前言：
前段时间接手了一个老项目，现在需要在此项目中添加一些新的需求，同事在开发过程中遇到了一些问题？
- 1.成功的状态到底是200还是0啊，订单系统200代表成功，而会员系统却是0代表成功。
- 2.接口返回的结果中，有些是用msg字段表示描述，有些又是用desc字段描述，前段处理起来比较麻烦能不能统一。
- 3.错误提示信息需要支持国际化。
其实这些问题，归根究底还是代码规范问题，我们需要将接口定义和全局异常统一处理，历史项目10多个工程，难道每个工程都去实现一遍，答案可定是不可能的。
1、解决方案
定义公共模块，实现统一接口定义规范和异常处理，其他的系统进行依赖和扩展即可。
2、具体实现
2.1 定义状态码统一接口
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public interface BaseResultCode { /** * 状态码 * @return */ int getCode(); /** * 提示信息 * @return */ String getMsg(); } |
2.2 公共模块状态码枚举类
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public enum ResultCode implements BaseResultCode { OK(200, "成功"), ERROR(300,"系统异常"), NEED_AUTH(301, "非法请求,请重新登录"), PARAMTER_ERROR(302, "参数错误"); //省略其他定义错误码 private int code; private String msg; private ResultCode(int code, String msg) { this.code = code; this.msg = msg; } public static ResultCode getValue(int code) { for (ResultCode errorCode : values()) { if (errorCode.getCode() == code) { return errorCode; } } return null; } //省略Get、Set方法 } |
2.3 定义全局自定义异常
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public class SysException extends RuntimeException { private static final long serialVersionUID = 5225171867523879342L; private int code; private String msg; private Object[] params; private BaseResultCode errorCode; public SysException() { super(); } public SysException(String message) { super(message); } public SysException(Throwable cause) { super(cause); } public SysException(int code ,String message) { this.code = code; this.msg = message; } public SysException(int code ,String message, Object[] params) { this(code, message); this.params= params; } public SysException(String message, Throwable cause) { super(message, cause); } public SysException(BaseResultCode errorCode) { this.errorCode = errorCode; } public SysException(String message, Object[] params) { super(message); this.params = params; } public SysException(BaseResultCode errorCode, String message, Object[] params) { this(message, params); this.errorCode = errorCode; }
/** * Construct by default * * @param message * message * @param parameters * parameters * @param cause * cause */ public SysException(String message, Object[] params, Throwable cause) { super(message, cause); this.params = params; }
public int getCode() { return code; } public void setCode(int code) { this.code = code; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } /** * @return the params */ public Object[] getParams() { return params; } /** * @param params * the params to set */ public void setParams(Object[] params) { this.params = params; } public BaseResultCode getErrorCode() { return errorCode; } public void setErrorCode(BaseResultCode errorCode) { this.errorCode = errorCode; }
} |
2.4 定义统一接口格式输出类
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public class Result implements Serializable { private static final long serialVersionUID = -1773941471021475043L; private Object data; private int code; private String msg; public Result() { } public Result(int code, Object data, String msg) { this.code = code; this.data = data; this.msg = msg; } public Result(int code, String desc) { this(code, null, desc); } public Result(BaseResultCode errorCode) { this(errorCode.getCode(), null, errorCode.getMsg()); } public static Result success() { return success(null); } public static Result success(Object data) { Result result = new Result(); result.setData(data); result.setCode(ResultCode.OK.getCode()); return result; } public static Result error(String msg) { Result result = new Result(); result.setCode(ResultCode.ERROR.getCode()); result.setMsg(msg); return result; } public static Result error(BaseResultCode baseCode) { Result result = new Result(); result.setCode(baseCode.getCode()); result.setMsg(baseCode.getMsg()); return result; } } |
个人建议：统一接口输出类不要定义为泛型类型
2.5 定义统一接口格式输出类
