四种连接数据库的方式

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1、四种连接数据库的方法（DriverManager、DataSource子类、DBCP、c3p0）2010-04-0720:58:40|分类：JAVA基础|字号订阅一、环境1、数据库驱动jar文件2、DBCP方法Commons-dbcp.jar:连接池的实现Commons-pool.jar:连接池实现的依赖库资源文件3、c3p0方法：c3p0-0.9.1.2.jar配置文件：c3p0-config.xml二、连接操作1. DriverManager方法；importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.SQ

2、LException;publicclassDBConnectionprivatestaticStringdriverClass=com.mysql.jdbc.DriverprivatestaticStringurl=jdbc:mysql:/localhost:3306/test;privatestaticStringusername=root;privatestaticStringpassword=123456;privatestaticConnectionconn=null;statictry/注册驱动/不要把conn=DriverManager.getConnection(url,use

3、rname,password);放在这里。防止所有用户都用一个ConnectionClass.forName(driverClass);catch(Exceptione)thrownewRuntimeException(e);publicstaticConnectiongetConnection()throwsSQLExceptionconn=DriverManager.getConnection(url,username,password);returnconn;使用DataSource子类方法；资源文件DBConnection.propertiesdriverClass=com.mysql

4、.jdbc.Driverurl=jdbc:mysql:localhost:3306/testusername=rootpassword=123456模拟数据连接池DataSourcePool.javapackagecn.langzi.jdbc.DataSource;importjava.ionputStream;importjava.io.PrintWriter;importjava.Iang.reflect.InvocationHandler;importjava.Iang.reflect.Method;importjava.Iang.reflect.Proxy;importjava.sql

5、.Connection;importjava.sql.DriverManager;importjava.sql.SQLException;importjava.util.LinkedList;importjava.util.Properties;importjavax.sql.DataSource;importjavax.sql.DataSource;publicclassDataSourcePoolimplementsDataSourceprivatestaticStringurl=nullprivatestaticStringusername=null;privatestaticStrin

6、gpassword=null;privatestaticintsize=10;privatestaticLinkedListlist=newLinkedList();statictryInputStreamin=DataSourcePool.class.getClassLoader().getResourceAsStream(”cn/langzi/jdbc/DataSource/DBConnection.properties);Propertiesprop=newProperties();prop.load(in);Class.forName(prop.getProperty(driverCl

7、ass);url=prop.getProperty(”url);username=prop.getProperty(username)；password=prop.getProperty(password);catch(Exceptione)thrownewExceptionlnlnitializerError(e);privatestaticDataSourcePoolpool=newDataSourcePool();/创建对象就初始化size个数据库连接privateDataSourcePool()for(inti=0;i0)/取到连接，即从list中弹出一个Connection连接fin

8、alConnectionconn=list.pop();/动态代理，返回一个代理对象return(Connection)Proxy.newProxyInstance(DataSourcePool.class.getClassLoade(),conn.getClass().getlnterfaces(),newlnvocationHandler()publicObjectinvoke(Objectproxy,Methodmethod,Objectargs)throwsThrowable/如果Connection调用的是close方法就将连接返回给数据连接池if(method.getName().

9、equals(”close)list.push(conn);returnnull;returnmethodnvoke(conn,args);)；/连接用完thrownewRuntimeException(”对不起，服务器繁忙！);OverridepublicConnectiongetConnection(Stringusername,Stringpassword)throwsSQLException/TODOAuto-generatedmethodstubreturnnull;OverridepublicPrintWritergetLogWriter()throwsSQLException/T

10、ODOAuto-generatedmethodstubreturnnull;OverridepublicintgetLoginTimeout()throwsSQLException/TODOAuto-generatedmethodstubreturn0;OverridepublicvoidsetLogWriter(PrintWriterout)throwsSQLException/TODOAuto-generatedmethodstubOverridepublicvoidsetLoginTimeout(intseconds)throwsSQLException/TODOAuto-generat

11、edmethodstubOverridepublicbooleanisWrapperFor(Classiface)throwsSQLException/TODOAuto-generatedmethodstubreturnfalse;OverridepublicTunwrap(Classiface)throwsSQLException/TODOAuto-generatedmethodstubreturnnull;packagecn.langzi.jdbc.DataSource;importjava.sql.Connection;importjava.sql.SQLException;public

12、classDBConnectionpublicstaticConnectiongetConnection()throwsSQLExceptionConnectionconn=DataSourcePool.getlnstance().getConnection();returnconn;DBCPJ法：资源文件：dbcpconfig.propertiesdriverClassName=com.mysql.jdbc.Driverurl=jdbc:mysql:localhost:3306/testusername=rootpassword=123456initialSize=10maxActive=5

13、0maxldle=20minldle=5maxWait=60000连接数据库：packagecn.langzi.jdbc.DBCP;importjava.io.10Exception;importjava.io.InputStream;importjava.sql.Connection;importjava.sql.SQLException;importjava.util.Properties;importjavax.sql.DataSource;mons.dbcp.BasicDataSourceFactory;publicclassDBConnectionprivatestaticDataS

14、ourcedataSource=null;statictry/获取资源文件InputStreamin=cn/langzi/jdDBConnection.class.getClassLoader().getResourceAsStream(”bc/DBCP/dbcpconfig.properties);Propertiesproperties=newProperties();/加载资源文件properties.load(in);/建立数据工厂BasicDataSourceFactorydataSourceFactory=newBasicDataSourceFactory();dataSource

15、=dataSourceFactory.createDataSource(properties);catch(Exceptione)/TODOAuto-generatedcatchblocke.printStackTrace();publicstaticConnectiongetConnection()throwsSQLExceptionreturndataSource.getConnection();c3p0方法：配置文件：c3p0-config.xmlv?xmlversion=1.0encoding=UTF-8?com.mysql.jdbc.Driverjdbc:mysql:localhos

16、t:3306/testroot123456510102005vuser-overridesuser=master-of-the-universevpropertyname=acquireIncrement1vpropertyname=initialPoolSize11550连接数据库：packagecnangzi.jdbc.c3p0;importjava.sql.Connection;importjava.sql.ResultSet;importjava.sql.SQLException;importjava.sql.Statement;importjavax.sql.DataSource;importcom.mchange.v2.c3p0.ComboPooledDataSource;publicclassDbConnectionprivatestaticDataSourcedataSource;staticdataSource=newComboPooledDataSource(”userApp);publicstaticConnectiongetConnectioon()throwsSQLExceptionreturndataSource.getConnection();