SpringMvc
初识SpringMvc
- 轻量级,简单易学
- 高效 , 基于请求响应的MVC框架
- 与Spring兼容性好,无缝结合
- 约定优于配置
- 功能强大:RESTful、数据验证、格式化、本地化、主题等
- 简洁灵活
Spring的web框架围绕DispatcherServlet设计。DispatcherServlet的作用是将请求分发到不同的处理器。从Spring 2.5开始,使用Java 5或者以上版本的用户可以采用基于注解的controller声明方式。
SpringMvc原理
执行流程:
1.设置web.xml中的DispatcherServlet:
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<!-- 配置DispatcherServlet,这个是核心,请求分发器 -->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 选择配置文件 -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
2.根据bean去找控制器,然后把路径返回:
<!--根据bean去找控制器,然后把路径返回-->
<bean id="/hello" class="com.dyd.controller.HelloController"/>
3.进入Control去处理获得的数据:
package com.dyd.controller;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.mvc.Controller;
//注意:这里我们先导入Controller接口
public class HelloController implements Controller {
public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
//ModelAndView 模型和视图
ModelAndView mv = new ModelAndView();
//封装对象,放在ModelAndView中。Model
mv.addObject("msg","HelloSpringMVC!");
//封装要跳转的视图,放在ModelAndView中
mv.setViewName("hello"); //: /WEB-INF/jsp/hello.jsp
return mv;
}
}
4.根据得到的数据去渲染前端:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
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.xsd">
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<!--视图解析器:DispatcherServlet给他的ModelAndView-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
<!--前缀-->
<property name="prefix" value="/WEB-INF/jsp/"/>
<!--后缀-->
<property name="suffix" value=".jsp"/>
</bean>
<!--根据bean去找控制器,然后把路径返回-->
<bean id="/hello" class="com.dyd.controller.HelloController"/>
</beans>
注解SpringMvc
spring.xml
<?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"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 自动扫描包,让指定包下的注解生效,由IOC容器统一管理 -->
<context:component-scan base-package="com.dyd.controller"/>
<!-- 让Spring MVC不处理静态资源 -->
<mvc:default-servlet-handler />
<!--
支持mvc注解驱动
在spring中一般采用@RequestMapping注解来完成映射关系
要想使@RequestMapping注解生效
必须向上下文中注册DefaultAnnotationHandlerMapping
和一个AnnotationMethodHandlerAdapter实例
这两个实例分别在类级别和方法级别处理。
而annotation-driven配置帮助我们自动完成上述两个实例的注入。
-->
<mvc:annotation-driven/>
<!-- 视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">
<!-- 前缀 -->
<property name="prefix" value="/WEB-INF/jsp/" />
<!-- 后缀 -->
<property name="suffix" value=".jsp" />
</bean>
</beans>
控制器:
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HelloController {
//指定路径
@RequestMapping("/hello")
public String hello(Model model){
//封装数据
model.addAttribute("msg","hello,springmvcAnnotation");
return "hello"; //WEB/INF/jsp/hello.jsp
}
}
RestFul风格
从?
