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springmvc异常处理

2017-05-09 09:12 561 查看
1、分析 
(1)使用Spring MVC提供的简单异常处理器SimpleMappingExceptionResolver; 

(2)实现Spring的异常处理接口HandlerExceptionResolver 自定义自己的异常处理器; 

(3)使用@ExceptionHandler注解实现异常处理;

2 实例

  2.1、异常类定义 

/**
* 系统业务异常
*/
public class BusinessException extends RuntimeException {

/** serialVersionUID */
private static final long serialVersionUID = 2332608236621015980L;

private String code;

public BusinessException() {
super();
}

public BusinessException(String message) {
super(message);
}

public BusinessException(String code, String message) {
super(message);
this.code = code;
}

public BusinessException(Throwable cause) {
super(cause);
}

public BusinessException(String message, Throwable cause) {
super(message, cause);
}

public BusinessException(String code, String message, Throwable cause) {
super(message, cause);
this.code = code;
}

public String getCode() {
return code;
}

public void setCode(String code) {
this.code = code;
}

}

public class ParameterException extends RuntimeException {

/** serialVersionUID */
private static final long serialVersionUID = 6417641452178955756L;

public ParameterException() {
super();
}

public ParameterException(String message) {
super(message);
}

public ParameterException(Throwable cause) {
super(cause);
}

public ParameterException(String message, Throwable cause) {
super(message, cause);
}
}


  2.2 Dao层代码 

@Repository("testDao")
public class TestDao {
public void exception(Integer id) throws Exception {
switch(id) {
case 1:
throw new BusinessException("12", "dao12");
case 2:
throw new BusinessException("22", "dao22");
case 3:
throw new BusinessException("32", "dao32");
case 4:
throw new BusinessException("42", "dao42");
case 5:
throw new BusinessException("52", "dao52");
default:
throw new ParameterException("Dao Parameter Error");
}
}
}


  2.3Service层代码 

public interface TestService {
public void exception(Integer id) throws Exception;

public void dao(Integer id) throws Exception;
}

@Service("testService")
public class TestServiceImpl implements TestService {
@Resource
private TestDao testDao;

public void exception(Integer id) throws Exception {
switch(id) {
case 1:
throw new BusinessException("11", "service11");
case 2:
throw new BusinessException("21", "service21");
case 3:
throw new BusinessException("31", "service31");
case 4:
throw new BusinessException("41", "service41");
case 5:
throw new BusinessException("51", "service51");
default:
throw new ParameterException("Service Parameter Error");
}
}

@Override
public void dao(Integer id) throws Exception {
testDao.exception(id);
}
}


  2.4 Controller层代码 

@Controller
public class TestController {
@Resource
private TestService testService;

@RequestMapping(value = "/controller.do", method = RequestMethod.GET)
public void controller(HttpServletResponse response, Integer id) throws Exception {
switch(id) {
case 1:
throw new BusinessException("10", "controller10");
case 2:
throw new BusinessException("20", "controller20");
case 3:
throw new BusinessException("30", "controller30");
case 4:
throw new BusinessException("40", "controller40");
case 5:
throw new BusinessException("50", "controller50");
default:
throw new ParameterException("Controller Parameter Error");
}
}

@RequestMapping(value = "/service.do", method = RequestMethod.GET)
public void service(HttpServletResponse response, Integer id) throws Exception {
testService.exception(id);
}

@RequestMapping(value = "/dao.do", method = RequestMethod.GET)
public void dao(HttpServletResponse response, Integer id) throws Exception {
testService.dao(id);
}
}


  2.5 JSP页面代码 

<%@ page contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Maven Demo</title>
</head>
<body>
<h1>所有的演示例子</h1>
<h3>Dao正常错误</h3>
<h3>Dao参数错误</h3>
<h3>Dao未知错误</h3>

<h3>Service正常错误</h3>
<h3>Service参数错误</h3>
<h3>Service未知错误</h3>

<h3>Controller正常错误</h3>
<h3>Controller参数错误</h3>
<h3>Controller未知错误</h3>

<h3>404错误</h3>
</body>
</html>


3、处理方式

3.1 使用SimpleMappingExceptionResolver实现异常处理 

1、在Spring的配置文件applicationContext.xml中增加以下内容: 

