔案,可以用@Value註解取到properties中的值
@ComponentScan 配置掃描類包 相當於<context:component-scan base-package="com.fireyao"/>
@EnableAspectJAutoProxy 表示開啟AOP代理自動配置
@EnableAspectJAutoProxy中proxyTargetClass屬性
proxyTargetClass = true ==> 使用cglib代理
proxyTargetClass = false(預設) ==> 使用JDK代理
那spring最基本的JavaConfig就這樣了.
是不是看上去很舒服,果然還是要用Java程式碼才爽.