@RestControllerAdvice 使用

Spring 3.2 新增 @ControllerAdvice 和 @RestControllerAdvice 注解。

@RestControllerAdvice is just a syntactic sugar for @ControllerAdvice + @ResponseBody。

类注解了 @ControllerAdvice 会被 Spring 扫描到，自动加载。

Usage

查看 @ControllerAdvice 定义可以看到其使用方式，注解的属性是用来划定 Advice 可以管理的 Controller 的范围，可以通过包名，类名，以及注解等等方式来划分。

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Component
public @interface ControllerAdvice {

	/**
	 * Alias for the {@link #basePackages} attribute.
	 * <p>Allows for more concise annotation declarations &mdash; for example,
	 * {@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 &mdash; for example,
	 * {@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 #basePackages} for specifying the packages
	 * in which to select controllers to be advised 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 advised by the {@code @ControllerAdvice} annotated class.
	 * @since 4.0
	 */
	Class<?>[] assignableTypes() default {};

	/**
	 * Array of annotation types.
	 * <p>Controllers that are annotated with at least one of the supplied annotation
	 * types will be advised by the {@code @ControllerAdvice} annotated class.
	 * <p>Consider creating a custom composed annotation or use a predefined one,
	 * like {@link RestController @RestController}.
	 * @since 4.0
	 */
	Class<? extends Annotation>[] annotations() default {};

}

basePackages 配置

//@ControllerAdvice("cn.myz.demo.controller")
//@ControllerAdvice(value = "cn.myz.demo.controller")
@ControllerAdvice(basePackages = {"cn.myz.demo.controller"})
public class GlobalExceptionHandler {}

basePackages 指定一个或多个包，这些包下的 Controller 都会被该 Advice 管理。

basePackageClasses

@ControllerAdvice(basePackageClasses = {MyController1.class})
public class GlobalExceptionHandler {}

是 basePackages 的一种变形，指定一个或多个 Controller 类，这些类所属的包及其子包下的所有 Controller 都被该 @ControllerAdvice 管理。

assignableTypes

@ControllerAdvice(assignableTypes = {MyController1.class})
public class GlobalExceptionHandler {}

assignableTypes：指定一个或多个 Controller 类，这些类被该 @ControllerAdvice 管理。

annotations

@ControllerAdvice(annotations = {RestController.class})
public class GlobalExceptionHandler {}

annotations：指定一个或多个注解，被这些注解所标记的 Controller 会被该 @ControllerAdvice 管理。

作用

@ControllerAdvice 注解可以将对 Controller 的全局配置放到一个位置
在 @ControllerAdvice 注解的类的方法，可以使用 @ExceptionHandler、@InitBinder、@ModelAttribute 注解到方法
- @ExceptionHandler：用于全局处理控制器里的异常，进行全局异常处理
- @InitBinder：用来设置WebDataBinder，用于自动绑定前台请求参数到Model中，全局数据预处理。
- @ModelAttribute：本来作用是绑定键值对到Model中，此处让全局的@RequestMapping都能获得在此处设置的键值对，全局数据绑定。
@ControllerAdvice注解将作用在所有注解了@RequestMapping的控制器的方法上。

全局异常处理

@Slf4j
@ControllerAdvice(annotations = {Controller.class, RestController.class})
public class WebControllerAdvice {

    @ResponseBody
    @ExceptionHandler
    public Map errorHandler(Exception ex) {
        Map errorMap = new HashMap();
        errorMap.put("code", 400);
        //判断异常的类型,返回不一样的返回值
        if (ex instanceof MissingServletRequestParameterException) {
            errorMap.put("msg", "缺少必需参数：" + ((MissingServletRequestParameterException) ex).getParameterName());
        } else if (ex instanceof MyException) {
            errorMap.put("msg", "这是自定义异常");
        }
        return errorMap;
    }

全局数据预处理

@ControllerAdvice
public class MyGlobalDataHandler {
    @ModelAttribute(name = "md")
    public Map<String,Object> getGlobalData(){
        HashMap<String, Object> map = new HashMap<>();
        map.put("age", 99);
        map.put("gender", "男");
        return map;
    }

绑定

@InitBind

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