swagger是什么？

swagger有什么用？

Swagger包含的工具集：

swagger的使用步骤：

swagger的相关注解：

Docket的源码

了解swagger的作用和概念
了解前后端分离
在SpringBoot中集成Swagger

swagger是什么？

swagger 是一个规范和完整的框架，用于生成、描述、调用和可视化 RESTful 风格的 Web 服务。
直接运行，可以在线测试API接口，API是前后端的重要联系纽带
支持多种语言（java, php...）
总体目标是使客户端和文件系统作为服务器以同样的速度来更新。
文件的方法，参数和模型紧密集成到服务器端的代码，允许API来始终保持同步。

swagger有什么用？

接口文档自动在线生成。
功能测试。

Swagger包含的工具集：

Swagger-tools：提供各种与Swagger进行集成和交互的工具。例如模式检验、Swagger1.2文档转换成Swagger2.0文档等功能。
Swagger-core：用于Java/Scala的Swagger实现。与JAX-RS(Jersey、Resteasy、CXF…）、Servlets和Play框架进行集成。
Swagger-js：用于JavaScript的Swagger实现。
Swagger-node-express：Swagger模块，用于node.js的Express web应用框架。
Swagger-ui：一个无依赖的HTML、JS和CSS集合，可以为Swagger兼容API动态生成优雅文档。
Swagger-codegen：一个模板驱动引擎，通过分析用户Swagger资源声明以各种语言生成客户端代码

swagger的使用步骤：

引入pomm的相关依赖
在代码中加入相应的配置，新建config包，写入swaggerConfig配置类
在basePackage指定的路径下使用swagger（使用api注解）
启动项目，浏览器打开http://ip:port/swagger-ui.html

swagger 的相关依赖：

</dependency>
  <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.9.2</version>
</dependency>

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.9.2</version>
</dependency>

swagger配置信息：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
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;

@Configuration//设置该类为spring配置类
@EnableSwagger2//开户swagger2
public class SwaggerConfig {

    /**
     * 创建API应用
     * apiInfo() 增加API相关信息
     * 通过select()函数返回一个ApiSelectorBuilder实例,用来控制哪些接口暴露给Swagger来展现，
     * 本例采用指定扫描的包路径来定义指定要建立API的目录。
     * .apis
     *    RequestHandlerSelectors 配置swagger扫描接口的方式
     *       basePackage() 指定要扫描哪些包
     *       any() 全部都扫描
     *       none() 全部不扫描
     *       withClassAnnotation() 扫描类上的注解 参数是一个注解的反射对象
     *       withMethodAnnotation() 扫描包上的注解
     *  .paths
     *    PathSelectors 路径扫描接口
     *       ant 配置以xxx 开头的路径
     *
     * @return
     */

    @Bean //设置该方法的返回值为spring管理的bean
    public Docket restApi() {//配置了swagger的docket的bean实例
        return new Docket(DocumentationType.SWAGGER_2)
                .groupName("标准接口")
                .apiInfo(apiInfo("Spring Boot中使用Swagger2构建RESTful APIs", "1.0"))
                .useDefaultResponseMessages(true)
                .forCodeGeneration(false)
                .select()
                
                //RequestHandlerSelectors配置要扫描接口的方式
                .apis(RequestHandlerSelectors.basePackage("com.example.learning.controller"))
                .paths(PathSelectors.any())
                .build();
    }

    /**
     * 创建该API的基本信息（这些基本信息会展现在文档页面中）
     * 访问地址：http://ip:port/swagger-ui.html
     *
     * @return
     */
    private ApiInfo apiInfo(String title, String version) {//配置Swagger页面信息
        return new ApiInfoBuilder()
                .title(title)
                .description("swagger")
                .termsOfServiceUrl("https://swagger.io")
                .contact("swagger")
                .version("1.0")
                .build();//构建者模式，快速构建一个对象
    }
}

使用swagger

import com.fasterxml.jackson.databind.ObjectMapper;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Map;

@RestController
@RequestMapping("/api")
@Api(tags = "标准演示接口")
public class ApiController {
    @Resource
    private ObjectMapper mapper;

