创建一个springboot工程最小化代码（json-lib的引入gradle方式）

   compile 'org.springframework.boot:spring-boot-starter-web:1.4.0.RELEASE'

   compile 'net.sf.json-lib:json-lib:2.4:jdk15'

   compile 'org.apache.httpcomponents:httpcore:4.4.10'
   compile 'org.apache.httpcomponents:httpmime:4.5.6'
   compile 'org.apache.httpcomponents:httpclient:4.5.6'

<!-- maven -->
<dependency>    
    <groupId>net.sf.json-lib</groupId>    
    <artifactId>json-lib</artifactId>    
    <version>2.4</version>    
    <classifier>jdk15</classifier>    
</dependency> 

最小代码的springboot工程：

settings.gradle:

/*
 * This settings file was generated by the Gradle 'init' task.
 *
 * The settings file is used to specify which projects to include in your build.
 * In a single project build this file can be empty or even removed.
 *
 * Detailed information about configuring a multi-project build in Gradle can be found
 * in the user guide at https://docs.gradle.org/4.3/userguide/multi_project_builds.html
 */

/*
// To declare projects as part of a multi-project build use the 'include' method
include 'shared'
include 'api'
include 'services:webservice'
*/

rootProject.name = 'testcase'

build.gradle

apply plugin: 'java-library'
apply plugin: 'org.springframework.boot'


buildscript {
    repositories {
        maven {
            name 'Aliyun Maven Repository'
            url "http://maven.aliyun.com/nexus/content/groups/public/"
        }
    }
    dependencies {
        classpath "org.springframework.boot:spring-boot-gradle-plugin:1.5.18.RELEASE"
        classpath "io.spring.gradle:dependency-management-plugin:1.0.5.RELEASE"
    }
}
// In this section you declare where to find the dependencies of your project
repositories {
    maven {
        name 'Aliyun Maven Repository'
        url "http://maven.aliyun.com/nexus/content/groups/public/"
    }
    jcenter()
}


springBoot {
    executable = true
    mainClass = 'com.casetest.TestCaseBoot'
}

dependencies {
    //Spring boot
    compile 'org.springframework.boot:spring-boot-starter-web:1.5.18.RELEASE'
    
    // Swagger2
    compile 'io.github.swagger2markup:swagger2markup:1.3.3'
    compile 'io.springfox:springfox-swagger2:2.9.0'
    compile 'io.springfox:springfox-swagger-ui:2.9.0'
    
    api 'org.apache.commons:commons-math3:3.6.1'
    
    implementation 'com.google.guava:guava:23.0'

    testImplementation 'junit:junit:4.12'
}

src下的文件：

package com.casetest;

import java.io.IOException;
import java.util.ArrayList;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Bean;

import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@EnableSwagger2
@SpringBootApplication
@ServletComponentScan   //启动器启动时，扫描本目录以及子目录带有的webservlet注解的
public class TestCaseBoot {

    public static void main(String[] args) throws IOException {
        SpringApplication.run(TestCaseBoot.class, args);
        System.out.println("success");
    }
    
    
    /*@Bean // 一定要加，不然这个方法不会运行 // 一定要返回ServletRegistrationBean
    public ServletRegistrationBean getServletRegistrationBean() { 
        ServletRegistrationBean bean = new ServletRegistrationBean(new CaseTwoServlet()); 
        bean.addUrlMappings("/secondServlet"); // 访问路径值
        return bean;
    }*/
    
    @Bean
    public Docket docket() {
        return new Docket(DocumentationType.SWAGGER_2).groupName("agent").select()
                .apis(RequestHandlerSelectors.basePackage("com.casetest"))
                .paths(PathSelectors.any())
                .paths(PathSelectors.ant("/api/**/*"))
                .build()
                .apiInfo(new ApiInfo("API", "这App等相关的API", "v3", "Terms of service",
                        new Contact("Test", "http://www.testcase.com", ""), "", "", new ArrayList<>()));
    }
}

package com.casetest.config;


import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
@ComponentScan({ 
    "com.casetest.rs", 
    "com.casetest.schedule",
    "com.casetest.service"
})
public class WebAutoConfiguration {

    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
    
}

package com.casetest.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("POST", "GET", "PUT", "OPTIONS", "DELETE")
                .maxAge(3600)
                .allowCredentials(true);
    }
}

package com.casetest.rs;

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

@RequestMapping("/api/case/one")
@RestController
public class CaseOneRS {

    @RequestMapping(value="/sayHi",method= {RequestMethod.GET})
    public String sayHi(String name) {
        return "Hi " + name;
    }
    
    @RequestMapping(value="/sayHi",method= {RequestMethod.POST})
    public String replyHi(String name) {
        return "me to " + name;
    }
    
}

package com.casetest.rs;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns="/api/case/two",loadOnStartup=1)
public class CaseTwoServlet extends HttpServlet{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("get....");
        super.doGet(req, resp);
    }
    
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("post....");
        super.doPost(req, resp);
    }
    
}