java鏈接數據庫 並修改表中數據

=================

package china;
import java.sql.*;
public class Person {
	public static void main(String[] args) {
		/*鏈接數據庫*/
		String url="jdbc:oracle:thin:@localhost:1521:root";
		String userName="SYSTEM"; 
		String passWord="123";
		Connection conn=null;
		Statement stmt = null;  
        ResultSet res = null; 
		try {
			Class.forName("oracle.jdbc.OracleDriver");
			conn=DriverManager.getConnection(url,userName,passWord);
            //操作數據庫-增刪改查
            //3.獲得操作數據庫聲明
            Statement st=conn.createStatement();//Statement聲明   createStatement創建聲明
            
            //4.DML 增加數據
            //執行更新操作
            //返回值代表該操作影響的數據記錄條數
            //int i=st.executeUpdate("insert into student(sno,sname,ssex)"
            //+"values('120','王五','男')");
            
            int i=st.executeUpdate("update minzu  set ceshi='考試1'  where id = 12  ");
            
            System.out.println("添加數據成功  返回值="+i);//返回值
			System.out.println("連接成功");
		} catch (Exception e) {
			// TODO Auto-generated catch block
			System.out.println("連接失敗");
			e.printStackTrace();
		};
		conn= null;
		Statement st = null;
		ResultSet rs = null;
	}
}

　　查詢

package china;
import java.sql.*;
public class Person {
	public static void main(String[] args) {
		/*鏈接數據庫*/
		String url="jdbc:oracle:thin:@localhost:1521:root";
		String userName="SYSTEM"; 
		String passWord="123";
		Connection conn=null;
		Statement stmt = null;  
        ResultSet res = null; 
		try {
			Class.forName("oracle.jdbc.OracleDriver");
			conn=DriverManager.getConnection(url,userName,passWord);
            //操作數據庫-增刪改查
            //3.獲得操作數據庫聲明
            Statement st=conn.createStatement();//Statement聲明   createStatement創建聲明
            
            //4.DML 增加數據
            //執行更新操作
            //返回值代表該操作影響的數據記錄條數
            //int i=st.executeUpdate("insert into student(sno,sname,ssex)"
            //+"values('120','王五','男')");
            
           // int i=st.executeUpdate("update minzu  set ceshi='考試1'  where id = 12  ");
            ResultSet rs=st.executeQuery("select id,name,ceshi from minzu");//執行查詢，把查詢結果賦值給結果集對象
            String id,name,ceshi;
            while(rs.next()) {
            	 id=rs.getString("id");//獲得id
            	 name=rs.getString("name");//
            	 ceshi=rs.getString("ceshi");//
            	 System.out.println(id+"\t"+name+"\t"+ceshi);
            }
		} catch (Exception e) {
			// TODO Auto-generated catch block
			System.out.println("連接失敗");
			e.printStackTrace();
		};
		conn= null;
		Statement st = null;
		ResultSet rs = null;
	}
}