Spring Boot (3)
error handling
1. User defined exception handling, return to the specified interface
In the method of controller error:
@RequestMapping("/error")
public String error() {
String str=null;
str.length();
return "test";
}In custom error page.html:
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
//Error
<span th:text="${#execInfo}"></span>
</body>
</html>
2. Catch exception, ExceptionHandler handling method
Exception in method
@RequestMapping("/error")
public String error() {
String str=null;
str.length();
return "test";
}
1) Handler handler ExceptionHandler catches the specified exception
@ExceptionHandler(value = {java.lang.NullPointerException.class})
public ModelAndView excuteException(Exception e){
ModelAndView mv=new ModelAndView();
mv.addObject("error",e.toString());
mv.setViewName("error1");
return mv;
}
2) jump to error1 view
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
error1 Interface
<span th:text="${#execInfo}"></span>
</body>
</html>
3. Global exception handling -- SimpleMappingExceptionResolver class
1) by creating a class and adding @ Configuration+@Bean annotation, you can register this bean when springboot starts
Load the bean when SpringBoot starts, and return to the specified interface in case of specified error
@Configuration
public class GlobalException {
@Bean
public SimpleMappingExceptionResolver getExceptionResolver(){
SimpleMappingExceptionResolver resolver=new SimpleMappingExceptionResolver();
Properties mappings=new Properties();
/*
* Parameter 1: type of exception, full name of exception type
* Parameter 2: view name
* */
mappings.put("java.lang.NullPointerException","error1");
resolver.setExceptionMappings(mappings);
return resolver;
}
}
2) wrong method
@RequestMapping("/error")
public String error() {
String str=null;
str.length();
return "test";
}
4. User defined exception class HandlerExceptionResolver
1) implement the methods in the HandlerExceptionResolver interface
@Configuration
public class GlobalException implements HandlerExceptionResolver {
/*Error type judgment on resolveException object*/
@Override
public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
ModelAndView mv=new ModelAndView();
if (e instanceof NullPointerException){
System.out.println("java.lang.NullPointerException");
mv.setViewName("test");
}
mv.addObject("error",e.toString());
return mv;
}
}2) methods for exceptions in the Controller
@RequestMapping("/error")
public String error() {
String str=null;
str.length();
return "test";
}3) when the specified error occurs, return the specified View html
test.html view
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
//Error
<span th:text="${error}"></span>
</body>
</html>