work on db connection basic

pom.xml

@@ -49,6 +49,13 @@
             <version>7.0.0</version>
         </dependency>
 
+        <!-- https://mvnrepository.com/artifact/commons-dbutils/commons-dbutils -->
+        <dependency>
+            <groupId>commons-dbutils</groupId>
+            <artifactId>commons-dbutils</artifactId>
+            <version>1.8.1</version>
+        </dependency>
+
         <!-- https://mvnrepository.com/artifact/org.mariadb.jdbc/mariadb-java-client -->
         <dependency>
             <groupId>org.mariadb.jdbc</groupId>

src/main/java/dev/mduchene/App.java

@@ -1,6 +1,15 @@
 package dev.mduchene;
 
 import io.javalin.Javalin;
+import org.apache.commons.dbutils.DbUtils;
+import org.apache.commons.dbutils.QueryRunner;
+import org.apache.commons.dbutils.handlers.ScalarHandler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.List;
 
 /** Hello world! */
 public class App {
@@ -12,6 +21,58 @@ public class App {
             .password("root")
             .build();
 
-    var app = Javalin.create(cnf -> {}).get("/", ctx -> ctx.result("Hello World")).start(3001);
+    db.init();
+
+    var app = Javalin.create(cnf -> {});
+    app.before(
+        ctx -> {
+          Connection connection = db.getConnection();
+          ctx.attribute("connection", connection);
+        });
+    app.after(
+        ctx -> {
+          Connection connection = ctx.attribute("connection");
+          if (connection != null) {
+            DbUtils.commitAndCloseQuietly(connection);
+          }
+        });
+
+    app.exception(
+        Exception.class,
+        (e, ctx) -> {
+          LoggerFactory.getLogger(App.class).error("error", e);
+
+          Connection connection = ctx.attribute("connection");
+          if (connection != null) {
+            DbUtils.rollbackAndCloseQuietly(connection);
+          }
+          ctx.status(500);
+        });
+
+    app.get(
+        "/",
+        ctx -> {
+          var r = new QueryRunner();
+          Integer query =
+              r.query(
+                  (Connection) ctx.attribute("connection"),
+                  "SELECT 1",
+                  resultSet -> {
+                    System.out.println("hello world");
+                    if (resultSet.next()) return resultSet.getInt(1);
+
+                    return null;
+                  });
+
+          ctx.result(query.toString());
+        });
+
+    app.get(
+        "/error",
+        ctx -> {
+          throw new RuntimeException("error");
+        });
+
+    app.start(3001);
   }
 }

src/main/java/dev/mduchene/Db.java

@@ -2,13 +2,19 @@ package dev.mduchene;
 
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
+import org.slf4j.LoggerFactory;
 
 import java.sql.Connection;
+import java.sql.SQLException;
 
 public class Db {
     private HikariDataSource dataSource;
     private Db() {}
 
+    public void init() {
+
+    }
+
     public static class Builder {
         private String url;
         private String user;
@@ -54,4 +60,5 @@ public class Db {
         connection.setAutoCommit(false);
         return connection;
     }
+
 }