Controller层方法参数校验和全局异常捕获

在表单提交时，controller都要验证从前端接受的参数，假如每个参数都手动判断会比较麻烦，可以采用验证框架来简化对参数的验证

1 导入依赖

        <!--JSR303参数校验开始-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <!--JSR303参数校验结束-->

 2 controller层方法形参添加Valid注解

    @RequestMapping("/do_login")
    @ResponseBody
    public Result<String> doLogin(HttpServletResponse response, @Valid LoginVo loginVo) {
        log.info(loginVo.toString());
        //登录
        String token = userService.login(response, loginVo);
        return Result.success(token);
    }

对请求参数的封装pojo

这里的NotNull 是框架自带的注解，IsMobile是自定义注解

public class LoginVo {

    @NotNull
    @IsMobile
    private String mobile;

    @NotNull
    @Length(min=6,max=16,message = "密码长度错误")
    private String password;

    public String getMobile() {
        return mobile;
    }
    public void setMobile(String mobile) {
        this.mobile = mobile;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    @Override
    public String toString() {
        return "LoginVo [mobile=" + mobile + ", password=" + password + "]";
    }
}

安装下面的方式自定义注解

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = {IsMobileValidator.class })
public @interface  IsMobile {
    
    boolean required() default true;
    
    String message() default "手机号码格式错误";

    Class<?>[] groups() default { };

    Class<? extends Payload>[] payload() default { };
}

public class IsMobileValidator implements ConstraintValidator<IsMobile, String> {

    private boolean required = false;
    
    public void initialize(IsMobile constraintAnnotation) {
        required = constraintAnnotation.required();
    }

    public boolean isValid(String value, ConstraintValidatorContext context) {
        if(required) {
            return ValidatorUtil.isMobile(value);
        }else {
            if(StringUtils.isEmpty(value)) {
                return true;
            }else {
                return ValidatorUtil.isMobile(value);
            }
        }
    }

}

3 全局异常捕获

public class GlobalException extends RuntimeException{

    private static final long serialVersionUID = 1L;
    
    private CodeMsg cm;
    
    public GlobalException(CodeMsg cm) {
        super(cm.toString());
        this.cm = cm;
    }

    public CodeMsg getCm() {
        return cm;
    }

}

@ControllerAdvice
@ResponseBody
public class GlobalExceptionHandler {
    @ExceptionHandler(value=Exception.class)
    public Result<String> exceptionHandler(HttpServletRequest request, Exception e){
        e.printStackTrace();
        if(e instanceof GlobalException) {
            GlobalException ex = (GlobalException)e;
            return Result.error(ex.getCm());
        }else if(e instanceof BindException) {
            BindException ex = (BindException)e;
            List<ObjectError> errors = ex.getAllErrors();
            ObjectError error = errors.get(0);
            String msg = error.getDefaultMessage();
            return Result.error(CodeMsg.BIND_ERROR.fillArgs(msg));
        }else {
            return Result.error(CodeMsg.SERVER_ERROR);
        }
    }
}

4 service层方法

    public String login(HttpServletResponse response, LoginVo loginVo) {
        if(loginVo == null) {
            throw new GlobalException(CodeMsg.SERVER_ERROR);
        }
        String mobile = loginVo.getMobile();
        String formPass = loginVo.getPassword();
        //判断手机号是否存在
        MiaoshaUser user = getById(Long.parseLong(mobile));
        if(user == null) {
            throw new GlobalException(CodeMsg.MOBILE_NOT_EXIST);
        }
        //验证密码
        String dbPass = user.getPassword();
        String saltDB = user.getSalt();
        String calcPass = MD5Util.formPassToDBPass(formPass, saltDB);
        if(!calcPass.equals(dbPass)) {
            throw new GlobalException(CodeMsg.PASSWORD_ERROR);
        }
        //生成cookie
        String token    = UUIDUtil.uuid();
        addCookie(response, token, user);
        return token;
    }

5 返回给前端的json

public class Result<T> {
    
    private int code;
    private String msg;
    private T data;
    
    /**
     *  成功时候的调用
     * */
    public static  <T> Result<T> success(T data){
        return new Result<T>(data);
    }
    
    /**
     *  失败时候的调用
     * */
    public static  <T> Result<T> error(CodeMsg codeMsg){
        return new Result<T>(codeMsg);
    }
    
    private Result(T data) {
        this.data = data;
    }
    
    private Result(int code, String msg) {
        this.code = code;
        this.msg = msg;
    }
    
    private Result(CodeMsg codeMsg) {
        if(codeMsg != null) {
            this.code = codeMsg.getCode();
            this.msg = codeMsg.getMsg();
        }
    }
    
    
    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;
    }
    public T getData() {
        return data;
    }
    public void setData(T data) {
        this.data = data;
    }
}

这样的好处是对参数校验只要添加注解就可以了。参数校验不通过会抛出BindException异常，BindException被全局异常处理器捕获，将错误信息返回给前端。

而且异常处理器也会捕获自定义的异常。

 

BindException