MVC
MVC介绍
- MVC:模型(Model)、视图(View)、控制器(Controller)
- Model: 数据获取对象(Dao)、服务(Service)
- View: 前端
- Controller:接受用户请求,交给Model处理,处理完毕交给View
- 典型的MVC是JSP + servlet + Javabean
HelloSpringMVC
- 配置文件版
- 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_4_0.xsd"
version="4.0">
<!--1.注册DispatcherServlet-->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--关联一个springmvc的配置文件:【servlet-name】-servlet.xml-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc-servlet.xml</param-value>
</init-param>
<!--启动级别-1-->
<load-on-startup>1</load-on-startup>
</servlet>
<!--/ 匹配所有的请求;(不包括.jsp)-->
<!--/* 匹配所有的请求;(包括.jsp)-->
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
- SpringMVC配置文件
<?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">
<!--处理映射器-->
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<!--处理器适配器-->
<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>
</beans>
- Controller
package com.kuang.controller;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//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/hello.jsp
return mv;
}
}
- 注册bean
<bean id="/hello" class="controller.HelloController/>
- jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Kuangshen</title>
</head>
<body>
${msg}
</body>
</html>
- 配置tomcat
- 注解版
- Spring MVC配置文件
<?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="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>
- Controller
package controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HelloController {
//真实访问地址 : 项目名/hello
@RequestMapping("/hello")
public String sayHello(Model model) {
//向模型中添加属性msg与值,可以在JSP页面中取出并渲染
model.addAttribute("msg","hello,SpringMVC");
//web-inf/jsp/hello.jsp
return "hello";
}
}
- 视图层
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>SpringMVC</title>
</head>
<body>
${msg}
</body>
</html>
原理
- 使用SpringMVC需要配置:处理器映射器、处理器适配器、视图解析器
- 需要手动配置视图解析器,处理器映射器、处理器适配器只需要开启注解驱动即可
<mvc:annotation-driven />
Controller
- 控制器提供应用程序的行为,通常通过接口定义或注解定义实现
- 实现Controller接口
// 实现这个接口可以获得控制器功能
public interface Controller {
// 处理请求,返回一个模型和视图对象
ModelAndView handleRequest(HttpServletRequest var1, HttpServletResponse var2) throws Exception;
}
- 使用注解
<context:component-scan base-package="controller"/>
//@Controller注解的类会自动添加到Spring上下文中
@Controller
public class ControllerTest2 {
//映射访问路径
@RequestMapping("/t2")
public String index(Model model){
//Spring MVC会自动实例化一个Model对象用于向视图中传值
model.addAttribute("msg", "ControllerTest2");
//返回视图位置
return "test";
}
}
RequestMapping
- @RequestMapping用于映射url到控制器类
RestFul风格:一个资源定位及资源操作的风格
@Controller
public class RestFulController {
//映射访问路径
@RequestMapping("/commit/{p1}/{p2}")
public String index(@PathVariable int p1, @PathVariable int p2, Model model) {
int result = p1+p2;
//Spring MVC会自动实例化一个Model对象用于向视图中传值
model.addAttribute("msg", "结果:"+result);
//返回视图位置
return "test";
}
}
//映射访问路径
@RequestMapping("/commit/{p1}/{p2}")
public String index(@PathVariable int p1, @PathVariable String p2, Model model) {
String result = p1+p2;
//Spring MVC会自动实例化一个Model对象用于向视图中传值
model.addAttribute("msg", "结果:"+result);
//返回视图位置
return "test";
}
//映射访问路径,必须是POST请求
@RequestMapping(value = "/hello",method = {RequestMethod.POST})
public String index2(Model model) {
model.addAttribute("msg", "hello!");
return "test";
}
//映射访问路径,必须是Get请求
@RequestMapping(value = "/hello",method = {RequestMethod.GET})
public String index2(Model model){
model.addAttribute("msg", "hello!");
return "test";
}
- Spring MVC 的 @RequestMapping 注解能够处理 HTTP 请求的方法, 比如 GET, PUT, POST, DELETE 以及 PATCH。
结果跳转方式
