c3p0-连接池配置.doc

3301000falseTestfalse100nullfalse60360151003rootpasswordselect id from test where id=1300falsetruerootfalseacquireIncrement - 5 acquireRetryAttempts - 30 acquireRetryDelay - 1000 autoCommitOnClose - false automaticTestTable - null breakAfterAcquireFailure - true checkoutTimeout - 0 connectionCustomizerClassName - null connectionTesterClassName - com.mchange.v2.c3p0.impl.DefaultConnectionTester dataSourceName - 1bqp8hc8ezqxpjc1hp9gny|704baa debugUnreturnedConnectionStackTraces - false description - null driverClass - com.mysql.jdbc.Driver factoryClassLocation - null forceIgnoreUnresolvedTransactions - false identityToken - 1bqp8hc8ezqxpjc1hp9gny|704baa idleConnectionTestPeriod - 60 initialPoolSize - 5 jdbcUrl - jdbc:mysql:/localhost:3306/db_temp?useUnicode=true&characterEncoding=utf-8 lastAcquisitionFailureDefaultUser - null maxAdministrativeTaskTime - 0 maxConnectionAge - 0 maxIdleTime - 60 maxIdleTimeExcessConnections - 0 maxPoolSize - 30 maxStatements - 0 maxStatementsPerConnection - 0 minPoolSize - 5 numHelperThreads - 3 numThreadsAwaitingCheckoutDefaultUser - 0 preferredTestQuery - null properties - user=*password=* propertyCycle - 0 testConnectionOnCheckin - false testConnectionOnCheckout - false unreturnedConnectionTimeout - 0 usesTraditionalReflectiveProxies - falsepackage com.paipaiestore.database.c3p0;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import javax.sql.DataSource;import com.mchange.v2.c3p0.DataSources;/* 数据连接池工厂* author samland* version 1.0, 2006-11*/public class DBPoolFactory private static DBPoolFactory dbpoolFactory = new DBPoolFactory();/* 连接池列表*/private static Map poollist = new HashMap();private DBPoolFactory()public static DBPoolFactory getInstance()return dbpoolFactory;/* 向连接池列表添加一个新的池化（Pooled）数据源* param key* param configFile 配置文件名。为了简化参数输入与便于外部维护，可以把配置好的文件传入这里分析*/public void add(String key, String configFile) /read config from file, and build a dbpool/* 向连接池列表添加一个新的池化（Pooled）数据源* param key* param driver 数据连接驱动，如com.mysql.jdbc.Driver* param url 连接串， 如jdbc:mysql:/localhost/samland* param username 数据库连接用户名，如samland* param password 数据库连接用户密码* throws Exception*/public void add(String key, String driver, String url, String username, String password)throws Exceptionif (key=null) throw new Exception(DBPool key CANNOT be null) ;Class.forName(driver);DataSource ds_unpooled = DataSources.unpooledDataSource(url, username, password);DataSource ds_pooled = DataSources.pooledDataSource( ds_unpooled );if (poollist.containsKey(key)poollist.remove(key);poollist.put(key, ds_pooled);/* 根据key字符串获取连接池* param key* return DBPool 连接池* throws Exception*/public DBPool getDBPool(String key) throws Exceptionif (key=null) throw new Exception(DBPool key CANNOT be null) ;DataSource ds = (DataSource)poollist.get(key);DBPool dbpool = new DBPool();dbpool.setDs_pooled(ds);return dbpool;/四、连接池的使用通过DBPool来获取数据库连接 （jdbc connection）。4.1 由DBPoolFactory工厂产生一个DBPool4.2 同时，DBPoolFactory工厂根据传入的参数key向这个DBPool注入数据源4.3 从DBPool产生线程内的Connection/package com.paipaiestore.database.c3p0;import java.sql.Connection;import java.sql.SQLException;import javax.sql.DataSource;public class DBPool /* 数据库连接。同一个线程使用同一个连接。*/protected static ThreadLocal connection = new ThreadLocal();/* 数据源，需由DBPoolFactory工厂注入*/private DataSource ds_pooled;/* 不能独立构造，必须从DBPoolFactory工厂产生*/protected DBPool()/* get 数据源* return*/public DataSource getDs_pooled() return ds_pooled;/* 注入数据源* param ds_pooled*/public void setDs_pooled(DataSource ds_pooled) this.ds_pooled = ds_pooled;/* 获得数据库连接* 同一个线程只返回相同的一个连接。* return Connection* throws SQLException*/public Connection getConnection() throws SQLExceptionConnection con = (Connection)connection.get();if (con=null) con = ds_pooled.getConnection();connection.set(con);return con;/五、改进线程内数据库连接的使用为了适应程序已经使用开的jdbc事务管理，因此需要改进DBPool成为Transaction类，而原来的DBPool则缩减为如下代码：/public class DBPool private DataSource ds_pooled;protected DBPool()public DataSource getDs_pooled() return ds_pooled;public void setDs_pooled(DataSource ds_pooled) this.ds_pooled = ds_pooled;/package com.paipaiestore.database.c3p0;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import javax.sql.DataSource;public class Transaction /* 数据库连接。同一个线程使用同一个连接。*/protected static ThreadLocal connection = new ThreadLocal();protected static boolean isInUsed = false;/* 开始一个事务* 如果当前线程的数据库连接不存在，则会新获得一个数据库连接* param key* throws Exception*/public static void beginTransaction(String key) throws ExceptionConnection conn = (Connection)connection.get();if (conn=null) conn = createConnection(key);setConnection(conn);conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);conn.setAutoCommit(false);isInUsed = true;/* 提交一个事务* throws SQLException*/public static void commitTransaction() throws SQLException Connection conn = (Connection)connection.get();mit();/* 回滚一个事务* throws SQLException*/public static void rollbackTransaction() throws SQLException Connection conn = (Connection)connection.get();conn.rollback();public static boolean getIsInUsed() return isInUsed;private static void closeConnection() try Connection conn = (Connection)connection.get();if (conn!=null) connection.set(null);conn.close();catch(SQLException sqlexception) private static void close(ResultSet rs)tryStatement st = rs.getStatement();Connection conn = st.getConnection();rs.close();st.close();conn.close();catch(Exception exception) /* 获得数据库连接* 同一个线程只返回相同的一个连接。* return* throws SQLException*/public static Connection getConnection() throws SQLException Connection conn = null;conn = (Connection)connection.get();if(conn = null)throw new NullPointerException();elsereturn conn;private static void setConnection(Connection conn)connection.set(conn);/* 获得一个新的数据库连接* param key* return Connection* throws Exception*/private static Connection createConnection(String key)throws Exception DBPoolFactory df = DBPoolFactory.getInstance();DataSource ds_pooled = df.getDBPool(key).getDs_pooled() ;Connection conn = ds_pooled.getConnection();df = null;return conn;/六、测试/package samland;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import com.paipaiestore.database.c3p0.DBPoolFactory;import com.paipaiestore.database.c3p0.Transaction;public class TestTransaction /* param args*/public static void main(String args) DBPoolFactory df = DBPoolFactory.getInstance();Connection con = null;Statement stmt = null;ResultSet rs = null;try df.add(jxc,com.mysql.jdbc.Driver,jdbc:mysql:/Transaction.beginTransaction(samland);con = Transaction.getConnection();stmt = con.createStatement();rs = stmt.executeQuery(SELECT * FROM users);while (rs.next()System.out.print( rs.getString(1) );System.out.print( rs.getString(2) );System.out.println( rs.getString(3) );TmitTransaction();df = null; catch (Exception e) e.printStackTrace();