SpringBoot Web开发精解

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Controller
@ResponseBody
public @interface RestController {
   @AliasFor(annotation = Controller.class)
   String value() default "";
}

@RequestMapping("/user/addUser/{id}")
public void addUser(@PathVariable("id") int id, @RequestParam("name") String name){
    //方法逻辑.....
}

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot</name>
    <description>springboot</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

package com.example.springboot.domain;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
/**
 * @author: 八尺妖剑
 * @date: 2022/4/6 17:59
 * @description: User实体
 * @blog:www.waer.ltd
 */
@Getter
@Setter
@ToString
public class User {
    private Integer id;
    private String name;
    private Integer age;
}

package com.example.springboot.controller;
import com.example.springboot.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author: 八尺妖剑
 * @date: 2022/4/6 18:03
 * @description: UserController
 * @blog:www.waer.ltd
 */
@SuppressWarnings({"all"})
@RestController
public class UserController {
    static ConcurrentHashMap<Integer, User> users = new ConcurrentHashMap<Integer, User>();

    /**
     * 查询用户列表
     * @return String
     */
    @GetMapping("/users")
    public String getUsers(){
        return users.toString();
    }

    /**
     * 添加用户
     * @param user 用户
     * @return
     */
    @PostMapping("/users")
    public String addUser(@RequestBody User user){
        users.put(user.getId(),user);
        return "添加成功!";
    }

    /**
     * 根据id查询用户信息
     * @param id id
     * @return
     */
    @GetMapping("/users/{id}")
    public User getUser(@PathVariable("id") Integer id){
        return users.get(id);
    }

    /**
     * 根据id更新用户信息
     * @param id id
     * @param user 用户
     * @return
     */
    @PutMapping("/users/{id}")
    public String putUser(@PathVariable("id") Integer id,@RequestBody User user){
        users.put(id,user);
        return "更新后的数据为:" + users.get(id);
    }

    /**
     * 根据用户id删除用户信息
     * @param id id
     * @return
     */
    @DeleteMapping("/users/{id}")
    public String deleteUser(@PathVariable("id") Integer id){
        users.remove(id);
        return "成功移除id=" + id + "的用户数据";
    }
}

/**
 * 扩展MVC配置
 */
@Configuration
public class MvcConfig implements WebMvcConfigurer {
    /**
     * 添加资源映射
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/upload/**")
                .addResourceLocations("classpath:/upload/");
    }

    ...
 }

@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class })
// 若系统中不存在WebMvcConfigurationSupport.class类，则该配置生效
@ConditionalOnMissingBean(WebMvcConfigurationSupport.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
@AutoConfigureAfter({ DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class,
                     ValidationAutoConfiguration.class })
public class WebMvcAutoConfiguration {
    ...
}

/**
 * @EnableWebMvc 注解导入的类，是WebMvcConfigurationSupport的子类
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
// 导入一个配置类
@Import(DelegatingWebMvcConfiguration.class)
public @interface EnableWebMvc {
}

/**
 * @EnableWebMvc 注解导入的类，是WebMvcConfigurationSupport的子类
 */
@Configuration(proxyBeanMethods = false)
public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {
    // 提供父类方法的默认实现
}

package com.example.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author: 八尺妖剑
 * @date: 2022/4/11 15:15
 * @description: 自定义一个webmvc配置类
 * @blog:www.waer.ltd
 */
@SuppressWarnings({"all"})
@Configuration
public class ExtendMvcConfig implements WebMvcConfigurer {
    /**
     * 添加资源映射器
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/upload/**")
                .addResourceLocations("classpath:/upload/");

    }

    /**
     * 添加视图控制器
     * @param registry
     */
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        //浏览器发送/index请求来到home.html
        registry.addViewController("/index").setViewName("home.html");
    }

    /**
     * 添加拦截器
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/test");
    }

    /**
     * 实现内部类，自定义拦截器
     */
    class MyInterceptor implements HandlerInterceptor{
        /**
         * 方法执行前调用
         * @param request
         * @param response
         * @param handler
         * @return
         * @throws Exception
         */
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            System.out.println("前置处理完成");
            return true;
        }

        /**
         * 方法执行后，视图渲染前
         * @param request
         * @param response
         * @param handler
         * @param modelAndView
         * @throws Exception
         */
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
            System.out.println("后置处理完成");
        }

        /**
         * 视图渲染后，返回前
         * @param request
         * @param response
         * @param handler
         * @param ex
         * @throws Exception
         */
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
            System.out.println("最终完成");
        }
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>this is home</h1>
</body>
</html>

package com.example.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author: 八尺妖剑
 * @date: 2022/4/11 15:32
 * @description:
 * @blog:www.waer.ltd
 */
@RestController
@SuppressWarnings({"all"})
public class TestController {
    @RequestMapping(value= "/test")
    public String test() {
        System.out.println("test");
        return "success";
    }
}

/**
 * 重写MVC配置
 */
@Configuration
public class CustomMvcConfig extends WebMvcConfigurationSupport {
    ...
}

/**
 * 重写MVC配置
 */
@EnableWebMvc
@Configuration
public class CustomMvcConfig  {
 ...
}