SpringMVC
SpringMVC
文章目录
- SpringMVC
- 1、执行原理
- 2、基于注解
- 3、RestFul风格
- 指定请求方式（默认get）
- 4、接收参数
- 5、解决中文乱码问题
- 6、JSON
- 6.1、jackJson
- 6.2、FastJson
- 7、整合mybatis
- pom.xml
- 编写database.properties数据库配置文件
- mybatisConfig.xml
- spring-dao.xml
- 8、整合spring
- spirng-mvc.xml
- springService.xml
- applicationContext.xml
- web.xml
- 9、Ajax
- 10、拦截器
1、执行原理
中心控制器
spring的web框架围绕dispatcherServlet设计，他的作用是分发请求。
例localhsot:8080/helloServlet/index
他会自动的去拆分
- localhost:8080我们的服务器域名
- helloServlet是我们在服务器的一个站点
- index表示一个控制器
2、基于注解
springmvc-servlet.xml
<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">
<context:component-scan base-package="com.ming.controller"/>
<mvc:default-servlet-handler />
<mvc:annotation-driven />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
bean>
beans>
web.xml
<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">
<servlet>
<servlet-name>SpringMVCservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springmvc-servlet.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>SpringMVCservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
web-app>
controller下的类,有点类似与flask的操作
@Controller
public class HelloController {
//url路径为hello
@RequestMapping("/hello")
public String hello(Model model){
model.addAttribute("msg", "你好springmvc");
return "hello"; //被视图解析器处理，返回给hello页面
}
}
hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
${msg}
3、RestFul风格
用斜杠分割参数
如localhost:8080/add/1/2
需要通过@RequestMapping设置
public class RestFulController {
@RequestMapping("/add/{a}/{b}")
public String add(@PathVariable int a, @PathVariable int b, Model model){
model.addAttribute("msg", a+b);
return "hello";
}
}
指定请求方式（默认get）
只允许post方法,可以设置method，也可以使用PostMapping
//@RequestMapping(value = "/add/{a}/{b}",method = RequestMethod.POST)
@PostMapping("/add/{a}/{b}")
public String add(@PathVariable int a, @PathVariable int b, Model model){
model.addAttribute("msg", a+b);
return "hello";
}
get方法
//@RequestMapping(value = "/add/{a}/{b}",method = RequestMethod.GET)
@GetMapping("/add/{a}/{b}")
public String add(@PathVariable int a, @PathVariable int b, Model model){
model.addAttribute("msg", a+b);
return "hello";
}
还有一些其他的注解
@PutMapping()
@PatchMapping()
@DeleteMapping()
优点
- 更加安全，参数不会暴露
4、接收参数
@Controller
@RequestMapping("/user")
public class UserController {
@GetMapping("/t1")
public String test1(@RequestParam("usernames") String name, Model model){
model.addAttribute("msg", name);
return "hello";
}
}
可以用@RequestParam设置参数别名，建议都用别名，显式的配置可以让代码可读性更高
5、解决中文乱码问题
web.xml
<filter>
<filter-name>encodingfilter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
6、JSON
jackjson或者fastjson
6.1、jackJson
导入jackjson依赖
<dependency>
<groupId>com.fasterxml.jackson.coregroupId>
<artifactId>jackson-databindartifactId>
<version>2.11.1version>
dependency>
由于返回的是json，所以不用去寻找页面只用返回字符串即可
@RequestMapping("/j1")
@ResponseBody //不会找页面，直接返回字符串
public String json1() throws JsonProcessingException {
ObjectMapper om = new ObjectMapper();
User user = new User(1,"作为",18);
String str = om.writeValueAsString(user); //转换为字符串
return str;
}
但是出现了中文乱码的问题，用springmvc-servlet.xml的配置去统一解决
<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>
返回数组型的json，只需要把对象添加到list集合中即可
@RequestMapping("/j2")
public String json2() throws JsonProcessingException {
List<User> list = new ArrayList<User>();
ObjectMapper om = new ObjectMapper();
User user1 = new User(1,"作为",18);
User user2 = new User(2,"作为",18);
User user3 = new User(3,"作为",18);
User user4 = new User(4,"作为",18);
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
String str = om.writeValueAsString(list);
return str;
}
@RestController 相当于这个类下面的所有方法都不寻找页面，返回字符串，省去@ResponBody的操作
@RestController
@RequestMapping("/g1")
public class UserController {
@RequestMapping("/j1")
// @ResponseBody //不会找页面，直接返回字符串
public String json1() throws JsonProcessingException {
ObjectMapper om = new ObjectMapper();
User user = new User(1,"作为",18);
String str = om.writeValueAsString(user);
return str;
}
@RequestMapping("/j2")
public String json2() throws JsonProcessingException {
List<User> list = new ArrayList<User>();
ObjectMapper om = new ObjectMapper();
User user1 = new User(1,"作为",18);
User user2 = new User(2,"作为",18);
User user3 = new User(3,"作为",18);
User user4 = new User(4,"作为",18);
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
String str = om.writeValueAsString(list);
return str;
}
6.2、FastJson
操作类似前端，简单
<dependency>
<groupId>com.alibabagroupId>
<artifactId>fastjsonartifactId>
<version>1.2.60version>
dependency>
可以实现java对象和json对象相互转换，
java对象和json字符串转换
7、整合mybatis
项目结构
--main
--java
--resourse
--applicationContext.xml
--database.properties
--mybatisConfig.xml
--spring-dao.xml
--spring-mvc.xml
--springService.xml
--web
--WEB-INF
--jsp
--web.xml
前期准备，导入依赖，资源过滤
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<groupId>org.examplegroupId>
<artifactId>ssmbuildartifactId>
<version>1.0-SNAPSHOTversion>
<dependencies>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.12version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>5.1.47version>
dependency>
<dependency>
<groupId>com.mchangegroupId>
<artifactId>c3p0artifactId>
<version>0.9.5.2version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>servlet-apiartifactId>
<version>2.5version>
dependency>
<dependency>
<groupId>javax.servlet.jspgroupId>
<artifactId>jsp-apiartifactId>
