自己封装了一个线程池,求大神帮忙看下有没有安全方面的问题

Question

自己封装的一个jdbc,给jdbc增加了一个连接池,但是不知道有没有问题,所以让大神们帮忙看下,我写的这个线程池有没有问题

package tool;


import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Properties;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;


public class Jdbc {

    //连接池中的连接
    private Connection conn;
    private ResultSet rs;
    private ResultSetMetaData md;
    private PreparedStatement ps;
    private JSONArray list;
    private JSONObject map;
    private String classpath = getClass().getResource("/").getPath();
    private String path = classpath + "jdbc.properties";
    private BlockingQueue<Connection> connections = new LinkedBlockingQueue<>();

    public Jdbc(){}

    /**
     * 初始化Jdbc连接池
     * @param poolSize 连接池大小
     * @throws IOException 
     * @throws ClassNotFoundException
     * @throws SQLException
     * @throws InterruptedException 
     */
    public void initJdbcPool() throws IOException, ClassNotFoundException, SQLException, InterruptedException {
        FileInputStream fis = new FileInputStream(path);
        Properties prop = new Properties();
        prop.load(fis);
        String url = prop.getProperty("db.url");
        String user = prop.getProperty("db.user");
        String psw = prop.getProperty("db.password");
        Integer connectionNum = Integer.parseInt(prop.getProperty("connectionNum"));
        Class.forName(prop.getProperty("driverClass"));
        for (int i = 0; i < connectionNum; i++) {
            //获取数据库的连接
            Connection dbConn = DriverManager.getConnection(url, user, psw);
            //System.out.println(dbConn);
            connections.put(dbConn);
        }       
    }
    public void destroyJdbcPool() {
        connections.clear();
    }
    /**
     * 从连接池中获取链接
     * @return
     * @throws InterruptedException 
     */
    private Connection getConnection() throws InterruptedException {

        return  connections.take();
    }
    /**
     * 把连接放回到连接池中,并关闭声明对象和结果集对象
     * @param connection 连接
     * @param ps 声明对象
     * @param rs 结果集对象
     * @throws SQLException
     * @throws InterruptedException 
     */
    private void backConnection(Connection connection,PreparedStatement ps,ResultSet rs) throws SQLException, InterruptedException {
        if(ps!=null) ps.close();
        if(rs!=null) rs.close();
        connections.put(connection);
    }

    /**
     * 执行dml操作
     * @param sql sql语句
     * @param objs 参数对象
     * @return
     */
    public boolean dml(String sql, Object... objs) {
        try {
            conn = getConnection();
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < objs.length; i++) {
                ps.setObject(i+1, objs[i]);
            }
            int flg = ps.executeUpdate();
            if(flg==1) {
                return true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            try {
                backConnection(conn,ps,rs);
            } catch (SQLException | InterruptedException e) {
                e.printStackTrace();
            }
        }
        return false;
    }

    /**
     * 全查
     * @param sql
     * @param objs
     * @return
     */
    public JSONArray find(String sql,Object...objs){
        list = new JSONArray();
        try {
            conn = getConnection();
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < objs.length; i++) {
                ps.setObject(i+1, objs[i]);
            }
            rs = ps.executeQuery();
            md = rs.getMetaData();
            while (rs.next()) {
                map = new JSONObject();
                for (int i = 1; i <= md.getColumnCount(); i++) {
                    String key = md.getColumnName(i);
                    Object value = rs.getObject(i);
                    map.put(key, value);
                }
                list.add(map);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            try {
                backConnection(conn,ps,rs);
            } catch (SQLException | InterruptedException e) {
                e.printStackTrace();
            }
        }
        return list;
    }
    /**
     * 单查
     * @param sql
     * @param objs
     * @return
     */
    public JSONObject findOne(String sql,Object...objs){
        JSONArray list = find(sql,objs);
        if(list!=null) {
            if(list.size()>0) {
                return list.getJSONObject(0);
            }
        }
        return null;
    }
    /**
     * 添加
     * @param sql
     * @param objs
     * @return 
     */
    public boolean add(String sql,Object...objs) {
        return dml(sql, objs);
    }

    /**
     * 修改
     * @param sql
     * @param objs
     * @return
     */
    public boolean mod(String sql,Object...objs){
        return dml(sql, objs);
    }

    /**
     * 删除
     * @param sql
     * @param objs
     * @return
     */
    public boolean del(String sql,Object...objs){
        return dml(sql, objs);
    }
}

jdbc.properties

 db.url=jdbc:mysql://127.0.0.1:3306/juser
db.user=root
db.password=root
driverClass=com.mysql.jdbc.Driver
connectionNum=30

Answer 1

连个同步锁都没加，你说会不会有问题？