Trang JSP gọi hàm xử lý truy vấn dữ liệu MySQL từ class Java
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<b> Trang JSP gọi hàm xử lý truy vấn dữ liệu MySQL từ class Java </b>
<i> </i>
<b>Dữ liệu: </b>
Tạo database db_news
Tạo table categories
<b>Class Java: </b>
Database.java
<b>package</b> nguyenhuuthe;
<b>import</b> java.sql.Connection;
<b>import</b> java.sql.DriverManager;
<b>import</b> java.sql.ResultSet;
<b>import</b> java.sql.Statement;
<b>import</b> java.util.ArrayList;
<b>import</b> java.util.List;
<b>import</b> java.util.logging.Level;
<b>import</b> java.util.logging.Logger;
<b>public</b> <b>class</b> Database {
<b>static</b> <b>final</b> String url =
"jdbc:mysql://localhost:3306/db_news?useUnicode=true&characterEncoding=UTF-8";
<b>static</b> <b>final</b> String username = "root";
<b>static</b> <b>final</b> String password = "123456";
<b>public</b> <b>static</b> Connection conn(){
<b>try</b>{
<i>Class.forName(</i>"com.mysql.jdbc.Driver");
<i>Connection con =DriverManager.getConnection(url, username, password); </i>
<b>return</b> con;
}
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<b>return</b> <b>null</b>;
}
}
<b>public</b> <b>static</b> String toUTF8(String isoString)
{
String utf8String = <b>null</b>;
<b>try</b>
{
<b>byte</b>[] stringBytesISO = isoString.getBytes("ISO-8859-1");
utf8String = <b>new</b> String(stringBytesISO, "UTF-8");
}<b>catch</b>(Exception e) {
System.out.println("Unsupported Encoding Exception is: " + e.getMessage());
utf8String = isoString;
}
<b>return</b> utf8String;
}
<b>public</b> <b>static</b> <b>void</b> insertCate(String id, String name) {
<b>try</b> {
<i> Connection con = conn(); </i>
Statement st = con.createStatement();
String sql="insert into categories values ("+ id +", '"+ name +"')";
st.executeUpdate(sql);
st.close();
con.close();
} <b>catch</b> (Exception ex) {
<i> Logger.getLogger(Database.</i><b>class</b>.getName()).log(
Level.SEVERE, <b>null</b>, ex);
}
}
<b>public</b> <b>static</b> List<String> selectCate() {
List<String> list = <b>new</b> ArrayList<String>();
<b>try</b> {
String sql = "select * from categories";
<i> Connection con = conn(); </i>
Statement stmt = con.createStatement();
ResultSet result = stmt.executeQuery(sql);
<b>while</b>(result.next())
{
list.add(result.getString(1));
list.add(result.getString(2));
}
con.close();
} <b>catch</b> (Exception ex) {
<i> Logger.getLogger(Database.</i><b>class</b>.getName()).log(
Level.SEVERE, <b>null</b>, ex);
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<b>return</b> list;
}
<b>public</b> <b>static</b> <b>void</b> deleteCate(String id) {
<b>try</b> {
String sql = "delete from categories where category_id = "+ id;
<i> Connection con = conn(); </i>
Statement st = con.createStatement();
st.executeUpdate(sql);
st.close();
con.close();
} <b>catch</b> (Exception ex) {
<i> Logger.getLogger(Database.</i><b>class</b>.getName()).log(
Level.SEVERE, <b>null</b>, ex);
}
}
}
add_categories.jsp
<%@page import=<i>"nguyenhuuthe.Database"%></i>
<%@ page contentType=<i>"text/html; charset=UTF-8"</i> pageEncoding=<i>"UTF-8"%></i>
<%@ page import=<i>"java.sql.*"</i> %>
<html>
<head>
<meta http-equiv=<i>"Content-Type"</i> content=<i>"text/html; charset=UTF-8"></i>
<title>Books database</title>
<link rel=<i>"stylesheet"</i> href=<i>"style.css" type</i>=<i>"text/css"></i>
</head>
<body>
<br>
<div class=<i>"navigator"></i>
<a id=<i>"currenttab"</i> href=<i>"add_categories.jsp"></i>Add</a>
<a href=<i>"delete_categories.jsp"></i>Delete</a>
</div>
<%
String id = request.getParameter("id");
String name = request.getParameter("name");
<b>if</b> (id != <b>null</b> && name != <b>null</b>) {
name = nguyenhuuthe.Database.toUTF8(name);
nguyenhuuthe.Database.insertCate(id, name);
}
%>
<br> <br> <br>
<form method=<i>"post"</i> action=<i>"add_categories.jsp"></i>
<table>
<tr>
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<td>ID</td><td><input type=<i>"text"</i> name=<i>"id"></td></i>
</tr>
<tr>
<td>Name</td><td><input type=<i>"text"</i> name=<i>"name"></td></i>
</tr>
</table>
<br>
<input type=<i>"submit"</i> value=<i>"submit"></i>
</form>
</body>
</html>
delete_categories.jsp
<%@page contentType=<i>"text/html"</i> pageEncoding=<i>"UTF-8"%></i>
<%@page import=<i>"java.util.*"</i> %>
<html>
<head>
<title>Manager Categories</title>
<link rel=<i>"stylesheet"</i> href=<i>"style.css"</i> type=<i>"text/css"></i>
</head>
<body>
<%
Enumeration<String> names = request.getParameterNames();
<b>while</b> (names.hasMoreElements()) {
String name = (String) names.nextElement();
StringBuffer sb = <b>new</b> StringBuffer(name);
sb.deleteCharAt(0);
nguyenhuuthe.Database.deleteCate(sb.toString());
}
%>
<br>
<div class=<i>"navigator"></i>
<a href=<i>"add_categories.jsp"></i>Add</a>
<a id=<i>"currenttab"</i> href=<i>"delete_categories.jsp"></i>Delete</a>
</div>
<br> <br> <br>
<form action=<i>"delete_categories.jsp"</i> method=<i>"post"></i>
<table>
<tr>
<th>ID</th>
<th>Name</th>
<th>Delete</th>
</tr>
<%
</div>
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<b>int</b> id = 0;
String box = <b>null</b>;
Iterator<String> it = list.iterator();
<b>while</b> (it.hasNext()) {
out.print("<tr>");
out.print("<td>");
id = Integer.parseInt(it.next());
out.print(id);
out.print("</td>");
out.print("<td>");
out.print(it.next());
out.print("</td>");
out.print("<td>");
box = "<input name=r" + id + " type='checkbox'>";
out.print(box);
out.print("</td>");
out.print("</tr>");
}
%>
</table>
<br>
<input type=<i>"submit"</i> value=<i>"Delete"></i>
</form>
</div>
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