Compile Dropwizard Code without migration.xml - java

I have a finalized database in SQL SERVER containing 50+ tables in it and needed to connect it with Dropwizard Code.
I am new to JAVA so my conception about Migrations.xml is it is used to create the tables in database or if any change in database is needed it will be updated through migrations.xml.
So if i don't need any change in database (as told earlier it is finalized).
Can i skip this migrations.xml file?
Need some experts advice please.

If you are handling your database changes elsewhere, then you have no need for any migration xml files within your dropwizard project. It's an optional module, you don't need to use it. You don't even need to include the dropwizard-migrations dependency if you don't want to include database updates in your dropwizard project. You can still connect to your database fine within dropwizard. The docs provide examples using modules dropwizard-jdbi and dropwizard-hibernate.
To connect to your database, add the appropriate code the your java configuration file and yml config as explained in the docs.
jdbi
http://www.dropwizard.io/0.9.2/docs/manual/jdbi.html
hibernate
http://www.dropwizard.io/0.9.2/docs/manual/hibernate.html

Related

How to avoid hard coded database credentials in code

I've been searching for a way to avoid hard coding my database credentials into my code base (mainly written in Java), but I haven't found many solutions. I read this post where they said a one way hash could be the answer. Is there another way of securely connecting to a database without running into the risk of someone decompiling your code?
Just to clarify, I'm not looking for code, rather a nudge in the right direction.
If you can used spring boot application, then you can configure using cloud config method. I have added some postgresql db connection details for your further reference. Please refer following link for spring boot cloud config. spring_cloud
spring.datasource.driverClassName=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://{{db_url}}:5432/{{db_name}}
spring.datasource.username=postgres
spring.datasource.password=
spring.datasource.maxActive=3
spring.datasource.maxIdle=3
spring.datasource.minIdle=2
spring.datasource.initialSize=2
spring.datasource.removeAbandoned=true
spring.datasource.tomcat.max-wait=10000
spring.datasource.tomcat.max-active=3
spring.datasource.tomcat.test-on-borrow=true
You could load a config file in your code. Define some kind of file, such as JSON or XML, and define all of your configurations in there. You could point to the file as a command line argument, or just hardcode the file path.
Here's a post talking about parsing JSON config in Java:
How to read json file into java with simple JSON library
You can refer to these post. They are basically just saying to either hash, store it in a property file or use an API. Some of the posts are not merely on Java but you can get ideas from them.
How can I avoid hardcoding the database connection password?
https://security.stackexchange.com/questions/36076/how-to-avoid-scripts-with-hardcoded-password
https://www.codeproject.com/Articles/1087423/Simplest-Way-to-Avoid-Hardcoding-of-the-Confidenti
The solution in our team, database as a service,other application use it's API to get database credentials,the request contains simple credentials like application name.
You have several options to avoid hard code values in your source code:
Properties using Advanced Platforms
Properties from Environment variables
Properties from SCM
Properties from File System
More details here:
https://stackoverflow.com/a/51268633/3957754

Multiple Data Source using Spring JPA

I am building a stand alone java application using Spring JPA frame
work. I am able to access the DB in below scenario: if I give the
DB details in application.properties file as
spring.datasource.url=******** spring.datasource.username=******
spring.datasource.password=******
then it's working properly.
but I have to create two DB connections in the same application so,
I changes the names as below
spring.Datasource1.url=********* spring.Datasource1.username=******
spring.Datasource1.password
spring.Datasource2.url=************ spring.Datasource2.username=****
spring.Datasource2.password=*****
then it's not working.
Can you please provide the solution for it?
I have uploaded my code base in below location.
https://github.com/nagtej/MultipleDataSource
This might be helpful to you http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-two-datasources
Also, to connect to multiple data sources you would need to manually configure a DataSource, EntityManagerFactory and JpaTransactionManager.
For this, you can have a look at code placed at https://github.com/spring-projects/spring-data-examples/tree/master/jpa/multiple-datasources
Another good example for this is shared at http://xantorohara.blogspot.com.au/2013/11/spring-boot-jdbc-with-multiple.html

