编写需要校验的model

import lombok.Data;

import javax.validation.constraints.Max;
import javax.validation.constraints.Min;

@Data
public class SchoolDto {

    @Min(value = 1, message = "page最小值为1")
    @Max(value = Integer.MAX_VALUE, message = "page过大")
    private Integer page = PageConstant.DEFAULT_PAGE;

    @Min(value = 1, message = "pageSize最小值为1")
    @Max(value = Integer.MAX_VALUE, message = "pageSize过大")
    private Integer pageSize = PageConstant.DEFAULT_PAGE_SIZE;
}

Controller中对参数的校验

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;

@RestController
@RequestMapping("/school")
public class SchoolController {

    @Autowired
    private SchoolService schoolService;

    @RequestMapping("/list")
    @ResponseBody
    public Result list(@Valid SchoolDto schoolDto, BindingResult bindingResult) {
        if (bindingResult.hasErrors()) {
            return Result.error(ResultEnum.PARAMS_ERROR.getCode(), ValidUtil.getAllErrorMessage(bindingResult));
        }

        return Result.success(schoolService.list(schoolDto));
    }
}

注意

用 @Valid 注解的参数后必须紧挨着一个 BindingResult 参数，否则 Spring 会在校验不通过时直接抛出异常

用到的工具方法

Controller 返回给客户端的 JSON 对象

import lombok.Data;

@Data
public class Result {

    private Integer code;
    private String msg;
    private Object data;

    public static Result success() {
        return success(null);
    }

    public static Result success(Object obj) {
        Result result = new Result();
        result.setCode(ResultEnum.SUCCESS.getCode());
        result.setMsg(ResultEnum.SUCCESS.getMsg());
        result.setData(obj);
        return result;
    }

    public static Result error(Integer code, String msg) {
        Result result = new Result();
        result.setCode(code);
        result.setMsg(msg);
        return result;
    }
}

得到参数校验的错误信息

import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;

public class ValidUtil {

    public static String getAllErrorMessage(BindingResult bindingResult) {
        StringBuilder result = new StringBuilder();
        for (ObjectError error : bindingResult.getAllErrors()) {
            result.append(error.getDefaultMessage()).append(";");
        }
        return result.toString();
    }
}