- ModelAndView
设置ModelAndView对象,根据view名称,和视图解析器跳转到指定页面
<!-- 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>
Controller类
public class ControllerTest1 implements Controller {
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
//返回一个模型视图对象
ModelAndView mv = new ModelAndView();
mv.addObject("msg","ControllerTest1");
mv.setViewName("test");
return mv;
}
}
- ServletAPI
-
通过HttpServletResponse进行输出
-
通过HttpServletResponse实现重定向
-
通过HttpServletResponse实现转发
@Controller
public class ResultGo {
@RequestMapping("/result/t1")
public void test1(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
rsp.getWriter().println("Hello,Spring BY servlet API");
}
@RequestMapping("/result/t2")
public void test2(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
rsp.sendRedirect("/index.jsp");
}
@RequestMapping("/result/t3")
public void test3(HttpServletRequest req, HttpServletResponse rsp) throws Exception {
//转发
req.setAttribute("msg","/result/t3");
req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,rsp);
}
}
- SpringMVC
- 无视图解析器
@Controller
public class ResultSpringMVC {
@RequestMapping("/rsm/t1")
public String test1(){
//转发
return "/index.jsp";
}
@RequestMapping("/rsm/t2")
public String test2() {
//转发二
return "forward:/index.jsp";
}
@RequestMapping("/rsm/t3")
public String test3() {
//重定向
return "redirect:/index.jsp";
}
}
- 有视图解析器
@Controller
public class ResultSpringMVC2 {
@RequestMapping("/rsm2/t1")
public String test1(){
//转发
return "test";
}
@RequestMapping("/rsm2/t2")
public String test2(){
//重定向
return "redirect:/index.jsp";
//return "redirect:hello.do"; //hello.do为另一个请求/
}
}
数据处理
处理提交数据
- 提交的域名称和处理方法的参数名一致
@RequestMapping("/hello")
public String hello(String name) {
System.out.println(name);
return "hello";
}
- 提交的域名称和处理方法的参数名不一致
@RequestMapping("/hello")
public String hello(@RequestParam("username") String name) {
System.out.println(name);
return "hello";
}
- 提交的是一个对象
public class User {
private int id;
private String name;
private int age;
//构造
//get/set
//tostring()
}
@RequestMapping("/user")
public String user(User user) {
System.out.println(user);
return "hello";
}
数据显示到前端
- ModelAndView
- ModelMap
@RequestMapping("/hello")
public String hello(@RequestParam("username") String name, ModelMap model){
//封装要显示到视图中的数据
//相当于req.setAttribute("name",name);
model.addAttribute("name",name);
System.out.println(name);
return "hello";
}
- Model
@RequestMapping("/ct2/hello")
public String hello(@RequestParam("username") String name, Model model){
//封装要显示到视图中的数据
//相当于req.setAttribute("name",name);
model.addAttribute("msg",name);
System.out.println(name);
return "test";
}
乱码问题 -> 过滤器
- 使用SpringMVC提供的过滤器
<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>
JSON:数据交换格式
-
JSON 和 JavaScript对象关系:JSON 是 JavaScript 对象的字符串表示法,它使用文本表示一个 JS 对象的信息,本质是一个字符串。
-
JSON和JavaScript对象互转
var json = JSON.stringify({a: 'Hello', b: 'World'});
//结果是 '{"a": "Hello", "b": "World"}'
var obj = JSON.parse('{"a": "Hello", "b": "World"}');
Jackon使用
- SpringMVC配置
<?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_4_0.xsd"
version="4.0">
<!--1.注册servlet-->
<servlet>
<servlet-name>SpringMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--通过初始化参数指定SpringMVC配置文件的位置,进行关联-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc-servlet.xml</param-value>
</init-param>
<!-- 启动顺序,数字越小,启动越早 -->
<load-on-startup>1</load-on-startup>
</servlet>
<!--所有请求都会被springmvc拦截 -->
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<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>
</web-app>
