连接数据库，对数据进行增删查改

//连接数据库
JDbc连接数据库过程：1.加载驱动 class.forName("oracle.jdbc.driver.OracleDriver")
2.建立连接 Connection conn=DriverManager.getConnection(url,user,password);
3.创建发送Sql语句的statement对象 Statement st=conn.createStatement();
4.发送sql语句：dml:执行跟新删除和插入用语句 st.executeUpdate(sql);
select 用：Resyltset rs=st.executeQuery(sql);
5,处理Resultset对象
while（rs.next()）{
....
}
6.释放对象 按照出现的顺序，反顺序进行释放
rs.close();st.close();conn.close();

package jdbc;

import java.io.BufferedInputStream;
import java.io.Closeable;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/*连接数据库 应用数据库配置文件 读到 数据库中登录
 * Properties 类表示了一个持久的属性集。
 * Properties 可保存在流中或从流中加载。属性列表中每个键及其对应值都是一个字符串。 
 * 
 * @auther:Shadow
 * @Date:2018.09.28
 * */

public class denglu {
	public static void main(String[] args) {
	 logOracle();
	}
	public static void logOracle() {
		Properties pro =new Properties();  
		InputStream is=null;
		Connection conn=null;
		try {   //读取properties数据库配置文件（数据库名字，密码，主机名）
			     is=new BufferedInputStream(new FileInputStream("D:\数据库配置文件\db.properties"));
			     pro.load(is);
			     String driver=pro.getProperty("driver");
			     String url=pro.getProperty("url");
				 String user=pro.getProperty("user");
				 String password=pro.getProperty("password");
				 //加载驱动
				 Class.forName(driver);
				 //建立连接
				 conn = DriverManager.getConnection(url, user, password);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			//释放IO
			ReleaseIo.free(is);
			//释放对象资源
			Releasejdbc.free(conn);
		}
	   
 }
	
	 
}

　　释放资源

package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/*jbac中 connection，statement，resultSet 释放资源的封装方法
 * @auther:Shadow
 * @Date：2018.09.28
 * */
public class Releasejdbc {
	public static void free(Connection conn, Statement st, ResultSet rs) {
	    free(rs);
	    free(conn, st);
	  }
	  
	  public static void free(Connection conn, Statement st) {
	    free(st);
	    free(conn);
	  }
	  
	  public static void free(Statement st, ResultSet rs) {
	    free(rs);
	    free(st);
	  }
	  
	  public static void free(Connection conn) {
	    try {
	      if(conn != null && !conn.isClosed()) {
	        conn.close();
	      }
	    } catch (SQLException e) {
	      // TODO Auto-generated catch block
	      e.printStackTrace();
	    }
	  }
	  
	  public static void free(Statement st) {
	    if(st != null) {
	      try {
	        st.close();
	      } catch (SQLException e) {
	        // TODO Auto-generated catch block
	        e.printStackTrace();
	      }
	    }
	  }
	  
	  public static void free(ResultSet rs) {
	    if(rs != null) {
	      try {
	        rs.close();
	      } catch (SQLException e) {
	        // TODO Auto-generated catch block
	        e.printStackTrace();
	      }
	    }
	  }
}

　　释放I/O资源

package jdbc;

import java.io.Closeable;
import java.io.IOException;
public class ReleaseIo {
 public static void free(Closeable...stream){
	 for(Closeable st:stream){
		 if(st != null){
			 try {
				st.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		 }
	 }
	
 }
}

db.properties文件

driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@localhost:1521:orcl
user=TESTUSER
password=123456

　　添加信息到数据库中

package jdbc;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Properties;

