springboot整合web

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整合Servlet、Filter、Listener

servlet

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//@WebServlet(name = "HelloServlet",urlPatterns = "/helloservlet")
public class HelloServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.service(req, resp);
        System.out.println("HelloServlet");
    }
}

启动器：

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@SpringBootApplication
public class AppServlet {
    public static void main(String[] args) {

        SpringApplication.run(AppServlet.class, args);
    }
    //Servlet 组件的注册，不用再在Servlet上添加注解
    @Bean
    public ServletRegistrationBean getServletRegistrationBean(){
        ServletRegistrationBean bean = new ServletRegistrationBean(new HelloServlet());
        bean.addUrlMappings("/helloservlet");
        return bean;
    }
}

运行可以直接在浏览器访问

Filter

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//@WebFilter
public class HelloFilter implements Filter {
    @Override
    public void destroy() {
    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
        System.out.println("进入 Filter");
        arg2.doFilter(arg0, arg1);
        System.out.println("离开 Filter");
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
    }
}

@SpringBootApplication
public class AppFilter {
    public static void main(String[] args) {

        SpringApplication.run(AppFilter.class, args);
    }

    //Servlet 组件的注册，不用再在Servlet上添加注解
    @Bean
   public ServletRegistrationBean getServletRegistrationBean(){
        ServletRegistrationBean bean = new ServletRegistrationBean(new HelloServlet());
        bean.addUrlMappings("/helloservlet");//bean.addInitParameter("paramName", "paramValue");
        return bean;
    }
    /**
     * 注册 Filter
     */
    @Bean
    public FilterRegistrationBean getFilterRegistrationBean() {
        FilterRegistrationBean bean = new FilterRegistrationBean(new HelloFilter());
        //bean.addUrlPatterns(new String[]{"*.do","*.jsp"});
        bean.addUrlPatterns("/helloservlet");
        return bean;
    }
}

Listener

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//@WebListener
public class HelloListener implements ServletContextListener {
    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
    }

    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        System.out.println("HelloListener..init.....");
    }
}

/**
* 注册 listener
*/
@Bean
public ServletListenerRegistrationBean<HelloListener> getServletListenerRegistrationBean(){
    ServletListenerRegistrationBean<HelloListener> bean= new ServletListenerRegistrationBean<HelloListener>(new HelloListener());
    return bean;
}

运行后直接在控制台显示HelloListener..init…..

访问静态资源和上传

注意目录名称必须是 static，在 src/main/webapp 目录名称必须要 webapp

html放在static中

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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>文件上传</title>
</head>
<body>
        <form action="fileUploadController" method="post" enctype="multipart/form-data">
                上传文件：<input type="file" name="filename"/><br/>
                <input type="submit"/>
        </form>
</body>
</html>
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@RestController //表示该类下的方法的返回值会自动做 json 格式的转换
public class FileUploadController {
    /*
     * 处理文件上传
     */
    @RequestMapping("/fileUploadController")
    public Map<String, Object> fileUpload(MultipartFile filename)throws Exception{
        System.out.println(filename.getOriginalFilename());
        filename.transferTo(new File("C:/"+filename.getOriginalFilename()));
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "ok");
        return map;
    }
}

@SpringBootApplication
public class App {
    public static void main(String[] args) {

        SpringApplication.run(App.class, args);
    }
}

启动访问index.html

上传成功

数据访问

@RestController
默认类中的方法都会以json的格式返回。

自定义Property，配置在application.properties中。

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com.hu.title=QQQ
com.hu.description=QQQa

自定义配置类@Component

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public class NeoProperties {
    @Value("${com.hu.title}")
    private String title;
    @Value("${com.hu.description}")
    private String description;
    //省略getter settet方法
}

整合视图层

jsp

在maven项目main文件夹下创建webapp/WEB-INF/jsp，添加user.jsp文件：

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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
</head>
<body>
<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
    </tr>
    <c:forEach items="${list }" var="user">
        <tr>
            <td>${user.id }</td>
            <td>${user.name }</td>
            <td>${user.age }</td>
        </tr>
    </c:forEach>
</table>
</body>
</html>

