SpringMVC conflicts with existing, non-compatible bean definition of same name and class solution, springmvc obtains bean

SpringMVC conflicts with existing, non-compatible bean definition of same name and class solution, springmvc obtains bean
Cause

Recently, a colleague from the project team encountered a problem. The module he was responsible for, SpringMVC Controller, and the Controller class names of other modules were duplicated, causing the whole project to fail.

The following error is reported in the background:

××Controller' for bean class [××ontroller] conflicts with existing, non-compatible bean definition of same name and class 

At lunch, he complained about the problem with me and said he could not find a solution.

Later I Thought About It. SpringMVC's Controller should adopt a key/value-like ing method. By default, the class name (not full class name) of cotroller is used as the key. In this way, if the two Contoller names under different packages are duplicated, the keys in controller map in SpringMVC container management will be repeated.

Solving this problem is also relatively simple.

In @ Controller, use the duplicate name.

For example:

test.controller.bill.BillSaveController

package test.controller.bill;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;/** * Created by liuch on 5/27/15. */@Controller@RequestMapping("/billsave")public class BillSaveController {    @RequestMapping("/dosave")    public String saveBill(){        return "billsave";    }}

And test. controller. bill. BillSaveController

package test.controller.billsave;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;/** * Created by liuch on 5/27/15. */@Controller@RequestMapping("/billsave_test")public class BillSaveController {    @RequestMapping("/test")    public String test(){        return "test";    }}

Although the above two codes are under different packages, that is, the full class names are different, but the class names are the same.

In this way, an error will be reported in the background when Tomcat is started:

SEVERE: Context initialization failedorg.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from ServletContext resource[/WEB-INF/dispatcher-servlet.xml]; nested exception is java.lang.IllegalStateException: Annotation-specified bean name 'billSaveController' for bean class [test.controller.billsave.BillSaveController] conflicts with existing, non-compatible bean definition of same name and class [test.controller.bill.BillSaveController]

Cause:

Because if the annotation @ Controller is used, SpringMVC writes the first letter of the class name in lower case by default and puts it in a map.

For example, in the above example, although the names of the two classes are different, they do not use the name when using the @ Controller annotation. When SpringMVC scans the Controller, it resolves all of them to billSaveController by default. Then, it uses the billSaveController as the key and places it in a global map.

In this way, two controllers with identical keys will appear. SpringMVC does not use the overwriting method to process controllers with different full-class names with the same key, and the preceding errors will occur during scanning.

Solution:

Use the name on @ Controller

For example, test. controller. bill. BillSaveController

package test.controller.bill;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;/** * Created by liuch on 5/27/15. */@Controller("testbillsave")@RequestMapping("/billsave")public class BillSaveController {    @RequestMapping("/dosave")    public String saveBill(){        return "billsave";    }}

In test. controller. billsave. BillSaveController, use:

package test.controller.billsave;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;/** * Created by liuch on 5/27/15. */@Controller("realbillsave")@RequestMapping("/billsave_test")public class BillSaveController {    @RequestMapping("/test")    public String test(){        return "test";    }}

In the above two controllers, you only need to ensure that one is named, but it is best to use both.

This is a good programming method, because you cannot guarantee that others will not use Controller with the same class name as you.

Postscript:

In the afternoon, I asked my colleagues to try it.