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@RestControllerAdvice public class SysExceptionHandler { public static Log logger = LogManager.getLogger(SysExceptionHandler.class); @ExceptionHandler(Exception.class) public Result handleException(HttpServletRequest request, Exception ex) { logger.error("Handle Exception Request Url:{},Exception:{}",request.getRequestURL(),ex); Result result = new Result(); //系统异常 if (ex instanceof SysException) { SysException se = (SysException) ex; BaseResultCode resultCode =se.getErrorCode(); if(resultCode==null) { result = Result.error(se.getMessage()); } else { result = new Result(resultCode.getCode(), StringUtil.isNotEmpty(se.getMessage())?se.getMessage():resultCode.getMsg()); } } //参数错误 else if (ex instanceof ConstraintViolationException) { ConstraintViolationException v = (ConstraintViolationException) ex; String message = v.getConstraintViolations().iterator().next() .getMessage(); result.setCode(ResultCode.PARAMTER_ERROR.getCode()); result.setMsg(ResultCode.PARAMTER_ERROR.getMsg() + ":" + message); } //参数错误 else if (ex instanceof BindException) { BindException v = (BindException) ex; String message = v.getAllErrors().stream().map(ObjectError::getDefaultMessage).collect(Collectors.joining(",")); result.setCode(ResultCode.PARAMTER_ERROR.getCode()); result.setMsg(ResultCode.PARAMTER_ERROR.getMsg() + ":" + message); } //参数错误 else if (ex instanceof MethodArgumentNotValidException) { MethodArgumentNotValidException v = (MethodArgumentNotValidException) ex; String message = v.getBindingResult().getAllErrors().stream().map(ObjectError::getDefaultMessage).collect(Collectors.joining(",")); result.setCode(ResultCode.PARAMTER_ERROR.getCode()); result.setMsg(ResultCode.PARAMTER_ERROR.getMsg() + ":" + message); } else { result = new Result(ResultCode.ERROR.getCode(),ExceptionUtil.getErrorMsg(ex)); } logger.info("exception handle reuslt:" + result); return result; } } |
上述定义已经可以实现全局接口和异常的统一处理，但是存在的如下问题
每个controller都需要返回Reesult类型，且每个方法都需要返回Result.success()或者Result.success(data)的结果，有点重复，需要进行优化。
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@GetMapping("addUser") public Result add() { for(int i=0;i<10;i++) { TUser user = new TUser(); //user.setOid(IdWorker.getId()); user.setName("shareing_"+i); user.setAge(i); userService.addUser(user); } return Result.success(); } |
2.6 接口统一输出优化
实现方式只需要实现ResponseBodyAdvice接口，重写beforeBodyWrite方法接口。
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@RestControllerAdvice public class ResponseAdvice implements ResponseBodyAdvice<Object> { private Logger logger = LoggerFactory.getLogger(ResponseAdvice.class); @Override public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) { return true; } @Override public Object beforeBodyWrite(Object o, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) { logger.info("before body write param:{}",o); if(o instanceof String) { //序列化结果输出 return FastJsonUtil.toJSONString(Result.success(o)); } else if (o instanceof Result) { return o; } return Result.success(o); } } |
经过优化后，controller输出可以根据业务的需求定义输出对象。
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@GetMapping("getUserByName") public TUser getUserByName1(@RequestParam String name) { logger.info("getUserByName paramter name:"+name); return userService.getUserByName(name); } |
2.7 子系统如何实现
子系统引入common的jar包，
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<dependency> <groupId>com.xx</groupId> <artifactId>xx-common</artifactId> <version>2.0</version> </dependency> |
3、子系统定义状态码，实现BaseResultCode接口
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public enum OrderModelErrorCode implements BaseResultCode { ORDER_STATUS_ERROR(1000, "订单状态不正确"); private int code; private String msg; private UserModelErrorCode(int code, String msg) { this.code = code; this.msg = msg; } @Override public int getCode() { return code; } @Override public String getMsg() { return msg; } } |
定义异常处理类，继承公共异常处理类SysExceptionHandler
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@RestControllerAdvice public class OrderModalExceptionHandle extends SysExceptionHandler { @Override public Result handleException(HttpServletRequest request, Exception ex) { return super.handleException(request, ex); //子系统可以扩展异常处理 } } |
子系统使用示例：
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@Override public Order getOrder(String orderId) { Order order =getOrder(orderId); //相关伪代码 if(order.getStatus()>120) { throw new SysException(OrderModelErrorCode.ORDER_STATUS_ERROR); } return order; } |
经过相关项目的重构，已经解决了第一个和第二问题，关于第三个国际化问题，将在后续的文章中讲解。
