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how to add a parameter to spring project before <projectname>/login and after <localhost>:<portnumber> without hardcode?

I'm working on a Spring MVC project. When I run the application the URL is:
http://localhost:8080/insureYou/login
but I want:
http://localhost:8080/contextroot/insureYou/login
Is there any way of doing it without hardcoding?

In a spring-boot project you can set the context-root by specifying the following property in the application.properties file:
server.servlet.context-path=/yourcontextroot
Without spring-boot, it depends on the webserver and Tomcat offers a number of options.
I would personally opt for a META-INF/context.xml file in your war file containing the necessary information but you can also include the information in the server.xml file or in a ROOT.xml file.
See the following links for further guidance:
How to set the context path of a web application in Tomcat 7.0
https://tomcat.apache.org/tomcat-8.0-doc/config/context.html
https://www.baeldung.com/tomcat-root-application
This type of deployment however sometimes is handled separately, through an Apache server reverse-proxy or through URL rewriting.
I recommend you ascertain whether this type of need is already taken care of by your company's deployment procedures, as you may not need to deal with it at all.

How to pass deployment dependant parameters to webapp

In projects I work(ed) on, deployment parameters - such as storage path or DB login - are usually given through a parameter file, which is stored in the war file.
I find that unsuitable because those values needs to be changed each time the webapp is packaged for a different deployment (dev vs prod, change of executing computer). The source code being versioned, this makes it even more bothering.
Is there some better option to pass parameters such as listed above?
By better, I mean:
practical: simple to setup, change and explain to others
separated from the war
as independent as possible to the web container (if dependent, I'm using tomcat in prod)
Edit
I chose the answer of #aksappy to reward the work done in the answer and because it provided several methods using standard tools. However, depending on the context I could go for any other solutions:
method of #Necreaux has best simplicity
method of #Luiggi Mendoza has a good design and is still simple
method of #OldCurmudgeon would be a really good one if the code covered other cases.

You can use a multitude of things based on your environment. Here are somethings which may be considered
Use datasources
The datasources defined in the server context removes the hard wired dependency of managing db configurations and connection pool from the web application. In Tomcat, this can be done as below in the context.xml
<Context>
...
<Resource name="jdbc/EmployeeDB" auth="Container"
type="javax.sql.DataSource"
description="Employees Database for HR Applications"/>
</Context>
Use Contexts
You can configure named values that will be made visible to the web application as environment entry resources, by nesting entries inside this element. For example, you can create an environment entry like this: (Source here). This can be set as context parameters or environment entries. They are equivalent to the entries made in a web.xml or a properties file except that they are available from the server's context.
Use database configurations and load those configuration at ServletContextListener
Another approach which I tend to follow is to create a relational schema of properties in a database. Instead of loading the properties file during server startup, load the properties from the database during start up.
public class ContextInitialize implements ServletContextListener {
private static Properties props;
public void contextInitialized(ServletContextEvent servletContextEvent) {
// connect to DB
// Load all the key values pairs as required
//put this into a Properties object, or create a hashtable, hashmap ..
}
//Getter
public String getProperty(String key){
// get value of key
}
//Setter
public void setProperty(String key, String value){
// set value to a key
}
}
Note: above is just an example.
Use environment variables or classpath variables
Use classpath / path variables in Environment variables and use System.getenv() in your java code to get these values as necessary.

We normally put our web app properties files in the Tomcat home folder. POJOS look on the launch folder. There will be other standard locations for other web servers.
final String tomcatHome = System.getProperty("catalina.home");
if (tomcatHome == null) {
// POJOs look in "."
searchPaths.add(".");
} else {
searchPaths.add(tomcatHome);
webApp = true;
}

An strategy is to pack all the properties and configuration files in an external jar and make this jar a dependency for your application(s): war, ear, etc. Then, you can deploy this jar in a common folder where the application server will load it and make it available for all the applications deployed there. This means that you will deploy the jar with the values for each environment once (or every time you need to change it, but its changes must be slow compared to the changes made to your main artifacts) and you can deploy and redeploy your war or any other project in your application server without problems.
In case of Tomcat, you may deploy this jar inside %CATALINA_HOME%/lib as explained in Tomcat Tutorial. Class Loader Definitions
To consume (read) these files in my application, I just load them like any other resource in my application.

