I don't have Entity classes in my project. My requirement is When I am connecting to DataBase Based on schema I have to Get the all Tables names from that schema.
Here I have a Schema as "companydb" with 5 tables. Below is my code to retrieve total number of tables from particular schema.
Here may be Exception occur by "Query". Query is not well here so what type of query I have to use and how Can I get List of tables.
persiatance.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemalocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
<persistence-unit name="reports" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/reports" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="root" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
</properties>
</persistence-unit>
</persistence>
GetTableList.java
@WebServlet("/GetTableList")
public class GetTableList extends HttpServlet {
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
EntityManager entityManager = EntityManagerUtil.getEmf()
.createEntityManager();
try {
Query query = entityManager.createQuery("SELECT * FROM companydb.tables");
List list = query.getResultList();
System.out.println(list);
Iterator iterator = list.iterator();
while (iterator.hasNext()) {
iterator.next();
}
out.print(list);
System.out.println("Data retrived successfully");
} catch (Exception e) {
e.printStackTrace();
} finally {
entityManager.close();
}
}
}
Exception is:
java.lang.IllegalArgumentException: An exception occurred while creating a query in EntityManager:
Exception Description: Syntax error parsing the query [SELECT * FROM companydb], line 1, column 7: unexpected token [*].
Internal Exception: NoViableAltException(93@[330:16: ( DISTINCT )?])
how can I over come.
