JDBC读取数据库中信息统一存入哈希表中，然后进行查删增改操作

从小伙伴那里拿来的源码

从数据库中读取数据然后存入哈希表中，然后再进行查删增改各种操作，再转为json数据与前段进行交互

package com.gxut.msqlutil;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;

import com.gxut.util.MyX509TrustManager;
import com.mysql.jdbc.Driver;
import com.mysql.jdbc.ResultSetMetaData;

public class Tools {       //工具类


public static Connection connect() {           //建立数据库连接
            Connection con=null;      
            Driver.getOSName();     
            String userName = "root", password = "root";
            String url = "jdbc:mysql://localhost:3306/wx003";
try {
if(con==null){
                      Class.forName("com.mysql.jdbc.Driver");
                      con = (Connection) DriverManager.getConnection(url, userName, password);
                }

            } catch (Exception ex) {
                ex.printStackTrace();
            }
return con;
        }

public static ArrayList query(String sql) {         //查询数据库函数

            Connection con = connect();
if(con==null){
return null;
            }

            ArrayList al = new ArrayList();        

try {

                PreparedStatement ps=  (PreparedStatement) con.prepareStatement(sql);           
                ResultSet rs= ps.executeQuery();

                ResultSetMetaData rsmd = (ResultSetMetaData) rs.getMetaData();
int colcount = rsmd.getColumnCount();//取得全部列数 

while (rs.next()) {
                     HashMap hm = new HashMap();
for (int i = 0; i < colcount; i++) {
                      hm.put(i + 1, rs.getObject(i + 1));                                   
                    }   //END for(int i=...)
                    al.add(hm);
                }

                rs.close();
                ps.close();
                con.close();
            } catch (SQLException ex) {
                 ex.printStackTrace();
            }
return al;
        }





public static void changeData(String sql) {     //插入、修改或者删除数据库数据
            Connection con = connect();

try {
                PreparedStatement ps = (PreparedStatement) con.prepareStatement(sql);
int result = ps.executeUpdate();
if (result > 0) {
                    System.out.println("操作成功！");
                }
                con.close();

            } catch (SQLException ex) {
                 ex.printStackTrace();
            }

        }

public static String code(String s) {       //解决浏览器中文乱码函数

            String str = s;

try {

byte b[] = str.getBytes("ISO-8859-1");

                str = new String(b);

return str;

            } catch (Exception e) {

                 e.printStackTrace();

            }
return str;

        }




public static SSLSocketFactory createTrustManager(){    //创建信任证书
//创建自己受信任的证书
            MyX509TrustManager[] tm = { new MyX509TrustManager() };
            SSLSocketFactory ssf=null;      
try {
                SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");           
                sslContext.init(null, tm, new java.security.SecureRandom());
// 从上述SSLContext对象中得到SSLSocketFactory对象
                 ssf = sslContext.getSocketFactory();           
            } catch (Exception e) {         
                e.printStackTrace();
            }
return ssf;

        }
public static  HttpsURLConnection getHttps(URL url,String requestMethod){       //返回安全https
              HttpsURLConnection https = null;
try {
                  https = (HttpsURLConnection) url.openConnection();
                  https.setSSLSocketFactory(Tools.createTrustManager());    //设置安全证书
                  https.setRequestMethod(requestMethod);      //必须是get方式请求 
                  https.setRequestProperty("Content-Type","application/x-www-form-urlencoded");    
                  https.setDoOutput(true);        
                  https.setDoInput(true);
                  https.setUseCaches(false);
                  System.setProperty("sun.net.client.defaultConnectTimeout", "30000");//连接超时30秒
                  System.setProperty("sun.net.client.defaultReadTimeout", "30000"); //读取超时30秒 
                  https.connect();
            } catch (IOException e) {
// TODO 自动生成的 catch 块
                e.printStackTrace();
            }
return https;    

         }

public static  HttpURLConnection getHttp(URL url,String requestMethod){    //返回http
             HttpURLConnection http=null;
try{
             http=   (HttpURLConnection) url.openConnection();    

             http.setRequestMethod(requestMethod);        
             http.setRequestProperty("Content-Type","application/x-www-form-urlencoded");    
             http.setDoOutput(true);        
             http.setDoInput(true);
             http.setUseCaches(false); 
             System.setProperty("sun.net.client.defaultConnectTimeout", "30000");//连接超时30秒
             System.setProperty("sun.net.client.defaultReadTimeout", "30000"); //读取超时30秒 
             http.connect();
             }
catch(Exception e){
                 e.printStackTrace();
             }
return http;
         }


/**
 * utf 编码
 * 
 * @param source
 * @return
 */
public static String urlEncodeUTF8(String source) {
                String result = source;
try {
                    result = java.net.URLEncoder.encode(source, "utf-8");
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
return result;
            }

}