基于spring boot的统一异常处理

一、springboot的默认异常处理

Spring Boot提供了一个默认的映射：/error，当处理中抛出异常之后，会转到该请求中处理，并且该请求有一个全局的错误页面用来展示异常内容。

例如这里我们认为制造一个异常

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

使用浏览器访问http://127.0.0.1:8080/boys

二、自定义的统一异常处理

虽然Spring Boot中实现了默认的error映射，但是在实际应用中，上面你的错误页面对用户来说并不够友好，我们通常需要去实现我们自己的异常提示。

1) 统一的异常处理类(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("【系统异常】{}", e);
            return ResultUtil.error(-, "未知错误");
        }
    }
}

2）自定义异常类(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）返回结果枚举(com.dechy.enums)

public enum ResultEnum {
    UNKONW_ERROR(-, "未知错误"),
    SUCCESS(, "成功"),
    TOOSHORT(, "身高太矮"),
    TOOHIGH(, "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）返回结果工具类(com.dechy.util)

public class ResultUtil {

    public static Result success(Object object) {
        Result result = new Result();
        result.setCode();
        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实体类(com.dechy.model)

@Entity
public class Boy {

    @Id
    @GeneratedValue
    private Integer id;

    @NotBlank(message = "这个字段必传")
    private String height;

    @Min(value = 100, message = "体重必须大于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）业务层具体使用时抛出异常，等待统一处理(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);
        }//...
    }