SpringMVC学习（一）

SpringMVC学习（一）

标签： springmvc

---

之前只是用了servlet+jsp+jdbc来写了一个登录注册程序，现在引入springmvc框架，并详细解释一个简单的springmvc需要哪些东西：

目录结构

---

首先是web.xml配置文件：

将请求交给spring的DispatcherServlet处理

<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">
    <servlet>
        <servlet-name>springmvcservlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
        
        <init-param>
            <param-name>contextConfigLocationparam-name>
            <param-value>/spring/spring-mvc.xmlparam-value>
        init-param>
        
        <load-on-startup>0load-on-startup>
    servlet>
    <servlet-mapping>
        <servlet-name>springmvcservlet-name>
        <url-pattern>/url-pattern>
    servlet-mapping>

    <welcome-file-list>
        <welcome-file>login.jspwelcome-file>
    welcome-file-list>
web-app>

然后是spring-mvc.xml配置文件

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns="http://www.springframework.org/schema/beans"
       xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
        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">

    
    <context:component-scan base-package="controller">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    context:component-scan>

    
    <context:component-scan base-package="service"/>

    
    <mvc:annotation-driven/>

    
    <bean id="viewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/"
          p:suffix=".jsp"/>

    
    <mvc:resources mapping="js/**"   location="/js/"/>
    <mvc:resources mapping="image/**"   location="/image/"/>
beans>

逐条解释

如果不加入
则找不到@controller注释的接口，则会报404错；

如果不加入
则报错@autowired至少需要一个存在bean，你可以手动加上即可,但是如果bean多了的话这样过于麻烦，所以可以配置这句话让spring直接帮你扫描、注入；

是告知Spring，我们启用注解驱动。然后Spring会自动为我们注册上面说到的几个Bean到工厂中，来处理我们的请求。不加会404

视图解析器就是给你找页面文件的，自行加入前缀和后缀

最后静态资源配置是让spring去给定的地方找静态资源，不加会找不到如js等资源。

ps

可以通过修改web.xml的servlet-mapping为其他的来避免这个问题，比如修改为：

<servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

jsp页面同样发送.do请求：

"login.do" method="get" class="my_form" οnsubmit="return validate()">
    ...

---

LoginController

package controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import service.LoginService;

/**
 * Created by Fate on 2016/7/21.
 */
@Controller
public class LoginController {
    @Autowired
    LoginService loginService;

    @RequestMapping(value = "login", method = RequestMethod.GET)
    public ModelAndView login(String username,String password) {
        ModelAndView mv=new ModelAndView("login");
        boolean result = loginService.login(username, password);
        if (result) {
            mv.setViewName("wel");
            return mv;
        }
        String msg = "用户名或密码不正确";
        mv.addObject("msg", msg);
        return mv;
    }
}

RegisterController

package controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import service.RegisterService;

@Controller
public class RegisterController {
    @Autowired
    RegisterService registerService;

    @RequestMapping("register")
    public ModelAndView register(@RequestParam(value = "username", required = false) String user, String password, String age) {
        ModelAndView mv = new ModelAndView("register");
        int ages = 0;
        if (!"".equals(age) && age != null) {
            ages = Integer.parseInt(age);
        }
        if (user == null || password == null) {
            return mv;
        }
        boolean result = registerService.register(user, password, ages);
        if (result) {
            mv.setViewName("wel");
            return mv;
        }
        String msg = "用户已存在";
        mv.addObject("msg", msg);
        return mv;
    }
}

加入@RequestParam可以进行参数重命名等操作绑定（将username改为user），required=false代表参数可以不存在（不加会绑定参数失败：Required String parameter ‘username’ is not present）。

不加这个注解的话spring会默认绑定名字一样的参数

需要的jar包：