Java-SpringMVC配置详解
概念
- SpringMVC是Spring的一部分。
- 什么是MVC？
- M（dao、service）V（html、jsp）C（Servlet）
- 他是纯Java实现的
- 核心三要素
- 处理器映射器：（BeanNameUrlHandlerMapping）
- 处理器适配器：（SimpleControllerHandlerAdapter）
- 视图解析器：（InternalResourceViewResolver）
- idea如何创建简单的web项目（基于Maven）？
- 新建父工程
- 在父工程中new一个module（普通Maven）
- 右击该module，依次点击
Add Frameworks Support->Web Application
- 官方文档：https://docs.spring.io/spring-framework/docs/current/reference/html/web.html#spring-web
一个简单的Servlet
- Maven添加
servlet-api,jsp-api依赖（其他spring-webmvc等此处省略）<dependency> <groupId>javax.servletgroupId> <artifactId>servlet-apiartifactId> <version>2.5version> <scope>providedscope> dependency> <dependency> <groupId>javax.servletgroupId> <artifactId>jsp-apiartifactId> <version>2.0version> <scope>providedscope> dependency> - 新建web项目（参考本文：idea如何创建简单的web项目（基于Maven）？）
- 新建类，让它继承HttpServlet类，并重写里边的doGet()、doPost()方法等
public class MyServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String msg = "hello."; String action = req.getParameter("action"); if (action.equals("add")) { msg = "执行了add方法。。。"; } req.getSession().setAttribute("msg", msg); req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } } - 在web.xml中配置servlet
<servlet> <servlet-name>MyServletservlet-name> <servlet-class>cn.cnyasin.servlet.MyServletservlet-class> servlet> <servlet-mapping> <servlet-name>MyServletservlet-name> <url-pattern>/servleturl-pattern> servlet-mapping> - idea设置中添加Application Servers：Tomcat（参考idea相关笔记）
为什么要学习SpringMVC？
- 特点
- 轻量级，简单易学
- 高效，基于请求响应的MVC架构
- 于Spring兼容性好，无缝结合
- 预定大于配置
- 功能强大：restful、数据验证、格式化、本地化、主题等
- 关键是都在用
- 所有的请求都是围绕DispatcherServlet[调度Servlet]设计
一个基于XML配置的SpringMVC
- 新建web项目（参考本文：idea如何创建简单的web项目（基于Maven）？）
- 确定导入了依赖
- 配置web.xml，注册DispatcherServlet
<servlet> <servlet-name>app1servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class> <init-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:app1-servlet.xmlparam-value> init-param> <load-on-startup>1load-on-startup> servlet> <servlet-mapping> <servlet-name>app1servlet-name> <url-pattern>/url-pattern> servlet-mapping> - 新建Spring配置：classpath:app1-servlet.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 "> <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/> <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> bean> <bean name="/hello" class="cn.cnyasin.controller.HelloController"/> beans> - 新建jsp目录：
/WEB-INF/jsp/ - 新建一个控制器类，让其实现Controller接口
package cn.cnyasin.controller; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class HelloController implements Controller { public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { ModelAndView view = new ModelAndView(); view.addObject("msg", "hello."); view.setViewName("hello"); return view; } } - 在jsp目录新建视图文件：
/WEB-INF/jsp/hello.jsp<%@ page contentType="text/html;charset=UTF-8" language="java" %>hello ${msg} - idea设置中添加Application Servers：Tomcat（参考idea相关笔记）
- run
- 问题：
- 配置无误，页面404？
- 排查module下是否有lib目录并且加载了全部依赖：
Project Structure -> Artifacts -> 你的module -> WEB-INF -> lib
- 排查module下是否有lib目录并且加载了全部依赖：
- 配置无误，页面404？
一个基于注解的SpringMVC
- 新建web项目（参考本文：idea如何创建简单的web项目（基于Maven）？）
- 确定导入了依赖
- 配置web.xml，注册DispatcherServlet
<servlet> <servlet-name>app1servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class> <init-param> <param-name>contextConfigLocationparam-name> <param-value>classpath:app1-servlet.xmlparam-value> init-param> <load-on-startup>1load-on-startup> servlet> <servlet-mapping> <servlet-name>app1servlet-name> <url-pattern>/url-pattern> servlet-mapping> - 新建Spring配置：classpath:app1-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="cn.cnyasin"/> <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> - 新建jsp目录：
