小编use*_*944的帖子

我尝试用java和jpa做函数searchBook.我有2个课程,分别是媒体和书.本书扩展了媒体.我将数据保存在不同的表中.我尝试从下面的查询中选择数据:

TypedQuery<Media> query = em.createQuery(
                "SELECT m.title, b.isbn, b.authors"
                        + " FROM Book b, Media m" + " WHERE b.isbn = :isbn"
                        + " OR lower(m.title) LIKE :title"
                        + " OR b.authors LIKE :authors", Media.class);
        query.setParameter("isbn", book.getisbn());
        query.setParameter("title", "%" + book.getTitle().toLowerCase()
                + "%");
        query.setParameter("authors", "%" + book.getAuthors() + "%");
        bookList = query.getResultList();

但是我得到了错误:

java.lang.IllegalArgumentException:无法为具有多个返回的查询创建TypedQuery

这是我第一次使用JPA.我找不到错误.

我试图通过使用CORS过滤器http://software.dzhuvinov.com/cors-filter-installation.html来解决Access-Control-Allow-Origin的问题.我按照说明操作,它只能GET而不是POST.我在Tomcat服务器上有Java servlet,我通过我的web应用程序调用这个servlet,代码在这里:

        var url = "http://server_url:8080/"
            + "gtpapi/testPlan/guid_" + planId + "/packages/" + packId + "/results";
        $.ajax({
            contentType : 'application/json',
            type : "POST",
            crossDomain: true,
            url : url,
            data : JSON.stringify(postData),
            async : false,
            dataType : 'json',
            error : function(XMLHttpRequest) {
                throw XMLHttpRequest.statusText;
            }
        });

这是我的web服务器的web.xml.

<filter>
    <!-- The CORS filter with parameters -->
    <filter-name>CORS</filter-name>
    <filter-class>com.thetransactioncompany.cors.CORSFilter</filter-class>

    <init-param>
        <param-name>cors.allowOrigin</param-name>
        <param-value>*</param-value>
    </init-param>
     <init-param>
        <param-name>cors.supportedMethods</param-name>
        <param-value>GET, HEAD, POST, OPTIONS</param-value>
   </init-param>
   <init-param>
        <param-name>cors.supportedHeaders</param-name>
        <param-value>Origin, Content-Type, X-Requested-With, Access-Control-Allow-Origin</param-value>
   </init-param>
    <init-param>
        <param-name>cors.supportsCredentials</param-name>
        <param-value>false</param-value>
   </init-param> …

我有一个非常奇怪的问题.我使用SharpZipLib库生成.zip.我发现.zip的大小比我的文本文件总大一点.我不知道出了什么问题.我也尝试谷歌,但我找不到与我的情况有关的任何内容.这是我的代码:

    protected void CompressFolder(string[] files, string outputPath)
    {
        using (ZipOutputStream s = new ZipOutputStream(File.Create(outputPath)))
        {
            s.SetLevel(0);
            foreach (string path in files)
            {
                ZipEntry entry = new ZipEntry(Path.GetFileName(path));
                entry.DateTime = DateTime.Now;
                entry.Size = new FileInfo(path).Length;
                s.PutNextEntry(entry);
                byte[] buffer = new byte[4096];
                int byteCount = 0;
                using (FileStream input = File.OpenRead(path))
                {
                    byteCount = input.Read(buffer, 0, buffer.Length);
                    while (byteCount > 0)
                    {
                        s.Write(buffer, 0, byteCount);
                        byteCount = input.Read(buffer, 0, buffer.Length);
                    }
                }
            }
        }
    }