Spring Boot 2.X(三)：使用 Spring MVC + MyBatis + Thymeleaf 開發 web 應用

時間 2020-01-12

標籤 spring boot 2.x 使用 mvc mybatis thymeleaf 開發 web 應用欄目 Spring 简体版

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前言

Spring MVC 是構建在 Servlet API 上的原生框架，並從一開始就包含在 Spring 框架中。本文主要經過簡述 Spring MVC 的架構及分析，並用 Spring Boot + Spring MVC + MyBatis （SSM）+ Thymeleaf（模板引擎）框架來簡單快速構建一個 Web 項目。css

Web MVC 架構及分析

MVC 三層架構如圖所示，紅色字體表明核心模塊。其中 MVC 各分層分別爲：html

Model （模型層）處理核心業務（數據）邏輯，模型對象負責在數據庫中存取數據。這裏的「數據」不只限於數據自己，還包括處理數據的邏輯。
View（視圖層）用於展現數據，一般數據依據模型數據建立。
Controller（控制器層）用於處理用戶輸入請求和響應輸出，從試圖讀取數據，控制用戶輸入，並向模型發送數據。Controller 是在 Model 和 View 之間雙向傳遞數據的中間協調者。

Spring MVC 架構及分析

Spring MVC 處理一個 HTTP 請求的流程，如圖所示：

整個過程詳細介紹：
1.用戶發送請求至前端控制器 DispatcherServlet。
2.DispatcherServlet 收到請求調用處理器映射器 HandlerMapping。
3.處理器映射器根據請求 URL 找到具體的 Controller 處理器返回給 DispatcherServlet。
4.DispatcherServlet 經過處理器適配器 HandlerAdapter 調用 Controller 處理請求。
5.執行 Controller 處理器的方法。
6.Controller 執行完成返回 ModelAndView。
7.HandlerAdapter 將 Controller 執行結果 ModelAndView 返回給 DispatcherServlet。
8.DispatcherServlet 將 ModelAndView 的 ViewName 傳給視圖解析器 ViewReslover。
9.ViewReslover 解析後返回具體的視圖 View。
10.DispatcherServlet 傳遞 Model 數據給 View，對 View 進行渲染（即將模型數據填充至視圖中）。
11-12.DispatcherServlet 響應用戶。前端

Spring Boot + Spring MVC + MyBatis + Thymeleaf

本段咱們主要經過構建項目，實現一個分頁查詢。java

1.項目構建

項目結構如圖所示：
mysql

1.1 pom 引入相關依賴

<?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>

        <!-- 熱部署模塊 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional> <!-- 這個須要爲 true 熱部署纔有效 -->
        </dependency>


        <!-- mysql 數據庫驅動. -->
        <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 {

    /**
     * 靜態資源配置
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {    
        registry.addResourceHandler("/statics/**").addResourceLocations("classpath:/statics/");//靜態資源路徑 css,js,img等
        registry.addResourceHandler("/templates/**").addResourceLocations("classpath:/templates/");//視圖
        registry.addResourceHandler("/mapper/**").addResourceLocations("classpath:/mapper/");//mapper.xml
        super.addResourceHandlers(registry);
        
    }

    /**
     * 視圖控制器配置
     */
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {    
        registry.addViewController("/").setViewName("/index");//設置默認跳轉視圖爲 /index
        registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
        super.addViewControllers(registry);
        
        
    }
    /**
     * 視圖解析器配置  控制controller String返回的頁面    視圖跳轉控制 
     */
    @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

UserServicegit

public interface UserService {

    PageInfo<UserEntity> getUserList(int pageNum, int pageSize);

}

UserServiceImplgithub

@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("當前頁："+pageData.getPageNum());
        System.out.println("頁面大小："+pageData.getPageSize());
        System.out.println("總數："+pageData.getTotal());    
        System.out.println("總頁數："+pageData.getPages());    
        return pageData;
    }
}

1.6 Dao

public interface UserDao {
    /**
     * 獲取全部用戶
     * @return
     */
    List<UserEntity> getAll();
    
}

記得在啓動類里加上@MapperScanweb

@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>
    <!-- 獲取全部用戶 -->
    <select id="getAll" resultMap="user">
        select * from t_user
    </select>
</mapper>

1.8 實體 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 頁面

<!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是一個用於Web和獨立環境的現代服務器端Java模板引擎。SpringBoot推薦使用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">性別</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'}">上一頁</a>
    
<a th:href="${'/user/list?pageNum='+(pageInfo.pageNum+1<=pageInfo.pages?pageInfo.pageNum+1:pageInfo.pages)+'&pageSize=10'}">下一頁</a>    
總數：<span th:text="${pageInfo.total}"></span>
</p>
</body>
</html>