0、写在前面的话
今天在工作中遇到一个需求，是这样的，需要连接很多的数据库（我这里300多个），去每个库执行一段sql，然后把结果进行处理
如果手工用数据库去连接那就太LOW了，而且300个诶大哥好辛苦，所以我的思路是写一个循环读取文件中的数据库ip地址，端口，用户名，密码，动态的去连接数据库，拿回返回结果再处理
现在把我的这个工具分享给大家，大神不用看了，只是jdbc的简单连接使用
1、使用场景
需要动态连接到很多数据库执行相同或则不同的业务
我只写了mysql和sql server的连接，后续使用可以直接扩展
2、废话不多说，直接看代码
package com.test.db;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
/**
* Careate by chenjin at 2017-09-25
* 动态连接数据库工具类
* </br>
* <p>
* 主要针对动态连接数据库
*/
public class DBHelper {
//数据库连接
private static Connection conn = null;
//数据库连接配置
private static DbPro dbPro = null;
private DBHelper() {
System.out.println(DBHelper.class.getName() + "该类不能初始化！！！");
}
/**
* 获取连接数据库拼接的URL
*
* @return
*/
private static String getUrl() {
//判断IP和端口是否是空的
if (dbPro == null || dbPro.getIp() == null || "".equals(dbPro.getIp())
|| dbPro.getPort() == null || "".equals(dbPro.getPort())) {
System.out.println("请初始化IP和端口！！！");
return null;
}
String urlStart;
if (dbPro.getSqlTyle() == SQL_TYPE.SQL_SERVER) {
urlStart = "jdbc:sqlserver://" + dbPro.getIp() + ":" + dbPro.getPort() + ";DatabaseName=" + dbPro.getDataBaseName();
} else if (dbPro.getSqlTyle() == SQL_TYPE.MYSQL) {
urlStart = "jdbc:mysql://" + dbPro.getIp() + ":" + dbPro.getPort() + "/" + dbPro.getDataBaseName();
} else {
System.out.println("未知数据库类型!!!");
urlStart = null;
}
return urlStart;
}
/**
* 初始化连接
*
* @param dbPro
* @return
*/
public static Connection initConn(DbPro dbPro) {
try {
if (dbPro == null) {
new RuntimeException("初始化参数dbPro不能为空！！");
return null;
}
DBHelper.dbPro = dbPro;
//加载对应驱动
Class.forName(dbPro.getDriver());
//超时时间
DriverManager.setLoginTimeout(dbPro.getLoginTimeOutSeconds());
String url = getUrl();
if (url == null || "".equals(url)) {
return null;
}
conn = DriverManager.getConnection(url, dbPro.getUserName(), dbPro.getPassWord());
System.out.println("数据库初始化连接成功！！！");
} catch (ClassNotFoundException e) {
System.out.println("数据库初始化连接【失败】");
e.printStackTrace();
closeConn();
} catch (SQLException e) {
System.out.println("数据库初始化连接【失败】");
e.printStackTrace();
closeConn();
} finally {
}
return conn;
}
public static void closeConn() {
if (conn != null) {
try {
conn.close();
System.out.println("关闭成功！！！");
} catch (SQLException e) {
e.printStackTrace();
System.out.println("连接关闭失败！！！" + e.getMessage());
}
} else {
System.out.println("连接为空,无需关闭！！！");
}
}
/**
* 执行SQL查询
*
* @param sql
* @return
*/
public static List<List<String>> exec(String sql) {
if (sql == null || sql.equals("")) {
System.out.println("sql为空，请先设置执行的SQL语句");
return null;
}
List<List<String>> allDatas = new ArrayList<List<String>>();
try {
if (conn == null) {
System.out.println("conn == null");
return null;
}
PreparedStatement preparedStatement = conn.prepareStatement(sql);
ResultSet resultSet = preparedStatement.executeQuery();
//获取到数据列数
int columnCount = resultSet.getMetaData().getColumnCount();
//column 列
//row 行
while (resultSet.next()) {
List<String> rows = new ArrayList<>();
for (int i = 1; i <= columnCount; i++) {
if (dbPro.isPrint()) {
if (i < columnCount) {
System.out.print(resultSet.getString(i) + "\t");
} else {
System.out.print(resultSet.getString(i));
}
}
rows.add(resultSet.getString(i));
}
if (dbPro.isPrint()) {
System.out.println();
}
allDatas.add(rows);
}
System.out.println("SQL 执行完成！！！" + sql);
} catch (SQLException e) {
e.printStackTrace();
}
return allDatas;
}
/**
* 执行SQL查询
*
* @return
*/
public static List<List<String>> exec() {
if (dbPro.getSql() == null || dbPro.getSql().equals("")) {
System.out.println("dbPro.getSql()为空，请先设置执行的SQL 语句");
return null;
}
return exec(dbPro.getSql());
}
/**
* 数据库配置类
*/
static class DbPro {
private String ip = null;
private String port = null;
private String driver = null;
private String userName = null;
private String passWord = null;
private String sql = null;
private String dataBaseName = null;
private SQL_TYPE sqlTyle = null;
private int loginTimeOutSeconds = 0;
private boolean isPrint = false;
public boolean isPrint() {
return isPrint;
}
public void setPrint(boolean print) {
isPrint = print;
}
public int getLoginTimeOutSeconds() {
return loginTimeOutSeconds;
}
public void setLoginTimeOutSeconds(int loginTimeOutSeconds) {
this.loginTimeOutSeconds = loginTimeOutSeconds;
}
public SQL_TYPE getSqlTyle() {
return sqlTyle;
}
public void setSqlTyle(SQL_TYPE sqlTyle) {
this.sqlTyle = sqlTyle;
}
public String getIp() {
return ip;
}
public void setIp(String ip) {
this.ip = ip;
}
public String getPort() {
return port;
}
public void setPort(String port) {
this.port = port;
}
public String getDriver() {
return driver;
}
public void setDriver(String driver) {
this.driver = driver;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
public String getSql() {
return sql;
}
public void setSql(String sql) {
this.sql = sql;
}
public String getDataBaseName() {
return dataBaseName;
}
public void setDataBaseName(String dataBaseName) {
this.dataBaseName = dataBaseName;
}
}
/**
* 数据库类型枚举
*/
enum SQL_TYPE {
MYSQL, SQL_SERVER
}
}