零配置文件搭建SpringMvc

零配置文件搭建SpringMvc

SpringMvc 流程原理

（1）用户发送请求至前端控制器DispatcherServlet；
（2） DispatcherServlet收到请求后，调用HandlerMapping处理器映射器，请求获取Handle；
（3）处理器映射器根据请求url找到具体的处理器，生成处理器对象及处理器拦截器(如果有则生成)一并返回给DispatcherServlet；
（4）DispatcherServlet通过HandlerAdapter处理器适配器调用处理器；
（5）执行处理器(Handler，也叫后端控制器)；
（6）Handler执行完成返回ModelAndView；
（7）HandlerAdapter将Handler执行结果ModelAndView返回给DispatcherServlet；
（8）DispatcherServlet将ModelAndView传给ViewResolver视图解析器进行解析；
（9）ViewResolver解析后返回具体View；
（10）DispatcherServlet对View进行渲染视图（即将模型数据填充至视图中）
（11）DispatcherServlet响应用户。

Spring MVC的主要组键

（1）前端控制器 DispatcherServlet（不需要程序员开发）
作用：接收请求、响应结果 相当于转发器，有了DispatcherServlet 就减少了其它组件之间的耦合度。
（2）处理器映射器HandlerMapping（不需要程序员开发）
作用：根据请求的URL来查找Handler
（3）处理器适配器HandlerAdapter
注意：在编写Handler的时候要按照HandlerAdapter要求的规则去编写，这样适配器HandlerAdapter才可以正确的去执行Handler。
（4）处理器Handler（需要程序员开发）
（5）视图解析器 ViewResolver（不需要程序员开发）
作用：进行视图的解析 根据视图逻辑名解析成真正的视图（view）
（6）视图View（需要程序员开发jsp）
View是一个接口， 它的实现类支持不同的视图类型（jsp，freemarker，pdf等等）

零配置文件搭建SpringMVC Start

1、pom文件：

<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.wisely</groupId>
    <artifactId>highlight_springmvc4</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <!-- Generic properties -->
        <java.version>1.7</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <!-- Web -->
        <jsp.version>2.2</jsp.version>
        <jstl.version>1.2</jstl.version>
        <servlet.version>3.1.0</servlet.version>
        <!-- Spring -->
        <spring-framework.version>4.1.5.RELEASE</spring-framework.version>
        <!-- Logging -->
        <logback.version>1.0.13</logback.version>
        <slf4j.version>1.7.5</slf4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- Spring MVC -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring-framework.version}</version>
        </dependency>

        <!-- 其他web依赖 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlet.version}</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>${jsp.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- Spring and Transactions -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring-framework.version}</version>
        </dependency>

        <!-- 使用SLF4J和LogBack作为日志 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-access</artifactId>
            <version>${logback.version}</version>
        </dependency>

        <!--对json和xml格式的支持 -->
        <dependency>
            <groupId>com.fasterxml.jackson.dataformat</groupId>
            <artifactId>jackson-dataformat-xml</artifactId>
            <version>2.5.3</version>
        </dependency>

        <!-- file upload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>
        <!-- 非必需，可简化IO操作 -->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.3</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring-framework.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2、MVC 配置Bean

import com.wisely.mypractice.interceptor.MyInterceptor;
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.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

@Configuration
//开启Mvc功能
@EnableWebMvc
//扫包
@ComponentScan("com.wisely.mypractice")
public class MyMvcConfig extends WebMvcConfigurerAdapter {

    //配置视图解析器
    @Bean
    public InternalResourceViewResolver viewResolver(){
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/classes/views/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        return viewResolver;
    }

    //配置静态文件路径(直接访问)
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry){
        registry.addResourceHandler("/assets/**").addResourceLocations("classpath:/inde/");
    }

    //将拦截器Bean纳入spring管理
    @Bean
    public MyInterceptor demoInterceptor(){
        return  new MyInterceptor();
    }

    //配置 拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry){
        registry.addInterceptor(demoInterceptor());
    }

