java-classic-code/httpservlet-support/MetaCubeHttpServletRequestWrapper.java

package com.primeton.dgs.kernel.core.web;


import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 *
 * 元数据旧架构支持 RESTFull API 扩展
 *
 *
 * <pre>
 *
 * Created by zhaopx.
 * User: zhaopx
 * Date: 2020/9/10
 * Time: 14:24
 *
 * </pre>
 *
 * @author zhaopx
 */
public class MetaCubeHttpServletRequestWrapper extends HttpServletRequestWrapper {


    /**
     * 元数据部分参数是从 payload 获得的，装饰 RestFull API
     */
    protected final Map<String, Object> payloadParameters = new HashMap<>();


    /**
     * Constructs a request object wrapping the given request.
     *
     * @param request the {@link HttpServletRequest} to be wrapped.
     * @throws IllegalArgumentException if the request is null
     */
    public MetaCubeHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
    }


    public MetaCubeHttpServletRequestWrapper(HttpServletRequest request, Map<String, Object> payloadParameters) {
        super(request);
        this.payloadParameters.putAll(payloadParameters);
    }

    @Override
    public String getParameter(String name) {
        String parameter = super.getParameter(name);
        // 获取参数，如果 form 中为空，则从 payload 中获取
        return parameter == null ? (String)payloadParameters.get(name) : parameter;
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] parameterValues = super.getParameterValues(name);
        // 获取参数，如果 form 中为空，则从 payload 中获取
        return parameterValues == null ? new String[]{ (String)payloadParameters.get(name)} : parameterValues;
    }

    @Override
    public Map<String, String[]> getParameterMap() {
        Map<String, String[]> parameterMap = new HashMap<>(super.getParameterMap());

        // 合并参数
        for (Map.Entry<String, Object> entry : payloadParameters.entrySet()) {
            parameterMap.put(entry.getKey(), new String[]{ (String)entry.getValue()});
        }
        return parameterMap;
    }

    @Override
    public Enumeration<String> getParameterNames() {
        Set<String> vector = new HashSet();
        // form 参数
        Enumeration<String> parameterNames = super.getParameterNames();
        while (parameterNames.hasMoreElements()) {
            vector.add(parameterNames.nextElement());
        }

        // payload 参数
        for (String s : payloadParameters.keySet()) {
            vector.add(s);
        }

        // 构造一次性返回
        return Collections.enumeration(vector);
    }
}