<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<!-- 定义默认的异常处理页面,当该异常类型的注册时使用 -->
<property name="defaultErrorView" value="error"></property>
<!-- 定义异常处理页面用来获取异常信息的变量名,默认名为exception -->
<property name="exceptionAttribute" value="ex"></property>
<!-- 定义需要特殊处理的异常,用类名或完全路径名作为key,异常也页名作为值 -->
<property name="exceptionMappings">
<props>
<prop key="cn.basttg.core.exception.BusinessException">error-business</prop>
<prop key="cn.basttg.core.exception.ParameterException">error-parameter</prop>

<!-- 这里还可以继续扩展对不同异常类型的处理 -->
</props>
</property>
</bean>


2、启动测试项目,经验证,Dao层、Service层、Controller层抛出的异常(业务异常BusinessException、参数异常ParameterException和其它的异常Exception)都能准确显示定义的异常处理页面,达到了统一异常处理的目标。 

3、从上面的集成过程可知,使用SimpleMappingExceptionResolver进行异常处理,具有集成简单、有良好的扩展性、对已有代码没有入侵性等优点,但该方法仅能获取到异常信息,若在出现异常时,对需要获取除异常以外的数据的情况不适用。

3.2 实现HandlerExceptionResolver 接口自定义异常处理器 

1、增加HandlerExceptionResolver 接口的实现类MyExceptionHandler,代码如下: 

public class MyExceptionHandler implements HandlerExceptionResolver {

public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,
Exception ex) {
Map<String, Object> model = new HashMap<String, Object>();
model.put("ex", ex);

// 根据不同错误转向不同页面
if(ex instanceof BusinessException) {
return new ModelAndView("error-business", model);
}else if(ex instanceof ParameterException) {
return new ModelAndView("error-parameter", model);
} else {
return new ModelAndView("error", model);
}
}
}


2、在Spring的配置文件applicationContext.xml中增加以下内容: 

<bean id="exceptionHandler" class="cn.basttg.core.exception.MyExceptionHandler"/>


3、启动测试项目,经验证,Dao层、Service层、Controller层抛出的异常(业务异常BusinessException、参数异常ParameterException和其它的异常Exception)都能准确显示定义的异常处理页面,达到了统一异常处理的目标。 

4、从上面的集成过程可知,使用实现HandlerExceptionResolver接口的异常处理器进行异常处理,具有集成简单、有良好的扩展性、对已有代码没有入侵性等优点,同时,在异常处理时能获取导致出现异常的对象,有利于提供更详细的异常处理信息。 

3.3 使用@ExceptionHandler注解实现异常处理 

1、增加BaseController类,并在类中使用@ExceptionHandler注解声明异常处理,代码如下:

public class BaseController {
/** 基于@ExceptionHandler异常处理 */
@ExceptionHandler
public String exp(HttpServletRequest request, Exception ex) {

request.setAttribute("ex", ex);

// 根据不同错误转向不同页面
if(ex instanceof BusinessException) {
return "error-business";
}else if(ex instanceof ParameterException) {
return "error-parameter";
} else {
return "error";
}
}
}


2、修改代码,使所有需要异常处理的Controller都继承该类,如下所示,修改后的TestController类继承于BaseController: 

public class TestController extends BaseController


3、启动测试项目,经验证,Dao层、Service层、Controller层抛出的异常(业务异常BusinessException、参数异常ParameterException和其它的异常Exception)都能准确显示定义的异常处理页面,达到了统一异常处理的目标。 

4、从上面的集成过程可知,使用@ExceptionHandler注解实现异常处理,具有集成简单、有扩展性好(只需要将要异常处理的Controller类继承于BaseController即可)、不需要附加Spring配置等优点,但该方法对已有代码存在入侵性(需要修改已有代码,使相关类继承于BaseController),在异常处理时不能获取除异常以外的数据。

4、通过@ContrillerAdvice处理

针对3的情况对代码存在一定的侵入性,在spring3.2引入注解ControllerAdvice,可以在项目中添加如下代码:

@ControllerAdvice
public class SpringExceptionHandler{
/**
* 全局处理Exception
* 错误的情况下返回500
* @param ex
* @param req
* @return
*/
@ExceptionHandler(value = {Exception.class})
public ResponseEntity<Object> handleOtherExceptions(final Exception ex, final WebRequest req) {
TResult tResult = new TResult();
tResult.setStatus(CodeType.V_500);
tResult.setErrorMessage(ex.getMessage());
return new ResponseEntity<Object>(tResult,HttpStatus.INTERNAL_SERVER_ERROR);
}

}

只要扫描到该类即可,此为全局处理
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标签:  SprinMVC 异常处理