spring boot整合知识（freemarker,原生servlet,filter,listener,拦截器，静态资源加载等）

本文所有的代码都在此项目中：https://gitee.com/zhangjunqing/spring-boot/tree/master/springboot-sample

1 搭建最简单spring boot web开发框架：

1.1首先引入maven依赖：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.springboot</groupId>
  <artifactId>springoot</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>springoot</name>
  <url>http://maven.apache.org</url>
  
  <!-- 使用spring boot必须有这依赖 -->
  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
     <!-- 引入web 服务器 tomcat，web框架是 spring web mvc-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

  </dependencies>
</project>

1.2 增加一个启动类：

package com.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication  //注意此类的包地址应该是最大的包，这样他就可以自动扫描其下包的所有类.否则也可以(scanBasePackages={"com.springboot.controller"})指定要扫描的包
public class App {
    public static void main(String[] args) throws Exception {
        SpringApplication.run(App.class, args);
    }
}

1.3 增加一个controller层

package com.springboot.controller;

import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/hello")
public class HelloController {
    
    @RequestMapping("/say")
    public @ResponseBody String sayHello() {
        return "hello";
    }
    
    
}

1.4 启动启动类后浏览器输入：http://localhost:8080/hello/say

注意：通过引入spring-boot-starter-web依赖，等同于项目引入了下面的依赖，等于此项目引入了spring，mvc，tomcat和实体类验证器hibernate validator(用于验证实体类的合法性，应用于程序安全加固方面，想学的可以看一下)

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
        </dependency>
    </dependencies>

项目地址：

https://gitee.com/zhangjunqing/spring-boot

2 增加freemarker支持

2.1 添加依赖

            <!-- freemarker支持 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>

2.2 在resources创建templates文件夹下创建freemarker模板文件freemarker.ftl

模板文件内容：

<!DOCTYPE html>  
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"  
      xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">  
    <head>  
        <title>Hello World!</title>  
    </head>  
    <body>  
       <p>  
           welcome ${name}  to freemarker!  
       </p>        
        
    </body>  
</html>

controller层：

package com.springboot.controller;

import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/hello")
public class HelloController {
    
    /**
     * 整合freemarker模板
     * @param map
     * @return
     */
    @RequestMapping("/freemarker")
    public String freemarker(Map<String, Object> map) {
        map.put("name", "topsec");
        return "freemarker";
    }
    
    
}

注意：spring boot集成freemarker会默认找resources/templates文件夹的内容。本人没有查找到spring boot直接跳转到html的方法。

3 增加原生servlet，listener，filter的支持

3.1 注意在启动类上添加ServletComponentScan注解，并且指定要扫秒的包名（必须）

package com.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication  //注意此类的包地址应该是最大的包，这样他就可以自动扫描其下包的所有类.否则也可以(scanBasePackages={"com.springboot.controller"})指定要扫描的包
@ServletComponentScan({"com.springboot.servlet.servlet","com.springboot.servlet.filter","com.springboot.servlet.listener"})//此注解用于支持原生的servlet
public class App {
    public static void main(String[] args) throws Exception {
        SpringApplication.run(App.class, args);
    }
}

3.2 @WebFilter(filterName="myFilter",urlPatterns="/*")表示使用原生过滤器，@WebListener原生监听器，@WebServlet(urlPatterns= {"/Myservlet"})表示原生servlet

原生servlet实例代码：

package com.springboot.servlet.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * servlet
 * @author 76524
 *
 */
@WebServlet(urlPatterns= {"/Myservlet"})
public class MyServlet extends HttpServlet{
       @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
            this.doPost(req, resp);
        }
        
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException {
            PrintWriter pw = resp.getWriter();
            pw.write("MyServlet");
            pw.flush();
            pw.close();
        }
        
        @Override
        public void init() throws ServletException {
           System.out.println("初始化********** MyServlet");
        }
}

原生监听器代码：

package com.springboot.servlet.listener;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

/**
 * 监听器
 * @author 76524
 *
 */
@WebListener
public class MyListener implements ServletContextListener{

    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("初始化myListener");
    }

    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("銷毀myListener");
    }

}

原生过滤器代码

package com.springboot.servlet.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;

/**
 * 过滤器
 * @author 76524
 *
 */
@WebFilter(filterName="myFilter",urlPatterns="/*")
public class MyFilter  implements Filter{

