SpringBoot项目搭建流程及thymeleaf的使用

对于数据访问层，无论是 SQL(关系型数据库) 还是 NOSQL(非关系型数据库)，Spring Boot 底层都是采用 Spring Data 的方式进行统一处理。

Sping Data 官网：https://spring.io/projects/spring-data
数据库相关的启动器 ：可以参考官方文档：
https://docs.spring.io/spring-boot/docs/2.2.5.RELEASE/reference/htmlsingle/#using-boot-starter

添加依赖pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!--添加了该依赖就要连接数据库不然会报错-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!--thymeleaf模板引擎-->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
	<groupId>org.thymeleaf</groupId>
	<artifactId>thymeleaf-spring5</artifactId>
</dependency>
<dependency>
	<groupId>org.thymeleaf.extras</groupId>
	<artifactId>thymeleaf-extras-java8time</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.21</version>
</dependency>

配置文件application.yaml

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource # 自定义数据源

    #Spring Boot 默认是不注入这些属性值的，需要自己绑定
    #druid 数据源专有配置
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true

    #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

banner.txt（springboot启动项目的图标）

命名为banner.txt文件，放在resources目录下

         *                 *                  *              *
                                                      *             *
                        *            *                             ___
  *               *                                          |     | |
        *              _________##                 *        / \    | |
                      @\\\\\\\\\##    *     |              |--o|===|-|
  *                  @@@\\\\\\\\##\       \|/|/            |---|   |d|
                    @@ @@\\\\\\\\\\\    \|\\|//|/     *   /     \  |w|
             *     @@@@@@@\\\\\\\\\\\    \|\|/|/         |  U    | |b|
                  @@@@@@@@@----------|    \\|//          |  S    |=| |
       __         @@ @@@ @@__________|     \|/           |  A    | | |
  ____|_@|_       @@@@@@@@@__________|     \|/           |_______| |_|
=|__ _____ |=     @@@@ .@@@__________|      |             |@| |@|  | |
____0_____0__\|/__@@@@__@@@__________|_\|/__|___\|/__\|/___________|_|_

                  -- 北纬

实体类Employee.java

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Employee {
    private Integer id;
    private String name;
    private String pwd;
    private String email;
    private int sex;// 0:女  1：男
    private String departmentID;
    private Department department;
    private Date birth;
    
}

mapper接口EmployeeMapper.java

@Repository
@Mapper
public interface EmployeeMapper {

    //查询所有员工
    public List<Employee> selectAllEmp();

    //添加员工信息
    public void addEmp(Employee employee);

    //删除员工信息
    public void deleteEmp(int id);

    //通过id查询员工信息
    public Employee selectEmpById(int id);

    //更新员工信息
    public void updateEmp(Employee employee);
}

映射文件EmployeeMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.helloword.mapper.EmployeeMapper"> <!-- 一般为数据表在持久层对应接口的完整路径 -->

    <!-- 查询数据表中所有数据,这相标签的id值要与数据表对应接口中的查询方法的名称要一样 -->
    <select id="selectAllEmp" resultType="com.example.helloword.entity.Employee">
        select * from springboot.emp
    </select>

    <insert id="addEmp" parameterType="com.example.helloword.entity.Employee">
        insert into emp(name,pwd,email,sex,departmentID,birth) values(#{name},#{pwd},#{email},#{sex},#{departmentID},#{birth})
    </insert>

    <delete id="deleteEmp" parameterType="int">
        delete from emp where id=#{id}
    </delete>

    <select id="selectEmpById" resultType="com.example.helloword.entity.Employee">
        select * from emp where id=#{id}
    </select>
    <update id="updateEmp" parameterType="com.example.helloword.entity.Employee">
        update emp set
        name=#{name},pwd=#{pwd},email=#{email},sex=#{sex},birth=#{birth} where id=#{id}
    </update>
</mapper>

业务层接口EmployeeService.java

public interface EmpService {
    //查询所有员工
    public List<Employee> selectAllEmp();
    //添加员工信息
    public void addEmp(Employee employee);
    //删除员工信息
    public void deleteEmp(int id);
    //通过id查询员工信息
    public Employee selectEmpById(int id);
    //更新员工信息
    public void updateEmp(Employee employee);

}

业务层实现类EmployeeServiceImpl.java

@Service("empService ")
public class EmpServiceImpl implements EmpService {
    @Autowired
    EmployeeMapper employeeMapper;
    @Override
    public List<Employee> selectAllEmp() {

        return employeeMapper.selectAllEmp();
    }

    @Override
    public void addEmp(Employee employee) {
         employeeMapper.addEmp(employee);
    }

    @Override
    public void deleteEmp(int id) {
        employeeMapper.deleteEmp(id);
    }

    @Override
    public Employee selectEmpById(int id) {
        return employeeMapper.selectEmpById(id);
    }

    @Override
    public void updateEmp(Employee employee) {
        employeeMapper.updateEmp(employee);
    }
}

控制层EmployeeController.java

@Controller
@ComponentScan(basePackages = {"com.example.helloword.config"})
public class EmployeeController {


    @Autowired
    EmployeeMapper employeeMapper;
    @Autowired
    DepartmentSerive departmentSerive;
    @Autowired
    EmpService empService;

    //查询所有的员工信息
    @GetMapping("/emps")
    public String queryEmp(Model model){
        List<Employee> empList = employeeMapper.selectAllEmp();
        model.addAttribute("emps",empList);
        for(Employee employee:empList){
            System.out.println("遍历employee:"+employee);
            System.out.println("遍历employee.getDepartmentID():===>"+employee.getBirth());
        }

        return "emp/list";
    }




    //查询部门号
    @GetMapping("/emp")
    public String selectDepartment(Model model){
        List<Department> departments = departmentSerive.selectAllDepartment();
        for(Department department:departments){
            System.out.println("遍历department：====="+department);
        }
        model.addAttribute("departments",departments);
        return "emp/add";
    }

