package cn.sasa.demo1;
import javax.sql.DataSource;
import org.apache.commons.dbcp2.BasicDataSource;
public class DBUtils {
private static BasicDataSource datasource = new BasicDataSource();
static {
/**
* 连接池：
* 存放连接的容器
* 不需要每次都创建连接、释放连接
*
* DataSource接口
* java为数据库连接池提供的公共接口：javax.sql.DataSource
* 常用的连接池： DBCP C3P0
*
* 导入jar包
* DBCP连接池：http://commons.apache.org/proper/commons-dbcp/download_dbcp.cgi
* Commons Pool：http://commons.apache.org/proper/commons-pool/download_pool.cgi
* DBCP依赖于Pool
* 只导入上面两个包运行如下代码会报错：java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
* 还需导入包commons-logging:http://commons.apache.org/proper/commons-logging/download_logging.cgi
*/
//数据库连接信息，必须
datasource.setDriverClassName(DBProperties.driver);
datasource.setUrl(DBProperties.url);
datasource.setUsername(DBProperties.user);
datasource.setPassword(DBProperties.pwd);
//连接池的配置，可选信息
datasource.setInitialSize(10);//初始化的连接数
//....
}
public static DataSource getDataSource() {
return datasource;
}
}package cn.sasa.demo1;
import java.sql.SQLException;
import java.util.List;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;
public class ConnectionPoolDemo {
static QueryRunner query = new QueryRunner(DBUtils.getDataSource());
public static void main(String[] args) {
select();
}
static void select() {
String sql = "SELECT * FROM product";
try {
List<Product> plist = query.query(sql, new BeanListHandler<Product>(Product.class));
for(Product product : plist) {
System.out.print(product.getPname()+"="+product.getPrice()+"\t");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package cn.sasa.demo1;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
public class DBProperties {
public static String driver = "";
public static String url = "";
public static String user = "";
public static String pwd = "";
static {
try {
InputStream input = DBProperties.class.getClassLoader().getResourceAsStream("database.properties");
Properties properties = new Properties();
properties.load(input);
driver = properties.getProperty("driver");
url = properties.getProperty("url");
user = properties.getProperty("user");
pwd = properties.getProperty("pwd");
}catch(IOException ex){
// ex.printStackTrace();
throw new RuntimeException("数据库信息获取失败");
}
}
}
package cn.sasa.demo1;
public class Product {
private int pid;
private String pname;
private double price;
private String ptype;
private String create_tm;
public Product() {}
public Product(int pid, String pname,double price,
String ptype, String create_tm) {
this.pid = pid;
this.pname = pname;
this.price = price;
this.ptype = ptype;
this.create_tm = create_tm;
}
public int getPid() {
return pid;
}
public void setPid(int pid) {
this.pid = pid;
}
public String getPname() {
return pname;
}
public void setPname(String pname) {
this.pname = pname;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public String getPtype() {
return ptype;
}
public void setPtype(String ptype) {
this.ptype = ptype;
}
public String getCreate_tm() {
return create_tm;
}
public void setCreate_tm(String create_tm) {
this.create_tm = create_tm;
}
}