SpringMVC大威天龙

一 SpringMVC简介

SpringMVC是Spring提供的一个强大而灵活的Web框架 借助于注解 SpringMVC提供了几乎是POJO的开发模式 使得控制器的开发和测试更加简单

 

二 SpringMVC优点

1. 角色划分清晰

2. 分工明确 而且扩展相当灵活

3. 和Spring其它框架无缝集成 是其它Web框架所不具备的

4. 功能强大的数据验证 格式化 绑定机制

5. 约定大于配置的契约式编程支持 基于注解的零配置支持等等

 

三 SpringMVC框架核心

DispatcherServlet 前端控制器

用户请求到达前端控制器 它就相当于MVC模式中的C DispatcherServlet是整个流程控制的中心 由它调用其它组件处理用户的请求 DispatcherServlet的存在降低了组件之间的耦合性

HandlerMapping 处理器映射器

SpringMVC三大组件之一 HandlerMapping负责根据用户请求URL找到Handler即处理器 SpringMVC提供了不同的映射器实现不同的映射方式 比如配置文件方式 实现接口方式 注解方式等等

Handler 处理器

Handler是继DispatcherServlet前端控制器的后端控制器 在DispatcherServlet的控制下Handler对具体的用户请求进行处理 由于Handler涉及到具体的用户业务请求 所以一般情况需要程序员根据业务需求开发Handler

HandlAdapter 处理器适配器

SpringMVC三大组件之一 通过HandlerAdapter对处理器进行执行 这是适配器模式的应用 通过扩展适配器可以对更多类型的处理器进行执行

ViewResolver 视图解析器

SpringMVC三大组件之一 ViewResolver负责将处理结果生成View视图 ViewResolver首先根据逻辑视图名解析成物理视图名即具体的页面地址 再生成View视图对象 最后对View进行渲染将处理结果通过页面展示给用户

View 视图

SpringMVC提供了很多View视图类型的支持 比如FreemarkerView PDFView等等 最常用的视图就是JSP 一般情况下需要通过页面标签或页面模版技术将模型数据通过页面展示给用户 需要程序员根据业务需求开发具体的页面

 

四 SpringMVC初体验

1. 新建一个Maven项目

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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.hy.springmvc</groupId>
    <artifactId>springmvc-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <!-- 定义依赖版本号 -->
    <properties>
        <javax.servlet-api.version>4.0.1</javax.servlet-api.version>
        <jsp-api.version>2.0</jsp-api.version>
        <jstl.version>1.2</jstl.version>
        <spring.version>5.0.5.RELEASE</spring.version>
        <jackson-databind.version>2.9.5</jackson-databind.version>
        <commons-fileupload.version>1.3.3</commons-fileupload.version>
    </properties>

    <!-- 管理jar版本号 -->
    <dependencyManagement>
        <dependencies>
            <!-- servlet -->
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>${javax.servlet-api.version}</version>
                <scope>provided</scope>
            </dependency>
            <!-- jsp -->
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>jsp-api</artifactId>
                <version>${jsp-api.version}</version>
                <scope>provided</scope>
            </dependency>
            <!-- jstl -->
            <dependency>
                <groupId>jstl</groupId>
                <artifactId>jstl</artifactId>
                <version>${jstl.version}</version>
            </dependency>
            <!-- spring -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-jdbc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-aspects</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-jms</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context-support</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- jackson(spring mvc need) -->
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>${jackson-databind.version}</version>
            </dependency>
            <!-- fileupload(spring mvc need) -->
            <dependency>
                <groupId>commons-fileupload</groupId>
                <artifactId>commons-fileupload</artifactId>
                <version>${commons-fileupload.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <!-- servlet -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- jsp -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jsp-api</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- jstl -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
        </dependency>
        <!-- spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jms</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
        </dependency>
        <!-- jackson(spring mvc need) -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <!-- fileupload(spring mvc need) -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- 编译 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.7.0</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <!-- tomcat7 -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <port>8080</port>
                    <path>/</path>
                    <uriEncoding>UTF-8</uriEncoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2. 新建webapp文件夹及子文件夹和web.xml

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <!-- 处理POST提交乱码 -->
    <filter>
        <filter-name>characterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>characterEncodingFilter</filter-name>
        <!-- 拦截所有 -->
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 前端控制器 -->
    <servlet>
        <servlet-name>spring-mvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:/spring-mvc.xml</param-value>
        </init-param>
        <!-- 配置SpringMVC启动时机
                1. 第一次被访问时启动 值为负数
                2. 随着容器启动而启动 值为0或正数 -->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring-mvc</servlet-name>
        <!-- 拦截所有(不包含jsp 包含js png css...) -->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

