SpringMVC基於程式碼的配置方式（零配置，無web.xml）

weixin_34162629發表於2017-07-30
SpringMVCWebXML

基於配置檔案的web專案維護起來可能會更方便，可是有時候我們會有一些特殊的需求，比方防止客戶胡亂更改配置，這時候我們須要給配置隱藏到程式碼中。

1.建立一個動態web專案（無需web.xml）

2.右鍵專案加入幾個package: com.easyweb.config (儲存專案配置) com.easyweb.controller （儲存springMvc controller）

3.在 com.easyweb.config 新建一個類 WebApplicationStartup 。這個類實現WebApplicationInitializer 介面，是專案的入口，作用相似於web.xml，詳細程式碼例如以下：

package com.easyweb.config;

import javax.servlet.MultipartConfigElement;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration.Dynamic;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * server啟動入口類
 * 
 * @author Administrator
 *
 */
public class WebApplicationStartup implements WebApplicationInitializer {

  private static final String SERVLET_NAME = "Spring-mvc";

  private static final long MAX_FILE_UPLOAD_SIZE = 1024 * 1024 * 5; // 5 Mb

  private static final int FILE_SIZE_THRESHOLD = 1024 * 1024; // After 1Mb

  private static final long MAX_REQUEST_SIZE = -1L; // No request size limit

  /**
   * server啟動呼叫此方法，在這裡能夠做配置 作用與web.xml同樣
   */
  @Override
  public void onStartup(ServletContext servletContext) throws ServletException {
    // 註冊springMvc的servlet
    this.addServlet(servletContext);
    // 註冊過濾器
    // servletContext.addFilter(arg0, arg1)
    // 註冊監聽器
    // servletContext.addListener(arg0);
  }

  /**
   * 註冊Spring servlet
   * 
   * @param servletContext
   */
  private void addServlet(ServletContext servletContext) {
    // 構建一個application context
    AnnotationConfigWebApplicationContext webContext = createWebContext(SpringMVC.class, ViewConfiguration.class);
    // 註冊spring mvc 的 servlet
    Dynamic dynamic = servletContext.addServlet(SERVLET_NAME, new DispatcherServlet(webContext));
    // 加入springMVC 同意訪問的Controller字尾
    dynamic.addMapping("*.html", "*.ajax", "*.css", "*.js", "*.gif", "*.jpg", "*.png");
    // 所有通過請用 “/”
    // dynamic.addMapping("/");
    dynamic.setLoadOnStartup(1);
    dynamic.setMultipartConfig(new MultipartConfigElement(null, MAX_FILE_UPLOAD_SIZE, MAX_REQUEST_SIZE, FILE_SIZE_THRESHOLD));
  }

  /**
   * 通過自己定義的配置類來例項化一個Web Application Context
   * 
   * @param annotatedClasses
   * @return
   */
  private AnnotationConfigWebApplicationContext createWebContext(Class<?

>... annotatedClasses) { AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext(); webContext.register(annotatedClasses); return webContext; } }

4.在com.easyweb.config 下加入類 SpringMVC 繼承 WebMvcConfigurerAdapter。這個類的作用是進行SpringMVC的一些配置，程式碼例如以下：

package com.easyweb.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
@EnableWebMvc
//指明controller所在的包名
@ComponentScan(basePackages = {"com.easyweb.controller"})
public class SpringMVC extends WebMvcConfigurerAdapter {

  /**
   * 非必須
   */
  @Override
  public void configureDefaultServletHandling(final DefaultServletHandlerConfigurer configurer) {
    configurer.enable();
  }

  /**
   * 假設專案的一些資原始檔放在/WEB-INF/resources/以下
   * 在瀏覽器訪問的地址就是相似：http://host:port/projectName/WEB-INF/resources/xxx.css
   * 可是加了例如以下定義之後就能夠這樣訪問：
   * http://host:port/projectName/resources/xxx.css
   * 非必須
   */
  @Override
  public void addResourceHandlers(final ResourceHandlerRegistry registry) {
    registry.addResourceHandler("/resources/**/*").addResourceLocations("/WEB-INF/resources/");
  }
}

5.加入view配置檔案com.easyweb.config下新建類ViewConfiguration，裡面能夠依據自己的須要定義檢視攔截器：

package com.easyweb.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.view.JstlView;
import org.springframework.web.servlet.view.UrlBasedViewResolver;
import org.springframework.web.servlet.view.tiles2.TilesConfigurer;
import org.springframework.web.servlet.view.tiles2.TilesView;

@Configuration
public class ViewConfiguration {

    @Bean
    public ViewResolver urlBasedViewResolver() {
        UrlBasedViewResolver viewResolver;
        viewResolver = new UrlBasedViewResolver();
        viewResolver.setOrder(2);
        viewResolver.setPrefix("/WEB-INF/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        // for debug envirment
        viewResolver.setCache(false);
        return viewResolver;
    }
    @Bean
    public ViewResolver tilesViewResolver() {
        UrlBasedViewResolver urlBasedViewResolver = new UrlBasedViewResolver();
        urlBasedViewResolver.setOrder(1);
        urlBasedViewResolver.setViewClass(TilesView.class);
        //urlBasedViewResolver.
        return urlBasedViewResolver;
    }
    @Bean
    public TilesConfigurer tilesConfigurer() {
        TilesConfigurer tilesConfigurer = new TilesConfigurer();
        tilesConfigurer.setDefinitions(new String[] { "classpath:tiles.xml" });
        return tilesConfigurer;
    }
}

6.本例中還用了tiles檢視解析器。替換了原始的include方式

7.完整程式碼已上傳
http://download.csdn.net/detail/u013816347/8998891

學習路上，歡迎評論指正。

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