原 spring boot 全局异常处理，以及自定义异常

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前提：我项目框架是 spring cloud 

1 配置全局异常处理类。

package com.mszl.candidate.exception;

import java.io.PrintWriter;
import java.io.StringWriter;
import javax.servlet.http.HttpServletRequest;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import com.manulife.utils.BusinessUtils;
import com.manulife.utils.ReturnMsgUtils;
import lombok.extern.slf4j.Slf4j;

@ControllerAdvice
@Slf4j
public class GlobalDefultExceptionHandler {
	
	//声明要捕获的异常
	@ExceptionHandler(Exception.class)
	@ResponseBody
	public ReturnMsgUtils defultExcepitonHandler(HttpServletRequest request, Exception e) {
		ReturnMsgUtils msg=null;
		if(e instanceof BusinessException) {
			BusinessException businessException = (BusinessException)e;
			msg=new ReturnMsgUtils(businessException.getCode(), businessException.getMessage());
			return msg;
		} else{
			Throwable t = e;
			StringWriter stringWriter= new StringWriter();
			PrintWriter writer= new PrintWriter(stringWriter); 
			t.printStackTrace(writer); 
			StringBuffer buffer= stringWriter.getBuffer(); 
			log.error(buffer.toString());
			msg = new ReturnMsgUtils(BusinessUtils.BUSINESS_CODE_201, BusinessUtils.BUSINESS_MSG_202,buffer.toString());
			return msg;
		}
	}
	
	
	
	
}

说明：

定义一个处理类，使用@ControllerAdvice注解。

@ControllerAdvice注解：控制器增强，一个被@Component注册的组件。

配合@ExceptionHandler来增强所有的@requestMapping方法。

2 自定义异常处理。如我们需要人为的抛出错误来进行事务的回滚

package com.mszl.candidate.exception;

public class BusinessException extends RuntimeException{
	
	private static final long serialVersionUID = 1L;
	
	// 自定义错误码
	private Integer code;
	
	// 自定义构造器，只保留一个，让其必须输入错误码及内容
	public BusinessException(int code, String msg) {
		super(msg);
		this.code = code;
	}
 
	public Integer getCode() {
		return code;
	}
 
	public void setCode(Integer code) {
		this.code = code;
	}
	


}

3 还要最最关键的一步，要在service实现层加上 @Transactional 注解，否则事务不会进行回滚。