本文为大家分享了java使用jdbc连接数据库的具体代码,供大家参考,具体内容如下
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package com.tr.jdbc;
import java.sql.connection;
import java.sql.resultset;
import java.sql.sqlexception;
import java.sql.statement;
import org.apache.commons.dbcp2.basicdatasource;
public class collectionfactory {
private final static string dbdriver = "com.mysql.jdbc.driver" ;
private final static string dburl= "jdbc:mysql://localhost:3306/xtest?useunicode=true&characterencoding=utf-8" ;
private final static string dbuser= "root" ;
private final static string dbpwd= "root" ;
private static basicdatasource datasource;
//创建dbcp的简单数据源并初始化相关属性
static {
datasource = new basicdatasource();
datasource.setdriverclassname(dbdriver);
datasource.seturl(dburl);
datasource.setusername(dbuser);
datasource.setpassword(dbpwd);
//指定数据库连接池初始化连接数
datasource.setinitialsize( 10 );
//设定同时向数据库申请的最大连接数
datasource.setmaxtotal( 50 );
//设置连接池中保持的最少连接数量
datasource.setminidle( 5 );
//其他属相...参考apache的公开文档
}
//创建数据库连接对象--并且多线程并发处理(注意connection导的是java.sql的包)
public static synchronized connection creatconnection(){
connection conn = null ;
if (datasource!= null &&!datasource.isclosed()){
try {
conn = datasource.getconnection();
} catch (sqlexception e) {
e.printstacktrace();
}
}
return conn;
}
public static void main(string[] args) {
string sql = "select * from s_t_user" ;
connection conn = creatconnection();
statement statement = null ;
resultset resultset = null ;
try {
statement = conn.createstatement();
resultset= statement.executequery(sql);
int row = 0 ;
while (resultset.next()){
row++;
system.out.println( "记录行" +row+ "col2:" +resultset.getstring( 2 ));
}
} catch (sqlexception e) {
e.printstacktrace();
} finally {
if (conn!= null ) {
try {
conn.close();
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
}
}
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一定要注意不能导错包,我刚才就是因为basicdatasource的包导错了,写成了import org.apache.tomcat.dbcp.dbcp2.basicdatasource;应该是import org.apache.commons.dbcp2.basicdatasource; 而一直报这样的错误:
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/xusheng_mr/article/details/70947768