Java_SpringBoot(6)之MVC的使用

SpringBoot MVC

应用一：开发Restful服务(推荐),(请求–>SpringMVC–>返回JSON结果)

创建Maven项目,在pom.xml文件中导入dependecy

<dependencies>
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

</dependencies>

在src/main/resources下创建application.properties文件并输入

server.port=8888
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/mysql
spring.datasource.driverClassName=com.mysql.jdbc.Driver

在src/main/java下创建com.xdl.entity目录,然后创建实体类Knowledge

在src/main/java下创建com.xdl.dao目录,然后创建接口KnowledgeDao

package cn.xdl.dao;
import cn.xdl.entity.Knowledge;
import org.springframework.data.jpa.repository.JpaRepository;
public interface KnowledgeDao extends JpaRepository<Knowledge, Integer>{

}

在src/main/java下创建com.xdl.web目录,然后创建KnowledgeController类

package cn.xdl.web;
import cn.xdl.dao.KnowledgeDao;
import cn.xdl.entity.Knowledge;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class KnowledgeController {

  @Autowired
  private KnowledgeDao knowledgeDao;

  //GET  按id查询某个知识点
  @GetMapping("/knowledge/{id}")
  public Knowledge load(@PathVariable("id")int id) {
    return knowledgeDao.findById(id).get();
  }

  //GET 分页查询知识点
  @GetMapping("/knowledge/list")
  public List<Knowledge> list(
    @RequestParam(name="page",required=false,defaultValue="1")int page,
    @RequestParam(name="size",required=false,defaultValue="3")int size){
    Pageable pageable = PageRequest.of(page-1, size);
    return knowledgeDao.findAll(pageable).getContent();
  }
}

在src/main/java下创建启动类

package cn.xdl;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class RunBoot {
  public static void main(String[] args) {
    SpringApplication.run(RunBoot.class, args);
  }
}

应用二：开发JSP应用 (请求–>SpringMVC–>JSP–>返回HTML响应结果)

创建Maven项目,在pom.xml文件中导入dependecy

<dependencies>
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <version>2.1.2.RELEASE</version>
  </dependency>

  <dependency>
      <groupId>org.apache.tomcat.embed</groupId>
      <artifactId>tomcat-embed-jasper</artifactId>
      <version>9.0.14</version>
  </dependency>

  <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
  </dependency>

</dependencies>

在src/main/resources下创建application.properties文件并输入

server.port=8888
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/mysql
spring.datasource.driverClassName=com.mysql.jdbc.Driver

#src/main/webapp
spring.mvc.view.prefix=/
spring.mvc.view.suffix=.jsp

在src/main/java下创建com.xdl.entity目录,然后创建实体类News

在src/main/java下创建com.xdl.dao目录,然后创建接口NewsDao

package cn.xdl.dao;
import org.springframework.data.jpa.repository.JpaRepository;
import cn.xdl.entity.News;
public interface NewsDao extends JpaRepository<News, Integer> {

}

在src/main/java下创建com.xdl.controller目录,然后创建NewsController类

package cn.xdl.controller;
import cn.xdl.dao.NewsDao;
import cn.xdl.entity.News;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import java.util.List;
@Controller
public class NewsController {

  @Autowired
  private NewsDao newsDao;

  @RequestMapping("/news/list")
  public ModelAndView list(
    @RequestParam(name="page",required=false,defaultValue="1")int pageIndex,
    @RequestParam(name="size",required=false,defaultValue="3")int size) {
    pageIndex--;//页数从0开始
    Pageable page = PageRequest.of(pageIndex, size);
    Page<News> p = newsDao.findAll(page);
    List<News> list = p.getContent();
    //ModelAndView
    ModelAndView mav = new ModelAndView();
    mav.setViewName("list");// /list.jsp
    mav.getModel().put("news", list);
    return mav;//将mav交给ViewResolver组件解析处理
  }
}

在src/main/下创建webapp目录,然后创建list.jsp

<%@ 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>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
  </head>
  <body>
    <h1>新闻列表</h1>
    <table>
      <c:forEach items="${news}" var="n" varStatus="vs">
        <tr>
          <td>${vs.count}</td>
          <td>${n.title }</td>
          <td>${n.release_time}</td>
        </tr>
      </c:forEach>
    </table>
  </body>
</html>

