这里只记录c3p0的数据源，不会涉及到其它方面和别的数据库连接池的对比
配置文件主要的实现方式有三种：
1.手写代码去加载一个配置文件
创建一个config.properties文件如下：
driverClass= com.mysql.jdbc.Driver
jdbcUrl = jdbc:mysql://127.0.0.1:3306/soc_db?autoReconnect=true&autoReconnectForPools=true
user = root
password = root
......
然后在java代码中：
public void closeInputStream(InputStream inputStream){
if(inputStream!=null){
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public InputStream loadResource(String resource) {
InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
if (in == null) {
in = PropertiesUtil.class.getResourceAsStream(resource);
}
return in;
}
public Properties getProperties(String resource){
LOG.debug("[Method] 读取数据库配置信息");
Properties properties = new Properties();
InputStream in = null;
try {
in = loadResource(resource);
if(in!=null){
properties.load(in);
}
} catch (IOException e) {
LOG.error("load properties error",e);
}finally {
closeInputStream(in);
}
LOG.debug(properties.getProperty("url"));
return properties;
}
Properties properties = PropertiesUtil.getInstance().getProperties("/resource/jindun.properties");
c3p0DataSource.setDriverClass(properties.getProperty("driverClass"));
c3p0DataSource.setDriverClass(properties.getProperty("jdbcUrl"));
c3p0DataSource.setDriverClass(properties.getProperty("user"));
c3p0DataSource.setDriverClass(properties.getProperty("password"));
......
2.在src下创建一个c3p0.properties文件（固定名字哦）
c3p0.driverClass=com.mysql.jdbc.Driver
c3p0.jdbcUrl=jdbc:mysql://10.30.79.10:3306/test
c3p0.user=root
c3p0.password=root
......
......
ComboPooledDataSource c3p0DataSource = new ComboPooledDataSource()
......
这样就可以直接使用了，不需要再去说明。
3.在src下创建一个c3p0-config.xml文件
（1）XML格式更加直观
（2）可以在文件中配置多个数据源
<c3p0-config>
<default-config>
<property name="user">root</property>
<property name="password">root</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/test</property> <property name="initialPoolSize">10</property>
<property name="maxIdleTime">30</property>
<property name="minPoolSize">10</property>
<property name="maxPoolSize">500</property> <!-- intergalactoApp adopts a different approach to configuring statement caching -->
<property name="maxStatements">0</property>
<property name="maxStatementsPerConnection">5</property> </default-config> <!-- This app is jindun -->
<named-config name="jinDunApp">
<property name="user">root</property>
<property name="password">root</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://10.30.79.10:3306/HrINetDB?autoReconnect=true&autoReconnectForPools=true</property> <property name="initialPoolSize">10</property>
<property name="maxIdleTime">30</property>
<property name="minPoolSize">10</property>
<property name="maxPoolSize">500</property> <!-- intergalactoApp adopts a different approach to configuring statement caching -->
<property name="maxStatements">0</property>
<property name="maxStatementsPerConnection">5</property> </named-config> <!-- This app is Tianji -->
<named-config name="tianJiApp">
<property name="user">root</property>
<property name="password">root</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://10.30.67.95:3306/config_db?autoReconnect=true&autoReconnectForPools=true</property> <property name="initialPoolSize">10</property>
<property name="maxIdleTime">30</property>
<property name="minPoolSize">10</property>
<property name="maxPoolSize">500</property> <!-- intergalactoApp adopts a different approach to configuring statement caching -->
<property name="maxStatements">0</property>
<property name="maxStatementsPerConnection">5</property> </c3p0-config>
public static void main(String[] args) {
// 默认配置
ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
// 固定名字配置
ComboPooledDataSource comboPooledDataSource2 = new ComboPooledDataSource("jinDunApp");
// 数据源使用
PreparedStatement psta;
ResultSet rs;
try {
// 这个的comboPooledDataSource改comboPooledDataSource2就执行jinDunApp配置了
Connection conn = comboPooledDataSource.getConnection();
psta = conn.prepareStatement("SELECT empName FROM t_sc_usermanager");
rs = psta.executeQuery();
while (rs.next() ){
System.out.println(rs.getString(1) + "\n");
}
} catch (SQLException e) {
e.printStackTrace();
}
}
上面就是一个实例。
配置的参数列表如下（具体含义可以查看参考资料）：
参考资料：