传参改变为路径传参,同时可以限制访问的方法,通过PathVariable来限制路径。
@Controller
public class RestFulController {
//http://localhost:8080/add?a=1&b=1
//RestFul:http://localhost:8080/add/a/b
@RequestMapping(value = "/add/{a}/{b}",method = RequestMethod.GET)
public String test1(@PathVariable int a,@PathVariable int b, Model model){
int res=a+b;
model.addAttribute("msg",res);
return "test";
}
}
请求参数及数据回显
@Controller
@RequestMapping("/user")
public class UserController {
//http://localhost:8080/user/t1?name=xxx
@GetMapping("/t1")
public String test1(@RequestParam("username") String name, Model model){
//1.接受前端参数
System.out.println("接受前端的参数为:"+name);
//2.将返回的结果传递给前端
model.addAttribute("msg",name);
//3.跳转视图
return "test";
}
//接受的是一个对象:id,name,age
/*
1.接受的是用户传递的参数,判断参数名字,假设名字在方法上可直接使用
2.传递的是user,匹配user如果一致则ok,否则匹配不到
*/
@RequestMapping("/t2")
public String test2(User user){
System.out.println(user);
return "test";
}
}
乱码问题
用过滤器解决乱码,在web.xml中加入配置文件:
<!-- 配置mvc乱码过滤 -->
<filter>
<filter-name>encoding</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>encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
或者用万能过滤器:
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;
/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {
@Override
public void destroy() {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
//处理response的字符编码
HttpServletResponse myResponse=(HttpServletResponse) response;
myResponse.setContentType("text/html;charset=UTF-8");
// 转型为与协议相关对象
HttpServletRequest httpServletRequest = (HttpServletRequest) request;
// 对request包装增强
HttpServletRequest myrequest = new MyRequest(httpServletRequest);
chain.doFilter(myrequest, response);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
}
//自定义request对象,HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;
//是否编码的标记
private boolean hasEncode;
//定义一个可以传入HttpServletRequest对象的构造函数,以便对其进行装饰
public MyRequest(HttpServletRequest request) {
super(request);// super必须写
this.request = request;
}
// 对需要增强方法 进行覆盖
@Override
public Map getParameterMap() {
// 先获得请求方式
String method = request.getMethod();
if (method.equalsIgnoreCase("post")) {
// post请求
try {
// 处理post乱码
request.setCharacterEncoding("utf-8");
return request.getParameterMap();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} else if (method.equalsIgnoreCase("get")) {
// get请求
Map<String, String[]> parameterMap = request.getParameterMap();
if (!hasEncode) { // 确保get手动编码逻辑只运行一次
for (String parameterName : parameterMap.keySet()) {
String[] values = parameterMap.get(parameterName);
if (values != null) {
for (int i = 0; i < values.length; i++) {
try {
// 处理get乱码
values[i] = new String(values[i]
.getBytes("ISO-8859-1"), "utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
}
}
hasEncode = true;
}
return parameterMap;
}
return super.getParameterMap();
}
//取一个值
@Override
public String getParameter(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
if (values == null) {
return null;
}
return values[0]; // 取回参数的第一个值
}
//取所有值
@Override
public String[] getParameterValues(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
return values;
}
}
JSON
后端部署后端,提供接口;前端独立部署,负责渲染后端的数据。其中用JSON传输。
JS解析:
<script type="text/javascript">
var user={
name:"dyd",
age:3,
sex:"male"
}
var json = JSON.stringify(user);
console.log(user);
console.log(json);
var obj = JSON.parse(json);
console.log(obj);
</script>
导入依赖包:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.0</version>
</dependency>
json乱码问题可以在springmvc-servlet.xml中添加配置:
<!-- json乱码配置 -->
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
测试:
@ResponseBody
@RequestMapping(value = "/j2")
public String json2() throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
List<User> userList = new ArrayList<User>();
//创建一个对象
User user1 = new User("dyd1",3,"男");
User user2 = new User("dyd2",3,"男");
User user3 = new User("dyd3",3,"男");
User user4 = new User("dyd4",3,"男");
userList.add(user1);
userList.add(user2);
userList.add(user3);
userList.add(user4);
String str = mapper.writeValueAsString(userList);
return str;
}
FastJson
导入fastjson的包:
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.60</version>
</dependency>
利用工具包:
public class FastJsonDemo {
public static void main(String[] args) {
//创建一个对象
User user1 = new User("秦疆1号", 3, "男");
User user2 = new User("秦疆2号", 3, "男");
User user3 = new User("秦疆3号", 3, "男");
User user4 = new User("秦疆4号", 3, "男");
List<User> list = new ArrayList<User>();
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
System.out.println("*******Java对象 转 JSON字符串*******");
String str1 = JSON.toJSONString(list);
System.out.println("JSON.toJSONString(list)==>"+str1);
String str2 = JSON.toJSONString(user1);
System.out.println("JSON.toJSONString(user1)==>"+str2);
System.out.println("\n****** JSON字符串 转 Java对象*******");
User jp_user1=JSON.parseObject(str2,User.class);
System.out.println("JSON.parseObject(str2,User.class)==>"+jp_user1);
