SpringMVC02——第一个MVC程序-注解版（high版！！！！）

注解版

1. 新建一个子项目，添加Web支持
2. 在pom.xml文件中引入相关的依赖：主要引入Spring框架核心库、SpringMVC、servlet，JSTL等。
3. 创建实体类Fruit

package com.pp.pojo;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Fruit {
    private String name; //水果名
    private double price; //价格
    private String producing_area;//产地

}

4. 编写实体类对应的Controller

package com.pp.controller;

import com.pp.pojo.Fruit;
import com.pp.service.FruitService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
public class FruitController {

    @Autowired
    FruitService fruitService;
    @RequestMapping("/fc")
    public String getFruit(Model model){
        //模拟Service获取水果商品列表
        List<Fruit> fruitLists=fruitService.queryFruitList();
        model.addAttribute("fruitList",fruitLists);
        return "fruitList";
    }

}

5. 配置SpringMVC，类似于Springmvc.xml

package com.pp.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
@ComponentScan("com.pp")//扫描包

public class SpringMVCConfig implements WebMvcConfigurer {

    //配置jsp视图解析器
    @Bean
    public InternalResourceViewResolver getViewResolver(){
        InternalResourceViewResolver viewResolver = new
                InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/jsp/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }
    //配置静态资源的处理
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

}

6. 配置WebConfig,原来的web.xml
   这里注意别导错包
   import javax.servlet.ServletRegistration.Dynamic;
   一定是这两个！不然会报错

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

package com.pp.config;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration.Dynamic;


public class WebConfig implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        // 加载Spring web用于配置
        AnnotationConfigWebApplicationContext ctx = new
                AnnotationConfigWebApplicationContext();
        ctx.register(SpringMVCConfig.class);
        ctx.setServletContext(servletContext);
        ctx.refresh();
// 创建dispatcherServlet
        Dynamic servlet = servletContext.addServlet("dispatcher", new
                DispatcherServlet(ctx));
        servlet.addMapping("/");
        servlet.setLoadOnStartup(1);
    }

}

到这里，以前的xml文件就完全被我们的Config给取代了！！！有没有很爽！！
接下来编写Service

7. FruitService类

package com.pp.service;

import com.pp.pojo.Fruit;

import java.util.List;

public interface FruitService {
    List<Fruit> queryFruitList();

}

对应的实现类

package com.pp.service;

import com.pp.pojo.Fruit;
import org.springframework.stereotype.Service;

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

@Service
public class FruitServiceImpl implements FruitService{
    @Override
    public List<Fruit> queryFruitList() {
        List<Fruit> fruitsList = new ArrayList<>();
        Fruit apple =Fruit.builder()
                .name("苹果")
                .price(19)
                .producing_area("山东烟台")
                .build();
        Fruit banana =Fruit.builder()
                .name("香蕉")
                .price(5)
                .producing_area("海南")
                .build();
        Fruit pear =Fruit.builder()
                .name("梨子")
                .price(8.5)
                .producing_area("汤山")
                .build();
        fruitsList.add(apple);
        fruitsList.add(pear);
        fruitsList.add(banana);
        return fruitsList;
    }
}

8. 编写jsp视图层！在WEB-INF/jsp下创建fruitList.jsp

<%--
  Created by IntelliJ IDEA.
  User: supanpan199919
  Date: 2021-05-08
  Time: 19:55
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h2>水果信息情况</h2>
<table border="1px" width="400px">
    <thead>
    <th>名称</th>
    <th>价格</th>
    <th>产地</th>
    </thead>
    <tbody>
    <c:forEach items="${fruitList}" var="fruit">
        <tr>
            <td>${fruit.name}</td>
            <td>${fruit.price}</td>
            <td>${fruit.producing_area}</td>
        </tr>
    </c:forEach>
    </tbody>
    <tfoot>
    <tr>
        <td colspan="3" align="center">@copy软件班</td>
    </tr>
    </tfoot>
</table>

</body>
</html>

最后！！！配置tom，启动测试