spring boot 统一异常处理

需求源自于任何一个业务的编写总会有各种各样的条件判断，需要时时手动抛出异常，又希望让接口返回友好的错误信息。

spring boot提供的帮助是自动将异常重定向到路由为/error的控制器

但是我们又希望手动抛出的异常与正常的数据返回为同一类型

所以我的解决方案由三个步骤组成：

1.一个异常枚举类 StatusCodeEnum.java

public enum StatusCodeEnum implements Serializable {
    SUCCESS(0, "成功"),
    ERROR(-1, "失败"),
    USER_INVALID(60000, "无效用户"),
    SYS_ARG_INVALID(11000, "无效参数"),

    ;
    private static final long serialVersionUID = 1L;
    private int code;
    private String msg;

    StatusCodeEnum(int code, String msg) {
        this.code = code;
        this.msg = msg;
    }
    public int getCode() {
        return code;
    }

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

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    //根据code获取对应枚举
    public static StatusCodeEnum getByCode(int code) {
        StatusCodeEnum[] values = StatusCodeEnum.values();

        for (StatusCodeEnum bizStatusCodeEnum : values) {
            if (bizStatusCodeEnum.code == code) {
                return bizStatusCodeEnum;
            }
        }
        return null;
    }
}

2.一个异常调用类 BaseException.java

因为抛出异常只能抛出字符串 所以这里使用了com.alibaba.fastjson.JSON包

public class BaseException {
    private int code;
    private String message;

    public static void error(StatusCodeEnum statusCodeEnum) throws Exception
    {
        error(statusCodeEnum.getCode(),statusCodeEnum.getMsg());
    }

    public static void error(String message) throws Exception
    {
        error(-1,message);
    }

    public static void error(int code,String message) throws Exception
    {
        BaseException baseException = new BaseException();
        baseException.setCode(code);
        baseException.setMessage(message);
        throw new Exception(JSON.toJSONString(baseException)) ;
    }

    public int getCode() {
        return code;
    }

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

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return "BaseException{" +
                "code=" + code +
                ", message='" + message + '\'' +
                '}';
    }
}

3.异常处理控制器 ErrorController.java

@Controller
public class ErrorController extends AbstractErrorController{

    @Autowired
    ObjectMapper objectMapper;

    public ErrorController() {
        super(new DefaultErrorAttributes());
    }

    @Override
    public String getErrorPath() {
        return null;
    }

    @RequestMapping("/error")
    @ResponseBody
    public BaseRs getErrorPath(HttpServletRequest request, HttpServletResponse response) {

        Map<String,Object> model = Collections.unmodifiableMap(getErrorAttributes(request,false));

        //获取异常 可将异常打印到日志
        Throwable cause = getCause(request);
        int status = (Integer)model.get("status");

        //自定义友好错误信息
        String msg = (String)model.get("message");

        JSONObject object = JSONObject.parseObject(msg);
        int code = object.getInteger("code");
        String message = object.getString("message");

        return new BaseRs(code,message);
    }

    protected Throwable getCause(HttpServletRequest request)
    {
        Throwable error = (Throwable)request.getAttribute("javax.servlet.error.exception");
        if(null == error){
            //MVC有可能会封装异常成ServletException ,需要调用getCause获取真正的异常
            while (error instanceof ServletException && error.getCause() != null){
                error = ((ServletException) error).getCause();
            }
        }
        return error;
    }
}

以上三个文件为异常处理的核心

其中的BaseRs类是统一数据返回

public class BaseRs<T> implements Serializable {

    private int code;

    private String message;

    public BaseRs() {
    }

    /**
     * 返回内容
     */
    private T content;

    public int getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }

    public T getContent() {
        return content;
    }

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

    public BaseRs(int code, String message, T content) {
        this.code = code;
        this.message = message;
        this.content = content;
    }

    public BaseRs(StatusCodeEnum status) {
        this.code = status.getCode();
        this.message = status.getMsg();
    }

    public BaseRs(StatusCodeEnum status, T content) {
        this.code = status.getCode();
        this.message = status.getMsg();
        this.content = content;
    }

    public static <V> BaseRs ok(V content) {
        return new BaseRs(StatusCodeEnum.SUCCESS, content);
    }

    public static BaseRs ok() {
        return new BaseRs(StatusCodeEnum.SUCCESS);
    }

    public static BaseRs error(StatusCodeEnum error) {
        return new BaseRs(error);
    }

    public void setCode(StatusCodeEnum status) {
        this.code = status.getCode();
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public void setContent(T content) {
        this.content = content;
    }

    @Override
    public String toString() {
        return "BaseRs{" +
                "code=" + code +
                ", message='" + message + '\'' +
                ", content=" + content +
                '}';
    }

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

最后的控制层代码以最简洁的方式调用即可：

@Controller
public class IndexController {
    @RequestMapping("/a")
    @ResponseBody
    public BaseRs a() throws Exception{
        boolean s = false;
        if(!s){
            BaseException.error(StatusCodeEnum.USER_INVALID);
        }
        return new BaseRs(StatusCodeEnum.SUCCESS);
    }
}

本篇博客的码云地址： https://gitee.com/zhao-baolin/springboot_error