    @PostMapping("/ps")
    @ApiOperation(value = "接受json参数", notes = "演示json参数是否接受成功")
    public String post(@ApiParam(name = "接收json参数", defaultValue = "{}")
                           @RequestBody String json) throws IOException {
        Map map = mapper.readValue(json, Map.class);
        System.out.println(map);
        return json;
    }
}

swagger的相关注解：

@Configuration：表明这是一个配置类
@EnableSwagger2：开启Swagger2
@Api：放在类上，说明该类的作用。
@ApiOperation：放在方法上，说明该方法的作用。
@ApiImplicitParams：用在方法上包含一组参数说明。
code：数字，例如400
message：信息，例如“请求参数没填好”
response：抛出异常的类
@ApiImplicitParam：用来注解来给方法入参增加说明，一个请求能数。
@ApiResponses：用于表示一组响应。
@ApiResponse：用在@ApiResponses中，一般用于表达一个错误的响应信息
@ApiModel：用对象来接收参数，描述一个Model的信息（一般用于在请求参数无法使用@ApiImplicitParam注解进行描述的时候）
@ApiModelProperty：用对象接收参数时，描述对象的一个字段
@ApiIgnore：使用该注解忽略这个API
@ApiError ：发生错误返回的信息

Docket的源码

/*
    Docket的源码

    Docket中拥有的属性，Swagger可更改这些属性
*/
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package springfox.documentation.spring.web.plugins;

import com.fasterxml.classmate.ResolvedType;
import com.fasterxml.classmate.TypeResolver;
import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Ordering;
import com.google.common.collect.Sets;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.springframework.web.bind.annotation.RequestMethod;
import springfox.documentation.PathProvider;
import springfox.documentation.annotations.Incubating;
import springfox.documentation.builders.BuilderDefaults;
import springfox.documentation.schema.AlternateTypeRule;
import springfox.documentation.schema.AlternateTypeRules;
import springfox.documentation.schema.CodeGenGenericTypeNamingStrategy;
import springfox.documentation.schema.DefaultGenericTypeNamingStrategy;
import springfox.documentation.schema.WildcardType;
import springfox.documentation.service.ApiDescription;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.ApiListingReference;
import springfox.documentation.service.Operation;
import springfox.documentation.service.Parameter;
import springfox.documentation.service.ResponseMessage;
import springfox.documentation.service.SecurityScheme;
import springfox.documentation.service.Tag;
import springfox.documentation.service.VendorExtension;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spi.schema.GenericTypeNamingStrategy;
import springfox.documentation.spi.service.DocumentationPlugin;
import springfox.documentation.spi.service.contexts.ApiSelector;
import springfox.documentation.spi.service.contexts.DocumentationContext;
import springfox.documentation.spi.service.contexts.DocumentationContextBuilder;
import springfox.documentation.spi.service.contexts.SecurityContext;

public class Docket implements DocumentationPlugin {
    public static final String DEFAULT_GROUP_NAME = "default";
    private final DocumentationType documentationType;
    private final List<SecurityContext> securityContexts = Lists.newArrayList();
    private final Map<RequestMethod, List<ResponseMessage>> responseMessages = Maps.newHashMap();
    private final List<Parameter> globalOperationParameters = Lists.newArrayList();
    private final List<Function<TypeResolver, AlternateTypeRule>> ruleBuilders = Lists.newArrayList();
    private final Set<Class> ignorableParameterTypes = Sets.newHashSet();
    private final Set<String> protocols = Sets.newHashSet();
    private final Set<String> produces = Sets.newHashSet();
    private final Set<String> consumes = Sets.newHashSet();
    private final Set<ResolvedType> additionalModels = Sets.newHashSet();
    private final Set<Tag> tags = Sets.newHashSet();
    private PathProvider pathProvider;
    private List<? extends SecurityScheme> securitySchemes;
    private Ordering<ApiListingReference> apiListingReferenceOrdering;
    private Ordering<ApiDescription> apiDescriptionOrdering;
    private Ordering<Operation> operationOrdering;
    private ApiInfo apiInfo;
    private String groupName;
    private boolean enabled;//是否启动swagger
    private GenericTypeNamingStrategy genericsNamingStrategy;
    private boolean applyDefaultResponseMessages;
    private String host;
    private Optional<String> pathMapping;
    private ApiSelector apiSelector;
    private boolean enableUrlTemplating;
    private List<VendorExtension> vendorExtensions;

