【JavaWeb】Spring MVC

W3C资源:https://www.w3cschool.cn/wkspring/dcu91icn.html

0.MVC

model-controler-view

Dao-Controller-Service

0.1在JavaWeb如何实现

用户在JSP页面点击、输入信息，传入servlet里，servlet get方法得到处理，然后使用model的处理方法，得到需要返回的数据，再通过servlet传入到jsp

model是JavaBean形式。

0.2 SpringMVC相比之前的实现方式有何好处？

用Controller做中间层的处理

1.Spring MVC 介绍

1.1 处理流程

1.2 Spring工程结构

1.3 写web工程需要配置的依赖

pom.xml

配置依赖，会自动从官网下载

<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		
		<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jasper</artifactId>
			<version>9.0.31</version>
		</dependency>

                <dependency>
			<groupId>org.springframework.boot</groupId>//设置为热启动
			<artifactId>spring-boot-devtools</artifactId>
		</dependency>

1.4 model相关的注解　

Bean的创建和获取

@Component

把普通pojo实例化到spring容器中

@prototype

加上这句则每次从容器中取到的都不一样

@Autowired

Autowired是自动链接

这个注解就是spring可以自动帮你把bean里面引用的对象的setter/getter方法省略，它会自动帮你set/get。

参考博客：https://blog.csdn.net/Fire_Sky_Ho/article/details/83214513?depth_1-utm_source=distribute.pc_relevant.none-task&utm_source=distribute.pc_relevant.none-task

2. 基础单例，使用thymleaf

2.0 pom.xml

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		
	<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
			
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
		</dependency>
			
		
		
		<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
	<!--  
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jasper</artifactId>
			<version>9.0.31</version>
		</dependency>

-->

主方法入口

package edu.example.hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class HelloApp {
   public static void main(String[] args) {
	   SpringApplication.run(HelloApp.class, args);
   }
}

2.1 创建学生类

package edu.example.hello;

import org.springframework.stereotype.Component;

@Component
public class Student {
	
 private String no;
 private String name;
 private int age;
 
 
 
public String getNo() {
	return no;
}
public void setNo(String no) {
	this.no = no;
}
public String getName() {
	return name;
}
public void setName(String name) {
	this.name = name;
}
public int getAge() {
	return age;
}
public void setAge(int age) {
	this.age = age;
}
 
}

2.2 home.html

2.2.0 Thymleaf语法

2.2.1 text

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<!-- 唯一标号 -->
<head>
<meta charset="UTF-8">
<title>Welcome</title>
</head>
<body>
<h2 th:text="YOU">Hello World!</h2>
</body>
</html>

　　此时只显示"YOU"而不显示“Hello World”

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<!-- 唯一标号 -->
<head>
<meta charset="UTF-8">
<title>Welcome</title>
</head>
<body>
<h2 th:text="${msg}">Hello World!</h2>
<h2 th:text="${student.name}"></h2>
</body>
</html>

2.3 Controller

package edu.example.hello;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {
	@Autowired
	private Student student;

@RequestMapping("/")
	   public String home(Model model) {
	        student.setNo("99");
	        student.setName("Li Ming");
	           System.out.println("hello Controller...");
		  model.addAttribute("msg","Welcome!THYmeLeaf!");
		  model.addAttribute("student",student);
		  return "home";
	   }

3. 批量实例

3.1 StudentFactory类

package edu.example.hello;

import java.util.ArrayList;
import java.util.List;

import org.springframework.stereotype.Component;
@Component
public class StudentFactory {
    public List<Student>getStudents(){
    	List<Student>list=new ArrayList<Student>();
    	for (int i=0;i<3;i++) {
    		Student student=new Student();
    		student.setNo("1720110"+(i+1));
    		student.setName("People"+(i+1));
    		list.add(student);
    	}
    	return list;
    }
}

3.2　Controller

package edu.example.hello;

import javax.servlet.http.HttpSession;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {
	@Autowired
//	private Student student;
       private StudentFactory sf;
	@GetMapping("/")
	public String home(Model model) {
		System.out.println("hello.get...");

		model.addAttribute("list",sf.getStudents());
		return "home";
	}
	@PostMapping("/")
	public String home(Model model, String no) {
		System.out.println("hello.post...");
		model.addAttribute("list", sf.findBy(no));
		return "home";
		
	}
}

get：不管访问多少次，拿到的结果都是一样的

post：可能得到不同的结果

不是很严格

　3.3 页面

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<!-- 唯一标号 -->
<head>
<meta charset="UTF-8">
<title>Welcome</title>
</head>
<body>
<h2 th:text="${msg}">Hello World!</h2>
<h2 th:text="${list[1].name}"></h2>
<ol >
<!-- 定义一个变量名 -->
   <li th:each="st:${list}"th:text="${st.name}"></li>
注意循环的foreach如果放在上面ol内，则序号都为1，要关注真正循环的地方
</ol>

 </body> </html>

<table border="1">
<tr><td>ID</td><td>Name</td></tr>

   <tr th:each="st:${list}"><td th:text="${st.no}"></td><td th:text="${st.name}"></td></tr>

    <form action="" method="post">
	no:<input type="text" name="no"/>
	<input type="submit">
</form>

posted @ 2020-03-14 16:36 SeasonBubble 阅读(218) 评论(0) 收藏举报

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【JavaWeb】Spring MVC

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