3. 创建jsp webapp/WEB-INF/jsp/index.jsp webapp/WEB-INF/jsp/success.jsp webapp/WEB-INF/jsp/exception.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <script type="text/javascript" src="http://code.jquery.com/jquery-1.4.1.min.js"></script>
    <script type="text/javascript">
        var param = '{"name":"祎哥哥", "age":18}';
        function json() {
            $.ajax({
                url: "${pageContext.request.contextPath}/test/postBody",
                data: param,
                contentType: "application/json;charset=UTF-8",
                type: "post",
                dataType: "json",
                success: function (data) {
                    alert(data.name + ", " + data.age);
                }
            });
        }
    </script>
</head>
<body>

<h3>初体验</h3>

${message}<br/><br/>

<a href="${pageContext.request.contextPath}/test/forward">转发</a><br/><br/>

<a href="${pageContext.request.contextPath}/test/redirect">重定向</a><br/><br/>

<a href="${pageContext.request.contextPath}/test/error">异常处理</a><br/><br/>

<a href="${pageContext.request.contextPath}/test/get?name=hy&age=18">GET请求 /test/get?name=hy&age=18</a><br/><br/>

<a href="${pageContext.request.contextPath}/test/getPath/黄祎">GET请求 /test/getPath/黄祎</a><br/><br/>

<p>普通表单 普通类型参数绑定 List类型参数绑定</p>
<form action="${pageContext.request.contextPath}/test/postList" method="post">
    姓名 <input type="text" name="name"/><br/>
    年龄 <input type="text" name="age"/><br/>
    爱好 <input type="checkbox" name="hobby" value="1"/>红中
    <input type="checkbox" name="hobby" value="2"/>发财
    <input type="checkbox" name="hobby" value="3"/>白板<br/>
    <input type="submit" value="提交"/>
</form>

<p>普通表单 普通类型参数绑定 数组类型参数绑定</p>
<form action="${pageContext.request.contextPath}/test/postArray" method="post">
    姓名 <input type="text" name="name"/><br/>
    年龄 <input type="text" name="age"/><br/>
    爱好 <input type="checkbox" name="hobby" value="1"/>红中
    <input type="checkbox" name="hobby" value="2"/>发财
    <input type="checkbox" name="hobby" value="3"/>白板<br/>
    <input type="submit" value="提交"/>
</form>

<p>普通表单 Model类型参数绑定</p>
<form action="${pageContext.request.contextPath}/test/postModel" method="post">
    姓名 <input type="text" name="name"/><br/>
    年龄 <input type="text" name="age"/><br/>
    爱好 <input type="checkbox" name="hobby" value="1"/>红中
    <input type="checkbox" name="hobby" value="2"/>发财
    <input type="checkbox" name="hobby" value="3"/>白板<br/>
    <input type="submit" value="提交"/>
</form>

<p>文件表单 单文件</p>
<form action="${pageContext.request.contextPath}/test/postSingleFile" enctype="multipart/form-data" method="post">
    姓名 <input type="text" name="name"/><br/>
    文件 <input type="file" name="file"/><br/>
    <input type="submit" value="提交"/>
</form>

<p>文件表单 多文件</p>
<form action="${pageContext.request.contextPath}/test/postMoreFile" enctype="multipart/form-data" method="post">
    姓名 <input type="text" name="name"/><br/>
    文件 <input type="file" name="file"/>
    <input type="file" name="file"/><br/>
    <input type="submit" value="提交"/>
</form>

<input type="button" value="请求体是json格式字符串" onclick="json()"/>

</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<h3>成功了</h3>

${user.toString()}

</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<h3>出错了</h3>

${error.toString()}

</body>
</html>

4. 配置常量 resources/resource.properties

### 常量 ###
NAME=HUANGYI

5. 创建配置文件 resources/spring-mvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context-4.2.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd">

    <!-- 引入配置文件 -->
    <context:property-placeholder location="classpath:*.properties" />

    <!-- 扫描的位置 -->
    <context:component-scan base-package="com.hy.springmvc.controller" />

