创建自定义异常类及封装web返回对象

1. 创建自定义异常类

选择继承RuntimeException父类而不选择Exception：后者类型的异常需要我们手动显式处理，要么try catch ，或者throw到上一层进行处理，而前者类型的异常可以进行隐式处理，节省了我们很多的手动处理异常的麻烦

package com.example.emos.wx.exception;
import lombok.Data;
@Data
public class EmosException extends RuntimeException{
    private String msg;
    private int code = 500;

    public EmosException(String msg) {
        super(msg);
        this.msg = msg;
    }

    public EmosException(String msg, Throwable e) {
        super(msg, e);
        this.msg = msg;
    }

    public EmosException(String msg, int code) {
        super(msg);
        this.msg = msg;
        this.code = code;
    }

    public EmosException(String msg, int code, Throwable e) {
        super(msg, e);
        this.msg = msg;
        this.code = code;
    }
}

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2. 封装web返回对象

统一标准，保证所有controller返回的数据格式一致
由于apache的httpcomponents库中的HttpStatus类封装了很多的状态码，我们可以利用这些状态码封装到返回的对象中。

<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpcore</artifactId>
	<version>4.4.13</version>
</dependency>

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再创建封装类 R类

package com.example.emos.wx.common.util;

import org.apache.http.HttpStatus;

import java.util.HashMap;
import java.util.Map;

public class R extends HashMap<String, Object> {

    public R() {
        put("code", HttpStatus.SC_OK);
        put("msg", "success");
    }

    public static R error() {
        return error(HttpStatus.SC_INTERNAL_SERVER_ERROR, "未知异常，请联系管理员");
    }

    public static R error(String msg) {
        return error(HttpStatus.SC_INTERNAL_SERVER_ERROR, msg);
    }

    public static R error(int code, String msg) {
        R r = new R();
        r.put("code", code);
        r.put("msg", msg);
        return r;
    }

    public static R ok(String msg) {
        R r = new R();
        r.put("msg", msg);
        return r;
    }

    public static R ok(Map<String, Object> map) {
        R r = new R();
        r.putAll(map);
        return r;
    }

    public static R ok() {
        return new R();
    }

    public R put(String key, Object value) {
        super.put(key, value);
        return this;
    }
}


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3. 利用Swagger创建Api文档

1. 配置依赖

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.9.2</version>
</dependency>
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2. 创建swagger配置类，初始化swagger

package com.example.emos.wx.config;

import io.swagger.annotations.ApiOperation;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.ApiKey;
import springfox.documentation.service.AuthorizationScope;
import springfox.documentation.service.SecurityReference;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spi.service.contexts.SecurityContext;
import springfox.documentation.spring.web.plugins.ApiSelectorBuilder;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

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

@Configuration
//启用swagger文档
@EnableSwagger2
public class SwaggerConfig {
    @Bean
    public Docket createRestApi() {
        Docket docket = new Docket(DocumentationType.SWAGGER_2);

        // ApiInfoBuilder 用于在Swagger界面上添加各种信息
        ApiInfoBuilder builder = new ApiInfoBuilder();
        builder.title("EMOS在线办公系统");
        ApiInfo apiInfo = builder.build();
        docket.apiInfo(apiInfo);

        // ApiSelectorBuilder 用来设置哪些类中的方法会生成到REST API中
        ApiSelectorBuilder selectorBuilder = docket.select();
        selectorBuilder.paths(PathSelectors.any()); //所有包下的类
        //使用@ApiOperation的方法会被提取到REST API中
        selectorBuilder.apis(RequestHandlerSelectors.withMethodAnnotation(ApiOperation.class));
        docket = selectorBuilder.build();
        /*
         * 下面的语句是开启对JWT的支持，当用户用Swagger调用受JWT认证保护的方法，
         * 必须要先提交参数（例如令牌）
         */
        //存储用户必须提交的参数
        List<ApiKey> apikey = new ArrayList();
        //规定用户需要输入什么参数
        apikey.add(new ApiKey("token", "token", "header"));
        docket.securitySchemes(apikey);

        //如果用户JWT认证通过，则在Swagger中全局有效
        AuthorizationScope scope = new AuthorizationScope("global", "accessEverything");
        AuthorizationScope[] scopeArray = {scope};
        //存储令牌和作用域
        SecurityReference reference = new SecurityReference("token", scopeArray);
        List refList = new ArrayList();
        refList.add(reference);
        SecurityContext context = SecurityContext.builder().securityReferences(refList).build();
        List cxtList = new ArrayList();
        cxtList.add(context);
        docket.securityContexts(cxtList);

        return docket;
    }
}

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其中常用的注解：

• @ApiModel：用来对类进行描述
• @ApiModelProperty：用来对类中的属性进行描述
• @Api：一般作用在controller类上，说明类的作用
• @ApiOperation：作用在方法上用来对方法进行说明