/WEB-INF/jsp/ - 新建一个控制器类，添加注解
package cn.cnyasin.controller; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; @Controller public class AnnotationController { @RequestMapping("/annotation") public String annotation(Model model){ model.addAttribute("msg", "annotation..."); return "annotation"; // return 视图文件名 } } - 在jsp目录新建视图文件：
/WEB-INF/jsp/annotation.jsp<%@ page contentType="text/html;charset=UTF-8" language="java" %>annotation ${msg} - 排查module下是否有lib目录并且加载了全部依赖：
Project Structure -> Artifacts -> 你的module -> WEB-INF -> lib - idea设置中添加Application Servers：Tomcat（参考idea相关笔记）
- run
一个restful风格的SpringMVC
- 具体步骤跟上边的基本一样，这里仅记录Controller代码
package cn.cnyasin.controller; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.*; @Controller public class RestfulController { /* 方式一 */ @RequestMapping("/rest/test/{a}/{b}") /* 方式二 */ // @RequestMapping(path = "/rest/test/{a}/{b}", method = RequestMethod.GET) /* 方式三 */ // @RequestMapping(value = "/rest/test/{a}/{b}", method = RequestMethod.GET) /* 方式四 */ // @GetMapping("/rest/test/{a}/{b}") // @PostMapping("/rest/test/{a}/{b}") public String test(@PathVariable int a, @PathVariable int b, Model model) { int sum = a + b; model.addAttribute("msg", sum); return "restful"; } }
重定向redirect
- 语法：
return "redirect:/foo/bar";// @PostMapping("/rest/test/{a}/{b}") public String test(@PathVariable int a, @PathVariable int b, Model model) { int sum = a + b; model.addAttribute("msg", sum); //return "redirect:/index.jsp"; return "redirect:/rest/test2"; } @GetMapping("/rest/test2") public String test2(Model model) { model.addAttribute("msg", "redirect ok..."); return "restful"; }
获取参数
- 建议所有参数都加上@RequestParam()
package cn.cnyasin.controller; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; @Controller public class EncodingController { @RequestMapping("/encoding/test1") public String test1(@RequestParam("data") String data, Model model) { model.addAttribute("msg", data); return "encoding"; } }
处理乱码问题
- 方式一：你可以自己写一个类，让其实现Filter接口，然后重写doFilter方法，然后注册到web.xml
- 自定义过滤器：MyFilter.java
package cn.cnyasin.utils; import javax.servlet.*; import java.io.IOException; public class MyFilter implements Filter { public void init(FilterConfig filterConfig) throws ServletException {} public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); chain.doFilter(request, response); } public void destroy() {} } - web.xml中添加：
<filter> <filter-name>MyFilterfilter-name> <filter-class>cn.cnyasin.utils.MyFilterfilter-class> filter> <filter-mapping> <filter-name>MyFilterfilter-name> <url-pattern>/*url-pattern> filter-mapping>
- 自定义过滤器：MyFilter.java
- 方式二：SpringMVC提供了强大的乱码过滤器，只需要在web.xml中添加：
<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>
JSON格式数据传输
- 实现方式
- 方式一
- 控制器使用@RestController注解
- 方法正常注解@RequestMapping、@GetMapping等
- 示例代码
@RestController public class JsonController { @RequestMapping("/json/test1") public String test1(){ return "test1"; } }
- 方拾二
- 控制器使用@Controller注解
- 方法除了使用正常注解@RequestMapping、@GetMapping等以外，额外添加一个@ResponseBody注解
- 示例代码
@Controller public class JsonController { @RequestMapping("/json/test1") @ResponseBody public String test1(){ return "test1"; } }
- 方式一
- 处理JSON乱码
- 方式一：produces参数（不推荐）
