java2practice

user table

CREATE TABLE 'user' (
'user_id' int(11) NOT NULL AUTO_INCREMENT,
'user_name' varchar(250) NOT NULL,
'password' varchar(250) DEFAULT NULL,
PRIMARY KEY ('user_id','user_name')
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1

role table

CREATE TABLE 'role' (
'role_id' int(11) NOT NULL AUTO_INCREMENT,
'role_name' varchar(250) NOT NULL,
PRIMARY KEY ('role_id','role_name')
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1

user_role join table

CREATE TABLE 'user_role' (
'user_id' int(11) NOT NULL,
'role_id' int(11) NOT NULL,
PRIMARY KEY ('user_id','role_id')
) ENGINE=InnoDB DEFAULT CHARSET=latin1

user and role has many to many relationship, and joining table is user_role

User.java

package com.java2practice.springsecurity.model;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="user")
public class User {
@Id
@GeneratedValue
@Column(name="user_id")
private Integer userId;

@Column(name="user_name")
private String userName;

@Column(name="password")
private String password;

@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "user_role", joinColumns = {
@JoinColumn(name = "USER_ID", nullable = false, updatable = false) },
inverseJoinColumns = { @JoinColumn(name = "ROLE_ID",
nullable = false, updatable = false) })

private Set<Role> userRoles = new HashSet<Role>(0);

public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
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 Set<Role> getUserRoles() {
return userRoles;
}
public void setUserRoles(Set<Role> userRoles) {
this.userRoles = userRoles;
}
}

Role.java

package com.java2practice.springsecurity.model;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="role")
public class Role {
@Id
@GeneratedValue
@Column(name="role_id")
private Integer roleId;

@Column(name="role_name")
private String roleName;

public Integer getRoleId() {
return roleId;
}
public void setRoleId(Integer roleId) {
this.roleId = roleId;
}
public String getRoleName() {
return roleName;
}
public void setRoleName(String roleName) {
this.roleName = roleName;
}
}

UserDao.java

package com.java2practice.springsecurity.dao;
import javax.annotation.Resource;
import org.apache.log4j.Logger;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Restrictions;

import com.java2practice.springsecurity.model.User;

public class UserDao {
Logger logger = Logger.getLogger(this.getClass());

@Resource
SessionFactory sessionFactory;

public User getUser(String userName){
logger.info("getUser called");
Session session = null;
try{
session = sessionFactory.openSession();
User user = (User) session.createCriteria(User.class).
add(Restrictions.eq("userName", userName)).uniqueResult();
return user;
}catch (Exception e) {
e.printStackTrace();
return null;
}
}
}

Our service has to implement org.springframework.security.core.userdetails.UserDetailsService
it has one method
public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException
this method returns org.springframework.security.core.userdetails.UserDetails
UserDetails user = new User(“username”, “password”,true, true, true, true, authorities);
like this we can convert our User to Spring UserDetails.

UserDetailsServiceImpl.java

package com.java2practice.springsecurity.service;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.authority.GrantedAuthorityImpl;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;

import com.java2practice.springsecurity.dao.UserDao;
import com.java2practice.springsecurity.model.Role;

@SuppressWarnings("deprecation")
public class UserDetailServiceImpl implements UserDetailsService{

Logger logger = Logger.getLogger(getClass());

@Autowired
UserDao userDao;

@Override
public UserDetails loadUserByUsername(String username)
throws UsernameNotFoundException {
try{
logger.info("loadUserByUsername ");

com.java2practice.springsecurity.model.User userFromDB =  userDao.getUser(username);
logger.info("got user from database "+userFromDB);
List<GrantedAuthorityImpl> authorities = new ArrayList<GrantedAuthorityImpl>();

for(Role role : userFromDB.getUserRoles()){
authorities.add(new GrantedAuthorityImpl(role.getRoleName()));
}

UserDetails user = new User(userFromDB.getUserName(), userFromDB.getPassword(),
true, true, true, true, authorities);

return user;
}catch(Exception e){
logger.error("error "+e);
return null;
}
}
}

WebController.java

package com.java2practice.springsecurity.controller;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class WebController {
Logger logger = Logger.getLogger(this.getClass());

@RequestMapping("/home")
public String home(){
logger.info("webcontroller");
return "home";
}
}

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:security="http://www.springframework.org/schema/security"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/security
http://www.springframework.org/schema/security/spring-security.xsd">

<context:annotation-config />

<context:property-placeholder location="classpath:db.properties" />

<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.user}" />
<property name="password" value="${jdbc.password}" />
</bean>

<bean id="sessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.java2practice.springsecurity.model" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">true</prop>
</props>

</property>
</bean>

<!-- A custom service where Spring will retrieve users and their corresponding    access levels -->
<bean id="userDetailServiceImpl"   class="com.java2practice.springsecurity.service.UserDetailServiceImpl"     autowire="byName" />