Spring Boot and Spring Data application with multiple DataSources created in runtime

I am developing a Spring Boot application that uses Spring Data JPA and will need to connect to many different databases e.g. PostreSQL, MySQL, MS-SQL, MongoDB.
I need to create all datasources in runtime i.e. user choose these data by GUI in started application:
-driver(one of the list),
-source,
-port,
-username,
-password.
And after all he writes native sql to choosen database and get results.
I read a lot of things about it in stack and spring forums(e.g. AbstractRoutingDataSource) but all of these tutorials show how to create datasources from xml configuration or static definition in java bean. It is possible to create many datsources in runtime? How to manage transactions and how to create many sessionFactories? It is possible to use #Transactional annotation? What is the best method to do this? Can someone explain me how to do this 'step by step'?
Hope it's not too late for an answer ;)
I developed a module which can be easily integrated in any spring project. It uses a meta-datasource to hold the tenant-datasource connection details.
For the tenant-datasource an AbstractRoutingDataSource is used.
Here you find my core implementation using the AbstractRoutingDataSource.
https://github.com/Dactabird/multitenancy
Here is an example to show how to integrate it. https://github.com/Dactabird/multitenancy-sample
In this example I'm using H2 embedded db. But of course you can use whatever you want.
Feel free to modify it for your purposes or to ask if questions are left!

How to see all tables in my h2 database at localhost:8082?

