[Fix] Connection Leaks

Author: sysnote8main

src/main/java/jp/azisaba/lgw/kdstatus/KDStatusReloaded.java

@@ -1,6 +1,7 @@
 package jp.azisaba.lgw.kdstatus;
 
 import java.io.File;
+import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.util.logging.Level;
@@ -66,7 +67,8 @@ public void onEnable() {
 
         if(sql.isConnected()){
             getLogger().info("SQL Testing...");
-            try(PreparedStatement pstmt = sql.getConnection().prepareStatement("SELECT 1")) {
+            try(Connection conn = sql.getConnection();
+                PreparedStatement pstmt = conn.prepareStatement("SELECT 1")) {
                 if(pstmt.executeQuery().next()) {
                     getLogger().info("SQL Test was success!");
                 } else {
@@ -120,8 +122,8 @@ public void onDisable() {
         if(sql.isConnected()){
             sql.close();
         }
-        saveTask.cancel();
-        dbCheckTask.cancel();
+        if(saveTask!=null) saveTask.cancel();
+        if(dbCheckTask!=null) dbCheckTask.cancel();
         Bukkit.getLogger().info(getName() + " disabled.");
     }
 

src/main/java/jp/azisaba/lgw/kdstatus/sql/HikariMySQLDatabase.java

@@ -53,6 +53,7 @@ public void connect() {
         config.setPassword(password);
         config.setJdbcUrl(jdbcUrl);
         config.setMaximumPoolSize(maxPoolSize);
+        config.setLeakDetectionThreshold(2000);
 //        config.setConnectionInitSql("SELECT 1");
         config.setAutoCommit(true);
         config.setConnectionTimeout(1500); // TODO change this
@@ -164,4 +165,14 @@ public boolean executeUpdate(String sql) {
             return false;
         }
     }
+
+    public boolean isConnectionAlive() {
+        try(Connection conn = getConnection();
+        PreparedStatement pstmt = conn.prepareStatement("SELECT 1");
+        ResultSet rs = pstmt.executeQuery()) {
+            return rs.next();
+        } catch (SQLException e) {
+            return false;
+        }
+    }
 }

src/main/java/jp/azisaba/lgw/kdstatus/sql/PlayerDataMySQLController.java

@@ -18,16 +18,16 @@ public class PlayerDataMySQLController {
 
     public void createTable(){
 
-        try{
-            plugin.getLogger().info("Creating database table...");
-            PreparedStatement ps = plugin.sql.getConnection().prepareStatement("CREATE TABLE IF NOT EXISTS kill_death_data "
+        try(Connection conn = plugin.sql.getConnection();
+            PreparedStatement ps = conn.prepareStatement("CREATE TABLE IF NOT EXISTS kill_death_data "
                     + "(uuid VARCHAR(64) NOT NULL ,name VARCHAR(36) NOT NULL," +
                     "kills INT DEFAULT 0, " +
                     "deaths INT DEFAULT 0 ," +
                     "daily_kills INT DEFAULT 0," +
                     "monthly_kills INT DEFAULT 0," +
                     "yearly_kills INT DEFAULT 0," +
-                    "last_updated BIGINT DEFAULT -1 )");
+                    "last_updated BIGINT DEFAULT -1 )")) {
+            plugin.getLogger().info("Creating database table...");
 
             ps.executeUpdate();
             ps.close();
@@ -246,13 +246,12 @@ public int getRank(UUID uuid,TimeUnit unit){
 
     public List<KillRankingData> getTopKillRankingData(TimeUnit unit, int count){
 
-        try {
-
-            PreparedStatement ps = plugin.sql.getConnection().prepareStatement("select uuid, name, " + unit.getSqlColumnName()
+        try(Connection conn = plugin.sql.getConnection();
+            PreparedStatement ps = conn.prepareStatement("select uuid, name, " + unit.getSqlColumnName()
                     + " from kill_death_data"
                     + " where last_updated >= ?"
                     + " order by " + unit.getSqlColumnName() + " DESC"
-                    + " LIMIT ?");
+                    + " LIMIT ?")) {
 
             ps.setLong(1,TimeUnit.getFirstMilliSecond(unit));
             ps.setInt(2,count);
@@ -275,8 +274,6 @@ public List<KillRankingData> getTopKillRankingData(TimeUnit unit, int count){
 
             }
 
-            ps.close();
-
             return ranking;
 
         } catch (SQLException throwables) {

src/main/java/jp/azisaba/lgw/kdstatus/task/DBConnectionCheckTask.java

@@ -4,6 +4,7 @@
 import lombok.RequiredArgsConstructor;
 import org.bukkit.scheduler.BukkitRunnable;
 
+import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.util.logging.Level;
@@ -13,19 +14,19 @@ public class DBConnectionCheckTask extends BukkitRunnable {
     private final KDStatusReloaded plugin;
     @Override
     public void run() {
-        try {
-            if(plugin.sql.getConnection() == null) {
+        try (Connection conn = plugin.sql.getConnection()){
+            if(conn == null) {
                 plugin.sql.connect();
             }
-            PreparedStatement pstmt = plugin.sql.getConnection().prepareStatement("SELECT 1");
-            if(pstmt.executeQuery().next()) {
-                if(plugin.getPluginConfig().showLogInConsole) {
-                    plugin.getLogger().info("SQL Connection is alive!");
+            try(Connection con = plugin.sql.getConnection();
+                PreparedStatement pstmt = con.prepareStatement("SELECT 1")) {
+                if (pstmt.executeQuery().next()) {
+                    if (plugin.getPluginConfig().showLogInConsole) {
+                        plugin.getLogger().info("SQL Connection is alive!");
+                    }
+                    return;
                 }
-                pstmt.close();
-                return;
             }
-            pstmt.close();
         } catch (SQLException e) {
             plugin.getLogger().log(Level.WARNING, "Failed to pass health check", e);
         }