如何关闭数据库连接？

[Iris5]

如何关闭数据库连接？

以下程序是一个片段，整个程序能够从excel文件中读取数据并插入数据库中。但是整个程序执行完毕后如何关闭数据库连接？请给出详细代码、并告知此代码放置何处？

补充：目前的状况是当读取excel多个值的时候，向数据库插入完毕，例如读取插5个值，mysql数据库会显示5个数据库连接（未关闭），如何使插值结束，同时关闭数据库连接？谢谢！！


package d123;


public class POIDZ {
public static Connection conn = null;
public static Statement stmt = null;
public static boolean connectDB2() {
try {
Class.forName("org.gjt.mm.mysql.Driver");
String url = "jdbc:mysql://localhost:3306/dstore";
conn = DriverManager.getConnection(url,"root","123");
stmt = conn.createStatement();
}
//捕获加载驱动程序异常
catch (ClassNotFoundException cnfex) {
cnfex.printStackTrace();
return false;
}
//捕获连接数据库异常
catch (SQLException sqlex) {

sqlex.printStackTrace();
//System.exit(1); // terminate program
return false;
}
return true;
}
public static boolean readExcelToDB2(String userName,String fahao) {
POIFSFileSystem fs = null;
HSSFWorkbook wb = null;
FileInputStream fjexl = null;
try {
fjexl = new FileInputStream("D:\\Tomcat6.0\\webapps\\aas\\upload\\"+userName+".xls");
fs = new POIFSFileSystem(fjexl);
wb = new HSSFWorkbook(fs);
fjexl.close();
} catch (IOException e) {
e.printStackTrace();
return false;
}
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row = null;
HSSFCell cell = null;

String shoudaot ="8";
long jieshoutimet =7;
int rowNum, cellNum;
int i;
rowNum = sheet.getLastRowNum();

for (i = 3; i <= 30; i++) { ---->第一个循环
row = sheet.getRow(i);
//cellNum = row.getLastCellNum();
try{
cell = row.getCell((short) 10);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
dongci = cell.getStringCellValue().trim();
dongci=new String(dongci.getBytes("GBK"),"latin1");
}catch(Exception e){
}
if (haomat!=0 & jieshou!="" & shengdan!=""){
String sql = "insert into dingzhi(user,name) values('"+userName+"','"+namet+"')";
try {
stmt.executeUpdate(sql);
shengdan="";
} catch (SQLException e1) {
e1.printStackTrace();
return false;
}
}
}
rowNum = sheet.getLastRowNum();

for (i = 3; i <= 30; i++) { ----》第二个循环
row = sheet.getRow(i);
//cellNum = row.getLastCellNum();
try{
cell = row.getCell((short) 0);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
name = cell.getStringCellValue().trim();
name=new String(name.getBytes("GBK"),"latin1");
name = name.substring(0, 20);
}catch(Exception e){

}
if (name!="-"){
String sql = "insert into listuser(username,liantong) values('"+name+"','"+liantong+"')";
try {
stmt.executeUpdate(sql);
} catch (SQLException e1) {
e1.printStackTrace();
return false;
}
}
}
return true;

}
}

[weberwong]

conn.close()就关了，在你程序用完连接后调用，最好放在finally里

[gao512008]

[Quote=引用 1 楼 weberwong 的回复:]

conn.close()就关了，在你程序用完连接后调用，最好放在finally里
[/Quote]UP

[woaiyanzic]

帅哥~~CONN和STMT都是要管的，否则你每次都NEW一个，然后就~~~关掉连接、流啊什么的都是用其close（）方法你可以看看相应的API这是个好习惯，其实这个问题看了API都不用发帖子的~~

[zhouxuegangjava163]

你好，楼主！
stmt.close();
conn.close();

[Iris5]

我对数据库操作不熟悉，能否把代码放在整个程序中？非常感谢！

[weberwong]

没找到你在哪调用的connectDB2()，在调用方的最后关闭连接，一般打开和关闭配对用就可以了

[woaiyanzic]

package d123;

import java.sql.Connection;
import java.sql.Statement;

public class POIDZ {
	public static Connection conn = null;
	public static Statement stmt = null;

	public static boolean connectDB2() {
		try {
			Class.forName("org.gjt.mm.mysql.Driver");
			String url = "jdbc:mysql://localhost:3306/dstore";
			conn = DriverManager.getConnection(url, "root", "123");
			stmt = conn.createStatement();
		}
		// 捕获加载驱动程序异常
		catch (ClassNotFoundException cnfex) {
			cnfex.printStackTrace();
			return false;
		}
		// 捕获连接数据库异常
		catch (SQLException sqlex) {

			sqlex.printStackTrace();
			// System.exit(1); // terminate program
			return false;
		}
		return true;
	}

	public static boolean readExcelToDB2(String userName,String fahao) {
	  POIFSFileSystem fs = null;
	  HSSFWorkbook wb = null;
	  FileInputStream fjexl = null;
	  try {
		  fjexl = new FileInputStream("D:\\Tomcat6.0\\webapps\\aas\\upload\\"+userName+".xls");
		  fs = new POIFSFileSystem(fjexl);
		  wb = new HSSFWorkbook(fs);
		  fjexl.close();
	  } catch (IOException e) {
		  e.printStackTrace();
		  return false;
	  }
	  HSSFSheet sheet = wb.getSheetAt(0);
	  HSSFRow row = null;
	  HSSFCell cell = null;
	 
	  String shoudaot ="8";
	  long jieshoutimet =7;
	  int rowNum, cellNum;
	  int i;
	  rowNum = sheet.getLastRowNum();
	
	  for (i = 3; i <= 30; i++) { ---->第一个循环
		  row = sheet.getRow(i);
		  // cellNum = row.getLastCellNum();
		 try{
		     cell = row.getCell((short) 10);
			 cell.setEncoding(HSSFCell.ENCODING_UTF_16);
			 dongci = cell.getStringCellValue().trim();
			 dongci=new String(dongci.getBytes("GBK"),"latin1");
		}catch(Exception e){
		}
		  if (haomat!=0 & jieshou!="" & shengdan!=""){
			  String sql = "insert into dingzhi(user,name) values('"+userName+"','"+namet+"')";
			  try {
				  stmt.executeUpdate(sql);
				  shengdan="";
			  } catch (SQLException e1) {
				  e1.printStackTrace();
				  return false;
			  }
			  stmt.close();
			  conn.close();
		  }
	  }
	  rowNum = sheet.getLastRowNum();
	
	  for (i = 3; i <= 30; i++) { ----》第二个循环
	  row = sheet.getRow(i);
	  // cellNum = row.getLastCellNum();
	  try{
		  cell = row.getCell((short) 0);
		 cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		 name = cell.getStringCellValue().trim();
		name=new String(name.getBytes("GBK"),"latin1");
		name = name.substring(0, 20);
		}catch(Exception e){
		
		}
	  if (name!="-"){
		  String sql = "insert into listuser(username,liantong) values('"+name+"','"+liantong+"')";
	  try {
		  stmt.executeUpdate(sql);
	  } catch (SQLException e1) {
		  e1.printStackTrace();
		  return false;
	  }
	  stmt.close();
	  conn.close();
	  }
	  }
	  return true;
	  
 }
}

这个代码格式真成问题看着很累啊