    <!-- 注解驱动 -->
    <mvc:annotation-driven />

    <!-- 文件上传实现类 id名称必须固定 -->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 默认编码 -->
        <property name="defaultEncoding" value="UTF-8" />
        <!-- 文件上传大小(单位B) 5M = 5 * 1024 * 1024 -->
        <property name="maxUploadSize" value="5242880" />
    </bean>

    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!-- 逻辑视图前缀 -->
        <property name="prefix" value="/WEB-INF/jsp" />
        <!-- 逻辑视图后缀 -->
        <property name="suffix" value=".jsp" />
    </bean>

    <!-- 加载静态资源 -->
    <mvc:default-servlet-handler />

    <!-- 拦截器 -->
    <mvc:interceptors>
        <mvc:interceptor>
            <!-- 拦截所有 -->
            <mvc:mapping path="/**" />
            <bean class="com.hy.springmvc.interceptor.Interceptor" />
        </mvc:interceptor>
        <!-- 多个拦截器 拦截器会顺序执行 -->
        <!--<mvc:interceptor>-->
        <!--<mvc:mapping path="/**" />-->
        <!--<bean />-->
        <!--</mvc:interceptor>-->
    </mvc:interceptors>

    <!-- 异常处理器 -->
    <bean class="com.hy.springmvc.exception.HttpErrorResolver" />
</beans>

6. 创建实体类 com.hy.springmvc.model.User com.hy.springmvc.model.HttpError

public class User {

    private String name;
    private Integer age;
    private Integer[] hobby;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer[] getHobby() {
        return hobby;
    }

    public void setHobby(Integer[] hobby) {
        this.hobby = hobby;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", hobby=" + Arrays.toString(hobby) +
                '}';
    }
}

public class HttpError extends Exception {

    private int code;
    private String message;

    public HttpError() {}

    public HttpError(int code, String message) {
        this.code = code;
        this.message = message;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    @Override
    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return "HttpError{" +
                "code=" + code +
                ", message='" + message + '\'' +
                '}';
    }
}

7. 创建拦截器 com.hy.springmvc.interceptor.Interceptor

public class Interceptor implements HandlerInterceptor {

    // Controller执行前调用此方法
    // 返回true继续执行 返回false中止执行
    // 这里可加入登录校验 权限拦截等
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println(" ========== preHandle ========== ");
        // 放行
        return true;
    }

    // Controller执行后 且未返回视图前 调用此方法
    // 这里可在返回用户前对模型数据进行加工处理 比如这里加入公用信息以便页面显示
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {}

    // Controller执行后 且视图返回后 调用此方法
    // 这里可得到执行Controller时的异常信息
    // 这里可记录操作日志
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {}
}

8. 创建异常处理器 com.hy.springmvc.exception.HttpErrorResolver

public class HttpErrorResolver implements HandlerExceptionResolver {

    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object o, Exception e) {
        // Object o 发生异常的具体位置
        System.out.println("resolveException = " + o.toString());
        // 写日志记录 发邮件提醒

        if (System.currentTimeMillis() % 2 == 0) {
            /** 有视图 **/
            HttpError error = e instanceof HttpError ? (HttpError) e : new HttpError(-1, "未知异常");
            ModelAndView view = new ModelAndView();
            view.addObject("error", error);
            view.setViewName("/exception");
            return view;

        } else {
            /** 无视图 **/
            HttpError error = e instanceof HttpError ? (HttpError) e : new HttpError(-1, "未知异常");
            try {
                response.setContentType("text/html;charset=UTF-8"); //解决返回中的中文乱码
                PrintWriter writer = response.getWriter();
                writer.write(error.toString());
                writer.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            return null;
        }
    }
}

9. 创建控制器 com.hy.springmvc.controller.TestController

@Controller
@RequestMapping("/test")
public class TestController {

    @Value("${NAME}")
    private String NAME;

    /**
     * @param model Model
     * @param accept @RequestHeader 获取指定请求头的值
     * @return 资源路径
     */
    @RequestMapping("/index")
    public String index(Model model, @RequestHeader("Accept") String accept) {
        model.addAttribute("message", NAME + " " + accept);
        return "/index";
    }

    /**
     * 转发
     * @return Mapping路径
     */
    @RequestMapping("/forward")
    public String forward() {
        return "forward:index";
    }

    /**
     * 重定向
     * @return Mapping路径
     */
    @RequestMapping("/redirect")
    public String redirect() {
        return "redirect:index";
    }

