package com.zbooksoft.gdmis.filter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Vector;
/**
 * @Description 重写request，实现request的参数修改
 * @Author fsr
 * @Date 2021/4/6
 **/
public class ParameterRequestWrapper extends HttpServletRequestWrapper {

    private Map<String, String[]> params = new HashMap<>();

    public ParameterRequestWrapper(HttpServletRequest request) {
        super(request);
        this.params.putAll(request.getParameterMap());
    }

    public ParameterRequestWrapper(HttpServletRequest request, Map<String, Object> extendParams) {
        this(request);
        //这里将扩展参数写入参数表
        addAllParameters(extendParams);
    }

    @Override
    public Enumeration<String> getParameterNames() {
        return new Vector(params.keySet()).elements();
    }

    @Override
    public String getParameter(String name) {
        String[] values = params.get(name);
        if (values == null || values.length == 0) {
            return null;
        }
        return values[0];
    }

    @Override
    public String[] getParameterValues(String name) {
        String[] values = params.get(name);
        if (values == null || values.length == 0) {
            return null;
        }
        return values;
    }

    private void addAllParameters(Map<String, Object> otherParams) {
        for (Map.Entry<String, Object> entry : otherParams.entrySet()) {
            addParameter(entry.getKey(), entry.getValue());
        }
    }

    private void addParameter(String name, Object value) {
        if (value != null) {
            if (value instanceof String[]) {
                params.put(name, (String[]) value);
            } else if (value instanceof String) {
                params.put(name, new String[]{(String) value});
            } else {
                params.put(name, new String[]{String.valueOf(value)});
            }
        }
    }
}