java.lang.OutOfMemoryError：

发布时间：2020-12-15 05:20:52 所属栏目：Java 来源：网络整理

导读：我正在尝试从数据库中检索的字节创建视频文件.该计划在几个小时之前运作良好.上传大文件后,当我尝试检索它时,它产生错误 java.lang.OutOfMemoryError：我的代码是： conn = prepareConnection(); StringBuilder sb=new StringBuilder(1024); sb.append("sel

我正在尝试从数据库中检索的字节创建视频文件.该计划在几个小时之前运作良好.上传大文件后,当我尝试检索它时,它产生错误 java.lang.OutOfMemoryError：

我的代码是：

conn = prepareConnection();
    StringBuilder sb=new StringBuilder(1024);
    sb.append("select videoname,videoid,videofull from ").append(uname.trim()).append("video");
    String sql=sb.toString();

    stmt = conn.prepareStatement(sql);
    ResultSet rs = stmt.executeQuery();

    while(rs.next()){
         byte[] videoData = rs.getBytes("videofull");       //#57
         int vid=rs.getInt("videoid");
         StringBuilder sb1 = new StringBuilder();
         sb1.append(vid);
         String videoid=sb1.toString();
         String vname=rs.getString("videoname");
         File file=new File("C:/Users/JamesPJ/Documents/skypark/skypark/WebContent/sp/resources/videos/"+vname+""+videoid+".mp4");

        if(file.exists() && !file.isDirectory()){
            continue;
        }
        else
        {
         FileOutputStream output = new FileOutputStream(file);
         IOUtils.write(videoData,output);
         output.close();
        }
       }
    request.setAttribute("uname",uname);
    RequestDispatcher dispatcher = request.getRequestDispatcher("/VideoList");
    if(dispatcher != null) {
        dispatcher.forward(request,response);
    }

控制台输出是：

Exception in thread "http-bio-8080-exec-3" java.lang.OutOfMemoryError: Java heap space
at oracle.sql.BLOB.getBytes(BLOB.java:217)
at oracle.jdbc.driver.T4CBlobAccessor.getBytes(T4CBlobAccessor.java:462)
at oracle.jdbc.driver.OracleResultSetImpl.getBytes(OracleResultSetImpl.java:716)
at oracle.jdbc.driver.OracleResultSet.getBytes(OracleResultSet.java:402)
at skypark.VideoFileCreator.doGet(VideoFileCreator.java:57)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:487)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
at skypark.VideoStream.processRequest(VideoStream.java:48)
at skypark.VideoStream.doGet(VideoStream.java:64)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

请有人告诉我这个错误告诉了什么.我需要纠正它…….谢谢…..

解决方法

这里,

byte[] videoData = rs.getBytes("videofull");

您将整个文件内容存储在服务器的内存中.你知道,byte []的一个字节占用Java内存的一个字节.如果您已经例如只有500MB的内存和文件超过500MB,那么你将得到这个错误.请注意,当10个用户同时请求50MB的视频文件时,您也会得到它.因此,如其他答案所示,增加Java内存只是一个临时解决方案,并没有经过深思熟虑.

您需要在InputStream的风格中获取它,以便在内部仅分配几个(千字节)字节作为内存中的流缓冲区而不是整个文件内容.

InputStream videoData = rs.getBinaryStream("videofull");

然后使用IOUtils #copy()将其写入所需的输出流(不要忘记在finally中关闭它们！).

FileOutputStream output = new FileOutputStream(file);
try {
    IOUtils.copy(videoData,output);
} finally {
    IOUtils.closeQuietly(output);
    IOUtils.closeQuietly(videoData);
}

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!