Java实现数据连接池Druid举例

url=jdbc:mysql://localhost:3306/github_demo?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=true
username=root
password=123456
name=zzs001
driverClassName=com.mysql.cj.jdbc.Driver
initialSize=4
maxActive=8
minIdle=0
maxWait=-1
poolPreparedStatements=false
maxOpenPreparedStatements=10
validationQuery=select 1 from dual
validationQueryTimeout=-1
testOnBorrow=false
testOnReturn=false
testWhileIdle=true
timeBetweenEvictionRunsMillis=-1
minEvictableIdleTimeMillis=1800000
defaultAutoCommit=true
defaultReadOnly=false
defaultTransactionIsolation=REPEATABLE_READ
defaultCatalog=github_demo
removeAbandoned=false
removeAbandonedTimeoutMillis=300*1000
logAbandoned=true
filters=log4j,wall,mergeStat
connectionProperties=druid.useGlobalDataSourceStat=true;druid.stat.logSlowSql=true;druid.stat.slowSqlMillis=5000
accessToUnderlyingConnectionAllowed=false
init=true

public class DruidDataSourceTest {

    @Test
    public void save() throws SQLException {
        // 创建sql
        String sql = "insert into demo_user values(null,?,?,?,?,?)";
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 获得连接
            connection = JDBCUtils.getConnection();
            // 开启事务设置非自动提交
            connection.setAutoCommit(false);
            // 获得Statement对象
            statement = connection.prepareStatement(sql);
            // 设置参数
            statement.setString(1, "zzf003");
            statement.setInt(2, 18);
            statement.setDate(3, new Date(System.currentTimeMillis()));
            statement.setDate(4, new Date(System.currentTimeMillis()));
            statement.setBoolean(5, false);
            // 执行
            statement.executeUpdate();
            // 提交事务
            connection.commit();
        } finally {
            // 释放资源
            JDBCUtils.release(connection, statement, null);
        }
    }
}

public class JDBCUtils {

    private static DataSource dataSource;
    private static ThreadLocal<Connection> tl = new ThreadLocal<>();
    private static final Log log = LogFactory.getLog(JDBCUtils.class);

    static {
        init();
    }

    private static void init() {
        Properties properties = new Properties();
        InputStream in = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
        try {
            properties.load(in);
            dataSource = DruidDataSourceFactory.createDataSource(properties);
        } catch(Exception e) {
            throw new RuntimeException("创建数据源失败", e);
        }
    }

    /**
     * <p>获取数据库连接对象的方法，线程安全</p>
     * @return: Connection
     */
    public static Connection getConnection() throws SQLException {
        // 从当前线程中获取连接对象
        Connection connection = tl.get();
        // 判断为空的话，创建连接并绑定到当前线程
        if(connection == null) {
            connection = createConnection();
            tl.set(connection);
        }
        return connection;
    }

    /**
     * <p>创建数据库连接</p>
     * @return: Connection
     * @throws SQLException 
     */
    private static Connection createConnection() throws SQLException {
        Connection conn = null;
        // 获得连接
        conn = dataSource.getConnection();
        return conn;
    }
}