[Java] Java读取properties文件连接数据库的方法示例

package util;
 
import java.sql.connection;
import java.sql.drivermanager;
import java.sql.sqlexception;
 
public class connectionmanager {
  public static connection getconnection() {
  connection conn = null;
  try {
    class.forname("com.mysql.jdbc.driver");
    string url = "jdbc:mysql://localhost:3306/mail";
    string username = "root";
    string password = "root";
    conn = drivermanager.getconnection(url, username, password);
  } catch (classnotfoundexception e1) {
    e1.printstacktrace();
  } catch (sqlexception e) {
    e.printstacktrace();
  }
  return conn;
  }
 
}

package util;
 
import java.io.ioexception;
import java.io.inputstream;
import java.sql.connection;
import java.sql.drivermanager;
import java.sql.sqlexception;
import java.util.properties;
 
public class jdbcutil {
  private static string dirvername;
  private static string url;
  private static string username;
  private static string password;
//  利用静态块i，在类加载的时候就被执行
  static{
  try {
//    用流读入properties配置文件
    inputstream inputstream = jdbcutil.class.getclassloader()
      .getresourceasstream("datebase.properties");
    properties properties = new properties();
//    从输入字节流读取属性列表（键和元素对）
    properties.load(inputstream);
//    用此属性列表中指定的键搜索属性，获取驱动，url，username，password
    dirvername = properties.getproperty("drivername");
    url = properties.getproperty("url");
    username = properties.getproperty("username");
    password = properties.getproperty("password");
    system.out.println(dirvername);
    system.out.println(url);
    system.out.println(username);
    system.out.println(password);
//    加载驱动
    class.forname(dirvername);
  } catch (ioexception e) {
    e.printstacktrace();
  } catch (classnotfoundexception e) {
    e.printstacktrace();
  }
 
  }
 
//  获取数据库连接
  public static connection getconnection() {
  connection conn=null;
  try {
    conn=drivermanager.getconnection(url, username, password);
  } catch (sqlexception e) {
    e.printstacktrace();
  }
  return conn;
  }
  
//测试
  public static void main(string[] args) {
  jdbcutil.getconnection();
  }
}

com.mysql.jdbc.driver
jdbc:mysql://localhost:3306/mail
root
root