基於spring boot的統一異常處理

一、springboot的默認異常處理

Spring Boot提供了一個默認的映射：/error，當處理中拋出異常之后，會轉到該請求中處理，並且該請求有一個全局的錯誤頁面用來展示異常內容。

例如這里我們認為制造一個異常

    @GetMapping(value = "/boys")
    public List<Boy> boyList() throws Exception{
        throw new Exception("錯誤");
    }

使用瀏覽器訪問http://127.0.0.1:8080/boys

二、自定義的統一異常處理

雖然Spring Boot中實現了默認的error映射，但是在實際應用中，上面你的錯誤頁面對用戶來說並不夠友好，我們通常需要去實現我們自己的異常提示。

1) 統一的異常處理類(com.dechy.handle)

@ControllerAdvice
public class ExceptionHandle {

    private final static Logger logger = LoggerFactory.getLogger(ExceptionHandle.class);

    @ExceptionHandler(value = Exception.class) @ResponseBody
    public Result handle(Exception e) {
        if (e instanceof BoyException) {
            BoyException boyException = (BoyException) e;
            return ResultUtil.error(boyException.getCode(), boyException.getMessage());
        }else {
            logger.error("【系統異常】{}", e);
            return ResultUtil.error(-1, "未知錯誤");
        }
    }
}

 2）自定義異常類(com.dechy.exception)

public class BoyException extends RuntimeException{

    private Integer code;

    public BoyException(ResultEnum resultEnum) {
        super(resultEnum.getMsg());
        this.code = resultEnum.getCode();
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }
}

3）返回結果枚舉(com.dechy.enums)

public enum ResultEnum {
    UNKONW_ERROR(-1, "未知錯誤"),
    SUCCESS(0, "成功"),
    TOOSHORT(100, "身高太矮"),
    TOOHIGH(101, "身高太高"),

    ;

    private Integer code;

    private String msg;

    ResultEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public Integer getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }
}

4）返回結果工具類(com.dechy.util)

public class ResultUtil {

    public static Result success(Object object) {
        Result result = new Result();
        result.setCode(0);
        result.setMsg("成功");
        result.setData(object);
        return result;
    }

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

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

5）Boy實體類(com.dechy.model)

@Entity
public class Boy {

    @Id
    @GeneratedValue
    private Integer id;

    @NotBlank(message = "這個字段必傳")
    private String height;

    @Min(value = 100, message = "體重必須大於100")
    private BigDecimal weight;

    public Integer getId (){
        return id;
    }

    public void setId (Integer id){
        this.id = id;
    }

    public String getHeight (){
        return height;
    }

    public void setHeight (String height){
        this.height = height;
    }

    public BigDecimal getWeight (){
        return weight;
    }

    public void setWeight (BigDecimal weight){
        this.weight = weight;
    }

    @Override
    public String toString (){
        return "Boy{" + "id=" + id + ", height='" + height + '\'' + ", weight=" + weight + '}';
    }
}

6）業務層具體使用時拋出異常，等待統一處理(com.dechy.service)

    public void chooseBoy(Integer id) throws Exception{
        Boy boy= boyRepository.findOne(id);
        Integer height= boy.getHeight();
        if (height < 100) {
            //返回"身高矮" code=100
            throw new BoyException(ResultEnum.TOOSHORT);
        }else if (height > 200) {
            //返回"身高太高" code=101
            throw new BoyException(ResultEnum.TOOHIGH);
        }//...
    }