I use JDBC and created h2 database called usaDB from sql script. Then I filled all tables with jdbc.
The problem is that after I connect to usaDB at localhost:8082 I cannot see on the left tree
my tables. There is only INFORMATION_SCHEMA database and rootUser which I specified creating usaDB.
How to view the content of tables in my h2 database?
I tried query SELECT * FROM INFORMATION_SCHEMA.TABLES.
But it returned many table names except those I created. My snapshot:
I had the same issue and the answer seems to be really stupid: when you type your database name you shouldn't add ".h2.db" suffix, for example, if you have db file "D:\somebase.h2.db" your connection string should be like "jdbc:h2:file:/D:/somebase". In other way jdbc creates new empty database file named "somebase.h2.db.h2.db" and you see what you see: only system tables.
You can use the SHOW command:
Using this command, you can lists the schemas, tables, or the columns of a table. e.g.:
SHOW TABLES
This problem drove me around the twist and besides this page I read many (many!) others until I solved it.
My Use Case was to see how a SpringBatch project created in STS using :: Spring Boot :: (v1.3.1.RELEASE) was going to behave with the H2 database; to do the latter, I needed to be able to get the H2 console running as well to query the DB results of the batch run.
This is what I did and found out:
Created an Web project in STS using Spring Boot:
Added the following to the pom.xml of the latter:
Added a Spring configuration file as follows to the project:
This solves the Web project deficiencies in STS. If you run the project now, you can access the H2 console as follows: http://localhost:8080/console
Now create a SpringBatch project in STS as follows (the alternative method creates a different template missing most of the classes for persisting data. This method creates 2 projects: one Complete, and the other an initial. Use the Complete in the following.):
The SpringBatch project created with STS uses an in memory H2 database that it CLOSES once the application run ends; once you run it, you can see this in the logging output.
So what we need is to create a new DataSource that overrides the default that ships with the project (if you are interested, just have a look at the log messages and you will see that it uses a default datasource...this is created from:
o.s.j.d.e.EmbeddedDatabaseFactory with the following parameters:
Starting embedded database: url='jdbc:hsqldb:mem:testdb', username='sa')
So, it starts an in memory, and then closes it. You have no chance of seeing the data with the H2 console; it has come and gone.
So, create a DataSource as follows:
You can of course use a properties file to map the parameters, and profiles for different DataSource instances...but I digress.
Now, make sure you set the bit that the red arrow in the picture is pointing to, to a location on your computer where a file can be persisted.
Running the SpringBatch (Complete project) you should now have a db file in that location after it runs (persisting Person data)
Run the Web project you configured previously in these steps, and you WILL :=) see your data, and all the Batch job and step run data (et voila!):
Painful but rewarding. Hope it helps you to really BOOTSTRAP :=)
I have met exactly this problem.
From what you describe, I suppose that you connect your jdbc with the "real" h2 server, but you are connecting on web application to database by the wrong mode (embedded-in-memory mode, aka h2mem). It means that h2 will create a new database in-memory, instead of using your true database stored elsewhere.
Please make sure that when you connect to this database, you use the mode Generic H2 (Server), NOTGeneric H2 (Embedded). You can refer to the picture below.
Version of jar file and installed h2 database should be same.
If in case you have created and populated H2 database table using maven dependency in spring boot, then please do change the JDBC URL as jdbc:h2:mem:testdb while connecting to H2 using web console.
It is an old question, but I came across the same problem. Eventually I found out that the default JDBC URL is pointing a test server rather than my application. After correcting it, I could access the right DB.
I tried with both Generic H2 (Embedded) and the Generic H2 (Server) options, both worked as long as the JDBC URL: is provided correctly.
In grails 4.0.1 the jdbc URL for development is jdbc:h2:mem:devDb. Check your application.yml file for the exact URL.
For the people who are using H2 in embedded(persistent mode) and want to "connect" to it from IntelliJ(other IDEs probably apply too).
Using for example jdbc url as follows: jdbc:h2:./database.h2
Note, that H2 does not allow implicit relative paths, and requires adding explicit ./
Relative paths are relative to current workdir
When you run your application, your workdir is most likely set to your project's root dir
On the other hand, IDE's workdir is most likely not your project's root
Hence, in IDE when "connecting" to your database you need to use absolute path like: jdbc:h2:/Users/me/projects/MyAwesomeProject/database.h2
For some reason IntelliJ by default also adds ;MV_STORE=false. It disables MVStore engine which in fact is currently used by default in H2.
So make sure that both your application and your IDE use the same store engine, as MVStore and PageStore have different file layouts.
Note that you cannot "connect" to your database if your application is using it because of locking. The other way around applies too.
In my case the issue was caused by the fact that I didn't set the h2 username, password in java. Unfortunatelly, Spring didn't display any errors to me, so it was not easy to figure out. Adding this lines to dataSource method helped me fix the issue:
dataSource.setUsername("sa");
dataSource.setPassword("");
Also, I should have specified the schema when creating tables in schema.sql
Selecting Generic H2 (Server) solved for me. We tempted to use default Generic H2 (Embedded) which is wrong.

Play! JPA: Enforce not to create Entity on load

I am connecting to an external database (i.e. Oracle 10g) using my Play 1.2.4 application.
I have provided all the DB details in the application.conf file, then added the ojdbc.jar in the classpath and the connection seems to work fine. But the problem is everytime when the application access some data for the first time. it is trying to create the entity table (which is already present) and hence throws an exception.
I don't want to create any table since its already there with some data, hence how can I avoid this?
There might be some configuration to set in the application.conf for accessing the external database where the table is already available(I believe), kindly help me on this.
Below is the conf file:
application.mode=dev
%prod.application.mode=prod
db.url=jdbc:oracle:thin:#localhost:1521/orcl
db.driver=oracle.jdbc.OracleDriver
db.user=****
db.pass=****
#%test.module.cobertura=${play.path}/modules/cobertura
%test.application.mode=dev
%test.db.url=jdbc:h2:mem:play;MODE=MYSQL;LOCK_MODE=0
%test.jpa.ddl=create
%test.mail.smtp=mock
Note: Presently I am connecting to the external Oracle database and not with the embedded H2 database.
In your application.conf set the following property to none:
jpa.ddl=none

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