JAR, WAR, EAR difference

Jar Package

The JAR file format is based on the popular ZIP file format;

Unlike ZIP files, JAR files are used not only for compression and publishing, but also for deploying and encapsulating libraries, components, and plug-ins , and can be used by tools like compilers and JVMs Direct Use ;

The only difference between a jar file and a ZIP file is that it contains a meta-inf/manifest in the contents of the jar file . MF file, this file is created automatically when the JAR file is generated.

Role:

1. As a toolkit and class library, this is the most basic role, in large projects, generally rely on n multi-jar package.
2. As a building block for application engineering and expansion, when developing large applications, the application is typically divided into several units, each packaged in jar packages and interdependent.
3. As a deployment unit for a component, applet, or plug-in program;
4. Used to package the secondary resources associated with the component.

The internal structure of the typical jar package is as follows:

Tools.jar

| Resource.xml//Resource configuration file

| Other.xml

|

|-meta-inf

| MANIFEST. MF//Jar Package description file

|-com//Class of package directory

|-test

Util.class//Java class file

War pack

WAR (Web Archive file) network application files are platform-independent file formats that allow many files to be combined into a single compressed file. War is dedicated to the Web .

JAVA Web Engineering, are published as a war package.

The internal structure of a typical war package is as follows:

Webapp.war

| index.jsp

|

|-images

|-meta-inf

|-web-inf

| Web. XML//War package description file

|

|-classes

| Action.class//Java class file

|

|-lib

Other.jar//Dependent jar Package

Share.jar

Ear Package

The JAR file created for the Java EE application is an EAR file (Enterprise JAR file), a platform-independent file format that allows many files to be combined into a single compressed file.

For enterprise projects, the ear package is actually comprised of a war package and several enterprise-level project profiles , and the general server chooses WebSphere and so on.

The internal structure of the typical ear package is as follows:

App.ear

| Ejb.jar//Ejb-jar bag

| Other.jar//Common jar Package

| Webapp.war//War pack

|

|-meta-inf

Application.xml//Ear profile

JAR, WAR, EAR difference