[bug] 带token的restjsr服务出图失败

（reviewed by ytt）

Author: Yuki-Zhao

src/openlayers/mapping/WebMap.js

@@ -4642,7 +4642,8 @@ export class WebMap extends Observable {
                 let sourcesNames = Object.keys(sources);
                 sourcesNames.forEach(function (sourceName) {
                     styles.sources[sourceName].tiles.forEach(function (tiles, i) {
-                        styles.sources[sourceName].tiles[i] = `${tiles}?${keyfix}=${credentialValue}`
+                      const splicing = tiles.includes('?') ? '&' : '?';
+                      styles.sources[sourceName].tiles[i] = `${tiles}${splicing}${keyfix}=${credentialValue}`;
                     })
                 })
             }