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前言
Spring MVC 是构建在 Servlet API 上的原生框架,并从一开始就包含在 Spring 框架中。本文主要通过简述 Spring MVC 的架构及分析,并用 Spring Boot + Spring MVC + MyBatis(SSM)+ Thymeleaf(模板引擎)框架来简单快速构建一个 Web 项目。
Web MVC 架构及分析
MVC 三层架构如图所示,红色字体代表核心模块。其中 MVC 各分层分别为:
- Model(模型层) 处理核心业务(数据)逻辑,模型对象负责在数据库中存取数据。这里的“数据”不仅限于数据本身,还包括处理数据的逻辑。
- View(视图层) 用于展示数据,通常数据依据模型数据创建。
- Controller(控制器层) 用于处理用户输入请求和响应输出,从试图读取数据,控制用户输入,并向模型发送数据。Controller 是在 Model 和 View 之间双向传递数据的中间协调者。
Spring MVC 架构及分析
Spring MVC 处理一个 HTTP 请求的流程,如图所示:
整个过程详细介绍:
1. 用户发送请求至前端控制器 DispatcherServlet。
2.DispatcherServlet 收到请求调用处理器映射器 HandlerMapping。
3. 处理器映射器根据请求 URL 找到具体的 Controller 处理器返回给 DispatcherServlet。
4.DispatcherServlet 通过处理器适配器 HandlerAdapter 调用 Controller 处理请求。
5. 执行 Controller 处理器的方法。
6.Controller 执行完成返回 ModelAndView。
7.HandlerAdapter 将 Controller 执行结果 ModelAndView 返回给 DispatcherServlet。
8.DispatcherServlet 将 ModelAndView 的 ViewName 传给视图解析器 ViewReslover。
9.ViewReslover 解析后返回具体的视图 View。
10.DispatcherServlet 传递 Model 数据给 View,对 View 进行渲染(即将模型数据填充至视图中)。
11-12.DispatcherServlet 响应用户。
Spring Boot + Spring MVC + MyBatis + Thymeleaf
本段我们主要通过构建项目,实现一个分页查询。
1. 项目构建
项目结构如图所示:
1.1 pom 引入相关依赖
<?xml version="1.0" encoding="UTF-8"?> | |
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> | |
<modelVersion>4.0.0</modelVersion> | |
<parent> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-starter-parent</artifactId> | |
<version>2.1.9.RELEASE</version> | |
<relativePath/> <!-- lookup parent from repository --> | |
</parent> | |
<groupId>cn.zwqh</groupId> | |
<artifactId>spring-boot-ssm-thymeleaf</artifactId> | |
<version>0.0.1-SNAPSHOT</version> | |
<name>spring-boot-ssm-thymeleaf</name> | |
<description>spring-boot-ssm-thymeleaf</description> | |
<properties> | |
<java.version>1.8</java.version> | |
</properties> | |
<dependencies> | |
<dependency> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-starter-web</artifactId> | |
</dependency> | |
<dependency> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-starter-test</artifactId> | |
<scope>test</scope> | |
</dependency> | |
<dependency> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-starter-jdbc</artifactId> | |
</dependency> | |
<!-- 热部署模块 --> | |
<dependency> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-devtools</artifactId> | |
<optional>true</optional> <!-- 这个需要为 true 热部署才有效 --> | |
</dependency> | |
<!-- mysql 数据库驱动. --> | |
<dependency> | |
<groupId>mysql</groupId> | |
<artifactId>mysql-connector-java</artifactId> | |
<scope>runtime</scope> | |
</dependency> | |
<!-- mybaits --> | |
<dependency> | |
<groupId>org.mybatis.spring.boot</groupId> | |
<artifactId>mybatis-spring-boot-starter</artifactId> | |
<version>2.1.0</version> | |
</dependency> | |
<!-- pagehelper --> | |
<dependency> | |
<groupId>com.github.pagehelper</groupId> | |
<artifactId>pagehelper-spring-boot-starter</artifactId> | |
<version>1.2.12</version> | |
</dependency> | |
<!-- thymeleaf --> | |
<dependency> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-starter-thymeleaf</artifactId> | |
</dependency> | |
</dependencies> | |
<build> | |
<plugins> | |
<plugin> | |
<groupId>org.springframework.boot</groupId> | |
<artifactId>spring-boot-maven-plugin</artifactId> | |
</plugin> | |
</plugins> | |
</build> | |
</project> |
1.2 WebMvcConfig 配置
package cn.zwqh.springboot.config; | |
import org.springframework.context.annotation.Configuration; | |
import org.springframework.core.Ordered; | |
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry; | |
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry; | |
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry; | |
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; | |
@Configuration | |
public class WebMvcConfig extends WebMvcConfigurationSupport { | |
/** | |
* 静态资源配置 | |
*/ | |
@Override | |
public void addResourceHandlers(ResourceHandlerRegistry registry) {registry.addResourceHandler("/statics/**").addResourceLocations("classpath:/statics/");// 静态资源路径 css,js,img 等 | |
registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");// 视图 | |
registry.addResourceHandler("/mapper/**").addResourceLocations("classpath:/mapper/");//mapper.xml | |
super.addResourceHandlers(registry); | |
} | |
/** | |
* 视图控制器配置 | |
*/ | |
@Override | |
public void addViewControllers(ViewControllerRegistry registry) {registry.addViewController("/").setViewName("/index");// 设置默认跳转视图为 /index | |
registry.setOrder(Ordered.HIGHEST_PRECEDENCE); | |
super.addViewControllers(registry); | |
} | |
/** | |
* 视图解析器配置 控制 controller String 返回的页面 视图跳转控制 | |
*/ | |
@Override | |