System.out.println("\n****** Java对象 转 JSON对象 ******");
JSONObject jsonObject1 = (JSONObject) JSON.toJSON(user2);
System.out.println("(JSONObject) JSON.toJSON(user2)==>"+jsonObject1.getString("name"));
System.out.println("\n****** JSON对象 转 Java对象 ******");
User to_java_user = JSON.toJavaObject(jsonObject1, User.class);
System.out.println("JSON.toJavaObject(jsonObject1, User.class)==>"+to_java_user);
}
}
Ajax
直接用前端JS进行书写:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>iframe测试体验页面无刷新</title>
<script>
function go(){
var url = document.getElementById("url").value;
document.getElementById("iframe1").src=url;
}
</script>
</head>
<body>
<div>
<p>请输入地址:</p>
<p>
<input type="text" id="url" value="https://www.bilibili.com/">
<input type="button" value="提交" onclick="go()">
</p>
</div>
<div>
<iframe id="iframe1" style="width: 100%;height: 500px"></iframe>
</div>
</body>
</html>
拦截器
创建com.dyd.config包,构建MyInterceptor:
package com.dyd.config;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MyInterceptor implements HandlerInterceptor {
//执行下一个拦截器,放行
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("====处理前====");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("====处理后====");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("====清理====");
}
}
在application中添加配置:
<!-- 拦截器配置 -->
<mvc:interceptors>
<mvc:interceptor>
<!-- 拦截所有请求 -->
<mvc:mapping path="/**"/>
<bean class="com.dyd.config.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
设置登录拦截
controlller:
package com.dyd.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpSession;
@Controller
@RequestMapping("/user")
public class LoginController {
@RequestMapping("/main")
public String main()
{
return "main";
}
@RequestMapping("/goLogin")
public String login()
{
return "login";
}
@RequestMapping("/login")
public String login(HttpSession session, String username, String password, Model model)
{
session.setAttribute("userLoginInfo",username);
model.addAttribute("username",username);
return "main";
}
@RequestMapping("/goOut")
public String login(HttpSession session)
{
session.removeAttribute("userLoginInfo");
return "login";
}
}
设置config中的login拦截:
package com.dyd.config;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class LoginInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession();
//登录页面也会放行
if(request.getRequestURI().contains("goLogin")) return true;
//第一次登录也没有session
if(request.getRequestURI().contains("login")) return true;
//判断是否设置session
if(session.getAttribute("userLoginInfo")!=null) return true;
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request,response);
return false;
}
}
利用aop进行横切:
<!-- 拦截器配置 -->
<mvc:interceptors>
<mvc:interceptor>
<!-- 拦截所有请求 -->
<mvc:mapping path="/**"/>
<bean class="com.dyd.config.MyInterceptor"/>
</mvc:interceptor>
<mvc:interceptor>
<!-- 拦截所有请求 -->
<mvc:mapping path="/user/**"/>
<bean class="com.dyd.config.LoginInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
文件上传
导入依赖包:
<dependencies>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
<!--导入高版本的api-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
</dependencies>
二进制流前端表单:
<form enctype="multipart/form-data" method="post" action="${pageContext.request.contextPath}/upFile">
<input type="file" name="file">
<input type="submit" value="upload">
</form>
Spring自带的文件上传,application.xml配置:
<!--4 文件上传配置-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="utf-8"/>
<!--最大上传大小:单位是1字节-->
<property name="maxUploadSize" value="10485760"/>
<property name="maxInMemorySize" value="40960"/>
</bean>
控制器:
@RestController
public class FileController {
@RequestMapping("/upFile")
public String upFile(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
//设置文件保存路径
String path = request.getServletContext().getRealPath("/upload");
System.out.println("path:" + path);
File realPath = new File(path);
if (!realPath.exists()) {
realPath.mkdir();
}
System.out.println("上传的文件地址:" + realPath);
//CommonsMultipartFile的方法写文件,简化
file.transferTo(new File(realPath + "/" + file.getOriginalFilename()));
return "redirect:/index.jsp";
}
}
文件下载
在文件上传的基础上,添加以下controller:
@RequestMapping(value = "/download")
public String downLoad(HttpServletResponse response, HttpServletRequest request) throws IOException {
//手动设置,要下载的图片地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "1.png";
//设置响应头
response.reset();//设置页面不缓存,清空buffer
response.setCharacterEncoding("UTF-8");
response.setContentType("multipart/form-data");//二进制传输数据
response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));
File file = new File(path, fileName);
//读取文件-输入流
InputStream input = new FileInputStream(file);
//写入文件-输出流
OutputStream out = response.getOutputStream();
byte[] buff = new byte[1024];
int index = 0;
while ((index = input.read(buff)) != -1) {
out.write(buff,0,index);
out.flush();
}
input.close();
out.close();
return "redirect:/index.jsp";
}