spring boot:使接口返回统一的RESTful格式数据(spring boot 2.3.1)

一，为什么要使用REST？

1,什么是REST?

REST是软件架构的规范体系，它把资源的状态用URL进行资源定位，

以HTTP动作(GET/POST/DELETE/PUT)描述操作

2,REST的优点？

  各大机构提供的api都是RESTful风格，

  这样有统一的规范，可以减少学习开发的成本

3,实现统一的返回格式要考虑哪些问题？

  首先是正常的数据返回

  其次是出错时的返回：

        未知异常：在spring boot中由controlleradvice统一处理

       我们给用户返回的错误: 我们使用自定义的BusinessException

  再次是一些原本由tomcat处理的报错：404等，

      我们也使用统一的格式返回

  需要注意的地方:异常并不是仅仅抛出即可，需要写到日志中供运维处理

说明：刘宏缔的架构森林是一个专注架构的博客，地址：https://www.cnblogs.com/architectforest

         对应的源码可以访问这里获取： https://github.com/liuhongdi/

说明：作者:刘宏缔 邮箱: 371125307@qq.com

二，演示项目的相关信息:

1,项目的地址:

https://github.com/liuhongdi/restresult

2,项目的相关说明:

   数据的返回:

   code:代码，为0是表示成功执行，非0表示出错

   msg:提示信息，通常供出错时报错

   data:页面上返回的数据:

          具体的格式由后端工程师和前端工程师之间约定

   以上格式也是最常用的返回格式

    我们用一个名为:ResultUtil的类对格式做了封装

3,项目的结构:

如图:

三，配置文件说明：

 1，pom.xml

        <!--validation begin-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <!--validation   end-->

        <!--aop begin-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <!--aop   end-->

        <!--log4j2 begin-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>

        <dependency>
            <groupId>com.lmax</groupId>
            <artifactId>disruptor</artifactId>
            <version>3.4.2</version>
        </dependency>
        <!--log4j2   end-->

        <!-- JSON解析fastjson begin-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.72</version>
        </dependency>
        <!-- JSON解析fastjson   end-->

        <!--commons-lang3-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>

说明：需要注意的是从2.3开始，validation不再默认被starter-web包含，使用时需要手动引入

2,application.properties

#log4j2
logging.config=classpath:log4j2.xml

指定了log4j2的配置文件路径

3,log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
    <Appenders>
        <Console name="STDOUT" target="SYSTEM_OUT">
            <PatternLayout pattern=".%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line]
                %-5level %logger{36} - %msg %n"/>
        </Console>
        <RollingFile immediateFlush="false"  name="ErrorFile" fileName="/data/logs/tomcatlogs/error.log"
                     filePattern="/data/logs/tomcatlogs/$${date:yyyy-MM}/error-%d{MM-dd-yyyy}-%i.log">
            <Filters>
                <ThresholdFilter level="INFO" />
            </Filters>
            <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
                <SizeBasedTriggeringPolicy size="102400KB"/>
            </Policies>
        </RollingFile>
        <RollingFile immediateFlush="false"  name="BusinessFile" fileName="/data/logs/tomcatlogs/bussiness.log"
                     filePattern="/data/logs/tomcatlogs/$${date:yyyy-MM}/bussiness-%d{MM-dd-yyyy}-%i.log">
            <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
                <SizeBasedTriggeringPolicy size="102400KB"/>
            </Policies>
        </RollingFile>
        <RollingFile immediateFlush="false"  name="BusinessErrorFile" fileName="/data/logs/tomcatlogs/bussinesserror.log"
                     filePattern="/data/logs/tomcatlogs/$${date:yyyy-MM}/bussinesserror-%d{MM-dd-yyyy}-%i.log">
            <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy />
                <SizeBasedTriggeringPolicy size="102400KB"/>
            </Policies>
        </RollingFile>
    </Appenders>
    <Loggers>
        <AsyncLogger name="BusinessFile" level="info" additivity="false" includeLocation="true">
            <appender-ref ref="BusinessFile"/>
        </AsyncLogger>
        <AsyncLogger name="BusinessErrorFile" level="info" additivity="false" includeLocation="true">
            <appender-ref ref="BusinessErrorFile"/>
        </AsyncLogger>
        <AsyncRoot level="info" includeLocation="true">
            <AppenderRef ref="STDOUT"/>
            <AppenderRef ref="ErrorFile" />
        </AsyncRoot>
    </Loggers>
</Configuration>

