Java：如何使用 Spring Boot 实现异常处理？

1、使用 @ExceptionHandler 注解处理局部异常(只能处理当前controller中的ArithmeticException和NullPointerException异常，缺点就是只能处理单个controller的异常)

@Controller
public class ExceptionHandlerController {
	
	@RequestMapping("/excep")
	public String exceptionMethod(Model model) throws Exception {
		String a=null;
		System.out.println(a.charAt(1));
		int num = 1/0;
		model.addAttribute("message", "没有抛出异常");
		return "index";
	}
 
	@ExceptionHandler(value = {ArithmeticException.class,NullPointerException.class})
	public String arithmeticExceptionHandle(Model model, Exception e) {
		model.addAttribute("message", "@ExceptionHandler" + e.getMessage());
		return "index";
	}
}

2、使用 @ControllerAdvice + @ExceptionHandler 注解处理全局异常(value后面可以填写数组)

@ControllerAdvice
public class ControllerAdviceException {
	
	@ExceptionHandler(value = {NullPointerException.class})
	public String NullPointerExceptionHandler(Model model, Exception e) {
		model.addAttribute("message", "@ControllerAdvice + @ExceptionHandler :" + e.getMessage());
		return "index";
	}
}

3、配置 SimpleMappingExceptionResolver 类处理异常（配置类）

@Configuration
public class SimpleMappingException {
	@Bean
	public SimpleMappingExceptionResolver getSimpleMappingExceptionResolver(){
 
		SimpleMappingExceptionResolver resolver = new SimpleMappingExceptionResolver();
		Properties mappings = new Properties();
		//第一个参数为异常全限定名，第二个为跳转视图名称
		mappings.put("java.lang.NullPointerException", "index");
		mappings.put("java.lang.ArithmeticException", "index");
		//设置异常与视图映射信息的
		resolver.setExceptionMappings(mappings);
		return resolver;
	}
}

4、实现 HandlerExceptionResolver 接口处理异常

@Configuration
public class HandlerException implements HandlerExceptionResolver {
	@Override
	public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
 
		ModelAndView modelAndView = new ModelAndView();
		modelAndView.addObject("message", "实现HandlerExceptionResolver接口");
 
		//判断不同异常类型，做不同视图跳转
		if(ex instanceof NullPointerException){
			modelAndView.setViewName("index");
		}
		if(ex instanceof ArithmeticException){
			modelAndView.setViewName("index");
		}
		return modelAndView;
	}
}