JDBC工具类

描述：使用JDBC封装了底层的增删改查用SQL来操作，支持事务操作，支持预处理SQL，支持properties配置数据库
配置文件存放目录和DatabaseUtil类存放目录相同

package util; 

import java.io.IOException; 
import java.io.InputStream; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.Properties; 

public class DatabaseUtil { 

private String jdbc = null; 
private String url = null; 
private String username = null; 
private String password = null; 
private Connection conn = null; 
private Statement st = null; 
private PreparedStatement ps = null; 
private ResultSet rs = null; 

private InputStream is = null; 
private Properties property = null; 

//手动写入数据库配置 
public DatabaseUtil() 
{ 
jdbc = ""; 
url = ""; 
username = ""; 
password = ""; 
try 
{ 
Class.forName(jdbc); 
} catch (ClassNotFoundException cnfe) 
{ 
cnfe.printStackTrace(); 
} 
} 

//通过properties文件写入数据库配置 
public DatabaseUtil(String properties_name) 
{ 
try 
{ 
is = DatabaseUtil.class.getResourceAsStream(properties_name); 
property = new Properties(); 
property.load(is); 
} catch (IOException ioe) { 
ioe.printStackTrace(); 
}finally 
{ 
try 
{ 
is.close(); 
is = null; 
} catch (IOException e) { 
e.printStackTrace(); 
} 
} 
jdbc = property.getProperty("jdbc"); 
url = property.getProperty("url"); 
username = property.getProperty("username"); 
password = property.getProperty("password"); 
try 
{ 
Class.forName(jdbc); 
} catch (ClassNotFoundException cnfe) 
{ 
cnfe.printStackTrace(); 
} 
} 

//实例化类时写入数据库配置 
public DatabaseUtil(String jdbc,String url,String username,String password) 
{ 
this.jdbc = jdbc; 
this.url = url; 
this.username = username; 
this.password = password; 
try 
{ 
Class.forName(jdbc); 
} catch (ClassNotFoundException cnfe) 
{ 
cnfe.printStackTrace(); 
} 
} 

//获得连接 
public Connection getConnection() 
{ 
try 
{ 
conn = DriverManager.getConnection(url,username,password); 
}catch (SQLException sqle) 
{ 
this.closeConnection(); 
sqle.printStackTrace(); 
} 
return conn; 
} 

//执行一条SQL语句 
public void executeUpdate(String sql) 
{ 
try { 
st = conn.createStatement(); 
if(sql!=null && !sql.equals("")) 
{ 
st.executeUpdate(sql); 
} 
} catch (SQLException sqle) 
{ 
sqle.printStackTrace(); 
}finally 
{ 
this.closeStatement(); 
} 
} 

//执行多条SQL语句，支持事务操作 
public void executeUpdate(String[] sqls) 
{ 
try { 
conn.setAutoCommit(false); 
st = conn.createStatement(); 
for(String sql:sqls) 
{ 
if(sql != null && !sql.equals("")) 
{ 
st.execute(sql); 
} 
} 
conn.commit(); 
} catch (SQLException e) { 
try 
{ 
conn.rollback(); 
} catch (SQLException sqle) { 
sqle.printStackTrace(); 
} 
e.printStackTrace(); 
}finally 
{ 
this.closeStatement(); 
} 
} 

//以预处理的形式执行一条SQL语句 
public void executeUpdatePrepared(String sql,String[] params) 
{ 
try { 
ps = conn.prepareStatement(sql); 
if(ps != null) 
{ 
for(int i=0;i<params.length;i++) 
{ 
ps.setString(i+1, params[i]); 
} 
ps.executeUpdate(); 
} 
} catch (SQLException sqle) 
{ 
sqle.printStackTrace(); 
}finally 
{ 
this.closePreparedStatement(); 
} 
} 

//以预处理的形式执行多条SQL语句，支持事务操作 
public void executeUpdatePrepared(String[] sqls,String[][] params) 
{ 
try 
{ 
conn.setAutoCommit(false); 
for(int i=0;i<sqls.length;i++) 
{ 
ps = conn.prepareStatement(sqls[i]); 
if(ps != null) 
{ 
for(int j=0;j<params[i].length;j++) 
{ 
ps.setString(j+1, params[i][j]); 
} 
ps.executeUpdate(); 
} 
} 
conn.commit(); 
} catch (SQLException sqle) 
{ 
try 
{ 
conn.rollback(); 
} catch (SQLException e) 
{ 
e.printStackTrace(); 
} 
sqle.printStackTrace(); 
}finally 
{ 
this.closePreparedStatement(); 
} 
} 

//查询一条SQL 
public ResultSet executeQuery(String sql) 
{ 
try 
{ 
st = conn.createStatement(); 
if(sql!=null && !sql.equals("")) 
{ 
rs = st.executeQuery(sql); 
} 
}catch(SQLException sqle) 
{ 
sqle.printStackTrace(); 
}finally 
{ 
//rs遍历后需要手动关闭的 
} 
return rs; 
} 

//预处理查询一条SQL 
public ResultSet executeQueryPrepared(String sql,String[] params) 
{ 
try 
{ 
ps = conn.prepareStatement(sql); 
if(ps != null) 
{ 
for(int i=0;i<params.length;i++) 
{ 
ps.setString(i+1, params[i]); 
} 
rs = ps.executeQuery(); 
} 
}catch(SQLException sqle) 
{ 
sqle.printStackTrace(); 
}finally 
{ 
//rs遍历后需要手动关闭的 
} 
return rs; 
} 

//关闭会话 
public void closeStatement() 
{ 
try 
{ 
if(st != null) 
{ 
st.close(); 
} 
} catch (SQLException sqle) { 
sqle.printStackTrace(); 
} 
} 

//关闭结果集 
public void closeResultSet() 
{ 
try 
{ 
rs.close(); 
}catch(SQLException sqle) 
{ 
sqle.printStackTrace(); 
} 
} 

//关闭预处理会话 
public void closePreparedStatement() 
{ 
try 
{ 
if(ps != null) 
{ 
ps.close(); 
} 
}catch(SQLException sqle) 
{ 
sqle.printStackTrace(); 
} 
} 

//关闭连接 
public void closeConnection() 
{ 
if(conn != null) 
{ 
try 
{ 
conn.close(); 
} catch (SQLException sqle) 
{ 
sqle.printStackTrace(); 
} 
} 
} 

} 

 

mysql.properties配置文件：

#数据库配置
jdbc=org.gjt.mm.mysql.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=123456