自定义异常

示例代码

import com.imooc.order.converter.OrderForm2OrderDtoConverter;
import com.imooc.order.dto.OrderDto;
import com.imooc.order.enums.ResultEnum;
import com.imooc.order.exception.OrderException;
import com.imooc.order.form.OrderForm;
import com.imooc.order.service.OrderService;
import com.imooc.order.utils.ResultVoUtil;
import com.imooc.order.vo.ResultVo;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.CollectionUtils;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.Map;

/**
 * 订单操作controller
 */
@RestController
@RequestMapping(value = "order")
@Slf4j
public class OrderController {

    @Autowired
    private OrderService orderService;

    @PostMapping("create")
    public ResultVo<Map<String, String>> create(OrderForm orderForm, BindingResult bindingResult) {
        // 校验参数，如果传递错误就抛出异常
        if (bindingResult.hasErrors()) {
            log.error("参数传递错误，orderForm={}", orderForm);
            throw new OrderException(ResultEnum.PARAM_ERROR.getCode(), bindingResult.getFieldError().getDefaultMessage());
        }
        // 转换参数
        OrderDto orderDto = OrderForm2OrderDtoConverter.conver(orderForm);
        if (CollectionUtils.isEmpty(orderDto.getDetailList())) {
            log.error("购物车信息不能为空，String={}", orderDto.getDetailList());
            throw new OrderException(ResultEnum.CART_ENPTY);
        }
        OrderDto dto = orderService.create(orderDto);

        Map<String, Object> map = new HashMap<>();
        map.put("id", dto.getOrderId());
        return ResultVoUtil.success(map);

    }

}

转换参数类 OrderForm2OrderDtoConverter

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.imooc.order.dataobject.OrderDetail;
import com.imooc.order.dto.OrderDto;
import com.imooc.order.enums.ResultEnum;
import com.imooc.order.exception.OrderException;
import com.imooc.order.form.OrderForm;
import lombok.extern.slf4j.Slf4j;

import java.util.ArrayList;
import java.util.List;

/**
 * 对象互相转换
 */
@Slf4j
public class OrderForm2OrderDtoConverter {

    public static OrderDto conver(OrderForm orderForm) {
        Gson gson = new Gson();
        OrderDto orderDto = new OrderDto();
        orderDto.setBuyerName(orderForm.getName());
        orderDto.setBuyerPhone(orderForm.getPhone());
        orderDto.setBuyerOpenid(orderForm.getOpenId());
        orderDto.setBuyerAddress(orderForm.getAddress());
        List<OrderDetail> list = new ArrayList<>();
        // 将订单详情的json字符串转为list
        try {
            list = gson.fromJson(orderForm.getItems(), new TypeToken<List<OrderDetail>>() {
            }.getType());
        } catch (Exception e) {
            log.error("订单详情参数转换错误，String={}", orderForm.getItems());
            // 抛出异常
            throw new OrderException(ResultEnum.PARAM_ERROR);
        }
        orderDto.setDetailList(list);
        return orderDto;
    }
}

上面的代码中如果再参数传递错误或查询无数据时我们可以自定义，让他抛出异常
1.先创建异常枚举类（定义相关异常描述和异常码）

@Getter
public enum ResultEnum {

    /**
     * 参数错误
     */
    PARAM_ERROR(1,"参数错误"),
    /**
     * 购物车不能为空
     */
    CART_ENPTY(2,"购物车不能为空"),
    ;

    private Integer code;

    private String message;


    ResultEnum(int code, String message) {
        this.code = code;
        this.message = message;
    }
}

2.创建异常类，继承RuntimeException。添加相应的构造方法

public class OrderException extends RuntimeException {

    private Integer code;

    public OrderException(Integer code, String message){
        super(message);
        this.code = code;
    }

    public OrderException(ResultEnum resultEnum){
        super(resultEnum.getMessage());
        this.code = resultEnum.getCode();
    }
}

异常的枚举类中可以进行扩展异常信息