@RequestMapping(value = "/json/test1", produces = "application/json;charset=utf-8") - 方式二：SpringMVC统一乱码解决（推荐）
- 在spring-mvc.xml中添加如下代码（此方法需要导入jackson依赖）
<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>
- 在spring-mvc.xml中添加如下代码（此方法需要导入jackson依赖）
- 方式一：produces参数（不推荐）
Jackson使用
- 结合上一节“JSON格式数据传输”代码
- Maven导入Jackson依赖
<dependency> <groupId>com.fasterxml.jackson.coregroupId> <artifactId>jackson-databindartifactId> <version>2.12.5version> dependency> - 更新lib目录，确定加入Jackson依赖
- 在控制器类中要使用json传输数据的方法中使用
@RestController public class JsonController { // @RequestMapping(value = "/json/test1", produces = "application/json;charset=utf-8") @RequestMapping(value = "/json/test1") public String test1() throws JsonProcessingException { HashMap user = new HashMap(); user.put("id", 123); user.put("name", "张三"); user.put("age", 12); List userList = new ArrayList(); userList.add(user); HashMap data = new HashMap(); data.put("total", 10); data.put("userList", userList); ObjectMapper objectMapper = new ObjectMapper(); String jsonStr = objectMapper.writeValueAsString(data); return jsonStr; } }
Fastjson使用
- 使用方法类似“Jackson”，但是据说bug较多，此处就不练习了
- Maven导入Jackson依赖
<dependency> <groupId>com.alibabagroupId> <artifactId>fastjsonartifactId> <version>1.2.76version> dependency>
SSM整合
- 依赖：
- Junit（junit）
- 数据库驱动（mysql-connector-java）
- 连接池（默认、c3p0、dhcp、druid等）
- Servlet（servlet-api）
- JSP（jsp-api，jstl）
- Mybatis（mybatis）
- Mybatis-Spring（mybatis-spring）
- Spring（spring-mvc，spring-jdbc）
- 整合分层后配置文件列表（具体文件内容已经单独列为一个文件夹：SSM分层配置）
- /pom.xml
- /web/WEB-INF/web.xml
- /classpath:jdbc.properties
- /classpath:mybatis-config.xml
- /classpath:applicationContext.xml
- /classpath:spring-mvc.xml
- /classpath:spring-service.xml
- /classpath:spring-dao.xml
- 整合分层后以书籍查询为例代码演示
- cn.cnyasin.pojo.Book.jsva
package cn.cnyasin.pojo; public class Book { private int id; private String name; private int status; private long createdAt; // getter,setter... } - cn.cnyasin.dao.BookMapper.java
package cn.cnyasin.dao; import cn.cnyasin.pojo.Book; import java.util.List; public interface BookMapper { // 增加 int insertOne(Book book); // 修改 int updateOne(Book book); // 删除 int deleteOne(int id); // 一个 Book getOne(int id); // 所有 List<Book> getAll(); } - cn.cnyasin.dao.BookMapper.xml
DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="cn.cnyasin.dao.BookMapper"> <insert id="insertOne" parameterType="book"> insert into book (`name`, `status`, `created_at`) values (#{name}, #{status}, #{createdAt}) insert> <update id="updateOne" parameterType="book"> update book set `name` = #{name} where id = #{id} update> <delete id="deleteOne" parameterType="int"> delete from book where id = #{id} delete> <select id="getOne" resultType="book"> select * from book where id = #{id} select> <select id="getAll" resultMap="bookList"> select * from book select> <resultMap id="bookList" type="book"> <result property="createdAt" column="created_at"/> resultMap> mapper> - cn.cnyasin.service.BookService.java
package cn.cnyasin.service; import cn.cnyasin.pojo.Book; import java.util.List; public interface BookService { // 增加 int insertOne(Book book); // 修改 int updateOne(Book book); // 删除 int deleteOne(int id); // 一个 Book getOne(int id); // 所有 List<Book> getAll(); // 事务测试：插入&删除&查全部 List<Book> insertDeleteGetAll(Book book); } - cn.cnyasin.service.BookServiceImpl.java
