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how to get values to spring.boot.admin.client.username/ password from database?

I have spring boot admin project and now I hardcoded the username and passwords in application.properties file like this.
spring.boot.admin.client.username=user
spring.boot.admin.client.password=pass
spring.boot.admin.client.instance.metadata.user.name=user
spring.boot.admin.client.instance.metadata.user.password=pass
But want to get that values from database not hardcoded like this.I want to configs to connect to self register the admin server as a client.I am beginner to SpringBoot. How can I do it? Thanks.

So every configuration in an application.properties file can be configured via Javacode. First you have to create a Datasource for your project. Add the spring-data-jpa dependency to your project and config the datasource.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
more you can find here: A Guide to JPA with Spring
To configure for example the two properties spring.boot.admin.client.username=user and spring.boot.admin.client.password=pass you need to create a #Configuration class which creates a ClientProperties Bean.
#Configuration
public class AdminClientConfig {
private final JdbcTemplate jdbcTemplate;
private final Environment environment;
public AdminClientConfig(JdbcTemplate jdbcTemplate,
Environment environment) {
super();
this.jdbcTemplate = jdbcTemplate;
this.environment = environment;
}
#Bean
public ClientProperties clientProperties() {
ClientProperties cp = new ClientProperties(environment);
cp.setUsername(getUsername());
cp.setPassword(getPassword());
return cp;
}
private String getUsername() {
String username = jdbcTemplate.queryForObject(
"select username from AnyTable where id = ?",
new Object[] { "123" }, String.class);
return username;
}
private String getPassword() {
String password = jdbcTemplate.queryForObject(
"select password from AnyTable where id = ?",
new Object[] { "123" }, String.class);
return password;
}
}
So the JdbcTemplate has already a Database connection and creates the query to get the Username and Password from the Database. The ClientProperties Bean can then be set.
P.S.: This code is not tested but gives you a some hints to get the job done.

Can spring data r2dbc generate a schema?

I am creating a quick project using R2DBC and H2 to familiarize myself with this new reactive stuff. Made a repository that extends ReactiveCrudRepository and all is well with the world, as long as i use the DatabaseClient to issue a CREATE TABLE statement that matches my entity first...
I understand spring data R2DBC is not as fully featured as spring data JPA (yet?) but is there currently a way to generate the schema from the entity classes?
Thanks

No, there is currently no way to generate schema from entities with Spring Data R2DBC.
I'm using it in a project with Postgres DB and it's complicated to manage database migrations, but I managed to wire in Flyway with synchronous Postgre driver (Flyway doesn't work with reactive drivers yet) at startup to handle schema migrations.
Even though you still have to write your own CREATE TABLE statements which shouldn't be that hard and you could even modify your entities in some simple project to create JPA entities and let Hibernate create schema then copy-paste it into a migration file in your R2DBC project.

It is possible for tests and for production.
I production make sure your user has no access to change schema otherwise you may delete tables by mistake!!! or use a migration tool like flyway.
You need to put your schema.sql in the main resources and add the relevant properties
spring.r2dbc.initialization-mode=always
h2 for test and postgres for prod
I use gradle and the versions of driver are:
implementation 'org.springframework.boot.experimental:spring-boot-actuator-autoconfigure-r2dbc'
runtimeOnly 'com.h2database:h2'
runtimeOnly 'io.r2dbc:r2dbc-h2'
runtimeOnly 'io.r2dbc:r2dbc-postgresql'
runtimeOnly 'org.postgresql:postgresql'
testImplementation 'org.springframework.boot.experimental:spring-boot-test-autoconfigure-r2dbc'
The BOM version is
dependencyManagement {
imports {
mavenBom 'org.springframework.boot.experimental:spring-boot-bom-r2dbc:0.1.0.M3'
}
}

