https://github.com/jenetics/facilejdbc
FacileJDBC - Fast, simple and lightweight JDBC wrapper
https://github.com/jenetics/facilejdbc
database db dbms java java-sql-library jdbc jdbc-wrapper query sql
Last synced: 22 days ago
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FacileJDBC - Fast, simple and lightweight JDBC wrapper
- Host: GitHub
- URL: https://github.com/jenetics/facilejdbc
- Owner: jenetics
- Created: 2019-10-22T13:32:34.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2025-08-25T22:10:03.000Z (6 months ago)
- Last Synced: 2025-08-26T00:13:35.775Z (6 months ago)
- Topics: database, db, dbms, java, java-sql-library, jdbc, jdbc-wrapper, query, sql
- Language: Java
- Homepage:
- Size: 1.54 MB
- Stars: 40
- Watchers: 4
- Forks: 2
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
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**_For building and running the library, Java 17 (or above) is required._**
# Facile JDBC
_Making the JDBC usage simpler and less verbose._
## Overview
JDBC is the basic API for accessing relational databases. Being basic makes it quite tedious to use directly. This leads to higher level abstractions like [JPA](https://docs.oracle.com/javaee/7/tutorial/partpersist.htm). Using a full-grown _Object Relational Mapper_ on the other side might be to heavy weight for many uses cases. _FacileJDBC_ tries to fill the gap by making the low-level JDBC access less verbose and tedious. SQL is still used as a query language.
> The API of this library has been heavily influenced by the Scala [Anorm](https://playframework.github.io/anorm/) library.
#### _FacileJDBC_ gives you
> * A lightweight wrapper around the JDBC API.
> * The possibility to fill query parameters by _name_ instead of its position: Available via the `Param` interface.
> * Functions for creating (parsing) _entity_ objects from query `ResultSet`s: Available via the `RowParser` interface
> * Functions for splitting (deconstructing) _entity_ objects to DB columns: Available via the `Dctor` interface.
> * A `Query` object to putting all things together.
> * Lightweight transaction handling support.
#### _FacileJDBC_ is not
> * An OR-Mapper
> * A type safe query language
> * An SQL query builder
#### _FacileJDBC_ has no
> * DB-vendor specific code, uses 100% pure JDBC.
> * Query generation capabilities. The user is responsible for creating the proper SQL string.
> * Generated classes or dynamically generated proxies.
> * No connection pooling.
**Other Java DB libraries**
* [jOOQ](https://www.jooq.org/): Excellent library for accessing databases in a type safe way. Because of the different scope, it is more than a thin wrapper around the JDBC API.
* [Jdbi](http://jdbi.org/): Similar scope, but with a different approach.
## Examples
The following example show how to use _FacileJDBC_ for different use cases. For a detailed description of the API, also have a look at the [Javadoc](https://www.javadoc.io/doc/io.jenetics/facilejdbc).
### Executing queries
SQL queries are defined via the `Query` class. Since the `Query` class is immutable, it is safe to use it in a multi-threaded environment or define it as _static_ class member. The `Query` class is the main entry point of the _FacileJDBC_ library. For executing a query, all what it needs is a JDBC `Connection`.
```java
final Query query = Query.of("SELECT 1");
final boolean result = query.execute(conn)
```
The `execute` method returns a `boolean` value as specified in the [`PreparedStatement.execute()`](https://docs.oracle.com/en/java/javase/11/docs/api/java.sql/java/sql/PreparedStatement.html#execute()) method. The [Javadoc](https://www.javadoc.io/doc/io.jenetics/facilejdbc) documents the used methods of the `PreparedStatement` for every _execute_ method.
### Selecting objects
Usually, your selected rows will be stored in [DTO](https://en.wikipedia.org/wiki/Data_transfer_object) objects. For the _simple_ examples the following `Person` DTO will be used.
```java
public record Person(
String name,
String email,
String link
){}
```
The following query will select all persons which matches a given name _pattern_.
