Common Error Summary __ error finishing

1, cannot call Sendredirect () after the response has been committed

Cause: This error occurs because the program does not end the method after forwarding or redirecting

Resolve: Add return after Sendredirect () or RequestDispatcher (). ForWord (request,response); statement

2. Database link pstm.executequery (); Breakpoints can be seen

Statement has been closed and no further internal information-available hint

Reason: Link is not the same database or IP

Resolve: In a single operation of the database link in time to release the connection link in the DAO inside

3. Local @test Test error: Java.lang.OutOfMemoryError java head heap

Reason: The JVM's heap memory was exceeded during testing

Solution: MyEclipse----"Run-----> select Run Configuration or Debug run Configuration--------> in arguments----"

VM arguments inside input

-xmx1024m-xms512m-xx:maxpermsize=256m

Purpose: To enlarge the JVM heap memory

4. Eclipse Configuration Tomcat Automatic deployment (not available in Eclipse for Tomcat home server locations dimmed cannot be edited)

(1) First of all the projects deployed in the servers empty (2) and then the Tomcat v7.0 Server at localhost, point right to clean, and then double hit the open Server service.
5, caused by:java.net.UnknownHostException:struts.apache.orgWorkaround: (1) Check web.xml or Struts.xml or spring.xml or other XML to see if the header is wrong. (2) See if a DTD or XSD file is imported correctly; step pereferece-----> Input XML------> View XML Catalog
6, "server returned HTTP response code:505 for URL:" ErrorWorkaround: Do not have spaces in the file name or in the parameters of the URL because http1.1 does not support arguments with spaces
7, call the URL, note that the file name of the Chinese garbledWorkaround: transcoding, converting single-byte to specified format String name = new String (Request.getheader ("filename"). GetBytes ("Iso-8859-1"), "GBK");

8, 505 errorFor example: Server returned HTTP response code:505 for URL:HTTP://127.0.0.1:8080/MDWEB/COMMON/HANDOUTMP3TOMD?MP3NAME=/PLAY_BJ _pf01//bjyy-gxfc.mp3&mdip=172.16.63.3 description file name, or other contains "space"

9, browser access http://localhost:8080/project name appears white screenReason: Not configured in Web.xml file or Struts.xml or Spring.xml file <url-partten>?</url-partten> or the JSP page in the Struts.xml file is not configured to cause.
10, the MySQL database error

ERROR 1226 (42000): User ' root ' has exceeded ' max_questions ' resource (current value:4)

Resolve: Execute the following statement

GRANT USAGE on *.* to ' root ' @< ' host_name ' > with Max_queries_per_hour 100

11, MySQL error: 1130-host ... is not allowed to connect to this MySQL server

Execute the following statement:

Mysql>grant all privileges on *.*to ' root ' @ '% ' identifiedby ' password ' with GRANT OPTION;