ajax+servlet实例.docx

一、用户注册的JSP页面var XMLHttpReq; /创建XMLHttpRequest对象 function createXMLHttpRequest() if(window.XMLHttpRequest) /Mozilla 浏览器XMLHttpReq = new XMLHttpRequest();else if (window.ActiveXObject) / IE浏览器try XMLHttpReq = new ActiveXObject(Msxml2.XMLHTTP); catch (e) try XMLHttpReq = new ActiveXObject(Microsoft.XMLHTTP); catch (e) /发送请求函数function sendRequest(url) createXMLHttpRequest();XMLHttpReq.open(GET, url, true);XMLHttpReq.onreadystatechange = processResponse;/指定响应函数XMLHttpReq.send(null); / 发送请求/ 处理返回信息函数 function processResponse() if (XMLHttpReq.readyState = 4) / 判断对象状态 if (XMLHttpReq.status = 200) / 信息已经成功返回，开始处理信息 var res=XMLHttpReq.responseXML.getElementsByTagName(res)0.firstChild.data; window.alert(res); else /页面不正常 window.alert(您所请求的页面有异常。); / 注册函数 function signUp() var uname = document.myform.uname.value;var psw = document.myform.psw.value;var psw2 = document.myform.psw2.value;if(uname=) window.alert(用户名不能为空。);document.myform.uname.focus();return false;else if(psw!=psw2) window.alert(两次输入密码不同。);document.myform.psw.focus();return false;else sendRequest(signUp?uname=+ uname + &psw= + psw);用户名： 密  码： 重输密码： 运行图：二、处理AJAX请求的servletpackage classmate;import java.io.IOException;import java.io.PrintWriter;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class SignUpAction extends HttpServlet public void init(ServletConfig config) throws ServletException /* * 处理 请求方法. */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException /设置接收信息的字符集 request.setCharacterEncoding(UTF-8); /接收浏览器端提交的信息String uname = request.getParameter(uname);String psw = request.getParameter(psw);/设置输出信息的格式及字符集 response.setContentType(text/xml; charset=UTF-8); response.setHeader(Cache-Control, no-cache); /创建输出流对象 PrintWriter out = response.getWriter(); /依据验证结果输出不同的数据信息 out.println(); /数据库操作 DB db = new DB();ResultSet rs;int insRes = 0; String strSql=null; /判断用户名是否重复 strSql = select * from classuser where username=+ uname + ;rs = db.executeQuery(strSql);boolean bnoRepeat = false;try if ( !rs.next() bnoRepeat = true; catch (SQLException e) e.printStackTrace(); /用户名不重复,插入记录if (bnoRepeat) strSql = Insert Into classuser values(+ uname + , + psw + );insRes = db. executeUpdate(strSql); if(!bnoRepeat)out.println( + 注册失败!用户名已存在，重新输入用户名 + );else if(insRes0)out.println( + 注册成功！ + );elseout.println( + 注册失败！ + );out.println();out.close(); 三、数据库操作类：package classmate;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class DB Connection connect = null;ResultSet rs = null;public DB() try Class.forName(org.gjt.mm.mysql.Driver); /设置驱动程序类型catch(java.lang.ClassNotFoundException e) e.printStackTrace();/执行查询语句的方法public ResultSet executeQuery(String sql) try /建立与数据库服务器的连接 onnect = DriverManager.getConnection(jdbc:mysql:/:3306/test1, root, ); tatement stmt = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);rs = stmt.executeQuery(sql);/执行指定的数据查询语句 catch(SQLException ex) ex.printStackTrace();return rs; /执行增、删改语句的方法public int executeUpdate(String sql) int result = 0;try connect = DriverManager.getConnection(jdbc:mysql:/:3306/test1, root, ); Statement stmt = connect.createStatement();result = stmt.executeUpdate(sql);/执行指定的数据操作语句 catch(SQLException ex) System.err.println(ex.getMessage();return result;/关闭数据库连接的方法pub