```java
static final Query SELECT = Query.of("""
SELECT name, email, link
FROM person
WHERE name like :name
"""
);
```
Executing the select query is shown in the following code snippet. It also shows how query parameter are set and how the result rows are parsed.
```java
final List persons = SELECT
.on(value("name", "M%"))
.as(PARSER.list(), conn);
```
The `Query.on` method is used for filling the query parameters. The variables uses the usual syntax for SQL bind variables. With the `Param.value` factory method it is possible to fill the defined variables. The `Query.as` method executes the query and returns the parsed result rows. For converting the query result to a _DTO_, a `RowParser` is needed. With the `RowParser.list()` method you will tell the query that you expect 0 to _n_ result rows. If only one result is expected, you need to use the `RowParser.single()` or `RowParser.singleOp()` method.
The following code snippet shows the `RowParser` implementation for our `Person` DTO.
```java
static final RowParser PARSER = (row, conn) -> new Person(
row.getString("name"),
row.getString("email"),
row.getString("link")
);
```
Since the `RowParser` is a _functional_ interface it can be written as shown. The first function parameter represents the actual selected row and second parameter the JDBC `Connection` used for executing the query. In most cases the `conn` will not be used, but it is quite helpful for fetching dependent DTOs in a sub-query.
Whe you are useing Java `record`s as entity objects, you can create the `RowParser` with a simple factory method.
```java
static final RowParser PARSER = RowParser.of(Person.class);
```
### Lazy (stream) select
The _FacileJdbc_ library allows you to lazily fetch results from the DB. This might be useful when the selected data can cause an `OutOfMemoryError`.
```java
final var select = Query.of("SELECT * FROM person;");
// Make sure to close the returned stream.
try (var persons = select.as(PARSER.stream(), conn)) {
// Do some processing with the person stream.
persons.forEach(person -> ...);
}
```
It's important to _close_ the returned `Stream`, which will close the underlying `ResultSet` and `PreparedStatement`. Every `SQLException`, thrown while fetching the data from the DB, will be wrapped in an `UncheckedSQLException`.
_By setting the fetch-size, with the `Query.withFetchSize(int)` method, it is possible to control the amount of data fetched at once by the JDBC driver._
### Export selection result to CSV
Sometime it is convenient to export the whole selection result as CSV line.
```java
final var select = Query.of("SELECT * FROM book;");
final var csv = select.as(ResultSetParser.csvLine(), conn);
System.out.println(csv);
```
The printed CSV string will look like the following example.
```
"ID","PUBLISHED_AT","TITLE","ISBN","PAGES"
"0","1987-02-04","Auf der Suche nach der verlorenen Zeit","978-3518061756","5100"
"1","1945-01-04","Database Design for Mere Mortals","978-0321884497","654"
"2","1887-02-04","Der alte Mann und das Meer","B00JM4RD2S","142"
```
For a big result set it is possible to lazily stream the selected rows into a file.
```java
final var select = Query.of("SELECT * FROM book ORDER BY id;");
try (Stream lines = select.as(RowParser.csvLine().stream(), conn);
Writer out = Files.newBufferedWriter(Path.of("out.csv")))
{
lines.forEach(line -> {
try {
out.write(line);
out.write("\r\n");
} catch (IOException e) {
throw new UncheckedIOException(e);
}
});
}
```
The rows are written _without_ a header into the CSV file.
```
"0","1987-02-04","Auf der Suche nach der verlorenen Zeit","978-3518061756","5100"
"1","1945-01-04","Database Design for Mere Mortals","978-0321884497","654"
"2","1887-02-04","Der alte Mann und das Meer","B00JM4RD2S","142"
```
### Inserting objects
For inserting one new `Person` into the DB an _insert_ query have to be defined.
```java
static final Query INSERT = Query.of("""
INSERT INTO person(name, email, link)
VALUES(:name, :email, :link);
"""
);
```
When all bind variable has been set, it can be inserted by calling the `execute` method.
