Binary stream download zip or single file (spring + angular Js)

1. Back-end code:

public class DownloadActor extends AbstractSupportActor {
private Configuration configuration;
public LeaveQuestionDownloadActor() {
    configuration = new Configuration();
    configuration.setDefaultEncoding("UTF-8");
    // FTL文件所存在的位置
    configuration.setClassForTemplateLoading(this.getClass(), "");
}
public void Execute(Message message) throws Exception {
    // 查询下载文件所需数据
            String filename = 文件名 + ".doc";
            // 查询文件存储路径
            String downpath = this.getSqlSession().selectOne("XXX.XXX");
            // 判断该文件时候已经存在
            File outFile = new File(downpath + "/" + filename);
            if (outFile.exists()) {
                outFile.delete();
            }
            // 判断路径是否存在
            folder = new File(downpath);
            // 如果不存在，创建目录
            if (!folder.exists()) {
                folder.mkdirs();
            }
            try {
                Template t = configuration.getTemplate("Questionnaire.ftl");