@ControllerAdvice是Spring 3.2新增的注解，主要是用来Controller的一些公共的需求的低侵入性增强提供辅助，作用于@RequestMapping标注的方法上。
ControllerAdvice的定义如下：
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Component
public @interface ControllerAdvice {
/**
* Alias for the {@link #basePackages} attribute.
* <p>Allows for more concise annotation declarations e.g.:
* {@code @ControllerAdvice("org.my.pkg")} is equivalent to
* {@code @ControllerAdvice(basePackages="org.my.pkg")}.
* @since 4.0
* @see #basePackages()
*/
@AliasFor("basePackages")
String[] value() default {};
/**
* Array of base packages.
* <p>Controllers that belong to those base packages or sub-packages thereof
* will be included, e.g.: {@code @ControllerAdvice(basePackages="org.my.pkg")}
* or {@code @ControllerAdvice(basePackages={"org.my.pkg", "org.my.other.pkg"})}.
* <p>{@link #value} is an alias for this attribute, simply allowing for
* more concise use of the annotation.
* <p>Also consider using {@link #basePackageClasses()} as a type-safe
* alternative to String-based package names.
* @since 4.0
*/
@AliasFor("value")
String[] basePackages() default {};
/**
* Type-safe alternative to {@link #value()} for specifying the packages
* to select Controllers to be assisted by the {@code @ControllerAdvice}
* annotated class.
* <p>Consider creating a special no-op marker class or interface in each package
* that serves no purpose other than being referenced by this attribute.
* @since 4.0
*/
Class<?>[] basePackageClasses() default {};
/**
* Array of classes.
* <p>Controllers that are assignable to at least one of the given types
* will be assisted by the {@code @ControllerAdvice} annotated class.
* @since 4.0
*/
Class<?>[] assignableTypes() default {};
/**
* Array of annotations.
* <p>Controllers that are annotated with this/one of those annotation(s)
* will be assisted by the {@code @ControllerAdvice} annotated class.
* <p>Consider creating a special annotation or use a predefined one,
* like {@link RestController @RestController}.
* @since 4.0
*/
Class<? extends Annotation>[] annotations() default {};
}
和此注解配合使用的其他注解有：
- @ExceptionHandler 自定义的错误处理器
- @ModelAttribute 全局的对所有的controller的Model添加属性
- @InitBinder 对表单数据绑定
下面给一个例子：
import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ModelAttribute; import com.gongren.dlg.activity.exception.NoSessionException; /**
* springMVC的ControllerAdvice
*
* @author yzl
* @see [相关类/方法]（可选）
* @since [产品/模块版本] （可选）
*/
@ControllerAdvice
public class WebContextAdvice {
private static final Logger logger = LoggerFactory.getLogger(WebContextAdvice.class); /**
*
* 功能描述: <br>
* 应用上下文设值给Model对象
* 在jsp中使用:${ctx}
*
* @param request
* @return
* @see [相关类/方法](可选)
* @since [产品/模块版本](可选)
*/
@ModelAttribute(value="ctx")
public String setContextPath(HttpServletRequest request){
return request.getContextPath();
} /**
*
* 错误处理器
*
* @param e
* @return
* @see [相关类/方法](可选)
* @since [产品/模块版本](可选)
*/
@ExceptionHandler
public String handleIOException(HttpServletRequest request,HttpServletResponse response,Model model,Exception e) {
//请求类型,可以区分对待ajax和普通请求
String requestType = request.getHeader("X-Requested-With");
if(StringUtils.isNotBlank(requestType)){
//是ajax
try {
response.setCharacterEncoding("UTF-8");
response.setContentType("application/json; charset=utf-8"); PrintWriter writer = response.getWriter();
//具体操作
writer.write("json...");
//
writer.flush();
writer.close();
return null;
} catch (IOException e1) {
}
}
if(e instanceof NoSessionException){
logger.error("session超时，跳转到活动首页");
return "redirect:/mc/index";
}
logger.error("请求发生错误", e);
return "redirect:/mc/error";
}
}