<version>2.2version>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>jstlartifactId>
<version>1.2version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatisartifactId>
<version>3.5.2version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatis-springartifactId>
<version>2.0.2version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>5.1.9.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>5.1.9.RELEASEversion>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.16.10version>
dependency>
dependencies>
<build>
<resources>
<resource>
<directory>src/main/javadirectory>
<includes>
<include>**/*.propertiesinclude>
<include>**/*.xmlinclude>
includes>
<filtering>falsefiltering>
resource>
<resource>
<directory>src/main/resourcesdirectory>
<includes>
<include>**/*.propertiesinclude>
<include>**/*.xmlinclude>
includes>
<filtering>falsefiltering>
resource>
resources>
build>
project>
编写database.properties数据库配置文件
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/jdbcdemo?useSSL=true&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=123456
mybatisConfig.xml
大部分的配置交个spring管理：如配置数据源。
只需要设置别名，注册mapper
<configuration>
<typeAliases>
<package name="com.ming.pojo"/>
typeAliases>
<mappers>
<mapper class="com.ming.dao.bookmapper"/>
mappers>
configuration>
spring-dao.xml
<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
https://www.springframework.org/schema/context/spring-context.xsd">
<context:property-placeholder location="classpath:database.properties"/>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<property name="maxPoolSize" value="30"/>
<property name="minPoolSize" value="10"/>
<property name="autoCommitOnClose" value="false"/>
<property name="checkoutTimeout" value="10000"/>
<property name="acquireRetryAttempts" value="2"/>
bean>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="configLocation" value="classpath:mybatisConfig.xml"/>
bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<property name="basePackage" value="com.ming.dao"/>
bean>
beans>
8、整合spring
@Qualifier限定哪个bean应该被自动注入。当Spring无法判断出哪个bean应该被注入时，@Qualifier注解有助于消除歧义bean的自动注入
spirng-mvc.xml
<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
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<mvc:annotation-driven />
<mvc:default-servlet-handler/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
bean>
<context:component-scan base-package="com.ming.controller" />
beans>
springService.xml
<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">
<context:component-scan base-package="com.ming.service" />
<bean id="bookServiceImpl" class="com.ming.service.bookServiceImpl">
<property name="bookmapper" ref="bookmapper"/>
bean>
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
bean>
beans>
总的配置,
applicationContext.xml
<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">
<import resource="classpath:spring-dao.xml"/>
<import resource="classpath:springService.xml"/>
<import resource="classpath:spring-mvc.xml"/>
beans>
web.xml
其中配置dispatcherServlet分发，过滤器
<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">
<servlet>
<servlet-name>DispatcherServletservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:applicationContext.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
<servlet-name>DispatcherServletservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
<filter>
<filter-name>encodingFilterfilter-name>
<filter-class>
org.springframework.web.filter.CharacterEncodingFilter
filter-class>
<init-param>
<param-name>encodingparam-name>
<param-value>utf-8param-value>
init-param>
filter>
<filter-mapping>
<filter-name>encodingFilterfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
<session-config>
<session-timeout>15session-timeout>
session-config>
web-app>
9、Ajax
Ajax 即“Asynchronous Javascript And XML”（异步 JavaScript 和 XML），是指一种创建交互式、快速动态网页应用的网页开发技术，无需重新加载整个网页的情况下，能够更新部分网页的技术。
xhr代表ajax类型的请求
可以使用Jquery里面的函数实现ajax请求
转发和重定向有什么不同？
转发的话地址栏的请求是不会变的。重定向是重新发起一次请求，url会变
10、拦截器
-
拦截器是aop的具体应用
-
什么是拦截器？
Spring MVC中的拦截器（Interceptor）类似于Servlet中的过滤器（Filter），它主要用于拦截用户请求并作相应的处理。例如通过拦截器可以进行权限验证、记录请求信息的日志、判断用户是否登录等。
重写HandlerInterceptor的三个方法，分别是处理前，处理后和清理
public class myInterceptor implements HandlerInterceptor {
//return true;放行
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("处理前========");
return true;
}
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("处理后========");
}
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("清理========");
}
}
拦截器实现登录拦截功能
首先我们写一个类实现HandlerInterceptor，然后重写其中的preHandle方法
public class LoginInterceptor implements HandlerInterceptor {
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession();
//return true 就是放行，return false 就是拦截
//放行：登录
if(request.getRequestURI().contains("gologin")){
return true;
}
//登录页也放行,才能存session，如果不放行，不能执行提交后的方法
if(request.getRequestURI().contains("login")){
return true;
}
//没有登录，所以session为空,让他通过执行登录方法
if(session.getAttribute("username")!=null){
return true;
}
//重定向
request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
return false;
}
}
然后我们在applicationContext.xml中配置，拦截器是springmvc中的功能，所以用mvc标签打出就有提示
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/**"/>
<bean class="com.ming.config.myInterceptor">bean>
mvc:interceptor>
<mvc:interceptor>
<mvc:mapping path="/user/**"/>
<bean class="com.ming.config.LoginInterceptor"/>
mvc:interceptor>
mvc:interceptors>