自定义参数解析器接收多个实体参数

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最新推荐文章于 2024-08-06 11:46:17 发布

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分类专栏：自定义参数解析器基础文章标签： springmvc web

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自定义参数解析器

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本文介绍了如何在Spring MVC中创建自定义注解`DataObject`，用于标记方法参数，以及对应的解析器`RequestModelArgumentResolver`，该解析器从HTTP请求体中读取JSON数据并转换为指定的对象类型。通过配置自定义解析器，实现了对请求体中JSON数据的高效处理。

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自定义参数解析器接收多个实体参数

自定义注解

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 DataObject {
    boolean required() default true;
}

自定义解析器

import com.alibaba.fastjson.JSONObject;
import com.nuts.pangudatastatistic.common.annotation.DataObject;
import org.apache.commons.io.IOUtils;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
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.BufferedReader;
import java.io.IOException;

@Component
public class RequestModelArgumentResolver implements HandlerMethodArgumentResolver {
    private static final String JSON_REQUEST_BODY = "JSON_REQUEST_BODY";

    @Override
    public boolean supportsParameter(MethodParameter methodParameter) {
        return methodParameter.hasParameterAnnotation(DataObject.class);
    }

    @Override
    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
        String body = getJsonBody(nativeWebRequest);
        if(body.isEmpty()) {
            body = "{}";
        }
        JSONObject jsonBody = JSONObject.parseObject(body);
        return jsonBody.toJavaObject(methodParameter.getParameterType());
    }

    /**
     * 获取body中的数据
     * @param nativeWebRequest 请求
     * @return 请求中的body
     */
    private static String getJsonBody(NativeWebRequest nativeWebRequest) {
        String body = (String) nativeWebRequest.getAttribute(JSON_REQUEST_BODY, NativeWebRequest.SCOPE_REQUEST);
        if(body != null) {
            return body;
        }
        try {
            BufferedReader reader = nativeWebRequest.getNativeRequest(HttpServletRequest.class).getReader();
            body = IOUtils.toString(reader);
            nativeWebRequest.setAttribute(JSON_REQUEST_BODY, body, NativeWebRequest.SCOPE_REQUEST);
        } catch (IOException e) {
            return "";
        }
        return body;
    }
}

配置自定义解析器

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import java.util.List;

@Configuration
public class WebConfig extends WebMvcConfigurationSupport {
    @Autowired
    private RequestModelArgumentResolver requestModelArgumentResolver;

    @Override
    protected void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
        argumentResolvers.add(requestModelArgumentResolver);
    }
}