```java
final boolean inserted = INSERT
.on(
value("name", "foo"),
value("email", "foo@gmail.com"),
value("link", "http://google.com"))
.execute(conn);
```
Setting the bind variables this way is quite tedious, if you already have a filled `Person` DTO. Inserting the `Person` DTO directly you need to define the variable-field mapping. This is done via the `Dctor` (deconstructor) interface. The `Dctor` can be seen as the inverse function of the `RowParser`.
```java
private static final Dctor DCTOR = Dctor.of(
field("name", Person::name),
field("email", Person::email),
field("link", Person::link)
);
```
The `Dctor` interface also comes with a simple factory method for records.
```java
private static final Dctor DCTOR = Dctor.of(Person.class);
```
Once a deconstructor is defined for your DTO, you can easily insert single `Person` objects.
```java
final Person person = ...;
final boolean inserted = INSERT
.on(person, DCTOR)
.execute(conn);
```
If you are interested in the _automatically_ generated primary key of the insertion, you have to use the `executeInsert` method. This method returns an `Optional` in the case no primary key could be generated.
```java
final Optional inserted = INSERT
.on(...)
.executeInsert(conn);
```
or
```java
final Optional inserted = INSERT
.on(...)
.executeInsert(RowParser.int32(1), conn);
```
if you are needed to control the parsing of the generated primary key.
### Batch insertion
If you have a collection of `Person`s, you can insert it in one batch.
```java
final List persons = ...;
final Batch batch = Batch.of(persons, DCTOR);
final int[] counts = INSERT.executeUpdate(batch, conn);
```
For simple insertions, you can also do some kind of ad-hoc batch insertions.
```java
Query.of("INSERT INTO person(id, name) VALUES(:id, :name)")
.execute(
Batch.of(
List.of(value("id", 1), value("name", "Peter")),
List.of(value("id", 2), value("name", "Jack")),
List.of(value("id", 3), value("name", "John"))
),
conn
);
```
### Multi-value parameter
A parameter can be multi-value, like a sequence of IDs. In such case, values will be prepared to be passed appropriately in JDBC.
```java
final List results = Query.of("SELECT * FROM book WHERE id IN(:ids);")
.on(Param.values("ids", 1, 2, 3, 4))
.as(PARSER.list(), conn);
```
The created JDBC query string will look like this
```sql
SELECT * FROM book WHERE id IN(?,?,?,?);
```
filled with the value `1`, `2`, `3` and `4`.
### Custom parameter type
Sometimes it is not possible to use the available object conversions, available in the library. E.g. if you want to insert some _raw_ byte content via an `InputStream`.
```java
final var query = Query.of("INSERT INTO book(name, pdf) VALUES(:name, :pdf)");
try (var in = Files.newInputStream(Path.of("./book.pdf"))) {
final long id = query
.on(
Param.value("name", "For Whom the Bell Tolls"),
// Call a "special" statement set-method, when setting the parameter.
Param.of("pdf", (index, stmt) -> stmt.setBinaryStream(index, in)))
.executeInsert(conn)
.orElseThrow();
System.out.println("Inserted book with ID: " + id);
}
```
### Custom parameter conversion
It is possible to create automatic parameter value conversion via the SPI `SqlTypeMapper` class. Usually, it is not possible to insert an `URI` field directly into the DB. You have to convert it into a string object first.
```java
public record Person(
String name,
URI link
){}
static final Dctor DCTOR = Dctor.of(
Person.class,
Dctor.field("email", p -> p.link().toString())
);
```
If a mapper for the `URI` class is defined, it is possible to write the deconstructor more concise.
```java
static final Dctor DCTOR = Dctor.of(Person.class);
```
The implementation of such a mapping is quite simple and will look like showed
in the following code snippet.
```java
public class URIMapper extends SqlTypeMapper {
public Object convert(final Object value) {
if (value instanceof URI) {
return value.toString();
} else {
return value;
}
}
}
```
Add the following line
```java
org.acme.URIMapper
```
to the service definition file
```java
META-INF/services/io.jenetics.facilejdbc.spi.SqlTypeMapper
```
and you are done.
