Start to implement the database export tool

src/main/scala/gitbucket/core/util/JDBCUtil.scala

@@ -1,6 +1,8 @@
 package gitbucket.core.util
 
+import java.io.FileOutputStream
 import java.sql._
+import java.text.SimpleDateFormat
 import ControlUtil._
 import scala.collection.mutable.ListBuffer
 
@@ -58,6 +60,74 @@ object JDBCUtil {
       }
     }
 
+    def export(): Unit = {
+      val dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss")
+
+      using(new FileOutputStream("export.sql")) { out =>
+        val dbMeta = conn.getMetaData
+
+        allTables(dbMeta).foreach { tableName =>
+          val sb = new StringBuilder()
+
+          select(s"SELECT * FROM ${tableName}") { rs =>
+            sb.append(s"INSERT INTO ${tableName} (")
+            val rsMeta = rs.getMetaData
+            val columns = (1 to rsMeta.getColumnCount).map { i =>
+              (rsMeta.getColumnName(i), rsMeta.getColumnType(i))
+            }
+            sb.append(columns.map(_._1).mkString(", "))
+            sb.append(") VALUES (")
+            val values = columns.map { case (columnName, columnType) =>
+              columnType match {
+                case Types.BOOLEAN   => rs.getBoolean(columnName)
+                case Types.VARCHAR | Types.CLOB | Types.CHAR => rs.getString(columnName)
+                case Types.INTEGER   => rs.getInt(columnName)
+                case Types.TIMESTAMP => rs.getTimestamp(columnName)
+              }
+            }
+
+            val columnValues = values.map { value =>
+              value match {
+                case x: String    => "'" + x.replace("'", "''") + "'"
+                case x: Timestamp => "'" + dateFormat.format(x) + "'"
+                case null         => "NULL"
+                case x            => x
+              }
+            }
+            sb.append(columnValues.mkString(", "))
+            sb.append(");\n")
+          }
+
+          out.write(sb.toString.getBytes("UTF-8"))
+        }
+      }
+    }
+
+    private def parentTables(meta: DatabaseMetaData, tableName: String): Seq[String] = {
+      using(meta.getImportedKeys(null, null, tableName)) { rs =>
+        val parents = new ListBuffer[String]
+        while (rs.next) {
+          val tableName = rs.getString("PKTABLE_NAME")
+          parents += tableName
+          parents ++= parentTables(meta, tableName)
+        }
+        parents.toSeq
+      }
+    }
+
+    private def allTables(meta: DatabaseMetaData): Seq[String] = {
+      using(meta.getTables(null, null, "%", Seq("TABLE").toArray)) { rs =>
+        val tables = new ListBuffer[(String, Seq[String])]
+        while (rs.next) {
+          val name = rs.getString("TABLE_NAME")
+          if(name != "VERSIONS") {
+            tables += ((name, parentTables(meta, name)))
+          }
+        }
+        tables.sortWith { (a, b) => b._2.contains(a._1) }.map(_._1).toSeq
+      }
+    }
+
   }
 
 }