#330 Add README.md for JPA

querydsl-jpa/README.md

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+The JPA module provides integration with the JPA 2 persistence API.
+
+**Maven integration**
+
+ Add the following dependencies to your Maven project :
+
+    <dependency>
+      <groupId>com.mysema.querydsl</groupId>
+      <artifactId>querydsl-apt</artifactId>
+      <version>${querydsl.version}</version>
+      <scope>provided</scope>
+    </dependency>    
+        
+    <dependency>
+      <groupId>com.mysema.querydsl</groupId>
+      <artifactId>querydsl-jpa</artifactId>
+      <version>${querydsl.version}</version>
+    </dependency>
+    
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-log4j12</artifactId>
+      <version>1.6.1</version>
+    </dependency>   
+
+And now, configure the Maven APT plugin :
+
+    <project>
+      <build>
+      <plugins>
+        ...
+        <plugin>
+          <groupId>com.mysema.maven</groupId>
+          <artifactId>apt-maven-plugin</artifactId>
+          <version>1.0.6</version>
+          <executions>
+            <execution>
+              <goals>
+                <goal>process</goal>
+              </goals>
+              <configuration>
+                <outputDirectory>target/generated-sources/java</outputDirectory>
+                <processor>com.mysema.query.apt.jpa.JPAAnnotationProcessor</processor>
+              </configuration>
+            </execution>
+          </executions>
+        </plugin>
+        ...
+      </plugins>
+      </build>
+    </project>
+
+The JPAAnnotationProcessor finds domain types annotated with the javax.persistence.Entity annotation and generates query types for them.
+
+If you use Hibernate annotations in your domain types you should use the APT processor com.mysema.query.apt.hibernate.HibernateAnnotationProcessor instead.
+
+Run clean install and you will get your Query types generated into target/generated-sources/java.
+
+If you use Eclipse, run mvn eclipse:eclipse to update your Eclipse project to include target/generated-sources/java as a source folder.
+
+Now you are able to construct JPQL query instances and instances of the query domain model.     
+
+** Example query **
+
+    QCustomer customer = QCustomer.customer;
+    JPAQuery query = new JPAQuery(entityManager);
+    Customer bob = query.from(customer)
+      .where(customer.firstName.eq("Bob"))
+      .uniqueResult(customer);