公司项目JAVA开发规范总结(三)——异常处理篇

概述：该类是为了让在业务层，能够返回错误信息，而不涉及控制层的返回封装类，让业务层和控制层能有效隔离开来。

BusinessException类

@Data
public class BusinessException extends RuntimeException {
    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = "结果码 200:成功 500:具体异常信息 400:参数异常 401:未授权的请求 403:无权访问")
    private Integer statusCode =500;

    @ApiModelProperty(value = "错误码")
    private int errCode;

    @ApiModelProperty(value = "错误提示信息")
    private String msg;

    @ApiModelProperty(value = "数据体")
    private T data;

    public BusinessException() {
        super();
    }

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

    public BusinessException(Integer status, int code, String message) {
        super();
        this.statusCode = status;
        this.errCode = code;
        this.msg = message;
    }
}

在业务层Service中，下列错误反馈的例子

//例子一
try {
	int a =id/0;
} catch (Exception e) {
    throw new BusinessException(ReturnCode.server_exception_code,ReturnCode.server_exception_message,
                                ReturnCode.err_other_code,"计算出错");
}
//例子二
if (id==null){
    throw new BusinessException(ReturnCode.param_false_code,ReturnCode.param_false_message
                                ReturnCode.err_notexit_code,"参数不存在");
}

异常抛出之后，捕获异常的方式有两种：

方式一：由控制层进行局部捕获，返回结果

try {
	calculateService.count(id);
	return PacketHttpRes_V32.makeOKResponse();
} catch (BusinessException be){
	log.error("出错：", be.getResultCode_Msg());
	return PacketHttpRes_V32.makeResponse(be.getReturnCode(), be.getReturnCode_Msg(),
                                be.getResultCode(), be.getResultCode_Msg(),ex.getData());
}

方式二：进行全局捕获，返回结果

@ExceptionHandler(BusinessException.class)
@ResponseBody
public PacketHttpRes_V32 processBusinessException(BusinessException ex) {
    log.warn("捕获 BusinessException:  ReturnCode:{} , ReturnCodeMsg:{} ResultCode:{} , ResultMsg:{}",
             ex.getReturnCode(),ex.getReturnCode_Msg(),ex.getResultCode(),ex.getResultCode_Msg());
    return PacketHttpRes_V32.makeResponse(ex.getReturnCode(), ex.getReturnCode_Msg(),
                                ex.getResultCode(), ex.getResultCode_Msg(),ex.getData());
}

概述：该异常由于接口参数传入错误，使得异常抛出

IntegerValidator注解：

@Documented
@Target({ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = IntegerValidatorOfParams.class)
public @interface IntegerValidator {

	int[] params() default {};
	
    String message() default "参数不合法";

    Class[] groups() default {};

    Class[] payload() default {};
}

IntegerValidatorOfParams实现类

public class IntegerValidatorOfParams implements ConstraintValidator {

	private int[] params;
	
    @Override
    public void initialize(IntegerValidator integerValidator) {	
    	this.params=integerValidator.params();
    }
    
    @Override
    public boolean isValid(Object o, ConstraintValidatorContext constraintValidatorContext) {
        List list = Arrays.stream(params).boxed().collect(Collectors.toList());
    	return list.contains(o);
    }
}

使用案例：

@RestController
@RequestMapping("/TeachingPlan/ShareTpMgr")
@Validated
@Slf4j
@Api(tags = "教师端端共享教案库管理")
public class ShareTpMgrOfTeaController extends BaseController {
    
	@ApiOperation(value = "获取共享教材信息列表(中小学)", notes = "获取可访问的教材信息列表以及历史访问信息")
	@RequestMapping(value = "/GetCanVisBookList", method = RequestMethod.GET)
    public PacketHttpRes_V32 GetCanVisBookList(
        @ApiParam("用户ID") @NotBlank(message = "--UserID不能为空--") String UserID,

        @ApiParam("是否查询自己共享的，0或不传查询全部，1为查询自己共享的，2为查询非自己共享的")
        @RequestParam(value = "IsQueryBySelf", required = false, defaultValue = "0")
        @NotNull(message = "--IsQueryBySelf不能为空--")
        @IntegerValidator(params = {0, 1, 2}, message = "--IsQueryBySelf参数错误--") 
        Integer IsQueryBySelf,
        HttpServletResponse response
    )
}

全局捕获，返回结果

@ExceptionHandler(value = Exception.class)
public PacketHttpRes