    //设置文件上传最大字节
    @Bean
    public MultipartResolver multipartResolver(){
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
        multipartResolver.setMaxUploadSize(1000000);
        return  multipartResolver;
    }
}

3、拦截器Bean

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

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

public class MyInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler){
        long startTime = System.currentTimeMillis();
        request.setAttribute("startTime",startTime);
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView){
        long startTime = (Long)request.getAttribute("startTime");
        request.removeAttribute("startTime");
        long endTime = System.currentTimeMillis();
        System.out.println("本次请求处理时间为："+ new Long(endTime-startTime) + "ms");
        request.setAttribute("handlingTime",endTime - startTime);
    }
}

3、配置 WebApplicationInitializer  实现类 (项目启动会自动加载该类的实现类)

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

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

public class WebInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.register(MyMvcConfig.class);
        context.setServletContext(servletContext);

        ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher",new DispatcherServlet(context));
        //映射路径
        servlet.addMapping("/");
        servlet.setLoadOnStartup(1);
    }
}

4、拦截器

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

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

public class MyInterceptor extends HandlerInterceptorAdapter {

    //请求前执行
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler){
        long startTime = System.currentTimeMillis();
        request.setAttribute("startTime",startTime);
        return true;
    }

    //请求后执行
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView){
        long startTime = (Long)request.getAttribute("startTime");
        request.removeAttribute("startTime");
        long endTime = System.currentTimeMillis();
        System.out.println("本次请求处理时间为："+ new Long(endTime-startTime) + "ms");
        request.setAttribute("handlingTime",endTime - startTime);
    }
}

5、全局配置

import org.springframework.ui.Model;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.ModelAndView;

@ControllerAdvice
public class MyAdvice {

    //异常处理类( Exception.class 异常类型 ) 可以定义多个
    @ExceptionHandler(value = Exception.class)
    public ModelAndView exception(Exception exception, WebRequest request){
        ModelAndView modelAndView = new ModelAndView("error");
        modelAndView.addObject("errorMessage",exception.getMessage());
        return modelAndView;
    }

    //所有RequestMapping方法上 可以通过 ModelAttribute 形式获取值
    @ModelAttribute
    public void addAttributes(Model model){
        model.addAttribute("msg","额外信息");
    }

    //忽略请求属性(只针对用Bean接受)
    @InitBinder
    public void initBinder(WebDataBinder webDataBinder){
        webDataBinder.setDisallowedFields("id");
    }

}

6、Controller 控制器

import com.wisely.mypractice.domain.MyObj;
import org.apache.commons.io.FileUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;

@Controller
public class HelloController {

    @RequestMapping("/index")
    public String hello(){
        return "index";
    }

    @RequestMapping("/uploadToPage")
    public String uploadToPage(){
        return "upload";
    }

    @RequestMapping(value = "upload",method = RequestMethod.POST)
    public String upload(MultipartFile file){
        try{
            FileUtils.writeByteArrayToFile(new File("D:\\test\\"+file.getOriginalFilename()),file.getBytes());
            return "ok";
        }catch (IOException e){
            e.printStackTrace();
            return "wrong";
        }
    }

    @RequestMapping("/advice")
    public String getSomething(@ModelAttribute("msg") String msg,
                               MyObj obj){
        System.out.println("id：" + obj.getId());
        System.out.println("name：" + obj.getName());
        throw new IllegalArgumentException("非常抱歉，参数有误来自@ModelAttribute：" + msg);
    }

}

TODO：

　　1)、页面我没有进行 copy 到帖子里 自己编写一些简单页面就可以了

　　2)、代码暂时没放到 GitHab 上 我研究一下 弄好了会修改帖子给出下载路径(只要配上页面 代码完全是好用的哦 )

　　3)、个人 QQ 1036943655 有什么技术上见解 可以一起互相学习 毕竟本人会的也不多

　　4)、所有知识点借鉴于 Spring Boot 实战 （书）