转-spring boot web相关配置

spring boot web相关配置

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     spring boot集成了servlet容器，当咱们在pom文件中增长spring-boot-starter-web的maven依赖时，不作任何web相关的配置便能提供web服务，这还得归于spring boot 自动配置的功能（由于加了EnableAutoConfiguration的注解），帮咱们建立了一堆默认的配置，之前在web.xml中配置，如今均可以经过spring bean的方式进行配置，由spring来进行生命周期的管理，大多数状况下，咱们须要重载这些配置（例如修改服务的启动端口，contextpath,filter,listener,servlet,session超时时间等）

      1. servlet配置

     当应用只有默认的servlet（即DispatcherServlet）时，映射的url为/,存在其余的servlet时，映射的路径为servlet的注册的beanname(可经过@Component注解修改)，建立方式以下：

 

@Component("myServlet")
public class MyServlet implements Servlet{
    /**
     *
     * @see javax.servlet.Servlet#destroy()
     */
    @Override
    public void destroy() {
        System.out.println("destroy...");
    }
    /**
     * @return
     * @see javax.servlet.Servlet#getServletConfig()
     */
    @Override
    public ServletConfig getServletConfig() {
        return null;
    }
    /**
     * @return
     * @see javax.servlet.Servlet#getServletInfo()
     */
    @Override
    public String getServletInfo() {
        return null;
    }
    /**
     * @param arg0
     * @throws ServletException
     * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig)
     */
    @Override
    public void init(ServletConfig arg0) throws ServletException {
        System.out.println("servlet init...");
    }
    /**
     * @param arg0
     * @param arg1
     * @throws ServletException
     * @throws IOException
     * @see javax.servlet.Servlet#service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)
     */
    @Override
    public void service(ServletRequest arg0, ServletResponse arg1) throws ServletException,
                                                                    IOException {
        System.out.println("service...");
    }

   

 

    2. filter配置

    filter配置的映射是/*，建立方式以下：

 

@Component("myFilter")
public class MyFilter implements Filter{
    /**
     *
     * @see javax.servlet.Filter#destroy()
     */
    @Override
    public void destroy() {
        System.out.println("destroy...");
    }
    /**
     * @param arg0
     * @param arg1
     * @param arg2
     * @throws IOException
     * @throws ServletException
     * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
     */
    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
                                                                                        throws IOException,
                                                                    ServletException {
        System.out.println("doFilter...");
        arg2.doFilter(arg0, arg1);
    }
    /**
     * @param arg0
     * @throws ServletException
     * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
     */
    @Override
    public void init(FilterConfig arg0) throws ServletException {
        System.out.println("filter init...");
    }

}<span style="font-family: Arial, Helvetica, FreeSans, sans-serif; font-size: 13.3333330154419px; line-height: 17.3333339691162px; background-color: transparent;">   </span>

 

    

    3. listener配置

 

@Component("myListener")
public class MyListener implements ServletContextListener{
    /**
     * @param arg0
     * @see javax.servlet.ServletContextListener#contextDestroyed(javax.servlet.ServletContextEvent)
     */
    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        System.out.println("contextDestroyed...");
    }
    /**
     * @param arg0
     * @see javax.servlet.ServletContextListener#contextInitialized(javax.servlet.ServletContextEvent)
     */
    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        System.out.println("listener contextInitialized...");
    }

}

若是以为控制力度不够灵活（例如你想修改filter的映射），spring boot还提供了  ServletRegistrationBean，FilterRegistrationBean，ServletListenerRegistrationBean这3个东西来进行配置

 

    修改filter的映射

 

@Configuration
public class WebConfig {
    @Bean
    public FilterRegistrationBean filterRegistrationBean(MyFilter myFilter){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(myFilter);
        filterRegistrationBean.setEnabled(true);
        filterRegistrationBean.addUrlPatterns("/bb");
        return filterRegistrationBean;
    }
}

 

   4. 配置servlet 容器

    能够经过两种方式配置servlet容器，一种是经过properties文件，例如：

 

server.port=8081
server.address=127.0.0.1
server.sessionTimeout=30
server.contextPath=/springboot

完整的配置信息能够看这  http://github.com/spring-projects/spring-boot/tree/master/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

 

    另外一种方式是java代码的形式：

 

@Component
public class MyCustomizationBean implements EmbeddedServletContainerCustomizer  {
    /**
     * @param container
     * @see org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer#customize(org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer)
     */
    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {
         container.setContextPath("/sprintboot");
         container.setPort(8081);
         container.setSessionTimeout(30);
    }

}

   5. error 处理

 

   spring boot 提供了/error映射来进行错误处理，它会返回一个json来对错误信息进行描述（包含了http状态和异常信息）,例如404的错误

   

     固然能够定制错误页面，经过实现ErrorController接口，并将它装配起来便可，以下：     

 

@Controller
public class ErrorHandleController implements ErrorController {
    /**
     * @return
     * @see org.springframework.boot.autoconfigure.web.ErrorController#getErrorPath()
     */
    @Override
    public String getErrorPath() {
        return "/screen/error";
    }

    @RequestMapping
    public String errorHandle(){
        return getErrorPath();
    }
}

    还能够这样：

 

 

@Component
private class MyCustomizer implements EmbeddedServletContainerCustomizer {

    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {
        container.addErrorPages(new ErrorPage(HttpStatus.BAD_REQUEST, "/screen/error"));
    }

}

   6.模板引擎

 

    spring boot 会自动配置 FreeMarker,Thymeleaf,Velocity，只须要在pom中加入相应的依赖便可，例如应用Velocity   

 

<dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-velocity</artifactId>
</dependency>

    默认配置下spring boot会从src/main/resources/templates目录中去找模板

 

  7. jsp限制

    若是要在spring boot中使用jsp,得将应用打包成war,这里有配置的example https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-web-jsp