    /**
     * 异常处理
     * @return 资源路径
     */
    @RequestMapping("/error")
    public String error() {
        int i = 1 / 0; //模拟异常
        return "/index";
    }

    /**
     * @RequestMapping 作用在类上=第一级访问目录 作用在方法上=第二级访问目录
     * path=指定请求路径 path=指定请求方法 params=指定限制请求参数的条件 headers=指定限制请求头的条件
     * @param model Model
     * @param name 普通类型参数绑定
     * @param age @RequestParam 把请求中指定名称的参数传递给控制器中形参赋值
     *            name=请求参数中的名称 required=请求参数中是否必须提供此参数 defaultValue=默认值
     * @return 资源路径
     */
    @RequestMapping(path = "/get", method = RequestMethod.GET)
    public String get(Model model, String name, @RequestParam(name = "age", required = true, defaultValue = "0") Integer age) {
        User user = new User();
        user.setName(name);
        user.setAge(age);
        model.addAttribute("user", user);
        return "/success";
    }

    /**
     * @param model Model
     * @param name @PathVariable 绑定url中的占位符
     * @return 资源路径
     */
    @GetMapping("/getPath/{name}")
    public String getPath(Model model, @PathVariable String name) {
        User user = new User();
        user.setName(name);
        model.addAttribute("user", user);
        return "/success";
    }

    /**
     * @ResponseBody 将方法的返回值 以特定格式写入到响应体
     * @param name 普通类型参数绑定
     * @param age 普通类型参数绑定
     * @param hobby List类型参数绑定 必须添加@RequestParam
     * @return json格式字符串
     */
    @PostMapping("/postList")
    @ResponseBody
    public User postList(String name, Integer age, @RequestParam List<Integer> hobby) {
        Integer[] array = hobby.toArray(new Integer[0]);
        User user = new User();
        user.setName(name);
        user.setAge(age);
        user.setHobby(array);
        return user;
    }

    /**
     * @param name 普通类型参数绑定
     * @param age 普通类型参数绑定
     * @param hobby 数组类型参数绑定
     * @return json格式字符串
     */
    @PostMapping("/postArray")
    @ResponseBody
    public User postArray(String name, Integer age, Integer[] hobby) {
        User user = new User();
        user.setName(name);
        user.setAge(age);
        user.setHobby(hobby);
        return user;
    }

    /**
     * @param user Model类型参数绑定
     * @return json格式字符串
     */
    @PostMapping("/postModel")
    @ResponseBody
    public User postModel(User user) {
        return user;
    }

    /**
     * @param request HttpServletRequest
     * @param name 普通类型参数绑定
     * @param file 单文件
     * @return json格式字符串
     * @throws Exception 异常
     */
    @PostMapping("/postSingleFile")
    @ResponseBody
    public User postSingleFile(HttpServletRequest request, String name, MultipartFile file) throws Exception {
        String path = saveFile(request, file);
        User user = new User();
        user.setName(name + ", " + path);
        return user;
    }

    /**
     * @param request HttpServletRequest
     * @param name 普通类型参数绑定
     * @param file 多文件
     * @return json格式字符串
     * @throws Exception 异常
     */
    @PostMapping("/postMoreFile")
    @ResponseBody
    public User postMoreFile(HttpServletRequest request, String name, MultipartFile[] file) throws Exception {
        StringBuilder builder = new StringBuilder();
        if (null != file && 0 != file.length) {
            for (MultipartFile multipartFile : file) {
                String path = saveFile(request, multipartFile);
                builder.append(" ").append(path);
            }
        }
        User user = new User();
        user.setName(name + "," + builder.toString());
        return user;
    }

    /**
     * @param user @RequestBody 用于获取请求体的内容
     * @return json格式字符串
     */
    @PostMapping("/postBody")
    @ResponseBody
    public User postBody(@RequestBody User user) {
        return user;
    }

    private String saveFile(HttpServletRequest request, MultipartFile file) throws Exception {
        if (null != file && !file.isEmpty()) {
            String fileName = UUID.randomUUID().toString().replace("-", ""); //文件名
            String originalFilename = file.getOriginalFilename();
            String substring = originalFilename.substring(originalFilename.lastIndexOf("."));
            String path = request.getServletContext().getRealPath("/upload") + "/" + fileName + substring;
            file.transferTo(new File(path));
            return path;
        }
        return "";
    }
}

启动项目 访问 http://localhost:8080/test/index