That's how I solved this problem:
Controller:
#PostMapping(MAP + PATH_DDL_PROC_DB) //PATH_DDL_PROC_DB = "/database/{db}/{schema}/{table}"
public Flux<Object> createDbByDb(
#PathVariable("db") String db,
#PathVariable("schema") String schema,
#PathVariable("table") String table) {
return ddlProcService.createDbByDb(db,schema,table);
Service:
public Flux<Object> createDbByDb(String db,String schema,String table) {
return ddl.createDbByDb(db,schema,table);
}
Repository:
#Autowired
PostgresqlConnectionConfiguration.Builder connConfig;
public Flux<Object> createDbByDb(String db,String schema,String table) {
return createDb(db).thenMany(
Mono.from(connFactory(connConfig.database(db)).create())
.flatMapMany(
connection ->
Flux.from(connection
.createBatch()
.add(sqlCreateSchema(db))
.add(sqlCreateTable(db,table))
.add(sqlPopulateTable(db,table))
.execute()
)));
}
private Mono<Void> createDb(String db) {
PostgresqlConnectionFactory
connectionFactory = connFactory(connConfig);
DatabaseClient ddl = DatabaseClient.create(connectionFactory);
return ddl
.execute(sqlCreateDb(db))
.then();
}
Connection Class:
#Slf4j
#Configuration
#EnableR2dbcRepositories
public class Connection extends AbstractR2dbcConfiguration {
/*
**********************************************
* Spring Data JDBC:
* DDL: does not support JPA.
*
* R2DBC
* DDL:
* -does no support JPA
* -To achieve DDL, uses R2dbc.DataBaseClient
*
* DML:
* -it uses R2dbcREpositories
* -R2dbcRepositories is different than
* R2dbc.DataBaseClient
* ********************************************
*/
#Bean
public PostgresqlConnectionConfiguration.Builder connectionConfig() {
return PostgresqlConnectionConfiguration
.builder()
.host("db-r2dbc")
.port(5432)
.username("root")
.password("root");
}
#Bean
public PostgresqlConnectionFactory connectionFactory() {
return
new PostgresqlConnectionFactory(
connectionConfig().build()
);
}
}
DDL Scripts:
#Getter
#NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class DDLScripts {
public static final String SQL_GET_TASK = "select * from tasks";
public static String sqlCreateDb(String db) {
String sql = "create database %1$s;";
String[] sql1OrderedParams = quotify(new String[]{db});
String finalSql = format(sql,(Object[]) sql1OrderedParams);
return finalSql;
}
public static String sqlCreateSchema(String schema) {
String sql = "create schema if not exists %1$s;";
String[] sql1OrderedParams = quotify(new String[]{schema});
return format(sql,(Object[]) sql1OrderedParams);
}
public static String sqlCreateTable(String schema,String table) {
String sql1 = "create table %1$s.%2$s " +
"(id serial not null constraint tasks_pk primary key, " +
"lastname varchar not null); ";
String[] sql1OrderedParams = quotify(new String[]{schema,table});
String sql1Final = format(sql1,(Object[]) sql1OrderedParams);
String sql2 = "alter table %1$s.%2$s owner to root; ";
String[] sql2OrderedParams = quotify(new String[]{schema,table});
String sql2Final = format(sql2,(Object[]) sql2OrderedParams);
return sql1Final + sql2Final;
}
public static String sqlPopulateTable(String schema,String table) {
String sql = "insert into %1$s.%2$s values (1, 'schema-table-%3$s');";
String[] sql1OrderedParams = quotify(new String[]{schema,table,schema});
return format(sql,(Object[]) sql1OrderedParams);
}
private static String[] quotify(String[] stringArray) {
String[] returnArray = new String[stringArray.length];
for (int i = 0; i < stringArray.length; i++) {
returnArray[i] = "\"" + stringArray[i] + "\"";
}
return returnArray;
}
}

It is actually possible to load a schema by defining a specific class in this way:
import io.r2dbc.spi.ConnectionFactory
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.core.io.ClassPathResource
import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories
import org.springframework.r2dbc.connection.init.ConnectionFactoryInitializer
import org.springframework.r2dbc.connection.init.ResourceDatabasePopulator
#Configuration
#EnableR2dbcRepositories
class DbConfig {
#Bean
fun initializer(connectionFactory: ConnectionFactory): ConnectionFactoryInitializer {
val initializer = ConnectionFactoryInitializer()
initializer.setConnectionFactory(connectionFactory)
initializer.setDatabasePopulator(
ResourceDatabasePopulator(
ClassPathResource("schema.sql")
)
)
return initializer
}
}
Pay attention that IntelliJ gives an error "Could not autowire. No beans of 'ConnectionFactory' type found" but it is actually a false positive. So ignore it and build again your project.
The schema.sql file has to be put in resources folder.

Is there any way to write custom or native queries in Java JPA (DocumentDbRepository) while firing a query to azure-cosmosdb?

