大数据正式33

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大数据正式33

SpringMVC

Servlet缺点
1. 一个Servlet有8行配置文件
2. 一个Servlet只能处理一个业务
3. 一张表可能有4+n个Servlet，所以会有32+n行配置文件
4. 获取属性只能得到字符串类型，需要自己转换类型
5. 获取参数只能是request.getParameter()
SpringMVC优点
1. 不管工程中有多少servlet，只需要配置一个servlet分发器即可
2. springmvc中使用controller替代一个controller
3. 获取参数的类型支持自动装换，而且支持对象的自动封装
4. SpringMvc有多种获取参数的方式

SprigMVC入门案例

jar包
项目结构
整体流程

代码

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">    <!-- servlet分发器 -->    <servlet>        <servlet-name>springmvc</servlet-name>        <!-- 分发器 -->        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <!-- 注入配置文件的地址：创建spring容器 -->        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:/applicationContext-mvc.xml</param-value>        </init-param>    </servlet>    <servlet-mapping>        <servlet-name>springmvc</servlet-name>        <!-- /或*.action -->        <url-pattern>*.action</url-pattern>    </servlet-mapping>    <welcome-file-list>        <welcome-file>index.jsp</welcome-file>    </welcome-file-list></web-app>

applicationContext-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:aop="http://www.springframework.org/schema/aop" 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-3.2.xsd    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd ">    <!-- 扫描包 -->    <context:component-scan base-package="com.peng"></context:component-scan>    <!-- 扫描注解 -->    <context:annotation-config></context:annotation-config>    <bean name="/hello.action" class="com.peng.controller.HelloController"></bean></beans>

com.peng.controller

HelloController

package com.peng.controller;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.Controller;public class HelloController implements Controller {    public ModelAndView handleRequest(HttpServletRequest request,            HttpServletResponse response) throws Exception {        ModelAndView modelAndView = new ModelAndView();        modelAndView.setViewName("index.jsp");        modelAndView.addObject("msg", "hello");        return modelAndView;    }}

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%    String path = request.getContextPath();    String basePath = request.getScheme() + "://"            + request.getServerName() + ":" + request.getServerPort()            + path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--    <link rel="stylesheet" type="text/css" href="styles.css">    --></head><body>    This is my JSP page.    <br>    <h1>${msg}</h1></body></html>

访问名称
- http://localhost/SpringMVC_inroom/hello.action（注：端口为80）
执行结果

注解形式的SpringmMVC

package com.peng.controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;@Controllerpublic class HelloController {    @RequestMapping("/hello.action")    public String helloAction(Model model) {        model.addAttribute("msg", "hello,world!");        return "index";    }}

<?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:aop="http://www.springframework.org/schema/aop"    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-3.2.xsd    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd     http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd ">    <!-- 扫描包 -->    <context:component-scan base-package="com.peng"></context:component-scan>    <!-- 扫描注解 -->    <context:annotation-config></context:annotation-config>    <!-- SpringMVC的注解开关 -->    <mvc:annotation-driven></mvc:annotation-driven>    <!-- 资源解析器 -->    <bean        class="org.springframework.web.servlet.view.InternalResourceViewResolver">        <property name="prefix" value="/WEB-INF/"></property>        <property name="suffix" value=".jsp"></property>    </bean></beans>

添加前后缀的SpringMVC(applicationContext-mvc.xml)

<!-- 资源解析器 --><bean    class="org.springframework.web.servlet.view.InternalResourceViewResolver">    <property name="prefix" value="/WEB-INF/"></property>    <property name="suffix" value=".jsp"></property></bean>

解决乱码--过滤器(web.xml)

<!-- 乱码过滤器 -->    <filter>        <filter-name>characterFilter</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>characterFilter</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>

数据的获取

HttpServletRequest对象的getParameter方法

package com.peng.controller;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;@Controllerpublic class UserController {    @RequestMapping("/showAddUser.action")    public String showAddUser() {        return "addUser";    }    @RequestMapping("/addUser.action")    public String addUser(HttpServletRequest request, Model model) {        String username = request.getParameter("username");        System.out.println(username);        model.addAttribute("username", username);        return "addUser";    }}

与表单的name值一样的参数String username

参数名来控制

package com.peng.controller;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;@Controllerpublic class UserController {    @RequestMapping("/showAddUser.action")    public String showAddUser() {        return "addUser";    }    @RequestMapping("/addUser.action")    public String addUser(String username, Model model) {        System.out.println(username);        model.addAttribute("username", username);        return "addUser";    }}

bean对象 User

参数名来控制

package com.peng.controller;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;@Controllerpublic class UserController {    @RequestMapping("/showAddUser.action")    public String showAddUser() {        return "addUser";    }    @RequestMapping("/addUser.action")    public String addUser(User user, Model model) {        System.out.println(user.username);        model.addAttribute("username", user.username);        return "addUser";    }}