Two strategies I've used:
JVM Parameters -- Custom JVM parameters can be set by the container at startup. This can get a bit verbose though if you have a lot of settings.
Configuration Files -- These can be read by the application. Either the location is hardcoded, put inside the container path, or to get the best of both worlds, specify the location via a JVM parameter.

Can I have multiple Java webapps with overlapping paths?

I have a large collection of different independent (stateless) web services written in Java and compiled as WAR files. I want to deploy them to a single web application server.
If the URIs handled by the services in each WAR file began with a prefix I could use as a web app name, then this would be easy. I could, for instance, have
SALES WAR FILE: contains code for the following:
GET http://example.com/sales/widgets
POST http://example.com/sales/widgets
GET http://example.com/sales/sky-hooks
MARKETING WAR FILE: contains code for the following:
GET http://example.com/marketing/widgets
PUT http://example.com/marketing/sky-hooks
...in which case I would simply deploy two WAR files under the names "sales" and "marketing". However, I am not that fortunate. Instead, the URI paths handled by the components overlap. Something like this:
SALES WAR FILE: contains code for the following:
GET http://example.com/widgets/sales
POST http://example.com/widgets/sales
GET http://example.com/sky-hooks/sales
MARKETING WAR FILE: contains code for the following:
GET http://example.com/widgets/marketing
PUT http://example.com/sky-hooks/marketing
My question is how (if at all) I can deploy these on a single web application server.
I am open to suggestions that require a significant amount of work. For instance, my best-so-far idea is to build services that expect a component-name prefix before the regular URI path, then pipe all incoming traffic through a different server that knows what component each URI pattern falls into and modifies the URI to add that prefix. The difficulty with this approach is that tools like Swagger that read my source code will have a mistaken idea of what the URIs look like.
Any ideas?

If you're willing to put apache in front of your web container, you can use apache's mod_proxy to forward request to the right place.
One way this could work, would be deploy the separate wars at separate prefixes as in your first case (sales and marketing) and then use ProxyPass to send the requests to the correct place:
ProxyPass /widget/sales http://example.com/sales/widget
ProxyPass /sky-hooks/sales http://example.com/sales/sky-hooks
ProxyPass /widget/marketing http://example.com/marketing/widget
ProxyPass /sky-hooks/marketing http://example.com/marketing/sky-hooks
Its probably a better idea to just refactor your routing though - it might be hard to maintain.
(EDIT: I originally suggested mod_rewrite, but I wanted to make my answer more specific, and it looks like this could be done purely with proxying)

If I understand your question correctly, one of the solutions would be (I am assuming Tomcat is used but this should apply to most of the modern servlet containers):
1) Deploy your sales and marketing wars with different prefixes. I.e., using your example, they should be able to serve the following urls:
GET http://example.com/sales/widgets/sales
POST http://example.com/sales/widgets/sales
GET http://example.com/sales/sky-hooks/sales
GET http://example.com/marketing/widgets/marketing
PUT http://example.com/marketing/sky-hooks/marketing
2) Use UrlRewriteFilter to craft lightweight web application that will be deployed to your servlet container root prefix (for Tomcat it is called ROOT.war) and will rewrite urls in incoming requests to point to relevant web application.
In other words, incoming request like:
/widgets/sales
will be transformed to:
/sales/widgets/sales
... and delivered to sales webapp.
Similarly, in response urls like:
/sales/widgets/sales
will be rewritten to:
/widgets/sales
3) Deploy this war to root of your servlet container.
This approach is somewhat similar to the one suggested by #nont but does not require apache as a frontend as the rewriting functionality will be handled by root web application (UrlRewriteFilter basically implements mod_rewrite functionality).
In other words you'll be able to deploy all your applications (including this rewrite application that is deployed to the root prefix) to single server alleviating need for extra intermediate proxy/rewrite servers.

