@ControllerAdvice：全局異常處理示例

全局異常處理

用@ControllerAdvice標記全局異常處理的類

項目地址：https://github.com/zz790609619/LeetCodeRecord.git

@ControllerAdvice
這是一個增強的 Controller標籤。使用這個 ControllerAdvice，可以實現三個方面的功能：

1. 全局異常處理
2. 設置全局變量，也就是設置完，每個接口能獲取到整個參數
3. 數據預處理

@ControllerAdvice修飾的類

package com.example.demo.config;

import com.example.demo.entity.model.ResponseDto;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Map;

@ControllerAdvice
public class GlobalControllerAdvice {
    /**
     * 所有異常處理
     * @param request
     * @param e
     * @return
     * @throws Exception
     */
    @ExceptionHandler(value = Exception.class)
    public @ResponseBody
    ResponseDto exceptionHandler(HttpServletRequest request,Exception e)throws Exception{
        ResponseDto dto=new ResponseDto();
        dto.setErrorCode(1001);
        dto.setMessage("Exception:"+e.getMessage());
        return dto;
    }

    /**
     * 空指針異常處理
     * @param request
     * @param e
     * @return
     * @throws NullPointerException
     */
    @ExceptionHandler(value = NullPointerException.class)
    public @ResponseBody
    ResponseDto exceptionHandler(HttpServletRequest request,NullPointerException e)throws NullPointerException{
        ResponseDto dto=new ResponseDto();
        dto.setErrorCode(1002);
        dto.setMessage("NullPointerException:"+e.getMessage());
        return dto;
    }

    /**
     * 全局變量
     * @return
     */
    @ModelAttribute(name="ww")
    public Map<String,Object> globalData() {
        HashMap<String, Object> map = new HashMap<>();
        map.put("ww", "helloQ");
        return map;
    }

    /**
     * 數據預處理
     * @param binder
     */
    @InitBinder("helloA")
    public void b(WebDataBinder binder) {
        binder.setFieldDefaultPrefix("helloA.");
    }
    @InitBinder("helloB")
    public void a(WebDataBinder binder) {
        binder.setFieldDefaultPrefix("helloB.");
    }

}

使用場景：

package com.example.demo.controller;

import com.aliyun.openservices.shade.com.alibaba.fastjson.JSON;
import com.example.demo.entity.model.ResponseDto;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Map;

@RestController
@RequestMapping(value = "/test")
public class UserNodeController {
    @RequestMapping(value = "/index")
    public String index(){
        return "/index";
    }

    /**
     * 異常報錯
     * 訪問路徑：http://127.0.0.1:8090/test/exception
     * 不走全局處理類結果：{"message": "NoEnterGlobalException" }
     * 最後返回結果： {"errorCode": 1001,"message": "Exception:4","data": null }
     */
    @RequestMapping(value = "/exception")
    public ResponseDto getException(){
        int[] arr = {1, 2, 3};
        System.out.println(arr[4]);
        ResponseDto dto=new ResponseDto();
        dto.setMessage("NoEnterGlobalException");
        return dto;
    }
    /**
     * 空指針異常報錯
     * 訪問路徑：http://127.0.0.1:8090/test/nullPointException
     * 不走全局處理類結果：{"message": "NoEnterGlobalNullPointException" }
     * 最後返回結果：{"errorCode": 1002,"message": "NullPointerException:null","data": null }
     */
    @RequestMapping(value = "/nullPointException")
    public ResponseDto getNullPointException(){
        Object obj = null;
        obj.toString();
        ResponseDto dto=new ResponseDto();
        dto.setMessage("NoEnterGlobalNullPointException");
        return dto;
    }
    /**
     * 獲取全局變量
     * 訪問路徑：http://127.0.0.1:8090/test/getGlobalParm
     * 返回結果：{"ww":{"ww":"helloQ"}}
     */
    @RequestMapping(value = "/getGlobalParm")
    public String getGlobalParm(Model model){
        Map<String, Object> map = model.asMap();
        return JSON.toJSONString(map);
    }

    /**
     * 獲取預處理後的數據
     * 訪問地址及參數：http://127.0.0.1:8090/test/getPreprocessedData?helloA.errorCode=1&helloA.message=a&helloA.data=a&helloB.errorCode=2&helloB.message=b&helloB.data=b
     * 返回結果：dtoA:{"data":"a","errorCode":1,"message":"a"},dtoB:{"data":"b","errorCode":2,"message":"b"}
     */
    @RequestMapping(value = "/getPreprocessedData")
    public String getPreprocessedData(@ModelAttribute("helloA")ResponseDto dtoA,@ModelAttribute("helloB")ResponseDto dtoB){
        return "dtoA:"+JSON.toJSONString(dtoA)+",dtoB:"+JSON.toJSONString(dtoB);
    }
}