    public Docket(DocumentationType documentationType) {
        this.apiInfo = ApiInfo.DEFAULT;
        this.groupName = "default";
        this.enabled = true;
        this.genericsNamingStrategy = new DefaultGenericTypeNamingStrategy();
        this.applyDefaultResponseMessages = true;
        this.host = "";
        this.pathMapping = Optional.absent();
        this.apiSelector = ApiSelector.DEFAULT;
        this.enableUrlTemplating = false;
        this.vendorExtensions = Lists.newArrayList();
        this.documentationType = documentationType;
    }

    public Docket extensions(List<VendorExtension> vendorExtensions) {
        this.vendorExtensions.addAll(vendorExtensions);
        return this;
    }

    public Docket apiInfo(ApiInfo apiInfo) {
        this.apiInfo = (ApiInfo)BuilderDefaults.defaultIfAbsent(apiInfo, apiInfo);
        return this;
    }

    public Docket securitySchemes(List<? extends SecurityScheme> securitySchemes) {
        this.securitySchemes = securitySchemes;
        return this;
    }

    public Docket securityContexts(List<SecurityContext> securityContexts) {
        this.securityContexts.addAll(securityContexts);
        return this;
    }

    public Docket groupName(String groupName) {
        this.groupName = (String)BuilderDefaults.defaultIfAbsent(groupName, this.groupName);
        return this;
    }

    public Docket pathProvider(PathProvider pathProvider) {
        this.pathProvider = pathProvider;
        return this;
    }

    public Docket globalResponseMessage(RequestMethod requestMethod, List<ResponseMessage> responseMessages) {
        this.responseMessages.put(requestMethod, responseMessages);
        return this;
    }

    public Docket globalOperationParameters(List<Parameter> operationParameters) {
        this.globalOperationParameters.addAll(BuilderDefaults.nullToEmptyList(operationParameters));
        return this;
    }

    public Docket ignoredParameterTypes(Class... classes) {
        this.ignorableParameterTypes.addAll(Arrays.asList(classes));
        return this;
    }

    public Docket produces(Set<String> produces) {
        this.produces.addAll(produces);
        return this;
    }

    public Docket consumes(Set<String> consumes) {
        this.consumes.addAll(consumes);
        return this;
    }

    @Incubating("2.3")
    public Docket host(String host) {
        this.host = (String)BuilderDefaults.defaultIfAbsent(host, this.host);
        return this;
    }

    public Docket protocols(Set<String> protocols) {
        this.protocols.addAll(protocols);
        return this;
    }

    public Docket alternateTypeRules(AlternateTypeRule... alternateTypeRules) {
        this.ruleBuilders.addAll(FluentIterable.from(Lists.newArrayList(alternateTypeRules)).transform(this.identityRuleBuilder()).toList());
        return this;
    }

    public Docket operationOrdering(Ordering<Operation> operationOrdering) {
        this.operationOrdering = operationOrdering;
        return this;
    }

    public Docket directModelSubstitute(Class clazz, Class with) {
        this.ruleBuilders.add(this.newSubstitutionFunction(clazz, with));
        return this;
    }

    public Docket genericModelSubstitutes(Class... genericClasses) {
        Class[] arr$ = genericClasses;
        int len$ = genericClasses.length;

        for(int i$ = 0; i$ < len$; ++i$) {
            Class clz = arr$[i$];
            this.ruleBuilders.add(this.newGenericSubstitutionFunction(clz));
        }

        return this;
    }

    public Docket useDefaultResponseMessages(boolean apply) {
        this.applyDefaultResponseMessages = apply;
        return this;
    }

    public Docket apiListingReferenceOrdering(Ordering<ApiListingReference> apiListingReferenceOrdering) {
        this.apiListingReferenceOrdering = apiListingReferenceOrdering;
        return this;
    }

    public Docket apiDescriptionOrdering(Ordering<ApiDescription> apiDescriptionOrdering) {
        this.apiDescriptionOrdering = apiDescriptionOrdering;
        return this;
    }

    public Docket enable(boolean externallyConfiguredFlag) {
        this.enabled = externallyConfiguredFlag;
        return this;
    }

    public Docket forCodeGeneration(boolean forCodeGen) {
        if (forCodeGen) {
            this.genericsNamingStrategy = new CodeGenGenericTypeNamingStrategy();
        }

        return this;
    }

    public Docket pathMapping(String path) {
        this.pathMapping = Optional.fromNullable(path);
        return this;
    }

