Error 20 is reported for Tomcat deployment

Is the spring package placed, is the location right?

Cause: An error is reported as soon as it is started, because the boot port 8080 is occupied.

Solution: Check what program port 8080 is occupied, end the program to release port 8080, and restart the project.

The steps are as follows:

1. Press the win+r key on the keyboard on the computer desktop to open the running window, enter cmd, and click OK;

2. Enter netstat -ano| in the cmd window that opensfindstr 8080 to view the processes that are using port 8080.

3. Run the following command to end the process taskkill pid 25216 f:

4. Run the tomcat server again and start it successfully.

1. When you start the server, the project will report an error, and the reason for the error is that the port is occupied.

2. Solution, press the window key + R key and enter cmd to open the DOS window.

3、netstat -ano|findstr 8080 to view the processes that are using port 8080.

4. Run the following command to end the process taskkill pid 25216 f.

5. Run the Tomcat server again and start it successfully.

Start the Tomcat Error Solution:

1. Check whether the published location jar has been published;

2. Change the package quotation of the interface;

Changed to: <>

3. Delete all the projects in this and redeploy them.

In the JDK, select the JDK version installed on your computer from the drop-down menu under Tomcat JDK Name.

In order to be lazy, I use multiple tomcat at the same time, so it's very convenient to start the file name with the project name.

Try the following:

First of all, carefully check both tomcat's. Do not reconfigure port 9999

Then, because 9999 is not necessarily occupied by tomcat, check if 9999 is occupied by other programs as follows:

Enter the Loading Console (cmd):

netstat -aon |findstr 9999 can find the process ID of the process that occupies port 9999.

tasklist |findstr 4216 to check the process name (assuming that 4216 is the process number queried in the previous step).

If so, be cautious to see if the process is useful. If it didn't work, it was shot directly; If it works, the tomcat that wants to use port 9999 should be replaced with another port.

There are many reasons for such an error as Critical when tomcat starts, such as missing or miswriting in your configuration statement or missing some jar packages, etc., which may occur.

I found that many friends on the Internet have encountered such error messages and are helpless, often spend a lot of time, and in the final analysis, I don't know how to know how the error is generated, because tomcat (which is often used tomcat) will only give a very simple two-line error message in the console.

But did you know that although tomcat only gives a simple two-line error message in the console, it actually gives a very detailed error message in the tomcat log message? I'm sure many friends complain that tomcat doesn't give enough clarity on the error message, maybe the previous version is like this, and the monkey doesn't know it very well, but at least the version is definitely not like this, and it's very detailed in the log.

If you are debugging on a local machine, the log file will usually be stored at the following path

tomcat such a directory that you can view such as:

Such a log file, for example, the monkey today encountered such an error message printed by tomcat in the console: Critical: error filterstart, and then by looking at the logs mentioned above, it is quickly known what caused the error, as shown in the following example:

Critical: Exception starting filter struts2

unable to load configuration. –file:/test/webroot/web-inf/classes/:2:7

at :58)

at :360)

at :403)

at :190)

at :275)

at :397)

at :108)

at :3709)

at :4356)

And quickly corrected it accordingly and solved the problem, so Zi Monkey hopes that this article can help solve such problems.

It should be caused by the fact that the version of Tomcat in your Ubuntu is different from the version of Tomcat in Windows.

It is recommended that you install the same Tomcat and JDK in Ubuntu as the Windows version.

Or you can try it like this:

Right in the tomcat file, put.

classname=""/

Turn this listener off.

Is this problem solved, I also had the same problem.

Take a look at the driver of your database connection, whether there is a mistake in the spelling of the url, and whether the corresponding database jar package has been added!

Reason: This is caused by the wrong JDK version.

Solution: 1. That is, if you use a certain version of JDK to compile a class and run it on another version of JDK, this kind of exception is prone to occur (often occurs when the higher version is compiled and the lower version is run).

2. Obviously, the JDK you use for Tomcat is different from the JDK you compile, so it's OK to change to a consistent version.

Method 2: 1. Add the set method and get method of the sessionfactory to the corresponding daoimpl.

private sessionfactory sessionfactory;

public sessionfactory getsessionfactory()

public void setsessionfactory(sessionfactory sessionfactory)

Inherit jdbcdaosupport.

userdaoimpl extends jdbcdaosupport