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:
[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-phe98Pbv-1570697030393)(https://img.zwqh.top/article/2019/10/1570607009720.png)]
示例代码
非特殊说明,本文版权归 朝雾轻寒 所有,转载请注明出处.
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
转载:https://blog.csdn.net/u014217825/article/details/102485476