### Selecting/inserting object _graphs_
The previous examples shows the basic usage of the library. It is possible to use this for all needed select and insert queries, as you will do it with plain JDBC. If you need to select or insert _small_ object graphs, this becomes fast tedious as well.
Lets extend our initial example an convert the _link_ of the `Person` into an object
```java
public record Person(
String name,
String email,
Link link
){}
```
and with a `Link` class, which will look like the following.
```java
public record Link(
String name,
URI link
){}
```
It is now possible to create one `RowParser` and one `Dctor` which automatically takes care about the linked `Link` object. The new parser will look like the following code snippet.
```java
static final RowParser PERSON_PARSER = (row, conn) -> new Person(
row.getString("name"),
row.getString("email"),
selectLink(row.getLong("link_id"), conn)
);
```
With the shown deconstructor.
```java
static final Dctor PERSON_DCTOR = Dctor.of(
Person.class,
field("link_id", (p, c) -> insertLink(p.link(), c))
);
```
The needed helper methods are responsible for selecting/inserting the `Link` object.
```java
static final RowParser LINK_PARSER = (row, conn) -> new Link(
row.getString("name"),
URI.create(row.getString("url"))
);
static final Dctor LINK_DCTOR = Dctor.of(
field("name", Link::name),
field("url", l -> l.url.toString())
);
static Link selectLink(final Long linkId, final Connection conn)
throws SQLException
{
return Query.of("SELECT * FROM link WHERE id = :id")
.on(value("id", linkId))
.as(LINK_PARSER.singleNull(), conn);
}
static Long insertLink(final Link link, final Connection conn)
throws SQLException
{
return Query.of("INSERT INTO link(name, url) VALUES(:name, :url")
.on(link, LINK_DCTOR)
.executeInsert(conn)
.orElseThrow();
}
```
It is still necessary to implement the sub-inserts and sub-selects, but this can be re-used in other queries, where inserting and selecting of `Link`s is needed. Note that this is not an automatic OR-mapping mechanism. The user is still in charge for the concrete implementation.
> **Note**
>
> Although the described feature is quite expressive and may solve some selection/insertion task in an elegant way, does not mean you have to use it. Just treat it as additional possibility.
### Transaction handling
_FacileJDBC_ also contains two interfaces for simple transaction handling. The `Transaction` interface defines methods for executing one or more queries in a transactional context.
```java
final Transaction transaction = ...;
// Inserting a new link into the DB and returning
// the primary key of the newly inserted row.
final long id = transaction.apply(conn -> insertLink(link, conn));
```
If you are not interested in the return value of the SQL execution, you can use the `accept` method instead. In the case of an error, the connection is rolled back. If everything works fine, the connection is committed.
```java
transaction.accept(conn -> insertLink(link, conn));
```
The second interface is the `Transactional` interface, which represents the _transactional_ capability, typically exposed by a database. In this sense, it can be seen as a minimal database interface, just by exposing a `Connection` factory method, `Transactional::connection`. Since `Transactional` is a functional interface, it can easily created by defining the `Connection` factory method.
```java
final Transactional db = () -> DriverManager.getConnection(
"jdbc:hsqldb:mem:testdb",
"SA",
""
);
```
The example above shows how to create a `Transactional` instance for a HSQLDB in-memory database, perfectly usable for testing purposes. Then it can be used for performing some SQL inserts.
```java
final long bookId = db.transaction().apply(conn ->
Book.insert(book, conn)
);
```
For production code you usually have a `DataSource`, which represents the connection to the DB. It's equally easy to create a `Transactional` object from a given `DataSource` instance.
```java
final DataSource ds = ...;
final Transactional db = ds::getConnection;
```
## Release notes
### [2.1.1](https://github.com/jenetics/facilejdbc/releases/tag/v2.1.1)
#### Bug
* [#53](https://github.com/jenetics/facilejdbc/issues/53): RTimeout not being set on the `Query` object.
_[All Release Notes](RELEASE_NOTES.md)_
## License
The library is licensed under the [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0.html).
Copyright 2019-2025 Franz Wilhelmstötter
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and