JavaWeb銜接數據庫MySQL的操作技巧。本站提示廣大學習愛好者：（JavaWeb銜接數據庫MySQL的操作技巧）文章只能為提供參考，不一定能成為您想要的結果。以下是JavaWeb銜接數據庫MySQL的操作技巧正文
數據庫是編程中重要的一局部，它囊括了數據操作，數據耐久化等各方面。在每一門編程言語中都占有相當大的比例。
本次，我以MySQL為例，運用MVC編程思想(請參閱我之前的博客)。復雜演示一下JavaWeb對數據庫的操作。
1：我們需求掌握復雜的SQL語句，並且會復雜操作圖形化的數據庫。我們在數據庫建一個表(Users)可以在外面隨意添加幾條數據。
2：接上去，我們取得驅動並銜接到MySQL。
package com.joker.web.db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBConnection {
private static Connection con = null;
// 驅動順序名
private static String driverName = "com.mysql.jdbc.Driver";
// 數據庫用戶名
private static String userName = "root";
// 密碼 1
private static String userPasswd = "*****";
// 數據庫名
private static String dbName = "jokertest";
// 聯合字符串
private static String url = "jdbc:mysql://localhost/" + dbName + "?user="
+ userName + "&password=" + userPasswd
+ "&useUnicode=true&characterEncoding=gbk";
public static Connection getConnection() {
try {
// 1.驅動
Class.forName(driverName);
// 2. 銜接數據庫 堅持銜接
con = DriverManager.getConnection(url);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return con;
}
public static void closeConnection() {
if (con != null) {
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}<span >
</span>
3.寫我們的Dao文件,即對數據庫的增刪改查
package com.joker.web.dao;
import java.sql.*;
import java.util.*;
import com.joker.web.db.DBConnection;
import com.joker.web.entity.User;
public class UserDao {
// 查找一切數據，前往List集合
public List<User> selectAll() {
Connection con = DBConnection.getConnection();// 銜接數據庫 堅持銜接
Statement stmt;
List<User> list = new ArrayList<User>();
try {
stmt = con.createStatement();// 執行SQL語句
ResultSet rs = stmt.executeQuery("SELECT * FROM users");// 查找
// 數據前往後果集
while (rs.next()) {
User user = new User();
user.setId(rs.getInt("id"));
user.setUserName(rs.getString("USER_NAME"));
user.setDisplayName(rs.getString("DISPLAY_NAME"));
user.setPwd(rs.getString("PWD"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBConnection.closeConnection();
}
return list;
}
// 按條件查找
// where USER_NAME='"+ name + "' and PWD='" + pwd + "'
public User selectWhere(String whereOption) {
Connection con = DBConnection.getConnection();// 銜接數據庫 堅持銜接
Statement stmt;
User user = null;
try {
stmt = con.createStatement();// 執行SQL語句
String sql = "SELECT * FROM users ";
if (!whereOption.equals("")) {
sql += whereOption;
}
// 查找數據前往後果集
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
user = new User();
user.setUserName(rs.getString("USER_NAME"));
user.setDisplayName(rs.getString("DISPLAY_NAME"));
user.setPwd(rs.getString("PWD"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBConnection.closeConnection();
}
return user;
}
// 新增
public int insert(User user) {
Connection con = DBConnection.getConnection();
PreparedStatement pstmt = null;
String sql = " insert into users(user_name,pwd,display_name) values(?,?,?)";
// 添加用prepareStatement
int count = 0;
try {
pstmt = con.prepareStatement(sql);
pstmt.setString(1, user.getUserName());
pstmt.setString(2, user.getPwd());
pstmt.setString(3, user.getDisplayName());
count = pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return count;
}
// 修正
public int upDate(User user) {
Connection con = DBConnection.getConnection();
PreparedStatement pstmt = null;
String sql = " update users " + " set user_name = ? , " + " pwd = ? , "
+ " display_name= ? " + " where id= ? ";
int count = 0;
try {
pstmt = con.prepareStatement(sql);
pstmt.setString(1, user.getUserName());
pstmt.setString(2, user.getPwd());
pstmt.setString(3, user.getDisplayName());
pstmt.setInt(4, user.getId());
count = pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return count;
}
// 刪除
public int delete(int id) {
Connection con = DBConnection.getConnection();
PreparedStatement pstmt = null;
String sql = " delete from users where id = ?";
int count = 0;
try {
pstmt = con.prepareStatement(sql);
pstmt.setInt(1, id);
count = pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
DBConnection.closeConnection();
}
return count;
}
public List<User> selectPage(int from, int rows) {
Connection con = DBConnection.getConnection();// 銜接數據庫 堅持銜接
Statement stmt;
List<User> list = new ArrayList<User>();
try {
stmt = con.createStatement();// 執行SQL語句
ResultSet rs = stmt.executeQuery("SELECT * FROM users LIMIT "
+ from + "," + rows);
while (rs.next()) {
User user = new User();
user.setId(rs.getInt("id"));
