连接数据库

package YouBiao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TestYouBiao {
    static String className="com.mysql.jdbc.Driver";
    static String url="jdbc:mysql://127.0.0.1/pei_test";
    static String user="root";
    static String passWord="123456";
    static String sql="select * from blade_dept";
    public static void test() {
        try {
            Class.forName(className);
            Connection conn=DriverManager.getConnection(url, user, passWord);
            PreparedStatement prs=conn.prepareStatement(sql);
            ResultSet rs=prs.executeQuery();
            List<Map<String,Object>>list=new ArrayList<Map<String,Object>>();
            ResultSetMetaData rsd=rs.getMetaData();
            int columnCount=rsd.getColumnCount();
            while(rs.next()) {
                Map<String,Object>map=new HashMap<String, Object>();
                for(int i=1;i<columnCount;i++) {
                    map.put(rsd.getColumnName(i), rs.getObject(i));
                }
                list.add(map);
            }
            System.out.println("list======"+list);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        test();
    }

}

 

package YouBiao;

public interface IYouBiao {
    static String url = "jdbc:mysql://127.0.0.1/pei_test";  
    static String name = "com.mysql.jdbc.Driver";  
    static String user = "root";  
    static String password = "123456";
    static String sql="select * from blade_dept";

}

package YouBiao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TestYouBiao {
    public static Connection conn=null;
    public static PreparedStatement ps=null;
     static ResultSet ret = null;  
    public static List<Map<String,Object>> test() {
        try {
            Class.forName(IYouBiao.name);
            conn=DriverManager.getConnection(IYouBiao.url,IYouBiao.user, IYouBiao.password);
            ps=conn.prepareStatement(IYouBiao.sql);
            ret=ps.executeQuery();
            System.out.println("ret================"+ret);
            List<Map<String,Object>>list=new ArrayList<Map<String,Object>>();
            ResultSetMetaData md = ret.getMetaData(); //获得结果集结构信息,元数据
            int columnCount = md.getColumnCount();   //获得列数 
            while (ret.next()) {
                Map<String,Object> rowData = new HashMap<String,Object>();
                for (int i = 1; i <= columnCount; i++) {
                    rowData.put(md.getColumnName(i), ret.getObject(i));
                }
                list.add(rowData);
            }
            System.out.println("list================"+list);
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    public static void main(String[] args) {
        List<Map<String,Object>>list=test();
        System.out.println("list====="+list);
    }

}