JDBC

Utilities for working with the raw JDBC api.

Includes

• Utilities for reading data from ResultSets
• A SettableParameter interface, for when String Templates are re-previewed.

Dependency Information

Maven

<dependency>
    <groupId>dev.mccue</groupId>
    <artifactId>jdbc</artifactId>
    <version>2024.08.02</version>
</dependency>

Gradle

dependencies {
    implementation("dev.mccue:jdbc:2024.08.02")
}

Usage

These examples use sqlite.

Read nullable primitive types

ResultSets includes helpers for reading potentially null primitive types from a ResultSet

import dev.mccue.jdbc.ResultSets;

void main() throws Exception {
    var db = new SQLiteDataSource();
    db.setUrl("jdbc:sqlite:test.db");

    try (var conn = db.getConnection()) {
        try (var stmt = conn.prepareStatement("""
                SELECT number
                FROM widget
                LIMIT 1
                """)) {
            var rs = stmt.executeQuery();

            // Methods exist for all primitives except char 
            // (which doesn't have a method on ResultSet)
            var number = ResultSets.getIntegerNullable(rs, "number");
        }
    }
}

Read non-null primitive types

If you want to read a column that is primitive, but you assume is not null, there are helpers which will throw a SQLException early if that assumption is violated.

import dev.mccue.jdbc.ResultSets;

void main() throws Exception {
    var db = new SQLiteDataSource();
    db.setUrl("jdbc:sqlite:test.db");

    try (var conn = db.getConnection()) {
        try (var stmt = conn.prepareStatement("""
                SELECT number
                FROM widget
                LIMIT 1
                """)) {
            var rs = stmt.executeQuery();

            // Methods exist for all primitives except char 
            // (which doesn't have a method on ResultSet)
            var number = ResultSets.getIntegerNotNull(rs, "number");
        }
    }
}

Read a row as a Record

Often when going through a ResultSet you will want to materialize a whole row.

import dev.mccue.jdbc.ResultSets;

public record Widget(int number) {}

void main() throws Exception {
    var db = new SQLiteDataSource();
    db.setUrl("jdbc:sqlite:test.db");

    try (var conn = db.getConnection()) {
        try (var stmt = conn.prepareStatement("""
                SELECT number
                FROM widget
                LIMIT 1
                """)) {
            var rs = stmt.executeQuery();
            var widget = ResultSets.getRecord(rs, Widget.class);

            System.out.println(widget);
        }
    }
}

Read a row as a Record with customized mappings

If the name of a record component doesn't line up with what you want pulled from a ResultSet, you can use the @Column annotation.

import dev.mccue.jdbc.Column;
import dev.mccue.jdbc.ResultSets;

public record Widget(@Column(label = "number") int n) {
}

void main() throws Exception {
    var db = new SQLiteDataSource();
    db.setUrl("jdbc:sqlite:test.db");

    try (var conn = db.getConnection()) {
        try (var stmt = conn.prepareStatement("""
                SELECT number
                FROM widget
                LIMIT 1
                """)) {
            var rs = stmt.executeQuery();
            var widget = ResultSets.getRecord(rs, Widget.class);

            System.out.println(widget);
        }
    }
}

Read a row as a Record, customizing how a column is gotten from a ResultSet.

import dev.mccue.jdbc.Column;
import dev.mccue.jdbc.DefaultRecordComponentGetter;
import dev.mccue.jdbc.ResultSets;

import java.lang.reflect.RecordComponent;
import java.sql.ResultSet;
import java.sql.SQLException;

public record Text(String contents) {}

public static final class CustomRecordComponentGetter 
        extends DefaultRecordComponentGetter {
    @Override
    protected Object getIndexedRecordComponent(ResultSet rs, RecordComponent recordComponent, int index) throws SQLException {
        return new Text(rs.getString(index));
    }

    @Override
    protected Object getLabeledRecordComponent(ResultSet rs, RecordComponent recordComponent, String label) throws SQLException {
        return new Text(rs.getString(label));
    }
}

public record Widget(
        @Column(label = "number") 
        int n,
        @Column(
                recordComponentGetter = CustomRecordComponentGetter.class
        )
        Text name) {
}

void main() throws Exception {
    var db = new SQLiteDataSource();
    db.setUrl("jdbc:sqlite:test.db");

    try (var conn = db.getConnection()) {
        try (var stmt = conn.prepareStatement("""
                SELECT number, name
                FROM widget
                LIMIT 1
                """)) {
            var rs = stmt.executeQuery();
            var widget = ResultSets.getRecord(rs, Widget.class);

            System.out.println(widget);
        }
    }
}