user.setUserName(rs.getString("USER_NAME"));
user.setDisplayName(rs.getString("DISPLAY_NAME"));
user.setPwd(rs.getString("PWD"));
list.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBConnection.closeConnection();
}
return list;
}
// 前往一切數劇條數
public int selectCount() {
Connection con = DBConnection.getConnection();// 銜接數據庫 堅持銜接
Statement stmt;
int count =0 ;
try {
stmt = con.createStatement();// 執行SQL語句
ResultSet rs = stmt.executeQuery("SELECT count(1) count FROM users");
while (rs.next()) {
count = rs.getInt("count");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBConnection.closeConnection();
}
return count;
}
}<span >
</span>
4.運用Servlet當控制器，在Servlet對網頁上的數據停止操作。
package com.joker.web.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import com.joker.web.dao.UserDao;
import com.joker.web.entity.User;
public class UserServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public UserServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String action = request.getParameter("action");
if (action.equals("select")) {
select(request, response);
} else if (action.equals("update")) {
update(request, response);
} else if (action.equals("add")) {
insert(request, response);
} else if (action.equals("delete")) {
delete(request, response);
}
}
// 新增
private void insert(HttpServletRequest request, HttpServletResponse response)
throws IOException {
String uName = request.getParameter("userName");
String pwd = request.getParameter("user");
String dName = request.getParameter("displayName");
User user = new User();
user.setUserName(uName);
user.setPwd(pwd);
user.setDisplayName(dName);
UserDao uDao = new UserDao();
int affCount = uDao.insert(user);
PrintWriter out = response.getWriter();
// 將受影響數據的數量前往給jsp
out.print(affCount);
}
// 刪除
private void delete(HttpServletRequest request, HttpServletResponse response)
throws IOException {
String[] ids = request.getParameterValues("uid[]");
UserDao ud = new UserDao();
int count = 0;
for (int i = 0; i < ids.length; i++) {
count += ud.delete(Integer.parseInt(ids[i]));
}
PrintWriter out = response.getWriter();
out.print(count);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException
* if an error occurs
*/
public void init() throws ServletException {
System.out.println("處室執行！！！！！！！！！！！！！！！");
}
// 查詢
public void select(HttpServletRequest request, HttpServletResponse response)
throws IOException {
String page = request.getParameter("page");
String rows = request.getParameter("rows");
System.out.println("page:" + page + " rows:" + rows);
UserDao ud = new UserDao();
int rowsCount = Integer.parseInt(rows);
int from = (Integer.parseInt(page) - 1) * rowsCount;
List<User> list = ud.selectPage(from, rowsCount);
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("total", ud.selectCount());
map.put("rows", list);
// JSONArray ja = JSONArray.fromObject(list);
JSONObject jo = JSONObject.fromObject(map);// 單條數據
PrintWriter out = response.getWriter();
System.out.println(jo.toString());
// 將json數據前往給jspData-grid的url。
out.println(jo.toString());
}
// 修正
public void update(HttpServletRequest request, HttpServletResponse response)
throws IOException {
String id = request.getParameter("id");
String uName = request.getParameter("userName");
String pwd = request.getParameter("pwd");
String dName = request.getParameter("displayName");
User user = new User();
user.setId(Integer.parseInt(id));
user.setUserName(uName);
user.setPwd(pwd);
user.setDisplayName(dName);
UserDao uDao = new UserDao();
int affCount = uDao.upDate(user);
PrintWriter out = response.getWriter();
// 將受影響數據的數量前往給jsp
out.print(affCount);
}
}<span >
</span>
5.運用Easy-UI框架，是數據庫內容在頁面停止顯示
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML>
<html>
<head>
<base href="<%=basePath%>" rel="external nofollow" >
<title>main.jsp</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<link rel="stylesheet" href="CSS/easyui.css" rel="external nofollow" type="text/css"></link>
<link rel="stylesheet" href="CSS/icon.css" rel="external nofollow" type="text/css"></link>
<script type="text/javascript" src="JS/jquery-1.8.2.min.js"></script>
<script type="text/javascript" src="JS/jquery.easyui.min.js"></script>
<script type="text/javascript">
var addFlags = true;
$(function() {
$('#dg')
.datagrid(
{