First, Determine How the Deployments may be Configured
Are you sure the absolute URIs must overlap? The context root will prefix the path supported by each service, unless the absolute path has somehow been coded into the application itself. The first step is to enable direct access to each WAR file, either through unique context roots or application instances.
Option 1: Set the Context Root for each WAR File Explicitly
The context root for a war file is set at deploy time. For some servers, this can be set outside of the web application using an external deployment descriptor. For Tomcat, it may embedded within META-INF/context.xml. See http://tomcat.apache.org/tomcat-7.0-doc/config/context.html for more information.
Option 2: Separate the Context Root Instances using Multiple Containers
Alternatively, deploy each war file to a separate instance of a Java EE servlet container, each running on a different port. This will solve the deployment conflict in the case of a hard-coded absolute path.
Finally, Set up a Virtual Host and Proxy the Requests via Apache and mod_jk
Once the context roots instances have been made uniquely accessible by one of the previous methods, configure an instance of Apache to serve as a reverse-proxy. First, set up a virtual host to handle requests for the externally visible URI. Next, configure mod_jk to route the requests to the correct WAR file deployment. See http://tomcat.apache.org/connectors-doc/webserver_howto/apache.html for more details.
Afterthoughts
The above solution approach is generic for this type of problem and will require some knowledge of Apache and Tomcat configuration, which were chosen as example reverse-proxy and Java EE servlet technologies for its implementation. Additional detail on the deployment constraints would help to determine an optimal solution. In general, identifying the hard constraints on what may be changed versus what may not be changed should guide you quickly to a solution.

The obvious slotuion is to rename the wars, or refactor so that the appropriate mappings are in the correct place.
Anything else is going to be a bit hacky, you can't change the war name, even to soemthing like below :
SALES WAR FILE: contains code for the following:
GET http://example.com/webapp1/widgets/sales
POST http://example.com/webapp1/widgets/sales
GET http://example.com/webapp1/sky-hooks/sales
MARKETING WAR FILE: contains code for the following:
GET http://example.com/webapp2/widgets/marketing
PUT http://example.com/webapp2/sky-hooks/marketing
You could also create another war for routing/filtering, that redirects everything appropriately - but that also relies on altering url somewhat.

This is a use case for Reverse Proxy. If your web server is Apache, as suggested by #nont proxy_mod can be used to create a reverse proxy.
I know that IBM Http Server (IHS) also allows this mod.

Can tomcat store variables/properties that get called from a war

I want to be able to deploy my app using ANT to Tomcat.
I don't want the process to be any different for dev and prod. However the two use different databases i.e. myapp and myapp-dev
How can I make this happen? Can I store a variable in the different tomcat containers and make the application call the name of the database from Tomcat.
Or if what I am asking is ridiculous what is the generally accepted way to achieve deploying to dev and prod with the same process.

The generic way is to put the configuration string in a JNDI entry.
If JNDI is not a possible solution, then a property file in the right location (so it shows up in the classpath of the WAR files) is also useful, but needs careful documentation.
Have you considered letting the web container manage the database connection pool, so you only need a single one pr container, which then can be retrieved through JNDI?

How to parameterize the initialization of a web application (not a servlet)

I have a web application which I wish to configure via settings in an external folder (external to the container and to the .war file). Therefore I want to inject just a single setting into my webapp which is the root folder of my configurations. The reasons for doing this are so that the maintenance team can update configuration settings in nice plain text files without having to re-deploy the war file.
My question is, what is the best way to parametrize a web application in the case of just a single configuration setting. I know I can use a JVM arg and then detect it from my initialization servlet. Ideally, I'd like something that I can put in the server.xml (not the web.xml file) that can be programmatically acquired from my ServletContextListener.contextInitialized(ServletContextEvent paramServletContextEvent) method.
Is there a way to do this using the ServletContextListener approach or is another way?

We are using -Dconfig.location=/foo/bar/config.properties and it works fine. It's a JVM arg, so it goes to the startup script.
You can register properties via JNDI in server.xml, but I'm not convinced this is a better option. server.xml or catalina.sh - both are container-level