DBUtils的综合应用--DBUtils连接池管理工具对连接池的管理

来源：互联网发布：淘宝军用正品望远镜编辑：程序博客网时间：2024/06/08 11:26

1.首先在Tomcat的conf/context.xml中作如下配置。

</Context>

2.在配置中引入mysql-connector-java-5.1.11-bin.jar和commons-dbutils-1.3.jar

3.创建一个得到连接的类DBHelper.java

package com.jxau;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;

public class DBHelper {
public static QueryRunner getQueryRunner(){
  DataSource ds=null;
  try{
   Context context=new InitialContext();
   ds=(DataSource)context.lookup("java:/comp/env/jdbc/mysqlds");
  }catch(Exception e){
   e.printStackTrace();
   System.out.println("加载数据库出错！！！");
  }
  QueryRunner qr=new QueryRunner(ds);
  return qr;
}
}

4.在应用程序中调用DBHelper.java来操作数据库，如：

package com.jxau;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.dbutils.QueryRunner;

import com.jxau.*;

public class CateGoryServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

  response.setContentType("text/html");
  request.setCharacterEncoding("UTF-8");

  String method=request.getParameter("method");


  if(method.equals("add")){
   this.add(request, response);
  }else if(method.equals("delete")){
   this.delete(request,response);
  }

}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

  this.doGet(request, response);
}

public void delete(HttpServletRequest request,HttpServletResponse response)
   throws ServletException,IOException{

}

public void add(HttpServletRequest request,HttpServletResponse response)
   throws ServletException,IOException{
  response.setCharacterEncoding("UTF-8");
  String name=request.getParameter("name");
  String level=request.getParameter("level");
  String sql="insert into category(name,level) values(?,?)";
  String params[]={name,level};

  QueryRunner qr=DBHelper.getQueryRunner();

  int result=0;
  String message="";
  try {
   result=qr.update(sql, params);
  } catch (SQLException e) {
   e.printStackTrace();
  }

  if(result==1){
   message="博客添加分类成功";
  }else{
   message="博客添加分类失败";
  }

  request.setAttribute("message", message);
  request.getRequestDispatcher("/add.jsp").forward(request, response);
}

}

5.查询的时候一般用以下的方式，它更体现了面向对象的思想。

List<Blog> list=(List<Blog>)qr.query(sql, new BeanListHandler(Blog.class));
Blog blog=(Blog)list.get(0);

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