Web服務器連接Mysql登錄查詢功能小測試
需要的工具
Mysql、Eclipse ide、tomcat（工程中需要的jar包：mysql-connector-java-8.0.19.jar）
因爲我的Mysql是8.0.19版本的所以下載是這個，如果是5開頭的版本，最好是下載5版本開頭的jar，博主就因爲這個的錯誤失敗很多次，其中網上很多的資源使用還會有錯誤。具體添加方法見博客link
需要jar資源的可以私我[email protected] | [email protected]
一、數據庫中的配置：見下圖。
數據庫名稱mydb 表：user 表中內容（username，password）
二、數據庫配置好後，開始寫程序
下面是建立工程的目錄
多餘的我就不說了，直接上代碼
MyServlet.java中的內容
package cdu.nls.login;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class MyServlet
*/
@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String ID = request.getParameter("ID");
String PW= request.getParameter("PW");
boolean type=false;
response.setContentType("text/html; charset=UTF-8");
PrintWriter out = response.getWriter();
try {
Class.forName("com.mysql.jdbc.Driver");//加載數據庫驅動，註冊到管理器
String url = "jdbc:mysql://localhost:3306/mydb?serverTimezone= UTC&characterEncoding=utf-8";
Connection con = DriverManager.getConnection(url,ID,PW);
if(con != null) {
out.println("mysql connection successful!");
con.close();
request.getRequestDispatcher("user_login.jsp").forward(request,response);
System.out.print("login_mysql_successful\n");
out.print("haha");
}
else {
out.println("mysql connection failture!");
}
} catch(ClassNotFoundException e) {
e.printStackTrace();
}catch (SQLException e) {
e.printStackTrace();
}
out.println(type);
out.flush();
out.close();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
Myservlet1.java中的內容：此部分功能是連接Mysql並查詢內容
package cdu.nls.login;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.DriverManager;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.Connection;
@WebServlet("/MyServlet1")
public class MyServlet1 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String user2 = request.getParameter("username");
String pass2= request.getParameter("password");
boolean type= false;
PrintWriter out = response.getWriter();
java.sql.Statement stmt = null;//設置stmt全局變量
System.out.print("獲取jsp界面的：");
System.out.print(" "+user2);
System.out.print(" ");
System.out.print("length:"+user2.length());
System.out.print(" "+pass2);
System.out.print(" ");
System.out.print("length:"+pass2.length());
try
{
Class.forName("com.mysql.jdbc.Driver");//加載數據庫驅動，註冊到管理器
String url = "jdbc:mysql://localhost:3306/mydb?serverTimezone= UTC&characterEncoding=utf-8";
Connection con = DriverManager.getConnection(url,"root","123456");//此處
stmt = con.createStatement();//實例化Statement對象，用stmt接收
String sql;//定義一個string類型的數據變量sql
sql = "SELECT username, password FROM user";//用sql接收數據庫語句
ResultSet rs = stmt.executeQuery(sql); //執行sql
// 展開結果集數據庫
while(rs.next()){
// 通過字段檢索
String use1 = rs.getString("username");
String pass1 = rs.getString("password");
System.out.print("\nmysql中獲取的內容：\nmysql_username: " + use1);
System.out.print(" ");System.out.print("length:"+use1.length());
System.out.print(" mysql_password: " + pass1);System.out.print(" ");
System.out.print("length:"+pass1.length());
if(use1.contentEquals(user2) &&pass1.contentEquals(pass2))
{
type=true;
System.out.print("\nlogin mysql successful!");
out.print("\nlogin mysql successful!");
}
}
// 完成後關閉
rs.close();
stmt.close();
con.close();
}
catch(Exception ex)
{
ex.printStackTrace();
}
finally
{
// con.Close();
out.print(type);
out.flush();
out.close();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
index.jsp(首頁：登錄Mysql的用戶名密碼，成功跳轉到user_login.jsp)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import = "java.sql.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>hello（此頁登錄您的數據庫用戶名和密碼）</h1>
<form id="from1" action="MyServlet" method="post">
<table>
<tr><td>用戶名</td><td><input type="text" name="ID"></td></tr>
<tr><td>密碼</td><td><input type="password" name="PW"></td></tr>
<tr><td colspan = "3" align = "center"><input type = "submit" value = "login_mysql" id = "btnde1" onclick="del(id)"/></td></tr>
</table>
</form>
</body>
</html>
user_login.jsp(登錄數據表中存放的內容，功能就是查詢數據庫信息)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<td colspan = "3" align = "center">
<h1>user login（此頁是您數據庫中數據表中存的內容）</h1></td>
<form id="from1" action="MyServlet1" method="post">
<table>
<tr><td>username</td><td><input type="text" name="username"></td></tr>
<tr><td>password</td><td><input type="password" name="password"></td></tr>
<tr><td colspan = "3" align = "center"><input type = "submit" value = "login" id = "btnde2" onclick="del(id)"/></td></tr>
</table>
</form>
</body>
</html>
運行成功
1.index.jsp(輸入您的數據庫用戶名密碼)
2.成功後跳轉界面user_login.jsp(現在輸入user表中的存放內容)
3.成功返回信息（下面打印你輸入的信息及mysql中查詢的信息）