<?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">
<!-- 自动扫描指定的包,下面所有注解类交给IOC容器管理 -->
<context:component-scan base-package="com.kuang.controller"/>
<!-- 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>
@Controller
public class UserController {
@RequestMapping("/json1")
@ResponseBody
public String json1() throws JsonProcessingException {
//创建一个jackson的对象映射器,用来解析数据
ObjectMapper mapper = new ObjectMapper();
//创建一个对象
User user = new User("秦疆1号", 3, "男");
//将我们的对象解析成为json格式
String str = mapper.writeValueAsString(user);
//由于@ResponseBody注解,这里会将str转成json格式返回;十分方便
return str;
}
}
- 乱码解决
<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>
- 返回json字符串
@RestController
public class UserController {
//produces:指定响应体返回类型和编码
@RequestMapping(value = "/json1")
public String json1() throws JsonProcessingException {
//创建一个jackson的对象映射器,用来解析数据
ObjectMapper mapper = new ObjectMapper();
//创建一个对象
User user = new User("秦疆1号", 3, "男");
//将我们的对象解析成为json格式
String str = mapper.writeValueAsString(user);
//由于@ResponseBody注解,这里会将str转成json格式返回;十分方便
return str;
}
}
- 输出时间对象:自定义时间格式
@RequestMapping("/json4")
public String json4() throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
//不使用时间戳的方式
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
//自定义日期格式对象
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
//指定日期格式
mapper.setDateFormat(sdf);
Date date = new Date();
String str = mapper.writeValueAsString(date);
return str;
}
- 抽象为工具类
package utils;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import java.text.SimpleDateFormat;
public class JsonUtils {
public static String getJson(Object object) {
return getJson(object,"yyyy-MM-dd HH:mm:ss");
}
public static String getJson(Object object,String dateFormat) {
ObjectMapper mapper = new ObjectMapper();
//不使用时间差的方式
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
//自定义日期格式对象
SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
//指定日期格式
mapper.setDateFormat(sdf);
try {
return mapper.writeValueAsString(object);
} catch (JsonProcessingException e) {
e.printStackTrace();
}
return null;
}
}
@RequestMapping("/json5")
public String json5() throws JsonProcessingException {
Date date = new Date();
String json = JsonUtils.getJson(date);
return json;
}
-
FastJson
-
JSONObject 代表 json 对象
-
JSONObject实现了Map接口, 猜想 JSONObject底层操作是由Map实现的。
-
JSONObject对应json对象,通过各种形式的get()方法可以获取json对象中的数据,也可利用诸如size(),isEmpty()等方法获取"键:值"对的个数和判断是否为空。其本质是通过实现Map接口并调用接口中的方法完成的。
-
-
JSONArray 代表 json 对象数组
- 内部是有List接口中的方法来完成操作的。
-
JSON代表 JSONObject和JSONArray的转化
-
JSON类源码分析与使用
-
仔细观察这些方法,主要是实现json对象,json对象数组,javabean对象,json字符串之间的相互转化。
-
package controller;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import pojo.User;
import java.util.ArrayList;
import java.util.List;
public class FastJsonDemo {
public static void main(String[] args) {
//创建一个对象
User user1 = new User("zcs1", 3, "男");
User user2 = new User("zcs2", 3, "男");
User user3 = new User("zcs3", 3, "男");
User user4 = new User("zcs4", 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("
****** 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("
****** 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("
****** 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:异步的JavaScript和XML
- HttpServletResponse实现
@Controller
public class AjaxController {
@RequestMapping("/a1")
public void ajax1(String name , HttpServletResponse response) throws IOException {
if ("admin".equals(name)){
response.getWriter().print("true");
}else{
response.getWriter().print("false");
}
}
}
