JAVA留言板_java项目实例源码

java实现简单留言板功能的代码实例

数据库对应的表：

guestbook：id ,name,phone,email,title,content,time;                   id

新建web project：guestbook

build Path：引入连接数据库的驱动的类库

在webRoot目录中加入：

+faceditor

+js

web.xml

代码：

xmlns=”http://java.sun.com/xml/ns/javaee”

xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance”

xsi:schemaLocation=”http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd”>

AddMessageServlet

webbook.guestbook.AddMessageServlet

GetMessagesServlet

webbook.guestbook.GetMessagesServlet

AddMessageServlet

/servlet/addMessage

GetMessagesServlet

/servlet/getMessages

addMessage.htm

代码：

add message

请您输入留言

查看留言

content.html

display content

validation-config.xml

代码；

———————————————————————

******************************************************

这是一个很有用的工具类，包含了：

判读字符串参数是否为空：validateNull(String args)

判断输入的字符串参数是否为空或者是”null”字符：chanageNull(String source, String target)

过滤,n 字符的方法：filterHtml(String input)

*****************************************************

———————————————————————

StringUtil.java

代码：

package webbook.util;

public class StringUtil {

/**

* 判断输入的字符串参数是否为空。

* @param args 输入的字串

* @return true/false

*/

public static boolean validateNull(String args) {

if (args == null || args.length() == 0) {

return true;

} else {

return false;

}

}

/**

* 判断输入的字符串参数是否为空或者是”null”字符,如果是,就返回target参数,如果不是,就返回source参数。

*/

public static String chanageNull(String source, String target) {

if (source == null || source.length() == 0 || source.equalsIgnoreCase(“null”)) {

return target;

} else {

return source;

}

}

/**

* 过滤,n 字符的方法。

* @param input 需要过滤的字符

* @return 完成过滤以后的字符串

*/

public static String filterHtml(String input) {

if (input == null) {

return null;

}

if (input.length() == 0) {

return input;

}

input = input.replaceAll(“&”, “&”);

input = input.replaceAll(“

input = input.replaceAll(“>”, “>”);

input = input.replaceAll(” “, ” “);

input = input.replaceAll(“‘”, “‘”);

input = input.replaceAll(“””, “””);

input = input.replaceAll(“n”, “
“);

return input;

}

}

AddmessageServlet.java

代码；

package webbook.guestbook;

import java.io.IOException;

import java.io.PrintWriter;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.SQLException;

import java.text.SimpleDateFormat;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import webbook.util.StringUtil;

public class AddMessageServlet extends HttpServlet {

private static final long serialVersionUID = -8349454122547148005L;

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

String url = “jdbc:oracle:thin:@192.168.1.20:1521:ora9”;

String username = “scott”;

String password = “tiger”;

String sql = “insert into guestbook (id,name,email,phone,title,content,time) values(gb_seq.nextval,?,?,?,?,?,?)”;

int result = 0;

Connection conn = null;

request.setCharacterEncoding(“utf-8”);

String name = request.getParameter(“name”);

String title = request.getParameter(“title”);

response.setContentType(“text/html;charset=utf-8”);

PrintWriter out = response.getWriter();

out.println(“”);

out.println(“

guestbook input page”);

out.println(“

“);

if (StringUtil.validateNull(name)) {

out.println(“对不起，姓名不能为空，请您重新输入！
“);

out.println(“添加新的留言
“);

} else if (StringUtil.validateNull(title)) {

out.println(“对不起，主题不能为空，请您重新输入！
“);

out.println(“添加新的留言
“);

} else {

try {

Class.forName(“oracle.jdbc.driver.OracleDriver”);

conn = DriverManager.getConnection(url, username, password);

PreparedStatement pstmt = conn.prepareStatement(sql);

pstmt.setString(1, StringUtil.filterHtml(name));

pstmt.setString(2, StringUtil.filterHtml(request.getParameter(“email”)));

pstmt.setString(3, StringUtil.filterHtml(request.getParameter(“phone”)));

pstmt.setString(4, StringUtil.filterHtml(title));

pstmt.setString(5, request.getParameter(“content”));

//设置格式化时间

SimpleDateFormat sdf = new SimpleDateFormat(“yyyy-MM-dd hh:mm:ss”);

pstmt.setString(6, sdf.format(new java.util.Date()));

result = pstmt.executeUpdate();

pstmt.close();

} catch (ClassNotFoundException e) {

e.printStackTrace();

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if (result == 0) {

out.println(“对不起，添加留言不成功，请您重新输入！
“);

out.println(“添加新的留言
“);

} else {

out.println(“祝贺您，成功添加留言。
“);

out.println(“查看所有留言内容
“);

}

out.println(“”);

out.println(“”);

out.flush();

out.close();

}

}

}

GetMessageServlet.java

代码：

package webbook.guestbook;

import java.io.*;

import java.sql.*;

import javax.servlet.*;

import javax.servlet.http.*;

import webbook.util.StringUtil;

public class GetMessagesServlet extends HttpServlet {

private static final long serialVersionUID = 5964428201228635704L;

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

String url = “jdbc:oracle:thin:@192.168.1.20:1521:ora9”;

String username = “scott”;

String password = “tiger”;

String sql = “select * from guestbook order by id desc”;

Connection conn = null;

response.setContentType(“text/html;charset=utf-8”);

PrintWriter out = response.getWriter();

out.println(“”);

out.println(“

display messages”);

out.println(“

“);

out.println(“添加新的留言内容
“);

out.println(“留言内容
“);

try {

Class.forName(“oracle.jdbc.driver.OracleDriver”);

conn = DriverManager.getConnection(url, username, password);

PreparedStatement pstmt = conn.prepareStatement(sql);

//查询结果是一个ResultSet对象。

ResultSet rs = pstmt.executeQuery();

while (rs.next()) {

this.printRow(out, rs);

}

rs.close();

pstmt.close();

} catch (ClassNotFoundException e) {

e.printStackTrace();

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

out.println(” “);

out.println(“”);

out.flush();

out.close();

}

private void printRow(PrintWriter out, ResultSet rs) throws SQLException {

out.println(“

out.println(“

编号”);

out.println(“

” + rs.getInt(“id”) + “”);

out.println(“

姓名” + rs.getString(“name”) + “”);

out.println(“

电话” +

StringUtil.chanageNull(rs.getString(“phone”), “没填”) +

“

“);

out.println(“

email” +

StringUtil.chanageNull(rs.getString(“email”), “没填”) +

“

“);

out.println(“

主题” + rs.getString(“title”) + ” “);

out.println(“

内容”);

out.println(“

” + StringUtil.chanageNull(rs.getString(“content”), “没填”) + “”);

out.println(“

时间” + rs.getString(“time”) + ” “);

out.println(“

“);

}

}