1.异常处理
- SpringBoot 中对于异常处理提供了五种处理方式
1.自定义错误页面
- SpringBoot 默认的处理异常的机制：SpringBoot默认的已经提供了一套处理异常的机制。一旦程序中出现了异常 SpringBoot 会向/error 的 url 发送请求。在 SpringBoot 中提供了一个名为 BasicErrorController 来处理/error 请求，然后跳转到默认显示异常的页面来展示异常信息。
- 如果我们需要将所有的异常同一跳转到自定义的错误页面，需要再 src/main/resources/templates 目录下创建 error.html 页面。注意：页面名称必须叫 error
2.通过@ExceptionHandler 注解处理异常
1.修改Controller
1.修改Controller
@Controller
public class UsersController {
@RequestMapping("/showInfo")
public String showInfo() {
String str = null;
str.length();
return "ok";
}
@ExceptionHandler(value = {java.lang.NullPointerException.class} )
public ModelAndView nullpointExcepitonHandler(Exception e){
ModelAndView mv = new ModelAndView();
mv.addObject("err",e.toString());
mv.setViewName("error1");
return mv;
}
}
2.创建页面
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>地球村公民</title>
</head>
<body>
出错了。。。
<span th:text="${err}"/>
</body>
</html>
3.通过@ControllerAdvice 与@ExceptionHandler 注解处理异常
@ControllerAdvice
public class GlobalException {
@ExceptionHandler(value = {java.lang.NullPointerException.class} )
public ModelAndView nullpointExcepitonHandler(Exception e){
ModelAndView mv = new ModelAndView();
mv.addObject("err",e.toString());
mv.setViewName("error1");
return mv;
}
@ExceptionHandler(value = {java.lang.ArithmeticException.class} )
public ModelAndView arithmeticExceptionHandler(Exception e){
ModelAndView mv = new ModelAndView();
mv.addObject("err",e.toString());
mv.setViewName("error2");
return mv;
}
}
4.通过 SimpleMappingExceptionResolver 对象处理异常
@Configuration
public class GlobalException2 {
/**
* 此方法返回值必须是SimpleMappingExceptionResolver对象
* @return
*/
@Bean
public SimpleMappingExceptionResolver getSimpleMappingExceptionResolver(){
SimpleMappingExceptionResolver resolver = new SimpleMappingExceptionResolver();
Properties properties = new Properties();
/**
参数一：异常类型，并且是全名
参数二：视图名称
*/
properties.put("java.lang.NullPointerException","error3");
properties.put("java.lang.ArithmeticException","error4");
resolver.setExceptionMappings(properties);
return resolver;
}
}
5.通过自定义 HandlerExceptionResolver 对象处理异常
@Configuration
public class GlobalException3 implements HandlerExceptionResolver {
@Override
public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler, Exception e) {
ModelAndView mv = new ModelAndView();
//判断不同异常类型，做不同视图的跳转
if (e instanceof NullPointerException) {
mv.setViewName("error5");
}
if (e instanceof ArithmeticException) {
mv.setViewName("error6");
}
mv.addObject("error", e.toString());
return mv;
}
}
2.Spring Boot 整合Junit单元测试
SpringBoot2.x 使用 Junit5 作为测试平台
1.修改 POM 文件添加 Test 启动器
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
2.编写测试代码
@SpringBootTest
class SpringbootexcepionandjunitApplicationTests {
@Autowired
private UsersServiceImpl usersService;
@Test
void suibian() {
this.usersService.addUser();
}
}