IDEA中设置

20200420155905

控制器

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@Controller
public class UserController {
    //此处模拟由数据库得到的数据
    static List<User> list;
    static{
        list = new ArrayList<>();
        list.add(new User(1, "江小白", 20));
        list.add(new User(2, "张三丰", 22));
        list.add(new User(3, "王八蛋", 24));
    }
    @RequestMapping("show")
    public String showUser(Model model) {
        model.addAttribute("list", list);
        //跳转视图
        return "user";
    }
}

application.properties配置文件

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spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp

POM.xml

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<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <!-- 需要继承父项目-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.8.RELEASE</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>
    <artifactId>spring-boot-view</artifactId>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <!-- 注入 SpringBoot 启动坐标 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- 测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- 对jsp的支持的依赖 -->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- jstl标签库 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>
    </dependencies>
</project>

启动器：

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// 启动器存放的位置。启动器可以和 controller 位于同一个包下，或者位于 controller 的上一级包中;
// 如放到 controller 的平级或及子包以下不能访问到，除非加上@ComponentScan("com.hu.controller")。
// @ComponentScan("com.hu.controller")
@SpringBootApplication
public class ViewApp {
    public static void main(String[] args) {
        SpringApplication.run(ViewApp.class, args);
    }
}

注意：There was an unexpected error (type=Not Found, status=404).

/WEB-INF/jsp/user.jsp问题：

解决方式：

20200420155827

freemarker

application.properties配置，这里基本是默认配置，可以不写也可以运行成功。

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spring.freemarker.template-loader-path=classpath:/templates/
spring.freemarker.charset=utf-8
spring.freemarker.cache=false
spring.freemarker.expose-request-attributes=true
spring.freemarker.expose-session-attributes=true
spring.freemarker.expose-spring-macro-helpers=true
spring.freemarker.suffix=.ftl

加入依赖：

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

创建文件：src\main\resources\templates\userhtml.ftl

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<html>
<head>
    <title>展示用户数据</title>
    <meta charset="utf-9"></meta>
</head>
<body>
<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>姓名</th>
        <th>年龄</th>
    </tr>
    <#list list as user >
        <tr>
            <td>${user.id}</td>
            <td>${user.name}</td>
            <td>${user.age}</td>
        </tr>
    </#list>
</table>
</body>
</html>

控制器：

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@Controller
public class UserController {
    //此处模拟由数据库得到的数据
    static List<User> list;
    static{
        list = new ArrayList<>();
        list.add(new User(1, "江小白", 20));
        list.add(new User(2, "张三丰", 22));
        list.add(new User(3, "王八蛋", 24));
    }
    @RequestMapping("userhtml")
    public String showUserToHTML(Model model) {
        model.addAttribute("list", list);
        //跳转视图
        return "userhtml";
    }
}

Thymeleaf

主要代码如下：

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

模板：templates/userthy.html

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<html>
<head>
    <title>Thymeleaf Demo</title>
    <meta charset="utf-9"></meta>
</head>
<body>
<table border="1" align="center" width="50%">
    <tr>
        <th>ID</th>
        <th>姓名</th>
        <th>年龄</th>
    </tr>
    <tr th:each="user : ${list}">
        <td th:text="${user.id}"</td>
        <td th:text="${user.name}"</td>
        <td th:text="${user.age}"</td>
    </tr>
</table>
</body>
</html>

控制器：

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@Controller
public class UserController {
    //此处模拟由数据库得到的数据
    static List<User> list;
    static{
        list = new ArrayList<>();
        list.add(new User(1, "江小白", 20));
        list.add(new User(2, "张三丰", 22));
        list.add(new User(3, "王八蛋", 24));
    }
    @RequestMapping("userthy")
    public String showUserToThy(Model model) {
        model.addAttribute("list", list);
        //跳转视图
        return "userthy";
    }
}
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