package cn.bdqn.bean; public class Dept { private Integer deptno; private String dname; private String loc; public Dept(Integer deptNo, String dname, String loc) { super(); this.deptno = deptNo; this.dname = dname; this.loc = loc; } public Dept() { super(); } public Integer getDeptno() { return deptno; } public void setDeptno(Integer deptNo) { this.deptno = deptNo; } public String getDname() { return dname; } public void setDname(String dname) { this.dname = dname; } public String getLoc() { return loc; } public void setLoc(String loc) { this.loc = loc; } @Override public String toString() { return "Dept [deptNo=" + deptno + ", dname=" + dname + ", loc=" + loc + "]"; } }
package cn.bdqn.test; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import cn.bdqn.bean.Dept; public class JDBCTest { public static void main(String[] args) { /** * 获取数据库连接的4要素 * 01.url * 02.driverClass * 03.userName * 04.password */ String driver="oracle.jdbc.driver.OracleDriver"; String url="jdbc:oracle:thin:@127.0.0.1:1521:orcl"; String userName="t10"; String password="t10"; /** * 创建jdbc需要的API */ Connection connection=null; PreparedStatement ps=null; ResultSet rs=null; try { Class.forName(driver); //加载驱动 connection= DriverManager.getConnection(url, userName, password);//获取连接 String sql="select * from dept where deptno=?"; //书写sql语句 ps=connection.prepareStatement(sql); //实例化ps对象 ps.setInt(1, 30);//给参数赋值 rs=ps.executeQuery(); //获取查询的结果集 while(rs.next()){ int deptno=rs.getInt("deptno"); String dName=rs.getString("dname"); String loc=rs.getString("loc"); Dept dept=new Dept(deptno, dName, loc); System.out.println(dept); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally{ try { //释放资源 rs.close(); ps.close(); connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } }
package cn.bdqn.test; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import cn.bdqn.bean.Dept; public class ORMTest { /** * 元数据: * Student * age * name * address * 这些属性都是用来描述Student对象特征的! 描述数据的数据就是元数据! * */ public static void main(String[] args) throws Exception, IllegalAccessException, ClassNotFoundException { //我们所写的实体类 String className="cn.bdqn.bean.Dept"; //通过反射获取这个类的实例 Object object=Class.forName(className).newInstance(); String driver="oracle.jdbc.driver.OracleDriver"; String url="jdbc:oracle:thin:@127.0.0.1:1521:orcl"; String userName="t10"; String password="t10"; /** * 创建jdbc需要的API */ Connection connection=null; PreparedStatement ps=null; ResultSet rs=null; try { Class.forName(driver); //加载驱动 connection= DriverManager.getConnection(url, userName, password);//获取连接 String sql="select * from dept where deptno=?"; //书写sql语句 ps=connection.prepareStatement(sql); //实例化ps对象 ps.setInt(1, 20);//给参数赋值 rs=ps.executeQuery(); //获取查询的结果集 while(rs.next()){ //01.获取元数据的结果集 ResultSetMetaData data = rs.getMetaData(); //02.获取数据库中有多少字段 int count = data.getColumnCount(); //03.循环获取字段的名称和类型 for (int i = 1; i <=count; i++) { String name= data.getColumnName(i); //字段名称 String type= data.getColumnTypeName(i); //字段类型 System.out.println(name+"====》"+type); //给我一个字段名称 ,我给你返回一个set字段名 给类中的属性 赋值 String method=getMethod(name); //04.判断 数据库中的字段类型 要和java中的数据类型相互匹配 if (type.equals("NUMBER")) { object.getClass().getMethod(method, Integer.class) .invoke(object, rs.getInt(name)); }else if(type.equals("VARCHAR2")){ object.getClass().getMethod(method, String.class) .invoke(object, rs.getString(name)); } } Dept dept=(Dept) object; System.out.println(dept); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); }finally{ try { //释放资源 rs.close(); ps.close(); connection.close(); } catch (SQLException e) { e.printStackTrace(); } } } /** *给我一个字段名称 ,我给你返回一个set字段名 给类中的属性 赋值 * @param name 字段名称 * @return setName() */ private static String getMethod(String name) { return "set"+name.substring(0, 1).toUpperCase()+name.substring(1).toLowerCase(); } }