Connected to azure-cosmosdb and able to fire default queries like findAll() and findById(String Id). But I can't write a native query using #Query annotation as the code is not considering it. Always considering the name of the function in respository class/interface. I need a way to fire a custom or native query to azure-cosmos db. ?!
Tried with #Query annotation. But not working.
List<MonitoringSessions> findBySessionID(#Param("sessionID") String sessionID);
#Query(nativeQuery = true, value = "SELECT * FROM MonitoringSessions M WHERE M.sessionID like :sessionID")
List<MonitoringSessions> findSessions(#Param("sessionID") String sessionID);
findBySessionID() is working as expected. findSessions() is not working. Below root error came while running the code.
Caused by: org.springframework.data.mapping.PropertyReferenceException: No property findSessions found for type MonitoringSessions

Thanks for the response. I got what I exactly wanted from the below link. Credit goes to Author of the link page.
https://cosmosdb.github.io/labs/java/technical_deep_dive/03-querying_the_database_using_sql.html
public class Program {
private final ExecutorService executorService;
private final Scheduler scheduler;
private AsyncDocumentClient client;
private final String databaseName = "UniversityDatabase";
private final String collectionId = "StudentCollection";
private int numberOfDocuments;
public Program() {
// public constructor
executorService = Executors.newFixedThreadPool(100);
scheduler = Schedulers.from(executorService);
client = new AsyncDocumentClient.Builder().withServiceEndpoint("uri")
.withMasterKeyOrResourceToken("key")
.withConnectionPolicy(ConnectionPolicy.GetDefault()).withConsistencyLevel(ConsistencyLevel.Eventual)
.build();
}
public static void main(String[] args) throws InterruptedException, JSONException {
FeedOptions options = new FeedOptions();
// as this is a multi collection enable cross partition query
options.setEnableCrossPartitionQuery(true);
// note that setMaxItemCount sets the number of items to return in a single page
// result
options.setMaxItemCount(5);
String sql = "SELECT TOP 5 s.studentAlias FROM coll s WHERE s.enrollmentYear = 2018 ORDER BY s.studentAlias";
Program p = new Program();
Observable<FeedResponse<Document>> documentQueryObservable = p.client
.queryDocuments("dbs/" + p.databaseName + "/colls/" + p.collectionId, sql, options);
// observable to an iterator
Iterator<FeedResponse<Document>> it = documentQueryObservable.toBlocking().getIterator();
while (it.hasNext()) {
FeedResponse<Document> page = it.next();
List<Document> results = page.getResults();
// here we iterate over all the items in the page result
for (Object doc : results) {
System.out.println(doc);
}
}
}
}

Servlet with jdbc response to client [duplicate]

This question already has answers here:
Show JDBC ResultSet in HTML in JSP page using MVC and DAO pattern
(6 answers)
Closed 6 years ago.
I have a database with houses, and HTML page with <SELECT>, where user need to select a district where the houses are located.
Servlet:
#WebServlet("/post")
public class HosesBaseServlet extends HttpServlet {
#Override
public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException{
//choice from html form
String choice = request.getParameter("district");
//Database parameters
final String DB_CONNECTION = "jdbc:mysql://localhost:3306/mydb2";
final String DB_USER = "root";
final String DB_PASSWORD = "root";
Connection conn;
try {
conn = DriverManager.getConnection(DB_CONNECTION, DB_USER, DB_PASSWORD);
System.out.println("Connection available");
PreparedStatement ps = conn.prepareStatement("SELECT Square, RoomNumbers, Price FROM houses WHERE District = " + choice);
}catch (SQLException ex) {
System.out.println("Fail to connect with base");
}
}
}
How can I put SQL select results into HTML page and give it back to client?
I created class House
public class Hosue implements Serializable {
private String price;
private String square;
private String RoomNumbers;
public String getPrice() {
return price;
}
public String getSquare() {
return square;}
public String getRoomNumbers() {
return RoomNumbers;}
public void setPrice(String price) {
this.price = price;
}
public void setSquare(String square) {
this.square = square;
}
public void setRoomNumbers(String roomNumbers) {
RoomNumbers = roomNumbers;
}
}
and houses
public class Houses {
public List<House> getList() {
}
}
and add script to my html. What next, how to add information from select to this list?

