注册页面的搭建

先用javaScript对form表单做处理

function dosubmit() {
var th = document.form1;
if (th.username.value == "") {
alert("用户名不能为空！！");
th.username.focus();
return;
}
if (th.realname.value == "") {
alert("姓名不能为空！！");
th.realname.focus();
return;
}
if (th.pswd.value == "") {
alert("密码不能为空！！");
th.pswd.focus();
return;
}
th.action="<%=path%>/servlet/RegisterAction";
th.submit();
}
</script>

还需要对jdbc连接mySql做简单的封装

package com.jdbc.util;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MySqlConnect {
private Connection conn;

private PreparedStatement preState;

private ResultSet resultSet;

public MySqlConnect() {
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
System.out.println("驱动注册成功！");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}

public Connection getConnect() {

try {
conn = DriverManager.getConnection("jdbc:mysql://localhost/mydata?"
+ "user=root&password=root");
System.out.println("数据库连接成功！");
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}

/**
* 封装的删除 增加 修改操作
*
* @param sql
*            执行的sql语句
* @param params
*            sql语句的占位符
* @return 操作是否成功
* @throws SQLException
*/
public boolean updataByPrepareStatement(String sql, List<Object> params)
throws SQLException {
boolean flag = false;
// 执行数据操作所影响的行数
int result = -1;
preState = conn.prepareStatement(sql);
int index = 1;
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
preState.setObject(index++, params.get(i));
}
}
result = preState.executeUpdate();
flag = result > 0 ? true : false;
return flag;

}

/**
* 封装单条语句查询
*
* @param sql
*            执行的sql语句
* @param params
*            执行sql语句的占位符
* @return 返回单条语句查询结果
* @throws SQLException
*/
public Map<String, Object> queryBySimpleResult(String sql,
List<Object> params) throws SQLException {
Map<String, Object> map = new HashMap<String, Object>();
preState = conn.prepareStatement(sql);
int index = 1;
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
preState.setObject(index++, params.get(i));
}
}
resultSet = preState.executeQuery();
ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
int column_long = resultSetMetaData.getColumnCount();
while (resultSet.next()) {
for (int i = 0; i < column_long; i++) {
String column_name = resultSetMetaData.getColumnName(i + 1);
Object column_value = resultSet.getObject(column_name);
if (column_value == null) {
column_value = "";
}
map.put(column_name, column_value);
}
}
return map;
}

/**
* 封装多条语句查询
*
* @param sql
* @param params
* @return
* @throws SQLException
*/
public List<Map<String, Object>> queryByMoreResults(String sql,
List<Object> params) throws SQLException {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
int index = 1;
preState = conn.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
preState.setObject(index++, params.get(i));
}
}
resultSet = preState.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int column_long = metaData.getColumnCount();
while (resultSet.next()) {
Map<String, Object> map = new HashMap<String, Object>();
for (int i = 0; i < column_long; i++) {
String cloumn_name = metaData.getColumnName(i + 1);
Object cloumn_Value = resultSet.getObject(cloumn_name);
if (cloumn_Value == null) {
cloumn_Value = "";
}
map.put(cloumn_name, cloumn_Value);
}
list.add(map);
}
return list;
}

/**
* 使用反射来查询单条数据
*
* @param sql
*            sql语句
* @param params
* @param cls
*            封装数据的类
* @return
* @throws Exception
*/
public <T> T refQueryBySimpleResult(String sql, List<Object> params,
Class<T> cls) throws Exception {
T resultObject = null;
int index = 1;
preState = conn.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
preState.setObject(index++, params.get(i));
}
}
resultSet = preState.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int column_long = metaData.getColumnCount();
while (resultSet.next()) {
// 通过反射机制完成实例
resultObject = cls.newInstance();
for (int i = 0; i < column_long; i++) {
String column_name = metaData.getColumnName(i + 1);
Object column_value = resultSet.getObject(column_name);
if (column_value == null) {
column_value = "";
}
// 获取类的成员变量
Field field = cls.getDeclaredField(column_name);
// 打开成员变量的private访问权限
field.setAccessible(true);
field.set(resultObject, column_value);
}
}
return resultObject;

}

/**
* 使用反射来查询多条数据
*
* @param sql
*            sql语句
* @param params
* @param cls
*            封装数据的类
* @return
* @throws Exception
*/
public <T> List<T> refQueryByMoreResult(String sql, List<Object> params,
Class<T> cls) throws Exception {
List<T> list = new ArrayList<T>();
int index = 1;
preState = conn.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
preState.setObject(index++, params.get(i));
}
}
resultSet = preState.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int column_long = metaData.getColumnCount();
while (resultSet.next()) {
// 通过反射机制完成实例
T resultObject = cls.newInstance();
for (int i = 0; i < column_long; i++) {
String column_name = metaData.getColumnName(i + 1);
Object column_value = resultSet.getObject(column_name);
if (column_value == null) {
column_value = "";
}
// 获取类的成员变量
Field field = cls.getDeclaredField(column_name);
// 打开成员变量的private访问权限
field.setAccessible(true);
field.set(resultObject, column_value);
}
list.add(resultObject);
}
return list;

}

// 释放连接
public void releaseConnect() {
if (resultSet != null) {
try {
resultSet.close();
resultSet = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
if (preState != null) {
try {
preState.close();
preState = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
conn = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
}

}

连接数据库需要jar包，以及一些简单的数据库操作，这里就不进行说明了

定义一个接口 用来完成用户注册 利用实现接口来解决单继承的窘境

package com.servlet.register.service;

import java.util.List;

public interface RegisterService {
public boolean registerUser(List<Object> params);
}

建立一个类来完成数据的访问

package com.servlet.register.dao;

import java.util.List;

import com.jdbc.util.MySqlConnect;
import com.servlet.register.service.RegisterService;

public class RegisterDao implements RegisterService {
private MySqlConnect util = null;

public RegisterDao() {
util = new MySqlConnect();
}

/* (non-Javadoc)
* 完成注册
* @see com.servlet.register.service.RegisterService#registerUser(java.util.List)
*/
public boolean registerUser(List<Object> params) {
boolean flage = false;
// 连接数据库
util.getConnect();
String sql = "insert into userinfo(username,password,realname) values(?,?,?)  ";
try {
// 执行sql语句
util.updataByPrepareStatement(sql, params);
flage=true;
} catch (Exception e) {
System.out.println("执行出错！");
} finally {
// 关闭数据库
util.releaseConnect();
}

return flage;
}

}

再建立一个类 来完成业务逻辑的处理

package com.servlet.register.action;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.servlet.register.dao.RegisterDao;
import com.servlet.register.service.RegisterService;

public class RegisterAction extends HttpServlet {

private static final long serialVersionUID = 1L;
private RegisterService service;

public RegisterAction() {
super();
}

public void destroy() {
super.destroy();
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 获得上下文路径
String path = request.getContextPath();
System.out.println("path  " + path);

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

String username = request.getParameter("username");
String password = request.getParameter("pswd");
String realname = request.getParameter("realname");

List<Object> params = new ArrayList<Object>();
params.add(username);
params.add(password);
params.add(realname);

boolean flag = service.registerUser(params);
if (flag) {
　　//跳转到登陆页面
response.sendRedirect(path + "/index.jsp");
}

}

public void init() throws ServletException {
// Put your code here
service = new RegisterDao();
}

}

总结一下，这种像三层架构或者MVC框架来编写的方式，结构清晰、耦合度低，可维护性高，可扩展性高，利于开发任务同步进行；容易适应需求变化等。