    //添加员工信息
    @PostMapping("/emp")
    public String addEmp(HttpServletRequest request,Employee employee){
        String name = request.getParameter("name");
        String pwd = request.getParameter("pwd");
        String birth = request.getParameter("birth");
        String departmentid = request.getParameter("department.id");
        System.out.println("密码："+pwd+"；用户名："+name+";出生日期："+birth+";departmentid："+departmentid);
        /*empService.addEmp(employee);*/
        employeeMapper.addEmp(employee);
        System.out.println("添加数据成功！");
        return "redirect:/emps";
    }


    //删除员工信息
    @GetMapping("/deleteEmp/{id}")
    public String deleteEmp(@PathVariable("id") int id){
        empService.deleteEmp(id);
        System.out.println("删除员工数据成功！");
        return "redirect:/emps";
    }

    //修改员工页面
    @GetMapping("/updateEmp/{id}")
    public String updateEmp(@PathVariable("id")int id,Model model){
        Employee employee = employeeMapper.selectEmpById(id);
        System.out.println("Did:"+employee.getDepartmentID());
        model.addAttribute("employee",employee);
        return "emp/update";
    }

    @PostMapping("/updateEmp")
    public String updateEmp(Employee employee){
        empService.updateEmp(employee);
        return "redirect:/emps";
    }
}

添加了thymeleaf模板引擎并启动IndexController控制器就可以跳转到index.html页面了

登录拦截配置类MyMvcConfig.java

@Configuration
public class MyMvcConfig implements WebMvcConfigurer  {

    /**
     * 配置服务器启动自动跳转到index.html页面中
     * @param registry
     */
    //配置服务器启动自动跳转到index.html页面中
    @Override
    public void addViewControllers(ViewControllerRegistry registry){
        /*配置一个服务器启动自动跳转到首页登录页面*/
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
        /*setViewName("dashboard")对应dashboard.html，相当于起一个别名为main.html*/
        registry.addViewController("/main.html").setViewName("dashboard");
    }

    //自定义的国际化组件
    @Bean
    public LocaleResolver localeResolver(){
        return new MyLocaleResolver();
    }

    /*配置拦截器请求Bean*/
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**")
                .excludePathPatterns("/index.html","/","/user/login","/css/**","/js/**","/img/**");
    }
}

LoginHandlerInterceptor.java

public class LoginHandlerInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //登录成功后，应该有一个用户的session
        Object loginUser = request.getSession().getAttribute("loginUser");
        if(loginUser==null){
            //没有登录，跳转到登录页面
            request.setAttribute("msg","没有权限，请先登录！");
            request.getRequestDispatcher("/index.html").forward(request,response);
            return false;
        }
        else {
            return true;
        }

    }
}

Thymeleaf模板引擎的使用

Thymeleaf 官网：https://www.thymeleaf.org/
Thymeleaf 在Github 的主页：https://github.com/thymeleaf/thymeleaf
Spring官方文档：找到我们对应的版本
https://docs.spring.io/spring-boot/docs/2.2.5.RELEASE/reference/htmlsingle/#using-boot-starter

thymeleaf依赖导入

<!--thymeleaf-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

Thymeleaf 语法学习

要学习语法，还是参考官网文档最为准确，我们找到对应的版本看一下；
Thymeleaf 官网：https://www.thymeleaf.org/ ， 简单看一下官网！我们去下载Thymeleaf的官方文档！

• 我们做个最简单的练习 ：我们需要查出一些数据，在页面中展示

@RequestMapping("/t1")
public String test1(Model model){
    //存入数据
    model.addAttribute("msg","Hello,Thymeleaf");
    //classpath:/templates/test.html
    return "test";
}

• 我们要使用thymeleaf，需要在html文件中导入命名空间的约束，方便提示。
• 我们可以去官方文档的#3中看一下命名空间拿来过来：

 xmlns:th="http://www.thymeleaf.org"

• 我们去编写下前端页面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>狂神说</title>
</head>
<body>
<h1>测试页面</h1>

<!--th:text就是将div中的内容设置为它指定的值，和之前学习的Vue一样-->
<div th:text="${msg}"></div>
</body>
</html>

• 我们编写一个Controller，放一些数据

@RequestMapping("/t2")
public String test2(Map<String,Object> map){
    //存入数据
    map.put("msg","<h1>Hello</h1>");
    map.put("users", Arrays.asList("qinjiang","kuangshen"));
    //classpath:/templates/test.html
    return "test";
}

• 测试页面取出数据

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>狂神说</title>
</head>
<body>
<h1>测试页面</h1>

<div th:text="${msg}"></div>
<!--不转义-->
<div th:utext="${msg}"></div>

<!--遍历数据-->
<!--th:each每次遍历都会生成当前这个标签：官网#9-->
<h4 th:each="user :${users}" th:text="${user}"></h4>

<h4>
    <!--行内写法：官网#12-->
    <span th:each="user:${users}">[[${user}]]</span>
</h4>

</body>
</html>

拓展SpringMVC

修改SpringBoot的默认配置
这么多的自动配置，原理都是一样的，通过这个WebMVC的自动配置原理分析，我们要学会一种学习方式，通过源码探究，得出结论
SpringBoot的底层，大量用到了这些设计细节思想，所以，没事需要多阅读源码！得出结论；
SpringBoot在自动配置很多组件的时候，先看容器中有没有用户自己配置的（如果用户自己配置@bean），如果有就用用户配置的，如果没有就用自动配置的；
如果有些组件可以存在多个，比如我们的视图解析器，就将用户配置的和自己默认的组合起来！