将数据库中的数据转换成Json

import java.sql.*;
import java.util.*;
import org.json.*;//引入相关包，包含在json.jar里

public class SqlJsonConvertor {
public static void main(String[] args) {
    String driver = "com.mysql.jdbc.Driver";
    String url = "jdbc:mysql://localhost:3306/phpwind";
    String user = "root";
    String passwd = "123456";
    String sql = "select * from pw_acloud_apis";
    
    try {
        Class.forName(driver);
        Connection con = DriverManager.getConnection(url, user, passwd);
        Statement st =  con.createStatement();
        ResultSet rs = st.executeQuery(sql);
        ResultSetMetaData rsmd = rs.getMetaData();
        int colnum = rsmd.getColumnCount();
        String val = "";
        String colName = "";
        JSONObject jobj = new JSONObject();
        JSONArray jArr = new JSONArray();
        
        while(rs.next()) {
            for(int i = 1; i<= colnum; i++) {
                colName = rsmd.getColumnLabel(i);
                if(1==i) {
                    val = new Integer(rs.getInt(colName)).toString();
                }else {
                    val = rs.getString(colName);
                }
                
                try {
                    jobj.put(colName, val);
                    
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }            
            }
            jArr.put(jobj);    
        }
        System.out.println("Here is the json String:");
        System.out.println(jArr.toString());
        
    }catch(ClassNotFoundException e) {
        System.out.println("Driver not found");
        e.printStackTrace();
    }catch(SQLException e) {
        e.printStackTrace();
    }    
}
}