java数据库操作类演示实例分享(java连接数据库)

package org.load.demo;

import java.io.ioexception;
import java.util.list;
import java.util.map;

import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;

import com.loadphp.simple4j.contentvalues;
import com.loadphp.simple4j.db;
import com.loadphp.simple4j.utils;

public class myservlet extends httpservlet {

 @override
 protected void doget(httpservletrequest req, httpservletresponse resp)
   throws servletexception, ioexception {
  string action = req.getparameter("action");
  if("show".equalsignorecase(action)) {
   this.findall(req, resp);
  }else if("del".equalsignorecase(action)) {
   this.del(req, resp);
  }else if("edit".equalsignorecase(action)) {
   this.find(req, resp);
  }else if("update".equalsignorecase(action)) {
   this.update(req, resp);
  }else if("insert".equalsignorecase(action)) {
   this.insert(req, resp);
  }
 }

 @override
 protected void dopost(httpservletrequest req, httpservletresponse resp)
   throws servletexception, ioexception {
  this.doget(req, resp);
 }
 

 private void findall(final httpservletrequest req, httpservletresponse resp) {
//  db db = this.getdb();
//  list<map<string, object>> userlist = db.findall("*");  // 查询全部
//  db.close();
//  req.setattribute("userlist", userlist);
//  try {
//   req.getrequestdispatcher("/index.jsp").forward(req, resp);
//  } catch (servletexception e) {
//   e.printstacktrace();
//  } catch (ioexception e) {
//   e.printstacktrace();
//  }

  db db = this.getdb();
  db.findall(new db.queryallcallback() {
   public void callback(list<map<string, object>> list) {
    req.setattribute("userlist", list);
   }
  }, "*");

  try {
   req.getrequestdispatcher("/index.jsp").forward(req, resp);
  } catch (servletexception e) {
   e.printstacktrace();
  } catch (ioexception e) {
   e.printstacktrace();
  }
 }

 private void del(httpservletrequest req, httpservletresponse resp) {
  db db = this.getdb();
  db.where(new contentvalues().put("id", req.getparameter("id"))).del();
  db.close();
  this.findall(req, resp);
 }

 private void find(final httpservletrequest req, httpservletresponse resp) {
  db db = this.getdb();
//  map<string, object> map = db.where(new contentvalues().put("id", req.getparameter("id"))).find(
//    "id", "name", "birthday", "pwd");

  db.find(new db.querycallback() {
   public void callback(map<string, object> map) {
    req.setattribute("user", map);
   }
  }, "id","name","birthday");

  db.close();

  try {
   req.getrequestdispatcher("/edit.jsp").forward(req, resp);
  } catch (servletexception e) {
   e.printstacktrace();
  } catch (ioexception e) {
   e.printstacktrace();
  }
 }

 private void insert(httpservletrequest req, httpservletresponse resp) {
  db db = this.getdb();
  db.insert(utils.params2array(req, 3, "null","user","birth","pwd"));
  db.close();
  this.findall(req, resp);
 }

 private void update(httpservletrequest req, httpservletresponse resp) {
  db db = this.getdb();
  db.where(new contentvalues().put("id", req.getparameter("id"))).update(
    new contentvalues().put("name", req.getparameter("user"))
      .put("pwd", utils.md5(req.getparameter("pwd")))
      .put("birthday", req.getparameter("birth")));
  db.close();
  this.findall(req, resp);
 }

 private db getdb() {
//  db.driver = "com.mysql.jdbc.driver";               // driver
  db.uri = "jdbc:mysql://localhost:3306/forjava";    // uri
//  db.user = "root";                                  // mysql用户名
//  db.pwd = "";            // mysql密码
  db.connect("utf-8");          // 连接数据库并设置编码
  return db.init("users");         // 设置操作的表名，并返回数据库操作对象
 }
}