之前小伙伴叫我帮她写毕业设计，然后想起这道茬。多记录下曾经写的东西，总之，方便你我他

直接上代码，这里是用的MySql数据库，数据库增删改查主要类

import java.lang.reflect.Field;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.List;/** * 通用增删改查基类 * @author  * */public class BaseDao {         private String user=MyProperties.getInstances().getProperty("user");     private String password=MyProperties.getInstances().getProperty("password");     private String url=MyProperties.getInstances().getProperty("url");     private static String driver=MyProperties.getInstances().getProperty("driver");     private Connection conn;     private PreparedStatement ps;     private ResultSet rs;     private static BaseDao dao;     private BaseDao(){};     public static BaseDao getInstance(){         if(dao==null){             synchronized (BaseDao.class) {                if(dao==null){                    dao=new BaseDao();                }            }         }         return dao;     }     static{         try {            Class.forName(driver);        } catch (ClassNotFoundException e) {            e.printStackTrace();        }     }     public void getConnection(){         try {            conn=DriverManager.getConnection(url,user,password);        } catch (SQLException e) {            e.printStackTrace();        }     }         /**     * 更新数据库     * @param sql sql语句     * @param obj 传递的参数     * @return     */     public int executeUpdate(String sql,Object[]obj,SearchBackCall back){         int num=0;         getConnection();         try {            ps=conn.prepareStatement(sql);            if(obj!=null&&obj.length>0){                for(int i=0;i
     
      0){                for(int i=0;i
     

然后是获取文件的类

import java.io.IOException;import java.io.InputStream;import java.util.Properties;/** * 这是读取文件类 */public class MyProperties extends Properties{private static MyProperties mProperties;private MyProperties(){    InputStream is=null;    try {        is=getClass().getResourceAsStream("/pro.properties");        this.load(is);    } catch (IOException e) {        // TODO Auto-generated catch block        e.printStackTrace();    }}        public static MyProperties getInstances(){        if(mProperties==null){        synchronized (MyProperties.class) {            if(mProperties==null){                mProperties=new MyProperties();            }        }    }    return mProperties;        } }

ok，有这两个就够了

然后举个例子，查询：

List
     
      list =BaseDao.getInstance().executeQuery(                "select * from "+GlobalVariable.TRANS_TABLE,                 null,                 TransObj.class);
     

删除:

int i=BaseDao.getInstance(). 　　　　　　　　executeUpdate("delete from "+GlobalVariable.CARD_TABLE+" where account=?" 　　　　　　　　,new String[]{account} 　　　　　　　　, null);

增加:

BaseDao.getInstance().executeUpdate("insert into "+GlobalVariable.USER_TABLE+"(idcard,account,mobile,name) values(?,?,?,?)"                    ,new Object[]{idCard,account,mobile,name},null);

修改:

int i=BaseDao.getInstance().executeUpdate(                "update "+GlobalVariable.CARD_TABLE+" set savetype=?,moneytype=?,isguashi=? where account=?",                new Object[]{savetype,moneytype,isguashi,account},null);

ok