架构的演变-优快云博客

本文链接：https://blog.youkuaiyun.com/mohaiyong/article/details/84299177

本文从两层架构到五层架构，介绍了不同阶段的软件架构设计思路及实现方式，包括简单的jsp+DB架构、分层的jsp+Entity/service+DB架构、引入ORM框架的jsp+service+Hibernate架构、结合MVC框架的jsp+struts+Service+Hibernate架构，以及使用IOC容器的jsp+struts+Hibernate+spring架构。

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架构的演变

一、两层架构(jsp+DB)

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>用户注册</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
    <form method="post" action="registerDeal.jsp">
    	用户名：<input type="text" name="username"><br>
    	密码：<input type="password" name="password"><br>
    	确认密码：<input type="password" name="password2"><br>
    	<input type="submit" value="提交"/>
    </form><br>
  </body>
</html>

registerDeal.jsp

<%@ page language="java" import="java.util.*, java.sql.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String username = request.getParameter("username");
String password = request.getParameter("password");
String password2 = request.getParameter("password2");
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/spring", "root", "bjsxt");

String sqlQuery = "select count(*) from user where username = ?";
PreparedStatement psQuery = conn.prepareStatement(sqlQuery);
psQuery.setString(1, username);
ResultSet rs = psQuery.executeQuery();
rs.next();
int count = rs.getInt(1);
if(count > 0) {
	response.sendRedirect("registerFail.jsp");
	psQuery.close();
	conn.close();
	return;
}

String sql = "insert into user values (null, ?, ?)";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, username);
ps.setString(2, password);
ps.executeUpdate();
ps.close();
conn.close();

response.sendRedirect("registerSuccess.jsp");
%>

二、三层架构（jsp+Entity/service+DB)

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>用户注册</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
    <form method="post" action="registerDeal.jsp">
    	用户名：<input type="text" name="username"><br>
    	密码：<input type="password" name="password"><br>
    	确认密码：<input type="password" name="password2"><br>
    	<input type="submit" value="提交"/>
    </form><br>
  </body>
</html>

registerDeal.jsp

<%@ page language="java" import="java.util.*, java.sql.*" pageEncoding="GB18030"%>
<%@ page import="com.bjsxt.registration.service.*" %>
<%@ page import="com.bjsxt.registration.model.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String username = request.getParameter("username");
String password = request.getParameter("password");
String password2 = request.getParameter("password2");

User u = new User();
u.setUsername(username);
u.setPassword(password);
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/spring", "root", "bjsxt");

UserManager um = new UserManager();
boolean exist = um.exists(u);
if(exist) {
	response.sendRedirect("registerFail.jsp");
	return;
}

um.add(u);
response.sendRedirect("registerSuccess.jsp");
%>

user.java

package com.bjsxt.registration.model;

import com.bjsxt.registration.service.UserManager;

//贫血模型 充血模型
public class User {
	private int id;
	private String username;
	private String password;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}

}

userManager.java

package com.bjsxt.registration.service;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.bjsxt.registration.model.User;

public class UserManager {
	public boolean exists(User u) throws Exception {
		Class.forName("com.mysql.jdbc.Driver");
		Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/spring", "root", "bjsxt");

		String sqlQuery = "select count(*) from user where username = ?";
		PreparedStatement psQuery = conn.prepareStatement(sqlQuery);
		psQuery.setString(1, u.getUsername());
		ResultSet rs = psQuery.executeQuery();
		rs.next();
		int count = rs.getInt(1);
		psQuery.close();
		conn.close();
		
		if(count > 0) {
			return true;
		}
		return false;
	}
	
	public void add(User u) throws Exception {
		Class.forName("com.mysql.jdbc.Driver");
		Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/spring", "root", "bjsxt");

		String sql = "insert into user values (null, ?, ?)";
		PreparedStatement ps = conn.prepareStatement(sql);
		ps.setString(1, u.getUsername());
		ps.setString(2, u.getPassword());
		ps.executeUpdate();
		ps.close();
		conn.close();

		
	
	}
}

三、三层架构（jsp+service+Hibernate）

registerDeal.jsp

<%@ page language="java" import="java.util.*, java.sql.*" pageEncoding="GB18030"%>
<%@ page import="com.bjsxt.registration.service.*" %>
<%@ page import="com.bjsxt.registration.model.*" %>
<%@ page import="com.bjsxt.registration.service.impl.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String username = request.getParameter("username");
String password = request.getParameter("password");
String password2 = request.getParameter("password2");