在src/main/java下创建启动类，同上应用一

应用三：开发Thymeleaf模板应用(推荐) (请求–>SpringMVC–>thymeleaf模板–>返回HTML响应结果)

模板技术：velocity、freemarker、thymeleaf

模板技术是对JSP技术的替代，由模板文件和模型数据构成。

1
2
3

velocity : *.vm + VTL
freemarker : *.ftl + FTL
thymeleaf : *.html + THTL

模板技术优点: 模板技术应用简单，JSP复杂; 模板技术效率高（模板(缓存)+模型=HTML结果），JSP(JSP–>Servlet–>HTML结果)

创建Maven项目,在pom.xml文件中导入dependecy

  <dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>2.1.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
        <version>2.1.2.RELEASE</version>
    </dependency>
</dependencies>

在src/main/resources下创建application.properties文件并输入

1	server.port=8888

在src/main/java下创建com.xdl.controller目录,然后创建HelloController类

package cn.xdl.web;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class HelloController {
  @RequestMapping("/hello")
  public ModelAndView  say() {
    ModelAndView mav = new ModelAndView();
    mav.setViewName("hello");//src/main/resources/templates/hello.html
    mav.getModel().put("msg", "XDL学习SpringBoot");
    return mav;
  }
}

在src/main/resorces下创建templates目录,然后在此目录下创建hello.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
  <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
  </head>
  <body>
    <h1 th:text="${msg}"></h1>
  </body>
</html>

在src/main/java下创建启动类，同上应用一

开发Thymeleaf模板应用(推荐)的扩展

在上述应用三的pom.xml文件中增加dependecy

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
    <version>2.1.2.RELEASE</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.47</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    <version>2.1.2.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>2.1.2.RELEASE</version>
</dependency>

在上述应用三的application.properties增加以下内容

spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/mysql
spring.datasource.driverClassName=com.mysql.jdbc.Driver

spring.thymeleaf.cache=false

在src/main/java下创建com.xdl.entity目录,然后创建实体类Knowledge

在src/main/java下创建com.xdl.dao目录,然后创建接口KnowledgeDao

package cn.xdl.dao;
import cn.xdl.entity.Knowledge;
import org.springframework.data.jpa.repository.JpaRepository;
public interface KnowledgeDao extends JpaRepository<Knowledge, Integer>{

}

在上述应用三的src/main/java/controller目录下,创建KnowledgeController类

package cn.xdl.web;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import cn.xdl.dao.KnowledgeDao;
import cn.xdl.entity.Knowledge;
@Controller
public class KnowledgeController {
  @Autowired
  private KnowledgeDao knowledgeDao;

  @RequestMapping("/knowledge/list")
  public ModelAndView list(
    @RequestParam(name="page",required=false,defaultValue="1")int page,
    @RequestParam(name="size",required=false,defaultValue="3")int size) {
    Pageable pageable = PageRequest.of(page-1, size);
    Page<Knowledge> pageContent = knowledgeDao.findAll(pageable);
    ModelAndView mav = new ModelAndView();
    mav.setViewName("list");//list.html
    mav.getModel().put("knows", pageContent.getContent());
    mav.getModel().put("current",pageContent.getNumber()+1);
    mav.getModel().put("total", pageContent.getTotalPages());
    return mav;
  }
}

在上述应用三的src/main/resorces/templates目录下创建list.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
  <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
  </head>
  <body>
    <h1>列表显示</h1>
    <span th:text="${current}"></span>
    /
    <span th:text="${total}"></span>
    <table>
      <tr th:each="know : ${knows}">
        <td th:text="${know.id}"></td>
        <td th:text="${know.name}"></td>
      </tr>
    </table>
    <a href="/knowledge/list?page=1">第一页</a>
    <a th:if="${current>1}" th:href="@{/knowledge/list(page=${current-1})}">上一页</a>
    <a th:if="${current<total}" th:href="@{/knowledge/list(page=${current+1})}">下一页</a>
    <a th:href="@{/knowledge/list(page=${total})}">最后一页</a>

    <select>
      <option th:each="know : ${knows}" th:text="${know.name}" th:value="${know.id}"></option>
    </select>
  </body>
</html>

在src/main/java下创建启动类，同上应用一