public void configureViewResolvers(ViewResolverRegistry registry) {// registry.viewResolver(new InternalResourceViewResolver("/jsp/", ".jsp")); | |
super.configureViewResolvers(registry); | |
} | |
} |
1.3 application.properties 配置
#thymeleaf | |
spring.thymeleaf.cache=false | |
#datasource | |
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver | |
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/db_test?useUnicode=true&characterEncoding=UTF-8&useSSL=true | |
spring.datasource.username=root | |
spring.datasource.password=root | |
#mybatis | |
mybatis.mapper-locations=classpath:/mapper/*.xml | |
#logging | |
logging.path=/user/local/log | |
logging.level.cn.zwqh=debug | |
logging.level.org.springframework.web=info | |
logging.level.org.mybatis=error |
1.4 Controller
@Controller | |
@RequestMapping("/user") | |
public class UserController { | |
@Autowired | |
private UserService userService; | |
@GetMapping("/list") | |
public ModelAndView showUserList(int pageNum, int pageSize) {PageInfo<UserEntity> pageInfo = userService.getUserList(pageNum, pageSize); | |
ModelAndView modelAndView=new ModelAndView(); | |
modelAndView.setViewName("index"); | |
modelAndView.addObject("pageInfo",pageInfo); | |
return modelAndView; | |
} | |
} |
1.5 Service 及 ServiceImpl
UserService
public interface UserService {PageInfo<UserEntity> getUserList(int pageNum, int pageSize); | |
} |
UserServiceImpl
@Service | |
public class UserServiceImpl implements UserService{ | |
@Autowired | |
private UserDao userDao; | |
@Override | |
public PageInfo<UserEntity> getUserList(int pageNum, int pageSize) {PageHelper.startPage(pageNum, pageSize); | |
List<UserEntity> list=userDao.getAll(); | |
PageInfo<UserEntity> pageData= new PageInfo<UserEntity>(list); | |
System.out.println("当前页:"+pageData.getPageNum()); | |
System.out.println("页面大小:"+pageData.getPageSize()); | |
System.out.println("总数:"+pageData.getTotal()); | |
System.out.println("总页数:"+pageData.getPages()); | |
return pageData; | |
} | |
} |
1.6 Dao
public interface UserDao { | |
/** | |
* 获取所有用户 | |
* @return | |
*/ | |
List<UserEntity> getAll();} |
记得在启动类里加上 @MapperScan
@SpringBootApplication | |
@MapperScan("cn.zwqh.springboot.dao") | |
public class SpringBootSsmThymeleafApplication {public static void main(String[] args) {SpringApplication.run(SpringBootSsmThymeleafApplication.class, args); | |
} | |
} |
1.7 Mapper.xml
<?xml version="1.0" encoding="UTF-8"?> | |
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" | |
"http://mybatis.org/dtd/mybatis-3-mapper.dtd"> | |
<mapper namespace="cn.zwqh.springboot.dao.UserDao"> | |
<resultMap type="cn.zwqh.springboot.model.UserEntity" id="user"> | |
<id property="id" column="id"/> | |
<result property="userName" column="user_name"/> | |
<result property="userSex" column="user_sex"/> | |
</resultMap> | |
<!-- 获取所有用户 --> | |
<select id="getAll" resultMap="user"> | |
select * from t_user | |
</select> | |
</mapper> | |
1.8 实体 UserEntity
public class UserEntity { | |
private Long id; | |
private String userName; | |
private String userSex; | |
public Long getId() {return id;} | |
public void setId(Long id) {this.id = id;} | |
public String getUserName() {return userName;} | |
public void setUserName(String userName) {this.userName = userName;} | |
public String getUserSex() {return userSex;} | |
public void setUserSex(String userSex) {this.userSex = userSex;} | |
} |
1.9 html 页面
<!DOCTYPE html> | |
<html lang="en" xmlns:th="http://www.thymeleaf.org"> | |
<head> | |
<meta charset="UTF-8"> | |
<title>Insert title here</title> | |
</head> | |
<body> | |
<p>Thymeleaf 是一个用于 Web 和独立环境的现代服务器端 Java 模板引擎。SpringBoot 推荐使用 Thymeleaf。</p> | |
<p> 下面是表格示例:</p> | |
<table border="1"> | |
<thead> | |
<tr> | |
<th width="100">ID</th> | |
<th width="100"> 姓名 </th> | |
<th width="100"> 性别 </th> | |
</tr> | |
</thead> | |
<tbody> | |
<tr th:each="user:${pageInfo.list}"> | |
<td th:text="${user.id}"></td> | |
<td th:text="${user.userName}"></td> | |
<td th:text="${user.userSex}"></td> | |
</tr> | |
</tbody> | |
</table> | |
<p> | |
<a th:href="${'/user/list?pageNum='+(pageInfo.pageNum-1>=1?pageInfo.pageNum-1:1)+'&pageSize=10'}"> 上一页 </a> | |
<a th:href="${'/user/list?pageNum='+(pageInfo.pageNum+1<=pageInfo.pages?pageInfo.pageNum+1:pageInfo.pages)+'&pageSize=10'}"> 下一页 </a> | |
总数:<span th:text="${pageInfo.total}"></span> | |
</p> | |
</body> | |
</html> |
测试
通过浏览器访问:http://127.0.0.1:8080/user/list?pageNum=1&pageSize=10 进行测试。效果如图:
示例代码
github
码云
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原文标题:Spring Boot 2.X(三):使用 Spring MVC + MyBatis + Thymeleaf 开发 web 应用
原文地址:https://www.zwqh.top/article/info/2
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