    @Incubating("2.1.0")
    public Docket enableUrlTemplating(boolean enabled) {
        this.enableUrlTemplating = enabled;
        return this;
    }

    public Docket additionalModels(ResolvedType first, ResolvedType... remaining) {
        this.additionalModels.add(first);
        this.additionalModels.addAll(Sets.newHashSet(remaining));
        return this;
    }

    public Docket tags(Tag first, Tag... remaining) {
        this.tags.add(first);
        this.tags.addAll(Sets.newHashSet(remaining));
        return this;
    }

    public ApiSelectorBuilder select() {
        return new ApiSelectorBuilder(this);
    }

    public DocumentationContext configure(DocumentationContextBuilder builder) {
        return builder.apiInfo(this.apiInfo).selector(this.apiSelector).applyDefaultResponseMessages(this.applyDefaultResponseMessages).additionalResponseMessages(this.responseMessages).additionalOperationParameters(this.globalOperationParameters).additionalIgnorableTypes(this.ignorableParameterTypes).ruleBuilders(this.ruleBuilders).groupName(this.groupName).pathProvider(this.pathProvider).securityContexts(this.securityContexts).securitySchemes(this.securitySchemes).apiListingReferenceOrdering(this.apiListingReferenceOrdering).apiDescriptionOrdering(this.apiDescriptionOrdering).operationOrdering(this.operationOrdering).produces(this.produces).consumes(this.consumes).host(this.host).protocols(this.protocols).genericsNaming(this.genericsNamingStrategy).pathMapping(this.pathMapping).enableUrlTemplating(this.enableUrlTemplating).additionalModels(this.additionalModels).tags(this.tags).vendorExtentions(this.vendorExtensions).build();
    }

    public String getGroupName() {
        return this.groupName;
    }

    public boolean isEnabled() {
        return this.enabled;
    }

    public DocumentationType getDocumentationType() {
        return this.documentationType;
    }

    public boolean supports(DocumentationType delimiter) {
        return this.documentationType.equals(delimiter);
    }

    private Function<AlternateTypeRule, Function<TypeResolver, AlternateTypeRule>> identityRuleBuilder() {
        return new Function<AlternateTypeRule, Function<TypeResolver, AlternateTypeRule>>() {
            public Function<TypeResolver, AlternateTypeRule> apply(AlternateTypeRule rule) {
                return Docket.this.identityFunction(rule);
            }
        };
    }

    private Function<TypeResolver, AlternateTypeRule> identityFunction(final AlternateTypeRule rule) {
        return new Function<TypeResolver, AlternateTypeRule>() {
            public AlternateTypeRule apply(TypeResolver typeResolver) {
                return rule;
            }
        };
    }

    Docket selector(ApiSelector apiSelector) {
        this.apiSelector = apiSelector;
        return this;
    }

    private Function<TypeResolver, AlternateTypeRule> newSubstitutionFunction(final Class clazz, final Class with) {
        return new Function<TypeResolver, AlternateTypeRule>() {
            public AlternateTypeRule apply(TypeResolver typeResolver) {
                return AlternateTypeRules.newRule(typeResolver.resolve(clazz, new Type[0]), typeResolver.resolve(with, new Type[0]), -2147480648);
            }
        };
    }

    private Function<TypeResolver, AlternateTypeRule> newGenericSubstitutionFunction(final Class clz) {
        return new Function<TypeResolver, AlternateTypeRule>() {
            public AlternateTypeRule apply(TypeResolver typeResolver) {
                return AlternateTypeRules.newRule(typeResolver.resolve(clz, new Type[]{WildcardType.class}), typeResolver.resolve(WildcardType.class, new Type[0]), -2147481648);
            }
        };
    }
}