说明：我们配置了三个日志文件：

ErrorFile：系统默认的错误日志,

BusinessErrorFile:主动返回的业务错误信息，

BusinessFile:与错误无关的业务数据

四，java代码说明

1，ResultUtil.java

public class ResultUtil implements Serializable {
    //uuid,用作唯一标识符，供序列化和反序列化时检测是否一致
    private static final long serialVersionUID = 7498483649536881777L;
    //标识代码，0表示成功，非0表示出错
    private Integer code;
    //提示信息，通常供报错时使用
    private String msg;
    //正常返回时返回的数据
    private Object data;

    public ResultUtil(Integer status, String msg, Object data) {
        this.code = status;
        this.msg = msg;
        this.data = data;
    }

    //返回成功数据
    public static ResultUtil success(Object data) {
        return new ResultUtil(ResponseCode.SUCCESS.getCode(), ResponseCode.SUCCESS.getMsg(), data);
    }
    //返回出错数据
    public static ResultUtil error(ResponseCode code) {
        return new ResultUtil(code.getCode(), code.getMsg(), null);
    }

    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }
    public void setData(Object data) {
        this.data = data;
    }
}

2,ResponseCode.java

 public enum ResponseCode {
    // 系统模块
    SUCCESS(0, "操作成功"),
    ERROR(1, "操作失败"),

    //web
    WEB_400(400,"错误请求"),
    WEB_401(401,"访问未得到授权"),
    WEB_404(404,"资源未找到"),
    WEB_500(500,"服务器内部错误"),
    WEB_UNKOWN(999,"未知错误"),

    //parameter
    ARG_TYPE_MISMATCH(1000,"参数类型错误"),
    ARG_BIND_EXCEPTION(1001,"参数绑定错误"),
    ARG_VIOLATION(1002,"参数不符合要求"),
    ARG_MISSING(1003,"参数未找到"),

    //sign error
    SIGN_NO_APPID(10001, "appId不能为空"),
    SIGN_NO_TIMESTAMP(10002, "timestamp不能为空"),
    SIGN_NO_SIGN(10003, "sign不能为空"),
    SIGN_NO_NONCE(10004, "nonce不能为空"),
    SIGN_TIMESTAMP_INVALID(10005, "timestamp无效"),
    SIGN_DUPLICATION(10006, "重复的请求"),
    SIGN_VERIFY_FAIL(10007, "sign签名校验失败"),
    ;

    ResponseCode(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    private Integer code;
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }

    private String msg;
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    public String toString(){
        return "code:"+code+";msg:"+msg;
    }
}

说明：这个枚举对象用来保存返回的错误code的信息，
         通常直接使用定义的常量来返回,在开发中既减少代码，又方便集中维护

3,MyControllerAdvice.java

@ControllerAdvice
public class MyControllerAdvice {

    private static Logger logger = LogManager.getLogger(MyControllerAdvice.class.getName());
    private static Logger loggerBE = LogManager.getLogger("BusinessErrorFile");

    //验证参数时不符合要求
    @ResponseBody
    @ExceptionHandler(value = ConstraintViolationException.class)
    public ResultUtil violationHandler(ConstraintViolationException e) {

        loggerBE.error("ConstraintViolationException: 
"+ ServletUtil.getUrl()+"
"+e.getMessage(), e);
        ResponseCode.ARG_VIOLATION.setMsg(e.getMessage());
        return ResultUtil.error(ResponseCode.ARG_VIOLATION);
    }

    //缺少应该传递的参数
    @ResponseBody
    @ExceptionHandler(value = MissingServletRequestParameterException.class)
    public ResultUtil missingParameterHandler(MissingServletRequestParameterException e) {
        loggerBE.error("MissingServletRequestParameterException: "+e.getMessage(), e);
        ResponseCode.ARG_MISSING.setMsg(e.getMessage());
        return ResultUtil.error(ResponseCode.ARG_MISSING);
    }

    //参数类型不匹配，用户输入的参数类型有错误时会报这个
    @ResponseBody
    @ExceptionHandler(value = MethodArgumentTypeMismatchException.class)
    public ResultUtil misMatchErrorHandler(MethodArgumentTypeMismatchException e) {

        loggerBE.error("MethodArgumentTypeMismatchException: 
"+ ServletUtil.getUrl()+"
"+e.getMessage(), e);
        ResponseCode.ARG_TYPE_MISMATCH.setMsg(e.getMessage());
        return ResultUtil.error(ResponseCode.ARG_TYPE_MISMATCH);
    }