You can solve your problem as said by Jeed in the previous answer. However, it would be better if you model your db entities with Java objects and use them to encapsulate information from and towards the db. You may also use the DAO programming pattern to better organize your code, thus you can define simple objects (beans) to model data (your database entities) and data access object (DAO object) in which you would encode interaction with the db (your jdbc code).
Then you will have something like this to query your db (this code will be in your servlet):
HouseDAO h=new HouseDAO(db connection param...)
ArrayList<House> list=h.selectHouses();
In the HouseDAO object you will create a method selectHouse in which you will basically move the jdbc code you have in your servlet right now. By the way, your are missing a part in which you call the method execute query from the ps object. This method returns a ResultSet object which contains the query result.
With the code above, you will have your data in the ArrayList list, and you can use the code suggested by Jeed to output it.
Clearly, if you want to avoid using jsp, you can print your html code directly in your servlet. I do not recommend this as you would merge view details with control and model code. This is not good especially if you are planning to change your view in the future.

Add result of your query to some List or custom object and set it as attribute in your request object.
request.setAttribute("result", result);
and then forward to your next page using RequestDispatcher.

Use Gson external Library for sending java-List into String form to
HTML,
Your Servlet Code looks likewise,
List<House> listofHouses = getList from Database;
Gson gson = new Gson();
String json_obj = gson.toJson(listofHouses);
response.getWriter().println(json_obj);
Your HTML(use Jquery-ajax for Handling result & send Request to
Servlet ) Code looks some what nearer likewise......
<script>
$.ajax({
url: 'Servlet.do?distinct=YOUR_SELECTED_district_NAME',
type: "POST/GET",
data: query,
dataType: 'application/json; charset=utf-8',
success: function (data) {
var returnedData = JSON.parse(data);
alert(data);
$.each(data, function(index, value) {
('#your_drop_down_tag_id').append($('<option>').text(value).attr('value', index));
});
}
});
</script>
NOTE: jquery-XXX.js file must be inclue into your project and into your html file properly.

Spring-HateoasTraverson how to get info from three tables

I have three tables in my database e.g. user, authority and role.
The table authority contains two fields user_id and role_id that are foreign keys.
The SQL statement is:
SELECT t1.id id, t3.id user_id, t3.username_x username_x, t2.id role_id, t2.desc_x desc_x
FROM `securitydashboard`.`authorities` AS t1
INNER JOIN `securitydashboard`.`role` AS t2
INNER JOIN `securitydashboard`.`user` AS t3
ON (t2.id = t1.role_id
AND t3.id = t1.user_id);
The result would be:
id user_id username_x role_id desc_x
1 1 admin 1 ROLE_ADMIN
2 1 admin 2 ROLE_USER
I am setting up the simple Spring-Hateoas project. It will be easier to get the info as above via "sql view" and run on Traverson.
I am struggling to get the info as above via Traverson without "sql view".
My java program as below is this:
public class UserResource extends ResourceSupport {
public String usernameX;
public String passwordX;
public String firstnameX;
public String lastnameX;
public EmailAddress emailX;
public Boolean enabledB;
public String saltX;
public AuthoritiesesById authority;
static class AuthoritiesesById {
public Roles role;
static class Roles {
String descX;
}
}
}
public class Test2 {
private static final ParameterizedTypeReference<PagedResources<Resource<UserResource>>> TYPE_REFERENCE = new ParameterizedTypeReference<PagedResources<Resource<UserResource>>>() {};
public static void main(String[] args) throws Exception {
String urlstring = "http://localhost:8085/RestDashboard";
URL url = new URL(urlstring);
URLConnection connection = url.openConnection();
connection.setRequestProperty("Accept", "application/json");
LinkDiscoverer discoverer = new HalLinkDiscoverer();
Link link = discoverer.findLinkWithRel("users", connection.getInputStream());
URI uri = new URI(urlstring);
Traverson traverson = new Traverson(uri, MediaTypes.HAL_JSON);
Map<String, Object> parameters = new HashMap<>();
PagedResources<Resource<UserResource>> resources = traverson.follow(link.getRel()).withTemplateParameters(parameters).toObject(TYPE_REFERENCE);
for (Resource<UserResource> resource : resources) {
System.out.print(resource.getContent().authority.role.descX);
}
}
}
The result returns null.
What do I do wrong?

I am not 100% sure if it is the problem, but you are extending your UserResource from ResourceSupport AND you are typing your TypeReference with Resource which results in the same actually.
Try it at least either with extending from ResourceSupport OR with typing it with Resource but not with both options at once.
UPDATE:
Try to instantiate your type reference with org.springframework.hateoas.mvc.TypeReferences.PagedResourcesType