java数据库连接技术（JDBC）

程序员文章站 2022-03-31 22:04:29

代码详解package jdbcDemo;import java.sql.Statement;import javax.naming.spi.DirStateFactory.Result;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;public class ConnectJdbc {Connecti...

代码详解

package jdbcDemo;

import java.sql.Statement;

import javax.naming.spi.DirStateFactory.Result;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

public class ConnectJdbc {
	
	Connection conn =null;
	public static void main(String[] args) throws Exception {
		ConnectJdbc  cj = new ConnectJdbc();
		cj.getCon();
		
		//新增表
		//cj.addTable();
		
		//删除表
//		cj.deleteTable();
		
//		查询
		cj.queryData();
		
		//删除
		//cj.deleteData(4456);
		
		//更新
		//cj.updateData(4456);
		
		//新增
		//cj.addData(4467, "Jake",5000);
		cj.closeCon();
		
		
	}
	
	
	
	//连接数据库
	public Connection getCon() throws Exception {

		//加载驱动
		Class.forName("oracle.jdbc.OracleDriver");
		//获得连接
		//参数1  数据库地址
		//参数2 数据库用户名
		//参数3 密码
		conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl",
				"scott","root");
		return conn;
		
	}
	
	//关闭数据库连接
	public void closeCon() throws Exception {
		conn.close();
	}
	
	//新增表
	public void addTable() throws Exception {
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();
		//写sql
		String sql = "create table utable(name varchar(20),pwd char(6))";
		//执行新增表语句,返回值为0
		int rs = st.executeUpdate(sql);	
		System.out.println(rs);
		if(rs==0) {
			System.out.println("创建用户表成功");
		}
	}
	
	//删除表
	public void deleteTable() throws Exception {
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();
		//写sql
		String sql = "drop table utable";
		//执行删除表语句,返回值为0
		int rs = st.executeUpdate(sql);	
		System.out.println(rs);
		if(rs==0) {
			System.out.println("用户表删除成功");
		}
	}
	
	//查询
	public void queryData() throws Exception {
		
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();
		
		//写sql
		String sql = "select * from emp";
		
		//查询,返回结果集，存放返回的数据集合
		ResultSet rs = st.executeQuery(sql);	
		while(rs.next()) {
			//取出一个字段，由于表中的empno为number,所以调用getInt()
			//由于ename为varchar2,所以调用getString()
			System.out.println(rs.getInt("empno")+" "+rs.getString("ename"));
		}
	}
	
	
	//删除
	public void deleteData(int id) throws Exception {
		
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();
		//写sql
		String sql = "delete from emp where empno="+id;
		//删除，返回值为删除的行数
		int rs = st.executeUpdate(sql);	
		if(rs>0) {
			System.out.println("删除成功");
		}
	}
	
	//更新
	public void updateData(int id) throws SQLException {
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();
		//写sql
		
		
		String sql = "update emp set sal=5000 where empno="+id;
		//更新的行数
		int rs = st.executeUpdate(sql);	
		if(rs>0) {
			System.out.println("更新成功");
		}
		
	}
	
	//新增
	public void addData(int empno,String ename,double salary) throws Exception {
		// 创建Statement对象   此对象帮我们执行sql
		Statement st = conn.createStatement();	
		//写sql
		String sql = "insert into emp(empno,ename,sal) values("+empno+",'"+ename+"',"+salary+")";
		//新增的行数
		int rs = st.executeUpdate(sql);	
		if(rs>0) {
			System.out.println("新增成功");
		}
	}
	
	
}