<bean id="userDao" class="com.java2practice.springsecurity.dao.UserDao" autowire="byName" />

<!-- This is where we configure Spring-Security -->
<security:http auto-config="true" use-expressions="true">

<security:form-login login-page="/login.jsp"
authentication-failure-url="/login.jsp?error=true"
default-target-url="/home.html" />

</security:http>

<!-- Declare an authentication-manager to use a custom userDetailsService -->
<security:authentication-manager>
<security:authentication-provider
user-service-ref="userDetailServiceImpl">
</security:authentication-provider>
</security:authentication-manager>

</beans>

dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

<context:component-scan base-package="com.java2practice.springsecurity.controller" />
<context:annotation-config />

<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/jsp/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>Spring4MVC</display-name>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>

<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>

<filter>
<filter-name>springSecurityFilterChain</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>

<filter-mapping>
<filter-name>springSecurityFilterChain</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<listener>
<listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>

</web-app>

login.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://www.springframework.org/tags" prefix="spring"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>

<c:if test="${param.error}">
Error occurred ${param.error }
</c:if>

</h1>
Login
<form action="j_spring_security_check" method="post">

<p>

<label for="j_username">Username</label> <input id="j_username"
name="j_username" type="text" />
</p>
<p>

<label for="j_password">Password</label> <input id="j_password"
name="j_password" type="password" />
</p>
<input type="submit" value="Login" />

</form>
</body>
</html>

home.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>

<!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>Home</title>
</head>
<body>

<h1>Welcome to Spring Security</h1>
</body>
</html>

Project Structure

In Spring 3.1 we have a feature called Caching, It caches the data based on java method execution, if the java method executed before with same parameters it returns the cached data, other wise it will execute the method and puts the data into cache.

To enable caching :

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cache="http://www.springframework.org/schema/cache"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd">
<cache:annotation-driven />
//your beans
</beans>

<cache:annotation-driven />  Will recognize the spring cache annotations @Cacheable and @CacheEvict

Spring cache provides

@Cacheable annotation and @CacheEvict annotation.

Put @Cacheable on the method which you want to cache.

Ex:

@Cacheable(value="messagecache", key="#id", condition="id < 10")

public String getMessage(int id){

return "hello"+id;

}

Here getMessage() method is marked with @Cacheable, whenever getMessage() is called it will check the messagecache, if the data is already in messagecache it will return that otherwise it will executes the getMessage() and returns data.

@Cacheable annotations has 3 attributes

1. Value : is the cache name and it is mandatory, in example it is “messagecache”
2. Key: based on this data will be cached and it is optional
3. Condition:  based on the condition data will be cached. In example if the id < 10 then only data will be cached otherwise won’t. it is optional

@CacheEvict annotation will be used to delete the data from existing cache.

@CacheEvict(“employees”)

public void saveEmployee(Employee e){

}

Here whenever a saveEmployee() is called cache will be deleted.

@CacheEvict has 5 attributes:

1. Value, 2 Key, 3 condition are similar to @Cacheable, apart from these 3 we have another 2 attributes
   1. allEntries : is a Boolean type and delete entire cache
   2. beforeInvocation: is Boolean type and will delete the cache before the method execution

Will go through one small example:

In this example I have used ehcache, refer www.ehcache.org for more information

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:cache="http://www.springframework.org/schema/cache"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">

<!-- Scans within the base package of the application for @Components to configure as beans -->
<context:component-scan base-package="com" />

<!-- Process cache annotations -->
<cache:annotation-driven />

<!-- Configuration for using Ehcache as the cache manager-->
<bean id="cacheManager" p:cache-manager-ref="ehcache"/>
<bean id="ehcache" p:config-location="classpath:ehcache.xml"/>

<bean id="employee" class="com.java2practice.model.Employee"/>

</beans>

ehcache.xml

<ehcache>
<diskStore path="java.io.tmpdir"/>
<cache name="employeeCache"
maxElementsInMemory="10000"
eternal="false"
timeToIdleSeconds="120"
timeToLiveSeconds="120"
overflowToDisk="true"
maxElementsOnDisk="10000000"
diskPersistent="false"
diskExpiryThreadIntervalSeconds="120"
memoryStoreEvictionPolicy="LRU"/>

</ehcache>

Employee pojo:

package com.java2practice.model;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cache.annotation.Cacheable;

public class Employee {

Logger logger = LoggerFactory.getLogger(getClass());

@Cacheable(value="employeeCache", key = "#id")
public String getEmployee(Integer id){
logger.info("get employee called");
return "employee"+id;
}

}

This Employee class is injected into controller:

Controller :

package com.java2practice.web;
import java.util.HashMap;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import com.java2practice.model.Employee;
@Controller
public class WebController {

@Autowired
Employee employee;

@RequestMapping("/index.htm")
public String homePage(@RequestParam(required= false) Integer id, HashMap<String, String> map){
map.put("message", employee.getEmployee(id));
return "index";
}
}

And finally here is my JSP code:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!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>Cache Example</title>
</head>
<body>
<h1>This is ${message }</h1>
</body>
</html>

First time for the URL : http://localhost:8080/springcache/index.htm?id=1

Employee class getEmployee() method will be executed and data will be placed in cache. second time for the same request with id=1 getEmployee() method wont be executed, this can be seen by using the log message “get employee called” prints only for the first time.