UserManager um = new UserManagerImpl();
boolean exist = um.exists(u);
if(exist) {
	response.sendRedirect("registerFail.jsp");
	return;
}

um.add(u);
response.sendRedirect("registerSuccess.jsp");
%>

Service层：UserManager.java

package com.bjsxt.registration.service;

import com.bjsxt.registration.model.User;

public interface UserManager {

	public abstract boolean exists(User u) throws Exception;

	public abstract void add(User u) throws Exception;

}

UserManagerImpl.java

package com.bjsxt.registration.service.impl;

import com.bjsxt.registration.dao.UserDao;
import com.bjsxt.registration.dao.impl.UserDaoImpl;
import com.bjsxt.registration.model.User;
import com.bjsxt.registration.service.UserManager;

public class UserManagerImpl implements UserManager {
	
	private UserDao userDao = new UserDaoImpl();
	
	public UserDao getUserDao() {
		return userDao;
	}

	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}

	/* (non-Javadoc)
	 * @see com.bjsxt.registration.service.impl.UserManager#exists(com.bjsxt.registration.model.User)
	 */
	public boolean exists(User u) throws Exception {
		return userDao.checkUserExistsWithName(u.getUsername());
		
	}
	
	/* (non-Javadoc)
	 * @see com.bjsxt.registration.service.impl.UserManager#add(com.bjsxt.registration.model.User)
	 */
	public void add(User u) throws Exception {
		userDao.save(u);
	}
}

Dao层（Hibernate）：UserDao.java

package com.bjsxt.registration.dao;

import com.bjsxt.registration.model.User;

public interface UserDao {
	public void save(User u);
	public boolean checkUserExistsWithName(String username);  
}

UserDaoImpl.java

package com.bjsxt.registration.dao.impl;

import org.hibernate.SessionFactory;
import org.hibernate.classic.Session;

import com.bjsxt.registration.dao.UserDao;
import com.bjsxt.registration.model.User;
import com.bjsxt.registration.util.HibernateUtil;

public class UserDaoImpl implements UserDao {

	public void save(User u) {
		SessionFactory sf = HibernateUtil.getSessionFactory();
		Session s = sf.getCurrentSession();
		s.beginTransaction();
		s.save(u);
		s.getTransaction().commit();
	}

	public boolean checkUserExistsWithName(String username) {
		SessionFactory sf = HibernateUtil.getSessionFactory();
		Session s = sf.getCurrentSession();
		s.beginTransaction();
		long count = (Long)s.createQuery("select count(*) from User u where u.username = :username")
			.setString("username", username)
			.uniqueResult();
		s.getTransaction().commit();
		if(count > 0) return true;
		return false;
	}

}

user.java(@Entity Hibernate注解)

package com.bjsxt.registration.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

import com.bjsxt.registration.service.impl.UserManagerImpl;

//贫血模型 充血模型
@Entity
public class User {
	private int id;
	private String username;
	private String password;
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}

}

四、jsp+struts+Service+Hibernate

UserManager um = new UserManagerImpl();
boolean exist = um.exists(u);
if(exist) {
	response.sendRedirect("registerFail.jsp");
	return;
}

上面的代码被struts2给取代了

在struts2处理类Action里面：
1.spring通过
@Resource
private UserManager userManager ;
注入封装了UserDao的service处理类，在action里面直接调用处理类操作

2.struts.xml配置文件中的Result取代了上面的跳转

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>用户注册</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
    <form method="post" action="user.action">
    	用户名：<input type="text" name="username"><br>
    	密码：<input type="password" name="password"><br>
    	确认密码：<input type="password" name="password2"><br>
    	<input type="submit" value="提交"/>
    </form><br>
  </body>
</html>

UserAction.java

package com.bjsxt.registration.action;

import javax.annotation.Resource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Component;

import com.bjsxt.registration.model.User;
import com.bjsxt.registration.service.UserManager;
import com.opensymphony.xwork2.ActionSupport;

@Component("user")
@Scope("prototype")
public class UserAction extends ActionSupport {
	
	private String username;
	private String password;
	private String password2;
	
	private UserManager um;
	
	
	
	public UserManager getUm() {
		return um;
	}
	
	@Resource(name="userManager")
	public void setUm(UserManager um) {
		this.um = um;
	}

	@Override
	public String execute() throws Exception {
		User u = new User();
		u.setUsername(username);
		u.setPassword(password);
		if(um.exists(u)) {
			return "fail";
		}
		um.add(u);
		return "success";
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public String getPassword2() {
		return password2;
	}

	public void setPassword2(String password2) {
		this.password2 = password2;
	}
	
}

五、jsp+struts+Hibernate+spring

spring把Dao注入到Daoimpl

Service注入到Serviceimpl

Dao注入到Service

Service注入到Action处理类

jsp页面*。action可以直接在action里面操作，跳转！