//更新数据库
public class update {
	
	public static void main(String[] args) {
		StudentVO st=new StudentVO();
		st.setSno(510);
		st.setName("李红");
		st.setSex("女");
		st.setBirthday(new Date(19961027));
		st.setNumber(1401);
		updateOracle(st);
	}

	private static void updateOracle(StudentVO stu) {
		String sql="insert into awer values"
				+ "(?,?,?,?,?)";
		 Properties pro =new Properties();  
		 InputStream is=null;
		 Connection conn=null;
		 //PreparedStatement是statement的子类
		 PreparedStatement ps = null;
		try {
			 is = new BufferedInputStream(new FileInputStream("D:\数据库配置文件\db.properties"));
			 pro.load(is);
		     String driver=pro.getProperty("driver");
		     String url=pro.getProperty("url");
			 String user=pro.getProperty("user");
			 String password=pro.getProperty("password");
			 Class.forName(driver);
			 conn = DriverManager.getConnection(url, user, password);
			 ps=conn.prepareStatement(sql);
			 ps.setDouble(1, stu.getSno());
			 ps.setString(2, stu.getName());
			 ps.setString(3, stu.getSex());
			 ps.setTimestamp(4, new Timestamp(stu.getBirthday().getTime()));
			 ps.setDouble(5, stu.getNumber());
			 ps.executeUpdate();
			
			 
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			 ReleaseIo.free(is);
			 Releasejdbc.free(conn, ps);
		}
		

	     
		
	}
	
	
	

}

　　创建一个对应数据库表格的类

package jdbc;

import java.util.Date;

public class StudentVO {
  private double sno;
  private String name;
  private String sex;
  private Date birthday;
  private double number;
public double getSno() {
	return sno;
}
public void setSno(double sno) {
	this.sno = sno;
}
public String getName() {
	return name;
}
public void setName(String name) {
	this.name = name;
}
public String getSex() {
	return sex;
}
public void setSex(String sex) {
	this.sex = sex;
}
public Date getBirthday() {
	return birthday;
}
public void setBirthday(Date birthday) {
	this.birthday = birthday;
}
public double getNumber() {
	return number;
}
public void setNumber(double number) {
	this.number = number;
}
  
}

　　查询数据库

package jdbc;

import oracle.jdbc.driver.OracleDriver;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/*对数据库进行查询
 * */
public class testselect {

	public static void main(String[] args) {
		select("101");

	}

	private static void select(String no) {
		// 主机名和服务名
		String url = "jdbc:oracle:thin:@localhost:1521:orcl";
		// 数据库服务名
		String user = "TESTUSER";
		// 密码
		String password = "123456";
		String sql = "select s.sno,s.name,s.birthday from awer s " + "where s.sno='" + no + "'";
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		// 1.加载驱动
		try {
			Class.forName("oracle.jdbc.driver.OracleDriver");
			conn = DriverManager.getConnection(url, user, password);
			// 3.通过数据库的连接操作数据库，实现增删改查（使用Statement类）
			st = conn.createStatement();
			rs = st.executeQuery(sql);
			// 4.处理数据库的返回结果(使用ResultSet类)
			while (rs.next()) {
				String sno = rs.getString("sno");
				String name = rs.getString("name");
				Date birthday = rs.getDate(3);
				System.out.println(sno + ", " + name + ", " + birthday);
			}

		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			Releasejdbc.free(conn, st, rs);
		}

	}

}

　　对数据库进行删除

package jdbc;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/*对数据库进行删除操作
 * */
public class delete {
	public static void main(String[] args) {
		daleteOracle("401");
	}

	private static void daleteOracle(String sno) {
		String sql = "delete awer a where a.sno='" + sno + "';";
		Properties pro = new Properties();
		InputStream is = null;
		Connection conn = null;
		Statement st = null;
		try {
			is = new BufferedInputStream(new FileInputStream("D:\数据库配置文件\db.properties"));
			pro.load(is);
			String driver = pro.getProperty("driver");
			String url = pro.getProperty("url");
			String user = pro.getProperty("user");
			String password = pro.getProperty("password");
			Class.forName(driver);
			conn = DriverManager.getConnection(url, user, password);
			// 通过数据库的连接操作数据库，实现删除（使用Statement类）
			st = conn.createStatement();
			st.executeUpdate(sql);

		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			ReleaseIo.free(is);
			Releasejdbc.free(conn, st);
		}

	}
}