DBCP连接池出现连接异常解决方案；

1.properties文件获取出错，将配置文件重新删掉再加入一个同名文件覆盖

2.关闭配置文件  避免被Myeclipse占用；

//工具包

package com.account.dao.util;

import java.io.InputStream;

import java.sql.Connection;

import java.sql.SQLException;

import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSourceFactory;

import datasource.dbcpDemo;

public enum jdcpUtil {
INSTANCE;
public static DataSource dataSource;
static{
try{
Properties p=new Properties();
InputStream in=Thread.currentThread().getContextClassLoader().
getResourceAsStream("dbcp.properties");
p.load(in);
dataSource = BasicDataSourceFactory.createDataSource(p);

System.out.println("配置文件读取成功");
System.out.println(dataSource.getConnection());
}catch(Exception e){
e.printStackTrace();
}

/* dataSource.setDriverClassName(p.getProperty("driverClassName"));
dataSource.setUsername(p.getProperty("userName"));
dataSource.setPassword(p.getProperty("password"));
dataSource.setUrl(p.getProperty("url"));
return dataSource.getConnection;
*/
}

public Connection getConn() {
System.out.println("正在进行链接");
try {
/* dataSource.setDriverClassName(p.getProperty("driverClassName"));
dataSource.setUsername(p.getProperty("userName"));
dataSource.setPassword(p.getProperty("password"));
dataSource.setUrl(p.getProperty("url"));*/
return dataSource.getConnection();
} catch (SQLException e) {

e.printStackTrace();

}
System.out.println("返回空");
return null;

}

}

//实现类

package datasource;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import org.junit.Test;

import com.account.dao.util.jdcpUtil;

public class dbcpDemo{
@Test
public void dbcpTest() throws Exception{
Connection conn = jdcpUtil.INSTANCE.getConn();
System.out.println("链接成功");
String sql="SELECT * FROM student";
PreparedStatement ps=conn.prepareStatement(sql);
ResultSet rs=ps.executeQuery();
while(rs.next()){
System.out.println(rs.getString("name")+"\t"+rs.getString("gender")
+"\t"+rs.getString("classes"));
}
}

}

//配置文件

driverClassName=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/student

username=root

password=root