Java 在数据库中插入blob数据

Java 在数据库中插入blob数据,java,sql,jsp,servlets,web-applications,Java,Sql,Jsp,Servlets,Web Applications,我想我对这段代码有点问题: 当我尝试在数据库中插入值时,我收到一个错误 PS:我尝试使用: setBinaryStream(int parameterIndex,InputStream x)-将根据需要从InputStream读取数据,直到到达文件末尾。这是在JDBC4.0(Java1.6)中添加的 setBinaryStream(int parameterIndex,InputStream x,int length)—数据将根据“长度”字节的需要从InputStream中读取 setBinar

我想我对这段代码有点问题: 当我尝试在数据库中插入值时,我收到一个错误

PS:我尝试使用:

  • setBinaryStream(int parameterIndex,InputStream x)-将根据需要从InputStream读取数据,直到到达文件末尾。这是在JDBC4.0(Java1.6)中添加的

  • setBinaryStream(int parameterIndex,InputStream x,int length)—数据将根据“长度”字节的需要从InputStream中读取

  • setBinaryStream(int-parameterIndex,InputStream x,long-length)——数据将根据“长度”字节的需要从InputStream中读取。这是在JDBC4.0(Java1.6)中添加的

  • 但每次我都会犯一个简单的错误。 我不知道一个人在做什么。。。。。我是一个代码猴子

    这是一节课:

    public class DataServlet extends HttpServlet{
        public void doPost(HttpServletRequest  request,HttpServletResponse response)throws ServletException,IOException {
    
            Connection conn = ConnectionToDB.connettiDB();                  
            InputStream inputstream = null;         
            Part filepart = request.getPart("image");
    
            inputstream = filepart.getInputStream();            
            try{
                 String sql = "insert into blob (data) values (?)";
                 PreparedStatement statement = conn.prepareStatement(sql);               
                 if (inputstream != null) {
                        // fetches input stream of the upload file for the blob column
                     statement.setBlob(1, inputstream);
                    }
    
                    // sends the statement to the database server
                    int row = statement.executeUpdate();
                    if (row > 0) {
                        System.out.println( "File uploaded and saved into database");
                    }
    
            } catch (SQLException ex) {
                 System.out.println( "ERROR: " + ex.getMessage());
                ex.printStackTrace();}
        }
    }
    
    这是错误消息:

             com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to
         your MySQL server version for the right syntax to use near 'blob
         (data) values (_binary'‰PNG
    
             \0\0\0
             IHDR\0\0\0\0\0\0\0\0\0;0®¢\0\' at line 1
                at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
                at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
                at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
         Source)
                at java.lang.reflect.Constructor.newInstance(Unknown Source)
                at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
                at com.mysql.jdbc.Util.getInstance(Util.java:386)
                at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052)
                at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609)
                at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541)
                at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2002)
                at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2163)
                at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2624)
                at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2127)
                at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2427)
                at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2345)
                at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2330)
                at com.CvManagement.src.servlet.DataServlet.doPost(DataServlet.java:69)
                at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
                at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
                at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
                at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
                at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
                at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
                at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
                at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
                at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
                at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
                at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
                at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
                at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
                at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
                at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
                at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
                at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
                at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
                at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
                at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
                at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
                at java.lang.Thread.run(Unknown Source)
    

    我最初认为这是驱动程序中的一个bug,这可能是错误的。最可能的问题是在查询中使用了不带引号的单词
    blob
    blob
    是一个对象名,因此当用作对象名时需要引用

    如果您将查询更改为:

    String sql = "insert into `blob` (data) values (?)";
    

    尝试使用
    PreparedStatement.setInputStream()
    而不是
    setBlob()
    也许这会对@a_horse\u和\u no_name有帮助方法setInputStream()对于类型PreparedStatement没有定义我将关闭它,因为@prsmax提供的链接似乎有帮助。对不起,我的意思是
    setBinaryStream()