java jdbc数据库连接代码封装

一个很好的封装jdbc数据库类

package cn.com.util;

import java.sql.*;
import java.util.*;

/**
* 数据库操作工具类
*
* @author Administrator
*
*/
public class DBUtil {
private static Connection con = null;// 连接对象
private static PreparedStatement psmt = null;// 预编译对象
private static ResultSet rs = null;// 结果集对象
private static CallableStatement csmt = null;// 过程对象
/**
* 获得连接对象
* @return
*/
public static Connection getConnetion() {
try {

Class.forName("com.mysql.jdbc.Driver");
con = DriverManager
.getConnection("jdbc:mysql://localhost:3306/mytest","root","gc7923959");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
System.out.println("找不到驱动");
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("数据库连接失败");
}
return con;
}

/**
*
* @param sql
* @return
*/
public static PreparedStatement getPreparedStatement(String sql) {
con = getConnetion();
try {
psmt = con.prepareStatement(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return psmt;
}
/**
* 查询获得所有
* @param sql
* @return 结果集
*/
public static ResultSet getResultSet(String sql) {
psmt = getPreparedStatement(sql);
try {
rs = psmt.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return rs;
}

/**
* 更新操作
* @param sql
* @param params
* @return 受影响的行数
*/
public static int executeUpdate(String sql, List<Object> params) {
int count = 0;

psmt = getPreparedStatement(sql);
bindPramas(psmt, params);
try {
count = psmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
CloseAll();
}

return count;
}

/**
* 查询 带参数
* @param sql
* @param params
* @return 结果集
*/
public static ResultSet executeQuery(String sql, List<Object> params) {
psmt = getPreparedStatement(sql);
if (params != null) {
bindPramas(psmt, params);
}
try {
rs = psmt.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(psmt);
return rs;
}

public static CallableStatement getCallableStatement(String sql) {
try {
csmt = getConnetion().prepareCall(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return csmt;

}

public static Object executeCallObject(String sql,
Map<Integer, Object> params) {
Object obj = null;
try {
int index = 0;// 输入参数下标
csmt = getCallableStatement(sql);
for (int i = 1; i <= params.size(); i++) {
if (params.get(i).toString().equals("Integer")) {
csmt.registerOutParameter(i, Types.INTEGER);
index = i;
} else {
csmt.setObject(i, params.get(i));
}

}

csmt.execute();
obj = csmt.getObject(index);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return obj;
}

public static void bindPramas(PreparedStatement psmt, List<Object> params) {
int index = 0;
if (params != null) {
for (Object p : params) {
try {
psmt.setObject(index + 1, p);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
index++;

}

}
}

public static void CloseAll() {
try {
if (con != null) {

con.close();

}
if (psmt != null) {
psmt.close();
}
if (rs != null) {
rs.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}