SpringBoot 2.x 开发案例之优雅的处理异常

异常怎么处理？撸主很久之前的项目都是在 Controller 层一个个 try 的，之后也曾自己写过AOP实现异常拦截处理。不过，这里给小伙伴推荐一款统一处理异常神器。

微服务、前后端分离的时代，应该很少有小伙伴使用模板了吧，大多都是返回Json数据。墙裂推荐大家使用 @RestControllerAdvice，可以用于定义@ExceptionHandler、@InitBinder、@ModelAttribute，并应用到所有@RequestMapping中。

@RestControllerAdvice
public class RrExceptionHandler {
	
	private Logger logger = LoggerFactory.getLogger(getClass());

	@ExceptionHandler(Exception.class)
	public Result handleException(Exception e){
		logger.error(e.getMessage(), e);
		return Result.error();
	}
	
	
	@ExceptionHandler(RrException.class)
	public Result handleRRException(RrException e){
		Result r = new Result();
		r.put("code", e.getCode());
		r.put("msg", e.getMessage());
		return r;
	}
	@ExceptionHandler(DuplicateKeyException.class)
	public Result handleDuplicateKeyException(DuplicateKeyException e){
		logger.error(e.getMessage(), e);
		return Result.error("数据库中已存在该记录");
	}
}

public class RrException extends RuntimeException {
	
	private static final long serialVersionUID = 1L;
	
    private String msg;
    
    private int code = 500;
    
    public RrException(String msg) {
		super(msg);
		this.msg = msg;
	}
	
	public RrException(String msg, Throwable e) {
		super(msg, e);
		this.msg = msg;
	}
	
	public RrException(String msg, int code) {
		super(msg);
		this.msg = msg;
		this.code = code;
	}
	
	public RrException(String msg, int code, Throwable e) {
		super(msg, e);
		this.msg = msg;
		this.code = code;
	}

	public String getMsg() {
		return msg;
	}

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

	public int getCode() {
		return code;
	}

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

public class Result extends HashMap {

	private static final long serialVersionUID = 1L;

	public Result() {
		put("code", 0);
	}

	public static Result error() {
		return error(500, "未知异常，请联系管理员");
	}

	public static Result error(String msg) {
		return error(500, msg);
	}

	public static Result error(int code, String msg) {
		Result r = new Result();
		r.put("code", code);
		r.put("msg", msg);
		return r;
	}

	public static Result ok(Object msg) {
		Result r = new Result();
		r.put("msg", msg);
		return r;
	}

	public static Result ok(Map map) {
		Result r = new Result();
		r.putAll(map);
		return r;
	}

	public static Result ok() {
		return new Result();
	}

	@Override
	public Result put(String key, Object value) {
		super.put(key, value);
		return this;
	}
}

我们尝试模拟一个经典异常：

@RequestMapping("eatChicken")
public Result eatChicken() {
     String 马化腾 = null;
     if(马化腾.equals("码云")){
  System.out.println("一起搞基");
     }
     return Result.ok();
}

前台输出：

{"msg":"未知异常，请联系管理员","code":500}

后台打印：

java.lang.NullPointerException: null
	at com.itstyle.chicken.module.tools.web.ArticleController.get(ArticleController.java:35)
	

是不是很爽，再也不用 try 了！！！

https://blog.52itstyle.vip/archives/5069/