And for the http://localhost:8080/springcache/index.htm?id=2

getEmployee() will be called and data will be placed in cache.

Here id is the Key, if id changes method will be executed and data will be placed in cache with the key.

When ever the requests comes for the @Cacheable annotated method, spring will check the key in corresponding cache if the cache has key in it. data will be returned from the cache other wise method will be executed.

Instead of ehcache we can use Spring SimpleCacheManager also:

<!-- Configuration for using SimpleCacheManager as the cache manager-->
 <bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager" >
 <property name="caches">
 <set>
 <bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean"  p:name="employeeCache"/>
 </set>
 </property>
 </bean>

Inversion of Control – Dependency Injection:

Instead of Object creating its dependencies, let container create and inject into Object. Control is being inverted from Object to Container.

Encapsulation says “The Caller should know its dependencies”

IOC  says “The Caller should know its dependency interfaces”

If the caller doesn’t know its dependencies and knows only interfaces, we can give any of the class to the Object.  Will explain with an example

Let’s Say we have a

package com.java2practice;
public class UsersListFromDB{
     public void printUsers(){
System.out.println(“printing users from database”);
     }
}

And UsersView to use the UsersListFromDB,

package com.java2practice;
public class UsersView{
 private UsersListFromDB userListFromDB = new UsersListFromDB();
 public void printUsers(){
      userListFromDB.printUsers();
 }
}

Now create a client program to access the UsersView.java

package com.java2practice;
public class UsersViewTest{
 public static void main(String[] args){
      UsersView usersView = new UsersView();
      usersView.printUsers();
 }
}

If we use like this, the object  UsersListFromDB is tightly coupled with UsersView. If we want to show UsersListFromExcel it won’t be possible.

For this we need to create an interface called

public interface UsersList{
       public void printUsers();
}

And make the UsersListFromDB, UsersListFromExcel implement the UsersList like below

public class UsersListFromDB implements UsersList{
       public void printUsers(){
System.out.println(“users list printing from database”);
       }
}

public class UsersListFromExcel implements UsersList{
       public void printUsers(){
System.out.println(“users list printing from excel”);
       }
}

Now we can change our UsersView class to

public class UsersView{
       private UsersList userList = new UsersListFromDB();
       public void printUsers(){
userList.printUsers();
       }
}

This concept is called interaface referencing. One of the object oriented principle Program to interface not program to class”

But still our problem is not solved, with out changing the UsersView we can not add UsersListFromExcel

Now We will try with Factory Design pattern

public class UsersFactory{
       public UsersList getUsersList(){
                 return new UsersListFromDB();
       }
}

In the UsersView.java we need to call this UsersFactory to get the appropriate object.

public UsersView{
       UsersList usersList = new UsersFactory().getUsersList();
       public void printUsers(){
usersList.printUsers();
       }
}

Now the client program will look like this

public class UsersViewTest{
       public static void main(String[] args){
              UsersView usersView = new UsersView();
              usersView.printUsers();
       }
}

This is more elegant and with out touching UsersView.java file we can switch to UsersListFromExcel  or UsersListFromDB by changing UsersFactory.

But still we need to change the UsersFactory.

With spring IOC our UsersView.java will look like this

public class UsersView{
       private UsersList usersList;
       public void setUsersList(UsersList usersList){
              this.usersList = usersList;
       }
       public void printUsers(){
             usersList.printUsers();
       }
}

That’s it, we don’t need to bother about instantiating the UsersList interface with its implemented classes.

To tell the container about our Java classes we need to write configuration file.

Bean-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

      <bean id="usersListFromDB" class="com.java2practice.UsersListFromDB"/>
      <bean id="usersListFromExcel" class="com.java2practice.UsersListFromExcel/">
      <bean id="userView">
<property ref=” usersListFromDB” />
      </bean>
</beans>

We have to write our client program to use all these:

public class UesrsViewTest{
       public static void main(String[] args){
              ApplicationContext context = new ClassPathXmlApplicationContext("bean-config.xml");
              UsersView usersView = (UsersView)context.getBean(“userView”);
              usersView.printUsers();
       }
}

Here ApplicationContext will read the bean configuration file and accordingly it will inject the dependencies into the UsersView.java

When we are calling context.getBean(“userView”) it will return UsersView with dependencies injected into it.

If we want to use UsersListFromExcel, just we need to change in configuration file

Then the out put will be “printing users from excel file”