链接末尾添加或修改 ?和参数名和值

int paramSymbol = linkurl.indexOf("?");
                if(paramSymbol == -1){
                    linkurl+="?sourcetype="+sourcetype;
                    url.setUrl(linkurl);
                }else{
                    int towardindex = linkurl.indexOf("sourcetype");
                    if(towardindex == -1){
                        linkurl+="sourcetype="+sourcetype;
                        url.setUrl(linkurl);
                    }else{
                        String replacedStr = linkurl.substring(towardindex, towardindex+12);
                        String replaceStr = "sourcetype="+sourcetype;
                        String linkurl_new = linkurl.replace(replacedStr, replaceStr);
                        url.setUrl(linkurl_new);
                    }
                }