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
<%--<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>--%>
<script src="${pageContext.request.contextPath}/statics/js/jquery-3.1.1.min.js"></script>
<script>
function a1() {
$.post({
url: "${pageContext.request.contextPath}/a1",
data: {'name':$("#txtName").val()},
success: function (data,status) {
alert(data);
alert(status);
}
});
}
</script>
</head>
<body>
<%--onblur:失去焦点触发事件--%>
用户名:<input type="text" id="txtName" onblur="a1()"/>
</body>
</html>
失去焦点触发事件 -> a1() -> 发起请求 -> 后台进行数据处理(HttpServletResponse) -> 返回前端
- SpringMVC实现
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private String name;
private int age;
private String sex;
}
@RequestMapping("/a2")
public List<User> ajax2(){
List<User> list = new ArrayList<User>();
list.add(new User("zcs01",3,"男"));
list.add(new User("zcs02",3,"男"));
list.add(new User("zcs03",3,"男"));
return list; //由于@RestController注解,将list转成json格式返回
}
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<input type="button" id="btn" value="获取数据"/>
<table width="80%" align="center">
<tr>
<td>姓名</td>
<td>年龄</td>
<td>性别</td>
</tr>
<tbody id="content">
</tbody>
</table>
<script src="${pageContext.request.contextPath}/statics/js/jquery-3.1.1.min.js"></script>
<script>
$(function () {
$("#btn").click(function () {
$.post("${pageContext.request.contextPath}/a2",function (data) {
console.log(data)
var html="";
for (var i = 0; i <data.length ; i++) {
html+= "<tr>" +
"<td>" + data[i].name + "</td>" +
"<td>" + data[i].age + "</td>" +
"<td>" + data[i].sex + "</td>" +
"</tr>"
}
$("#content").html(html);
});
})
})
</script>
</body>
</html>
- 用户名验证
@RequestMapping("/a3")
public String ajax3(String name, String pwd) {
String msg = "";
//模拟数据库中存在数据
if (name != null) {
if ("admin".equals(name)) {
msg = "OK";
}else {
msg = "用户名输入错误";
}
}
if (pwd!=null) {
if ("123456".equals(pwd)) {
msg = "OK";
}else {
msg = "密码输入有误";
}
}
return msg; //由于@RestController注解,将msg转成json格式返回
}
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>ajax</title>
<script src="${pageContext.request.contextPath}/statics/js/jquery-3.1.1.min.js"></script>
<script>
function a1() {
$.post({
url:"${pageContext.request.contextPath}/a3",
data:{'name':$("#name").val()},
success:function (data) {
if (data.toString()=='OK'){
$("#userInfo").css("color","green");
}else {
$("#userInfo").css("color","red");
}
$("#userInfo").html(data);
}
});
}
function a2() {
$.post({
url:"${pageContext.request.contextPath}/a3",
data:{'pwd':$("#pwd").val()},
success:function (data) {
if (data.toString()=='OK'){
$("#pwdInfo").css("color","green");
}else {
$("#pwdInfo").css("color","red");
}
$("#pwdInfo").html(data);
}
});
}
</script>
</head>
<body>
<p>
用户名:<input type="text" id="name" onblur="a1()"/>
<span id="userInfo"></span>
</p>
<p>
密码:<input type="text" id="pwd" onblur="a2()"/>
<span id="pwdInfo"></span>
</p>
</body>
</html>
拦截器:AOP思想的具体应用
-
过滤器
-
servlet规范中的一部分,任何java web工程都可以使用
-
在url-pattern中配置了/*之后,可以对所有要访问的资源进行拦截
-
-
拦截器
-
拦截器是SpringMVC框架自己的,只有使用了SpringMVC框架的工程才能使用
-
拦截器只会拦截访问的控制器方法, 如果访问的是jsp/html/css/image/js是不会进行拦截的
-
自定义拦截器
package interceptor;
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 {
//在请求处理的方法之前执行
//如果返回true执行下一个拦截器
//如果返回false就不执行下一个拦截器
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
System.out.println("------------处理前------------");
return true;
}
//在请求处理方法执行之后执行
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
System.out.println("------------处理后------------");
}
//在dispatcherServlet处理后执行,做清理工作.
