SpringBoot 统一异常处理

## 统一异常处理
```
/**
 * description: 统一异常处理
 *
 * @author quanhuan.huang
 * @version 1.0
 * @date 2021/3/9 17:12
 */
@ControllerAdvice
@ResponseBody
@Slf4j
public class ExceptionConfig {
    @ExceptionHandler(value = RuntimeException.class)
    public Result handlerRuntimeException(RuntimeException e, HttpServletRequest request) {
        log.error("运行异常，url={}", requst.getRequestURI(), e);
        return Result.fail(e);
    }

@ExceptionHandler(value = Exception.class)
    public Result handlerException(Exception e) {
        log.error(e.getMessage(), e);
        return Result.fail(e);
    }
	
	/**
     * 参数验证异常(前端json格式提交) 配合@Validated @Valid和@NotNull使用
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Result handleParameterException(MethodArgumentNotValidException e) {
        String message = logWrite(e.getBindingResult());
        return Result.fail(message);
    }
 
    /**
     * 参数验证异常(前端form表单格式提交)
     */
    @ExceptionHandler(BindException.class)
    public Result handlerBindException(BindException e) {
        String message = logWrite(e.getBindingResult());
        return Result.fail(message);
    }
    
    private String logWrite(BindingResult e) {
        StringBuilder message = new StringBuilder();
        for(FieldError item : e.getFieldErrors()){
            message.append(item.getField()).append(item.getDefaultMessage()).append(" \n");
        }
        log.error(message.toString(), e);
        return message.toString();
    }
}
```

## 优雅参数校验 @Validated @Valid和@NotNull
https://www.jianshu.com/p/3267689ebf1b
```
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.17.Final</version>
</dependency>
```

## 统一返回类
```
package com.xindeco.xdmail.entity;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import java.io.Serializable;

/**
 * description: 统一返回类
 *
 * @author quanhuan.huang
 * @version 1.0
 * @date 2021/2/4 16:07
 */
@ApiModel("统一返回类")
@Data
public class Result<T> implements Serializable {
    private static final long serialVersionUID = -3590682968045255221L;

public final static int SUCCESS_CODE = 1;

public final static int FAIL_CODE = 0;

/**
     * 消息名
     */
    @ApiModelProperty("程序执行结果，错误时为e.getmessage()")
    private String message;
    /**
     * 直接标记
     */
    @ApiModelProperty("true执行成功 false执行失败")
    private Boolean flag;
    /**
     * 信号编码
     */
    @ApiModelProperty("默认1为真,0为假，其余自定义")
    private Integer code;
    /**
     * 成功时携带数据
     */
    private T data;

public Result(String message, Boolean flag, Integer code, T data) {
        this.message = message;
        this.flag = flag;
        this.code = code;
        this.data = data;
    }

public static <T> Result success(T data) {
        return new Result(null, true, SUCCESS_CODE, data);
    }

public static <T> Result success(String message, T data) {
        return new Result(message, true, SUCCESS_CODE, data);
    }

public static <T> Result fail(String message) {
        return new Result(message, false, FAIL_CODE, null);
    }

public static <T> Result fail(Integer code, String message) {
        return new Result(message, false, code, null);
    }

public static <T> Result fail(Exception e) {
        return new Result(e.getLocalizedMessage(), false, FAIL_CODE, null);
    }
}

```