spring 自定引數解析器(HandlerMethodArgumentResolver)
阿新 • • 發佈:2018-11-15
由於之前用@RequestParam無法接受request payload 正文格式為json格式的字串,只能使用@RequestBody整個接收,覺得麻煩,但是spring自帶的引數解析器不具有這種功能,只能嘗試著用自定義引數解析器去解決。
自定義解析器需要實現HandlerMethodArgumentResolver介面,HandlerMethodArgumentResolver介面包含兩個介面:
介面說明:
supportsParameter:用於判定是否需要處理該引數分解,返回true為需要,並會去呼叫下面的方法resolveArgument。
resolveArgument:真正用於處理引數分解的方法,返回的Object就是controller方法上的形參物件。
1、自定義註解
package com.manqian.crm.resolver; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Target(ElementType.PARAMETER) @Retention(RetentionPolicy.RUNTIME) public @interface JsonParam { String value(); boolean required() default true; String defaultValue() default ""; }
若不想自定義註解,可以直接在實現HandlerMethodArgumentResolver的supportsParameter直接返回true
2、自定義引數解析器,實現HandlerMethodArgumentResolver介面
package com.manqian.crm.resolver; import com.jayway.jsonpath.JsonPath; import com.jayway.jsonpath.PathNotFoundException; import com.manqian.crm.api.exception.ParamCheckException; import org.apache.commons.io.IOUtils; import org.springframework.context.annotation.Configuration; import org.springframework.core.MethodParameter; import org.springframework.web.bind.support.WebDataBinderFactory; import org.springframework.web.context.request.NativeWebRequest; import org.springframework.web.method.support.HandlerMethodArgumentResolver; import org.springframework.web.method.support.ModelAndViewContainer; import javax.servlet.http.HttpServletRequest; import java.io.IOException; public class JsonPathArgumentResolver implements HandlerMethodArgumentResolver { private static final String JSON_REQUEST_BODY = "JSON_REQUEST_BODY"; //判斷是否支援要轉換的引數型別 @Override public boolean supportsParameter(MethodParameter parameter) { return parameter.hasParameterAnnotation(JsonParam.class); } //當支援後進行相應的轉換 @Override public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception { String body = getRequestBody(webRequest); Object val = null; try { val = JsonPath.read(body, parameter.getParameterAnnotation(JsonParam.class).value()); if (parameter.getParameterAnnotation(JsonParam.class).required() && val == null) { throw new ParamCheckException(parameter.getParameterAnnotation(JsonParam.class).value() + "不能為空"); } } catch (PathNotFoundException exception) { System.out.println(exception.getStackTrace()); if (parameter.getParameterAnnotation(JsonParam.class).required()) { // throw new ParamCheckException(parameter.getParameterAnnotation(JsonParam.class).value() + "不能為空"); throw exception; } } return val; } private String getRequestBody(NativeWebRequest webRequest) { HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class); String jsonBody = (String) servletRequest.getAttribute(JSON_REQUEST_BODY); if (jsonBody == null) { try { jsonBody = IOUtils.toString(servletRequest.getInputStream()); servletRequest.setAttribute(JSON_REQUEST_BODY, jsonBody); } catch (IOException e) { throw new RuntimeException(e); } } return jsonBody; } }
3、註冊自定義引數解析器
springboot方式:
1、
package com.demo;
import java.util.List;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import com.demo.mvc.component.MultiPersonArgumentResolver;
import com.demo.mvc.component.PersonArgumentResolver;
@SpringBootApplication
public class WebMvcConfiguration extends WebMvcConfigurationSupport {
@Override
protected void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
// 註冊JsonPathArgumentResolver的引數分解器
argumentResolvers.add(new JsonPathArgumentResolver());
}
}
2、
package com.manqian.crm.resolver;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import java.util.List;
@Configuration
public class ClientResourcesConfig extends WebMvcConfigurerAdapter {
@Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
// super.addArgumentResolvers(argumentResolvers);
argumentResolvers.add(new JsonPathArgumentResolver());
}
}
傳統XML格式:
1、
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean class="com.manqian.crm.resolver.JsonPathArgumentResolver"/>
</mvc:argument-resolvers>
</mvc:annotation-driven>
2、
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="jsonPathArgumentResolver">
<bean class="com.manqian.crm.resolver.JsonPathArgumentResolver"/>
</property>
</bean>
使用:
1、依賴:
com.jayway.jsonpath
json-path
2、controller方法使用@JsonParam接收引數