    //验证时绑定错误
    @ResponseBody
    @ExceptionHandler(value = BindException.class)
    public ResultUtil errorHandler(BindException ex) {
        BindingResult result = ex.getBindingResult();
        StringBuilder errorMsg = new StringBuilder();
        for (ObjectError error : result.getAllErrors()) {
            errorMsg.append(error.getDefaultMessage()).append(",");
        }
        errorMsg.delete(errorMsg.length() - 1, errorMsg.length());
        ResponseCode.ARG_BIND_EXCEPTION.setMsg(errorMsg.toString());
        loggerBE.error("BindException: 
"+ ServletUtil.getUrl()+"
"+errorMsg.toString(), ex);
        return ResultUtil.error(ResponseCode.ARG_BIND_EXCEPTION);
    }
    
    /*
    *@author:liuhongdi
    *@date:2020/7/7 下午3:06
    *@description:自定义的业务类异常的处理
     * @param se
    *@return:
    */
    @ResponseBody
    @ExceptionHandler(BusinessException.class)
    public ResultUtil serviceExceptionHandler(BusinessException se) {
        loggerBE.error("ServiceException: 
"+ ServletUtil.getUrl()+"
"+se.getResponseCode(), se);
        ResponseCode rcode = se.getResponseCode();
        return ResultUtil.error(rcode);
    }

    /*
    *@author:liuhongdi
    *@date:2020/7/7 下午3:05
    *@description:通用的对异常的处理
     * @param e
    *@return:
    */
    @ResponseBody
    @ExceptionHandler(Exception.class)
    public ResultUtil exceptionHandler(Exception e) {
        logger.error("Exception: 
"+ ServletUtil.getUrl(), e);
        return ResultUtil.error(ResponseCode.ERROR);
    }

    //主动抛出的异常的处理
    @ResponseBody
    @ExceptionHandler(ThrowException.class)
    public ResultUtil throwExceptionHandler(ThrowException e) {
        logger.error("ThrowException: 
"+ ServletUtil.getUrl()+"
" +e.getMsg(), e);
        return ResultUtil.error(ResponseCode.ERROR);
    }
}

说明：spring boot中用来处理异常的通用controller,
        需要用@ControllerAdvice这个注解声明

4,BusinessException

public class BusinessException extends RuntimeException{

    //返回响应的代码和提示信息
    private ResponseCode rcode;
    public BusinessException(ResponseCode rcode) {
        this.rcode = rcode;
    }

    public ResponseCode getResponseCode() {
        return this.rcode;
    }
    public void setResponseCode(ResponseCode rcode) {
        this.rcode = rcode;
    }
}

主动返回的报错信息

5,ErrorConfig.java

@Component
public class ErrorConfig implements ErrorPageRegistrar {
    @Override
    public void registerErrorPages(ErrorPageRegistry registry) {
        ErrorPage error400Page = new ErrorPage(HttpStatus.BAD_REQUEST, "/error/error/400");
        ErrorPage error401Page = new ErrorPage(HttpStatus.UNAUTHORIZED, "/error/error/401");
        ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/error/error/404");
        ErrorPage error500Page = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/error/error/500");
        registry.addErrorPages(error400Page,error401Page,error404Page,error500Page);
    }
}

用来定义错误页面的返回信息

说明：完整的代码大家可以在github上阅读

五，效果演示

1,测试参数验证:

http://127.0.0.1:8080/home/home

返回:

{"code":1001,"msg":"homeid参数必须为正数","data":null}

测试错误的类型:

http://127.0.0.1:8080/home/home?homeid=abc

返回:

{"code":1001,"msg":"Failed to convert property value of type 'java.lang.String' to required type 'int' for property 'homeid';
 nested exception is java.lang.NumberFormatException: For input string: "abc"","data":null}

正确的参数:

http://127.0.0.1:8080/home/home?homeid=10

返回:

{"code":0,"msg":"操作成功","data":"this is home"}

2,说明：

代码中还针对aop,interceptor等做了演示，供参考

六，查看spring boot的版本:

  .   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _    
( ( )\___ | '_ | '_| | '_ / _` |    
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.1.RELEASE)