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
System.out.println("------------清理------------");
}
}
<!--关于拦截器的配置-->
<mvc:interceptors>
<mvc:interceptor>
<!--/** 包括路径及其子路径-->
<!--/admin/* 拦截的是/admin/add等等这种 , /admin/add/user不会被拦截-->
<!--/admin/** 拦截的是/admin/下的所有-->
<mvc:mapping path="/**"/>
<!--bean配置的就是拦截器-->
<bean class="com.kuang.interceptor.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
package com.kuang.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
//测试拦截器的控制器
@Controller
public class InterceptorController {
@RequestMapping("/interceptor")
@ResponseBody
public String testFunction() {
System.out.println("控制器中的方法执行了");
return "hello";
}
}
<a href="${pageContext.request.contextPath}/interceptor">拦截器测试</a>
验证用户是否登录
-
有一个登陆页面,需要写一个controller访问页面。
-
登陆页面有一提交表单的动作。需要在controller中处理。判断用户名密码是否正确。如果正确,向session中写入用户信息。返回登陆成功。
-
拦截用户请求,判断用户是否登陆。如果用户已经登陆。放行, 如果用户未登陆,跳转到登陆页面
- 登录页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<h1>登录页面</h1>
<hr>
<body>
<form action="${pageContext.request.contextPath}/user/login">
用户名:<input type="text" name="username"> <br>
密码:<input type="password" name="pwd"> <br>
<input type="submit" value="提交">
</form>
</body>
</html>
- Controller处理请求
package controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpSession;
@Controller
@RequestMapping("/user")
public class UserController {
//跳转到登陆页面
@RequestMapping("/jumplogin")
public String jumpLogin() throws Exception {
return "login";
}
//跳转到成功页面
@RequestMapping("/jumpSuccess")
public String jumpSuccess() throws Exception {
return "success";
}
//登陆提交
@RequestMapping("/login")
public String login(HttpSession session, String username, String pwd) throws Exception {
// 向session记录用户身份信息
System.out.println("接收前端==="+username);
session.setAttribute("user", username);
return "success";
}
//退出登陆
@RequestMapping("logout")
public String logout(HttpSession session) throws Exception {
// session 过期
session.invalidate();
return "login";
}
}
- 登录成功页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1>登录成功页面</h1>
<hr>
${user}
<a href="${pageContext.request.contextPath}/user/logout">注销</a>
</body>
</html>
- 跳转
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<h1>首页</h1>
<hr>
<%--登录--%>
<a href="${pageContext.request.contextPath}/user/jumplogin">登录</a>
<a href="${pageContext.request.contextPath}/user/jumpSuccess">成功页面</a>
</body>
</html>
- 用户登录拦截器
package interceptor;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
public class LoginInterceptor implements HandlerInterceptor {
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws ServletException, IOException {
// 如果是登陆页面则放行
System.out.println("uri: " + request.getRequestURI());
if (request.getRequestURI().contains("login")) {
return true;
}
HttpSession session = request.getSession();
// 如果用户已登陆也放行
if(session.getAttribute("user") != null) {
return true;
}
// 用户没有登陆跳转到登陆页面
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
return false;
}
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
}
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
}
}
- 配置文件注册拦截器
<!--关于拦截器的配置-->
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/**"/>
<bean id="loginInterceptor" class="sinterceptor.LoginInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
文件上传
-
在上下文中配置MultipartResolver。
-
前端表单要求:为了能上传文件,必须将表单的method设置为POST,并将enctype设置为multipart/form-data。只有在这样的情况下,浏览器才会把用户选择的文件以二进制数据发送给服务器;
-
表单中的 enctype 属性做个详细的说明:
-
application/x-www=form-urlencoded:默认方式,只处理表单域中的 value 属性值,采用这种编码方式的表单会将表单域中的值处理成 URL 编码方式。
-
multipart/form-data:这种编码方式会以二进制流的方式来处理表单数据,这种编码方式会把文件域指定文件的内容也封装到请求参数中,不会对字符编码。
-
text/plain:除了把空格转换为 "+" 号外,其他字符都不做编码处理,这种方式适用直接通过表单发送邮件。
-
<form action="" enctype="multipart/form-data" method="post">
