Java如何实现数据库操作中的长尾词线程池功能？

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java实现线程池Neo4jPoolimport org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.sql.*;import java.util.LinkedList;import java.util.Timer;import java.util.TimerTask;

/** * Neo4j连接池 * Created by xuliugen on 2017/10/19. */

实现线程池Neo4jPool

import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.sql.*; import java.util.LinkedList; import java.util.Timer; import java.util.TimerTask; /** * Neo4j连接池 * Created by xuliugen on 2017/10/19. */ public class Neo4jPool { private static final Logger LOG = LoggerFactory.getLogger(Neo4jPool.class); /** * 最大连接数 */ private static final int NEO4J_CONN_MAX_LINK = 20; /** * 最小连接数 */ private static final int NEO4J_CONN_MIN_LINK = 5; /** * 每次增长的连接数 */ private static final int NEO4J_CONN_INCREASE_LINK = 5; /** * 链接超时时间 */ private static final int NEO4J_CONN_TIMER = 60000; //HTTP Driver private static final String NEO4J_BOLT_URL = "jdbc:neo4j:192.168.1.196:7474"; private static final String NEO4J_USERNAME = "neo4j"; private static final String NEO4J_PASSWORD = "neo4j"; /** * 当前连接数 */ private static int connectionCurrLink = 0; private static LinkedList datasourcePool = new LinkedList<>(); static { try { Class.forName("org.neo4j.jdbc.Driver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public Neo4jPool() { try { createConnection(0); } catch (Exception e1) { LOG.error("创建连接失败", e1); } // 通过构造函数启动定时器以达到定时释放空闲连接目的 Timer timer = new Timer(); timer.schedule(new TimerTask() { @Override public void run() { try { // 得到空闲连接，datasourcePool里面有几个对象就表示有几个空闲连接 int leisureLink = Neo4jPool.datasourcePool.size(); System.out.println(leisureLink); // 最小连接数 int connectionMinLink = NEO4J_CONN_MIN_LINK; // 当空闲连接大于DataSourcePool设置的最小连接数时则关闭 if (leisureLink > connectionMinLink) { for (int i = 0; i < leisureLink - connectionMinLink; i++) { Neo4jPool.closeConnection(Neo4jPool.getConnection()); connectionCurrLink--; } } else { System.out.println("保持最小连接,将继续保持连接池"); } } catch (NumberFormatException e) { throw new NumberFormatException("设置了无效的最小连接数"); } catch (Exception e) { e.printStackTrace(); } } }, 0, NEO4J_CONN_TIMER); } /** * 创建连接 * @param type * @throws Exception */ private static void createConnection(int type) throws Exception { try { int link = 0; switch (type) { case 0: link = NEO4J_CONN_MIN_LINK; break; case 1: // 如果当前连接+增长连接大于设定的最大连接数时，将使用最大连接数-当前连接的数量。以保持平衡 link = NEO4J_CONN_INCREASE_LINK; int maxLink = NEO4J_CONN_MAX_LINK; if (link + connectionCurrLink > maxLink) { link = maxLink - connectionCurrLink; } break; } for (int i = 0; i < link; i++) { datasourcePool.addLast(DriverManager.getConnection(NEO4J_BOLT_URL, NEO4J_USERNAME, NEO4J_PASSWORD)); connectionCurrLink++; } } catch (NumberFormatException n) { throw new NumberFormatException("配置连接参数有误"); } catch (Exception e) { e.printStackTrace(); throw new SQLException("超过最大连接数 ,无法创建更多连接"); } } /** * 获得连接 * @return * @throws Exception */ public static Connection getConnection() throws Exception { // 取连接加锁，防止并发取的同样的连接 synchronized (datasourcePool) { if (datasourcePool.size() > 0) { return datasourcePool.removeFirst(); } else if (connectionCurrLink < NEO4J_CONN_MAX_LINK) { createConnection(1); return datasourcePool.removeFirst(); } } return null; } /** * 关闭连接 * @param con * @throws SQLException */ public static void closeConnection(Connection con) throws SQLException { con.close(); } /** * 释放连接 * @param con */ public void freeConnection(Connection con) { datasourcePool.addLast(con); } public static void main(String[] args) { try { Connection conn = Neo4jPool.getConnection(); try (Statement stmt = conn.createStatement()) { ResultSet rs = stmt.executeQuery("MATCH (n) RETURN n LIMIT 1"); while (rs.next()) { System.out.println(rs.getString("n.name")); } } } catch (Exception e) { e.printStackTrace(); } } } 测试类

import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; /** * Created by xuliugen on 2017/10/19. */ public class Neo4jPoolTest { public static void main(String[] args) { Connection conn = null; try { conn = Neo4jPool.getConnection(); Statement stmt = conn.createStatement(); long start = System.currentTimeMillis(); ResultSet rs = stmt.executeQuery("MATCH (n:Alarm) RETURN n.name as name"); while (rs.next()) { System.out.println(rs.getString("name")); } long end = System.currentTimeMillis(); System.out.println(end - start); } catch (Exception e) { e.printStackTrace(); } finally { try { Neo4jPool.closeConnection(conn); } catch (SQLException e) { e.printStackTrace(); } } } }