title : '用戶列表',
url : 'servlet/UserServlet?action=select',
fitColumns : true,/* 自順應寬度 */
striped : true,/* 斑馬線效果 */
pagination : true,/* 底部顯示分頁工具欄 */
singleSelect : false,/* 只允許選擇一行 */
rownumbers : true,/* 顯示一個行號列 */
ctrlSelect : true,/* 允許運用Ctrl鍵+鼠標點擊的方式停止多選操作 */
iconCls : 'icon-ok',
checkOnSelect : true,/* 點擊行的時分該復選框就會被選中或取消選中 */
selectOnCheck : true,/* 單擊復選框將永遠選擇行 */
pagination : true,
nowrap : true,
rownumbers : true,
collapsible : true,//能否可折疊的
pageSize : 5,//每頁顯示的記載條數，默許為10
pageList : [ 2, 4 ,5],//可以設置每頁記載條數的列表
toolbar : [
{
text : '查詢',
iconCls : 'icon-search',
handler : function() {
$('#dg').datagrid('reload');
}
},
'-',
{
text : '修正',
iconCls : 'icon-edit',
handler : function() {
alert('協助按鈕');
}
},
'-',
{
text : '添加',
iconCls : 'icon-add',
handler : function() {
if(addFlags){
$('#dg').datagrid('insertRow',{
index: 0, // 索引從0開端
row: {}
});
var editIndex = 0;
$('#dg').datagrid('selectRow',editIndex)
.datagrid('beginEdit',editIndex);
addFlags = false;
}
/* , $('#dlg').dialog('open')
.dialog('center').dialog(
'setTitle',
'New User');
$('#fm').form('clear') */
}
},
'-',
{ text : '刪除',
iconCls : 'icon-remove',
handler : function() {
$.messager.confirm("信息確認","確定刪除嗎?",
function(ret) {
if (ret) {
var row = $("#dg").datagrid("getSelections");
if (row.length == 0) {
$.messager.alert("提示:","請選擇刪除的數據");
return;
}
var ids = [];
for ( var i = 0; i < row.length; i++) {
ids.push(row[i].id);
}
$.post("servlet/UserServlet?action=delete",
{uid : ids},
function(data) {
if (data > 0) {
$('#dg').datagrid('reload');
alert("刪除成功");
} else {
alert("刪除失敗");
}
});
}
});
}
} ],
columns : [ [
{
field : 'ck',
checkbox : true,
width : 50,
},
{
field : 'id',
hidden : true,
},
{
field : 'userName',
title : '用戶名',
align : 'center',
editor : 'text',
width : 100
},
{
field : 'pwd',
title : '密碼',
width : 100,
editor : 'text',
align : 'center'
},
{
field : 'displayName',
title : '級別',
width : 100,
height : 100,
editor : 'text',
align : 'center'
},
{
field : 'option',
title : '操作',
width : 100,
align : 'center',
formatter : function(value, row, index) {
if (row.editing) {
var s = '<a href="javascript:void(0);" rel="external nofollow" rel="external nofollow" onclick="saverow('
+ index + ')">保管</a>'+' '
+'<a href = "javascript:void(0);" onclick="canclerow('
+ index + ')">取消</a>';
return s;
} else {
var e = '<a href="javascript:void(0);" rel="external nofollow" rel="external nofollow" onclick="editrow('
+ index + ')">編輯</a>';
return e;
}
}
} ] ],
onBeforeEdit : function(index, row) {
row.editing = true;
$("#dg").datagrid("refreshRow", index);
},
onAfterEdit : function(index, row) {
row.editing = false;
$("#dg").datagrid("refreshRow", index);
}
});
//設置分頁控件
var p = $('#dg').datagrid('getPager');
$(p).pagination({
beforePageText : '第',//頁數文本框前顯示的漢字
afterPageText : '頁 共 {pages} 頁',
displayMsg : '以後顯示 {from} - {to} 條記載 共 {total} 條記載'
});
});
function editrow(index) {
var row = $("#dg").datagrid("getSelected");
if (row == null) {
alert("請選擇您要編輯的行");
return;
}
$("#dg").datagrid("beginEdit", index);
}
function saverow(index) {
$("#dg").datagrid("endEdit", index);
var row = $("#dg").datagrid("getSelected");
if(addFlags) {
dbSave(row);
} else {
dbAdd(row);
}
addFlags = true;
}
function canclerow(index) {
$("#dg").datagrid("rejectChanges");
$('#dg').datagrid('reload');
addFlags = true;
}
function dbSave(row) {
var name = row.userName;
var uid = row.id;
var pwd = row.pwd;
var dname = row.displayName;
$.post("servlet/UserServlet?action=update", {
id : uid,
userName : name,
pwd : pwd,
displayName : dname
}, function(data) {
if (data == "1") {
alert("修正成功");
} else {
alert("修正失敗");
}
});
alert(row.userName + "-" + row.pwd + "-" + row.displayName);
}
function dbAdd(row) {
var name = row.userName;
var pwd = row.pwd;
var dname = row.displayName;
$.post("servlet/UserServlet?action=add", {
userName : name,
pwd : pwd,
displayName : dname
}, function(data) {
if (data == "1") {
alert("添加成功");
} else {
alert("添加失敗");
}
});
}
</script>
<body>
<%-- ${sessionScope.user.userName}
${sessionScope.user.dislayName} --%>
<table class="easyui-datagrid" id="dg">
</table>
</body>
</html><span >
</span>
6.各個操作詳細圖片:
6.1添加:添加（張三 666 學生 這條數據）默許顯示五條數據
6.2 刪除剛剛拔出的數據
6.3 修正數據(修正的ID主鍵為10的數據)
以上所述是給大家引見的JavaWeb銜接數據庫MySQL的操作技巧，希望對大家有所協助，假如大家有任何疑問請給我留言，會及時回復大家的。在此也十分感激大家對網站的支持！