<input type="file" name="file"/>
<input type="submit">
</form>
-
Spring MVC为文件上传提供了直接的支持,这种支持是用即插即用的MultipartResolver实现的。
-
Spring MVC使用Apache Commons FileUpload技术实现了一个MultipartResolver实现类:
-
CommonsMultipartResolver。因此,SpringMVC的文件上传还需要依赖Apache Commons FileUpload的组件。
文件上传
- 导入文件
<!--文件上传-->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
<!--servlet-api导入高版本的-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
- 配置Bean
- bean的id必须为:multipartResolver,否则上传文件会报400的错误
<!--文件上传配置-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 请求的编码格式,必须和jSP的pageEncoding属性一致,以便正确读取表单的内容,默认为ISO-8859-1 -->
<property name="defaultEncoding" value="utf-8"/>
<!-- 上传文件大小上限,单位为字节(10485760=10M) -->
<property name="maxUploadSize" value="10485760"/>
<property name="maxInMemorySize" value="40960"/>
</bean>
-
CommonsMultipartFile 的 常用方法:
-
String getOriginalFilename():获取上传文件的原名
-
InputStream getInputStream():获取文件流
-
void transferTo(File dest):将上传文件保存到一个目录文件中
-
-
前端页面
<form action="/upload" enctype="multipart/form-data" method="post">
<input type="file" name="file"/>
<input type="submit" value="upload">
</form>
- Controller
package controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
import javax.servlet.http.HttpServletRequest;
import java.io.*;
@Controller
public class FileController {
//@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象
//批量上传CommonsMultipartFile则为数组即可
@RequestMapping("/upload")
public String fileUpload(@RequestParam("file") CommonsMultipartFile file , HttpServletRequest request) throws IOException {
//获取文件名 : file.getOriginalFilename();
String uploadFileName = file.getOriginalFilename();
//如果文件名为空,直接回到首页!
if ("".equals(uploadFileName)) {
return "redirect:/index.jsp";
}
System.out.println("上传文件名 : "+uploadFileName);
//上传路径保存设置
String path = request.getServletContext().getRealPath("/upload");
//如果路径不存在,创建一个
File realPath = new File(path);
if (!realPath.exists()) {
realPath.mkdir();
}
System.out.println("上传文件保存地址:"+realPath);
InputStream is = file.getInputStream(); //文件输入流
OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流
//读取写出
int len=0;
byte[] buffer = new byte[1024];
while ((len=is.read(buffer))!=-1) {
os.write(buffer,0,len);
os.flush();
}
os.close();
is.close();
return "redirect:/index.jsp";
}
}
- 采用file.Transto 来保存上传的文件
- Controller
/*
* 采用file.Transto 来保存上传的文件
*/
@RequestMapping("/upload2")
public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
//上传路径保存设置
String path = request.getServletContext().getRealPath("/upload");
File realPath = new File(path);
if (!realPath.exists()){
realPath.mkdir();
}
//上传文件地址
System.out.println("上传文件保存地址:"+realPath);
//通过CommonsMultipartFile的方法直接写文件(注意这个时候)
file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
return "redirect:/index.jsp";
}
文件下载
文件下载步骤:
-
设置 response 响应头
-
读取文件 -- InputStream
-
写出文件 -- OutputStream
-
执行操作
-
关闭流 (先开后关)
@RequestMapping(value="/download")
public String downloads(HttpServletResponse response ,HttpServletRequest request) throws Exception{
//要下载的图片地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "基础语法.jpg";
//1、设置response 响应头
response.reset(); //设置页面不缓存,清空buffer
response.setCharacterEncoding("UTF-8"); //字符编码
response.setContentType("multipart/form-data"); //二进制传输数据
//设置响应头
response.setHeader("Content-Disposition",
"attachment;fileName="+URLEncoder.encode(fileName, "UTF-8"));
File file = new File(path,fileName);
//2、 读取文件--输入流
InputStream input=new FileInputStream(file);
//3、 写出文件--输出流
OutputStream out = response.getOutputStream();
byte[] buff =new byte[1024];
int index=0;
//4、执行 写出操作
while((index= input.read(buff))!= -1){
out.write(buff, 0, index);
out.flush();
}
out.close();
input.close();
return null;
}
<a href="/download">点击下载</a>