对象中的对象

参数名来控制

dog.name

gog.age

class Dog{    private String name;    public void setName(String name){        this.name=name;    }    public String getName(){        return this.name;    }}

class User{    private dog;    public void setDog(Dog dog{        this.dog=dog;    }    public Dog getDog(){        return this.dog;    }}

package com.peng.controller;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;@Controllerpublic class UserController {    @RequestMapping("/showAddUser.action")    public String showAddUser() {        return "addUser";    }    @RequestMapping("/addUser.action")    public String addUser(String username, Model model) {        System.out.println(user.dog.name);        model.addAttribute("username", user.dog.name);        return "addUser";    }}

日期问题

格式问题

2017/12/25这个错误；2017-12-25这个可以；

解决（Controller中）

@InitBinder    public void InitBinder(ServletRequestDataBinder srdb) {        srdb.registerCustomEditor(java.util.Date.class, new CustomDateEditor(                new SimpleDateFormat("yyyy-MM-dd"), true));    }

参数的同名提交

String
```
a,b,c
```

例子

@RequestMapping("/addUser.action")public String addUser(        HttpServletRequest request,        Model model,        Date date,        String like) {    String username = request.getParameter("username");    System.out.println(username + date.toString() + like);    model.addAttribute("username", username);    return "addUser";}

String[]
```
{a,b,c}数组形式
```

例子

@RequestMapping("/addUser.action")public String addUser(        HttpServletRequest request,        Model model,        Date date,        String[] like) {    String username = request.getParameter("username");    System.out.println(username + date.toString() + Arrays.toString(like));    model.addAttribute("username", username);    return "addUser";}

参数名称不一致的问题

问题呈现
- form表单提交过来的name和参数中的name值不相同时--因为要见名知义，稍微改动了参数的名称
@RequestParam("hobby")String[] hobbies
@RequestParam
- value--对应form中的name值
- defaultValue--默认的值
- require--必须传过来时有参数

例子

@RequestMapping("/addUser.action")public String addUser(        HttpServletRequest request,        Model model,        Date date,        @RequestParam(value = "like", defaultValue = "啥也不喜欢！") String[] likes) {    String username = request.getParameter("username");    System.out.println(username + date.toString() + Arrays.toString(likes));    model.addAttribute("username", username);    return "addUser";}

文件上传

注意的坑
1. form中的参数
  1. method：post
  2. enctype：multipart/form-data
2. file文件标签
  1. 必须有name属性
3. 文件解析器
  1. 必须有id属性
  2. id属性的值必须是：multipartResolver

改三个地方

jsp中

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><!DOCTYPE HTML ><html><head><title>Add User</title></head><body bgcolor="#0000ff" text="#ffffff">    <form action="addUser.action" method="POST"        enctype="multipart/form-data">        <table border="1">            <tr>                <td>用户名：</td>                <td><input type="text" name="username" />                </td>            </tr>            <tr>                <td>时间：</td>                <td><input type="date" name="date" />                </td>            </tr>            <tr>                <td>上传文件：</td>                <td><input type="file" name="file" />                </td>            </tr>            <tr>                <td>爱好：</td>                <td>篮球<input type="checkbox" name="like" value="basketball" />                    足球<input type="checkbox" name="like" value="football" /> 乒乓球<input                    type="checkbox" name="like" value="pingpangball" />            </tr>            <tr>                <td>提交：</td>                <td><input type="submit" value="确认" />                </td>            </tr>        </table>    </form></body></html>

解析器（必须有id和class）

<!-- 文件上传解析器 -->    <bean id="multipartResolver"        class="org.springframework.web.multipart.commons.CommonsMultipartResolver">        <property name="defaultEncoding" value="utf-8"></property>        <property name="maxUploadSize" value="10485760000"></property>        <property name="maxInMemorySize" value="40960"></property>    </bean>

后台

package com.peng.controller;import java.io.File;import java.io.IOException;import java.text.SimpleDateFormat;import org.apache.commons.io.FileUtils;import org.springframework.beans.propertyeditors.CustomDateEditor;import org.springframework.stereotype.Controller;import org.springframework.web.bind.ServletRequestDataBinder;import org.springframework.web.bind.annotation.InitBinder;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.multipart.MultipartFile;@Controllerpublic class UserController {    @RequestMapping("/showAddUser.action")    public String showAddUser() {        return "addUser";    }    @RequestMapping("/addUser.action")    public String addUser(@RequestParam MultipartFile file) throws IOException {        FileUtils.writeByteArrayToFile(new File(                "C:\\Users\\Administrator.PC-20160710IJPJ\\Desktop\\haha.png"),                file.getBytes());        System.out.println(file.toString());        return "addUser";    }    @InitBinder    public void InitBinder(ServletRequestDataBinder srdb) {        srdb.registerCustomEditor(java.util.Date.class, new CustomDateEditor(                new SimpleDateFormat("yyyy-MM-dd"), true));    }}

请求和重定向

默认是转发
重定向--不能直接写界面，尤其是WEB-INF下的界面
```
return "redirect:请求"return "redirect:addUser.action"
```

补充

阅读全文

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