package cn.cnyasin.service; import cn.cnyasin.dao.BookMapper; import cn.cnyasin.pojo.Book; import java.util.List; public class BookServiceImpl implements BookService { private BookMapper bookMapper; public void setBookMapper(BookMapper bookMapper) { this.bookMapper = bookMapper; } public int insertOne(Book book) { return bookMapper.insertOne(book); } public int updateOne(Book book) { return bookMapper.updateOne(book); } public int deleteOne(int id) { return bookMapper.deleteOne(id); } public Book getOne(int id) { return bookMapper.getOne(id); } public List<Book> getAll() { return bookMapper.getAll(); } public List<Book> insertDeleteGetAll(Book book) { bookMapper.insertOne(book); int i = 10 / 0; bookMapper.deleteOne(15); return bookMapper.getAll(); } } - cn.cnyasin.controller.BookController.java
package cn.cnyasin.controller; import cn.cnyasin.pojo.Book; import cn.cnyasin.service.BookService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import java.util.List; @Controller public class BookController { @Autowired @Qualifier("bookServiceImpl") private BookService bookService; @RequestMapping("/book/list") public String getAllBook(Model model) { List<Book> list = bookService.getAll(); model.addAttribute("list", list); return "bookList"; } @RequestMapping("/book/insert") public String insertDeleteGetAll(Model model) { Book book = new Book(); book.setName("哈喽啊"); book.setStatus(1); book.setCreatedAt(new Date().getTime() / 1000); bookService.insertDeleteGetAll(book); return "redirect:/book/list"; } } - WEB-INF/index.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %>bookList - WEB-INF/jsp/bookList.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %>bookList 书籍列表
编号 名字 状态 时间 ${book.id} ${book.name} ${book.status} ${book.createdAt}
- cn.cnyasin.pojo.Book.jsva
SpringMVC拦截器（Interceptor）
- 概念？
- 类似于Servlet开发中的过滤器Filter，不过Filter是Tomcat容器部分的功能，而SpringMVC拦截器是spring的功能。
- 拦截器是Spring的AOP思想的具体应用。
- 过滤器和拦截器区别
- 过滤器Filter
- 是Servlet规范中的一部分，任何JavaWeb工程都可以拥有
- 在url-pattern中配置了/*以后，可以对所有要访问的资源过滤
- 拦截器
- 是SpringMVC自己的
- 拦截器只会拦截控制器方法，不会拦截任何静态资源
- 过滤器Filter
- 如何使用拦截器
- 自定义拦截器类，让其实现HandlerInterceptor接口，重写里边的三个方法
- 然后在Spring的配置文件中注入拦截器配置
- 核心代码
- /web/WEB-INF/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:applicationContext.xmlparam-value> init-param> <load-on-startup>1load-on-startup> servlet> <servlet-mapping> <servlet-name>springmvcservlet-name> <url-pattern>/url-pattern> servlet-mapping> <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> web-app> - classpath:applicationContext.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="cn.cnyasin.controller"/> <mvc:default-servlet-handler/> <mvc:annotation-driven/> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/**"/> <bean class="cn.cnyasin.interceptor.TokenInterceptor"/> mvc:interceptor> mvc:interceptors> beans> - cn.cnyasin.controller.Testcontroller.java
package cn.cnyasin.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class TestController { @RequestMapping("/test/test1") public String test1() { return "{json}"; } } - cn.cnyasin.interceptor.TokenInterceptor.java
package cn.cnyasin.interceptor; import org.springframework.web.servlet.HandlerInterceptor; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class TokenInterceptor implements HandlerInterceptor { public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { String token = request.getParameter("token"); System.out.println(token); if (null == token || !token.equals("token")) { request.getRequestDispatcher("/").forward(request, response); } return true; } }
- /web/WEB-INF/web.xml