SpringMVC入门

SpringMVC

快速入门

jar包
- commons-logging-1.1.3.jar
- spring-aop-4.0.0.RELEASE.jar
- spring-beans-4.0.0.RELEASE.jar
- spring-context-4.0.0.RELEASE.jar
- spring-core-4.0.0.RELEASE.jar
- spring-expression-4.0.0.RELEASE.jar
- spring-web-4.0.0.RELEASE.jar
- spring-webmvc-4.0.0.RELEASE.jar

在web.xml中配置DispatcherServlet

    <servlet>
     <servlet-name>dispatcherServlet</servlet-name>
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <init-param>
         <param-name>contextConfigLocation</param-name>
         <param-value>classpath:springMVC.xml</param-value>
     </init-param>
 </servlet>
 <servlet-mapping>
     <servlet-name>dispatcherServlet</servlet-name>
     <url-pattern>/</url-pattern>
 </servlet-mapping>

mvc.xml文件中配置

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:context="http://www.springframework.org/schema/context"
     xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context.xsd">
     <!--注解扫描-->
     <context:component-scan base-package="com.*"></context:component-scan>
     <!--配置视图解析器-->
     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/"></property>
         <property name="suffix" value=".jsp"></property>
     </bean>
 </beans>

编写Controller层标识

    package com.Controller;

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

    /**
    * @author Jamin <br>
    * @date 2019/3/28 14:35 <br>
    *     controller层
    */
    @Controller
    public class UserController {

    /**
    * helloword
    *
    * @return index页面
    */
    @RequestMapping(value = "/hello")
    public String hello() {
        System.out.println("Hello World");
        return "index";
    }
    }

获取数据

@RequestMapping:支持Ant风格资源地址
* – ?：匹配文件名中的一个字符
* – *：匹配文件名中的任意字符
* – ：匹配多层路径

@PathVarivable:将URL中的占位符参数绑定到控制台的处理方法的入参中

    @Controller
public class UserController {
/**
* helloword
*
* @return index页面
*/
@RequestMapping(value = "/hello}")
public String hello(@RequestParam(value = "name", required = false) String name) {
    System.out.println("Hello World");
    return "index";
}
}

@RequestParm

    @Controller
public class UserController {
/**
* helloword
*
* @return index页面
*/
@RequestMapping(value = "/hello}")
public String hello(@RequestParam(value = "name", required = false) String name) {
    System.out.println("Hello World");
    return "index";
}
}

@RequestHeader

 @Controller
 public class UserController {
 /**
 * helloword
 *
 * @return index页面
 */
 @RequestMapping(value = "/hello}")
 public String hello(@RequestHeader(value = "Host") String header) {
     System.out.println("Hello World" + header);
     return "index";
 }
 }

@CookieValue

    @Controller
public class UserController {
/**
* helloword
*
* @return index页面
*/
@RequestMapping(value = "/hello}")
public String hello(@CookieValue(value = "JSESSIONID") String cookie) {
    System.out.println("Hello World" + cookie);
    return "index";
}
}

使用 Servlet API 作为入参

HttpServletRequest
HttpServletResponse
HttpSession
java.security.Principa
Locale
InputStream
OutputStream
Reader
Writer

 @Controller
 public class UserController {
 /**
 * helloword
 *
 * @return index页面
 */
 @RequestMapping(value = "/hello}")
 public String hello(HttpServletRequest request) {
     System.out.println("Hello World");
     String name = request.getParameter("name");
     System.out.println(name);
     return "index";
 }
 }

输出数据

ModelAndView

    @Controller
public class UserController {
/**
* helloword
*
* @return index页面
*/
@RequestMapping("/hello")
public ModelAndView hello() {
    ModelAndView mav = new ModelAndView();
    mav.addObject("name","张三");
    mav.addObject("age","12");
    mav.setViewName("index");
    return mav;
}
}

Model

 @Controller
 public class UserController {
 /**
 * helloword
 *
 * @return index页面
 */
 @RequestMapping("/hello")
 public String hello(Model model) {
 model.addAttribute("name","zhangsan");
     return "index";
 }
 }

@SessionAttributes 赋值方法是同名赋值

 @SessionAttributes(value = "user")
 @Controller
 public class UserController {
 /**
 * helloword
 *
 * @return index页面
 */
 @RequestMapping("/hello")
 public ModelAndView hello() {
     ModelAndView mav = new ModelAndView();
     mav.addObject("user", "saddd");
     mav.setViewName("index");
     return mav;
 }
 }

Map

@Controller
public class UserController {
/**
* helloword
*
* @return index页面
*/
@RequestMapping("/hello")
public String hello(Map map) {
    map.put("name", "asnkjhauicgayucfyt");
    return "index";
}
}

@ResponseBody 返回值单独为一个页面

    @RequestMapping("del")
@ResponseBody
public String deleteUser(@RequestParam(value = "id") String id, HttpServletResponse response) {
    int i = us.deleteUser(Integer.parseInt(id));
    if (i > 0) {
    return "删除成功";
    } else {
    return "删除失败";
    }
}

@RequestBody 将前台的发送的json对象转换为java对象

  /**
* json对象序列化json字符串List接受
*
* @param jsonObject
* @return
*/

@RequestMapping("/json.do")
@ResponseBody
public void test3(@RequestBody List users) {
System.out.println(users);
}

#### springmvc请求原理
  第一步：发起请求到前端控制器(DispatcherServlet)
  第二步：前端控制器请求处理器映射器HandlerMapping查找 Handler (controller可以根据xml配置、注解进行查找)
  第三步：处理器映射器HandlerMapping向前端控制器返回Handler
  第四步：前端控制器调用处理器适配器HandlerAdapter去执行Handler
  第五步：处理器适配器去执行Handler
  第六步：Handler执行完成给处理器适配器返回ModelAndView
  第七步：处理器适配器向前端控制器返回ModelAndView
      ModelAndView是springmvc框架的一个底层对象，包括 Model和view
  第八步：前端控制器请求视图解析器View resolver去进行视图解析
      根据逻辑视图名解析成真正的视图(jsp)
  第九步：视图解析器向前端控制器返回View
  第十步：前端控制器进行视图渲染
      视图渲染将模型数据(在ModelAndView对象中)填充到request域
  第十一步：前端控制器向用户响应结果