    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub
        
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
            HttpServletRequest req = (HttpServletRequest)request;
            System.out.println(req.getRequestURL() + "------>myFilter");
            chain.doFilter(request, response);
        
    }

    public void destroy() {
        // TODO Auto-generated method stub
        
    }
    
}

3.3 查看结果

日志如下:

2017-10-14 22:02:45.209  INFO 11236 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'myFilter' to urls: [/*]
初始化myListener
2017-10-14 22:02:45.748  INFO 11236 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@1a6d8329: startup date [Sat Oct 14 22:02:42 CST 2017]; root of context hierarchy
2017-10-14 22:02:45.866  INFO 11236 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello/freemarker]}" onto public java.lang.String com.springboot.controller.HelloController.freemarker(java.util.Map<java.lang.String, java.lang.Object>)
2017-10-14 22:02:45.873  INFO 11236 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-10-14 22:02:45.874  INFO 11236 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-10-14 22:02:45.933  INFO 11236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-14 22:02:45.933  INFO 11236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-14 22:02:46.028  INFO 11236 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-10-14 22:02:46.354  INFO 11236 --- [           main] o.s.w.s.v.f.FreeMarkerConfigurer         : ClassTemplateLoader for Spring macros added to FreeMarker configuration
2017-10-14 22:02:46.650  INFO 11236 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-10-14 22:02:46.780  INFO 11236 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-10-14 22:02:46.786  INFO 11236 --- [           main] com.springboot.App                       : Started App in 5.249 seconds (JVM running for 5.927)
初始化********** MyServlet
http://localhost:8080/Myservlet------>myFilter
http://localhost:8080/Myservlet------>myFilter

4 通过WebMvcConfigurerAdapter指定拦截器和加载静态文件

4.1 实现WebMvcConfigurerAdapter接口：

package com.springboot.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import com.springboot.intercepter.MyIntercepter1;
import com.springboot.intercepter.MyIntercepter2;


@Configuration
public class MyConfigurerRegister extends WebMvcConfigurerAdapter {
    
    /**
     * 添加拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyIntercepter1()).addPathPatterns("/**");
        registry.addInterceptor(new MyIntercepter2()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
    
    
    /**
     * 加载静态文件
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/image/**")
                .addResourceLocations("classpath:/image/");
        registry.addResourceHandler("/file/**").addResourceLocations("file:D:\\code\\springboot\\springoot\\src\\main\\resources\\image"); //可以直接指定文件路径
        super.addResourceHandlers(registry);
    }

}

4.2 定义拦截器

拦截器1：

package com.springboot.intercepter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class MyIntercepter1 implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("-------MyIntercepter1  preHandle");
        return true;
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("-------MyIntercepter1  postHandle");
        // TODO Auto-generated method stub
        
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("-------MyIntercepter1  afterCompletion");
        // TODO Auto-generated method stub
        
    }

}

拦截器2

package com.springboot.intercepter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class MyIntercepter2 implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        // TODO Auto-generated method stub
        System.out.println("-------MyIntercepter2  preHandle");
        return true;
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("-------MyIntercepter2  postHandle");
        
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        // TODO Auto-generated method stub
        System.out.println("-------MyIntercepter2  afterCompletion");
        
    }

}

4.3 添加静态图片

4.4 运行结果

日志打印：

2017-10-14 23:23:36.147  INFO 16896 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 43 ms
http://localhost:8080/image/my.jpg------>myFilter
http://localhost:8080/image/my.jpg------>myFilter
http://localhost:8080/favicon.ico------>myFilter
http://localhost:8080/image/my.jpg------>myFilter
http://localhost:8080/favicon.ico------>myFilter
http://localhost:8080/image/my.jpg------>myFilter
http://localhost:8080/favicon.ico------>myFilter
http://localhost:8080/image/my.jpg------>myFilter
http://localhost:8080/favicon.ico------>myFilter

注意:

添加静态文件时可以直接指定静态文件的地址。如果不指定静态资源路径则其中默认配置的 /** 映射到 /static （或/public、/resources、/META-INF/resources），默认配置的 /webjars/** 映射到 classpath:/META-INF/resources/webjars/ ，上面的 static、public、resources 等目录都在 classpath: 下面（如 src/main/resources/static）。也可以通过配置文件来配置，不再举列子。

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原文地址：https://www.cnblogs.com/zhangjunqing/p/7668097.html