利用java封装JDBC操作

BaseDao.java

package util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.ArrayList;

import javax.naming.NamingException;

public abstract class BaseDao<T extends Object> {
/**
  * select a,b,c,from table where username='hao' limit 0,20
  *
  * @param sql
  * @param para
  * @param rsObjCall
  * @return
  */
protected List<T> executeQueryList(String sql, String[] para,ResultObjectCall<T> rsObjCall) {
  List<T> list = new ArrayList<T>();
  Connection conn = null;
  PreparedStatement pstm = null;
  ResultSet rs = null;
  try {
   conn = ConnectionFactory.getConnectionDB();
   pstm = conn.prepareStatement(sql);
   for (int i = 0; i < para.length; i++) {
    if (para[i] == null)
     para[i] = "";
    pstm.setObject(i + 1, para[i]);
   }
   rs = pstm.executeQuery();
   while (rs.next()) {
    list.add(rsObjCall.getResultObject(rs));
   }
  } catch (SQLException e) {
   e.printStackTrace();
  } catch (NamingException e) {
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } finally {
   this.destoryResource(conn, pstm, rs);
  }
  return list;
}

/**
  * select a,b,c from table where id=25
  *
  * @param sql
  * @param para
  * @param objCall
  * @return
  */
protected T executeQuery(String sql, String[] para,ResultObjectCall<T> objCall) {
  T t = null;
  Connection conn = null;
  PreparedStatement pstm = null;
  ResultSet rs = null;
  try {
   conn = ConnectionFactory.getConnectionDB();
   pstm = conn.prepareStatement(sql);
   for (int i = 0; i < para.length; i++) {
    if (para[i] == null)
     para[i] = "";
    pstm.setObject(i + 1, para[i]);
   }
   rs = pstm.executeQuery();
   if (rs.next()) {
    t = objCall.getResultObject(rs);
   }
  } catch (SQLException e) {
   e.printStackTrace();
  } catch (NamingException e) {
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } finally {
   this.destoryResource(conn, pstm, rs);
  }
  return t;
}

/**
  * select count(id) from table where id=?
  * select a from table where id=?
  * @param sql
  * @param para
  * @return
  */
protected Object getColumn(String sql, String[] para) {
  Object obj = null;
  Connection conn = null;
  PreparedStatement pstm = null;
  ResultSet rs = null;
  try {
   conn = ConnectionFactory.getConnectionDB();
   pstm = conn.prepareStatement(sql);
   for (int i = 0; i < para.length; i++) {
    if (para[i] == null)
     para[i] = "";
    pstm.setObject(i + 1, para[i]);
   }
   rs = pstm.executeQuery();
   if (rs.next()) {
    obj = rs.getObject(1);
   }
  } catch (SQLException e) {
  } catch (NamingException e) {
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } finally {
   this.destoryResource(conn, pstm, rs);
  }
  return obj;
}
/**
  * update table set col=? where id=?
  *
  * @param sql
  * @param para
  * @throws SQLException
  */
protected int executeUpdate(String sql, String[] para) {
  int result=0;
  Connection conn = null;
  PreparedStatement pstm = null;
  try {
   conn = ConnectionFactory.getConnectionDB();
   pstm = conn.prepareStatement(sql);
   for (int i = 0; i < para.length; i++) {
    if (para[i] == null)
     para[i] = "";
    pstm.setObject(i + 1, para[i]);
   }
   result=pstm.executeUpdate();
  } catch (SQLException e) {
   e.printStackTrace();
  } catch (NamingException e) {
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } finally {
   this.destoryResource(conn, pstm);
  }
  return result;
}


/**
  * insert into diary(userid,username,title,content)values(?,?,?,?)
  *
  * @param sql
  * @param para
  * @return
  * @throws SQLException
  */
protected long executeInsert(String sql, String[] para) {
  long currentId = 0;
  Connection conn = null;
  PreparedStatement pstm = null;
  ResultSet rs = null;
  try {
   conn = ConnectionFactory.getConnectionDB();
   pstm = conn.prepareStatement(sql);
   for (int i = 0; i < para.length; i++) {
    if (para[i] == null)
     para[i] = "";
    pstm.setObject(i + 1, para[i]);
   }
   pstm.executeUpdate();
   rs = pstm.getGeneratedKeys();
   if (rs.next()) {
    currentId = rs.getLong(1);
   }
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   this.destoryResource(conn, pstm, rs);
  }
  return currentId;
}

/**
  * destoryResource
  *
  * @param conn
  * @param pstm
  * @param rs
  */
private void destoryResource(Connection conn, PreparedStatement pstm,ResultSet rs) {
  try {
   if (pstm != null)
    pstm.close();
   if (rs != null)
    rs.close();
   if (conn != null)
    conn.close();
  } catch (SQLException e) {
  }
}

/**
  * destoryResource
  *
  * @param conn
  * @param pstm
  */
private void destoryResource(Connection conn, PreparedStatement pstm) {
  try {
   if (pstm != null)
    pstm.close();
   if (conn != null)
    conn.close();
  } catch (SQLException e) {
  }
}
}

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ResultObjectCall.java

package util;

import java.sql.ResultSet;
import java.sql.SQLException;

public abstract class ResultObjectCall<T extends Object> {
public abstract T getResultObject(ResultSet rs) throws SQLException;
}
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这样我们在做程序的时候，只需要写sql和sql里面的参数了。

定义个java类TestBaseDaoImpl来实现对日志的一些操作，需要这样定义，Diary是我们的实例类：

public class TestBaseDaoImpl extends BaseDao<Diary>

例如插入记录：

public long intertRecord(){
  String sql="insert into diary(userid,username,title,content)values(?,?,?,?)";
  return this.executeInsert(sql, new String[]{"1","bokee","photobokee","photo.bokee.com/huangjunhua"});
}

例如查询一个列表：

public List<Diary> loadDiaryList(){
  String sql="select diaryid,userid,username,title,content,publishtime from diary where diaryid=? order by diaryid desc";
  List<Diary> list= this.executeQueryList(sql,new String[]{"1"}, new ResultObjectCall<Diary>() {
   public Diary getResultObject(ResultSet rs) throws SQLException {
    Diary d=new Diary();
    d.setDiaryId(rs.getLong(1));
    d.setUserId(rs.getLong(2));
    d.setUserName(rs.getString(3));
    d.setTitle(rs.getString(4));
    d.setContent(rs.getString(5));
    d.setPublishtime(rs.getTimestamp(6));
    return d;
   }
  });
  return list;
}

这样就ok了，非常简单吧

我为了能够控制sql的书写，所以把sql的控制放在自己的程序里面了，没有再做封装。

数据库目前针对msyql，jdk版本是1.6.0