session保存到Redis简单实现

在负载均衡情况下，如果用户访问不同的机器，如果没有做session同步，用户就会被提出，这样用户体验非常不好，所以我们很远必要做session同步，把session放到reids缓存服务器就能很好的解决问题。下面是代码简单的实现。

一、配置web.xml过滤器：

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<filter>
<filter-name>sessionFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>sessionFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

二、配置对应的过滤器名字：

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<bean id="sessionFilter" class="com.plateno.interceptor.SessionFilter">
<property name="redisTemplate" ref="redisTemplate"/>
</bean>

三、SessionFilter的实现：

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public class SessionFilter extends GenericFilterBean {
private RedisTemplate redisTemplate;
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
System.out.println("filter");
HttpServletRequest re = (HttpServletRequest)request;
HttpServletResponse res = (HttpServletResponse)response;
TerryHttpServletRequestWrapper wrapper = new TerryHttpServletRequestWrapper(re,res,redisTemplate);
chain.doFilter(wrapper, response);
}
public RedisTemplate getRedisTemplate() {
return redisTemplate;
}
public void setRedisTemplate(RedisTemplate redisTemplate) {
this.redisTemplate = redisTemplate;
}
}

四、TerryHttpServletRequestWrapper的实现：

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public class TerryHttpServletRequestWrapper extends HttpServletRequestWrapper {
private CacheHttpSession session;
private HttpServletResponse response;
private RedisTemplate redisTemplate;
public TerryHttpServletRequestWrapper(HttpServletRequest request, HttpServletResponse response,RedisTemplate redisTemplate) {
super(request);
this.response = response;
this.redisTemplate = redisTemplate;
}
@Override
public HttpSession getSession(boolean create) {
if(session != null) {
return session;
}
String sid = "terry" + System.currentTimeMillis();
writeSidToCookie(sid);
session = new CacheHttpSession(null,sid,redisTemplate);
return session;
}
@Override
public HttpSession getSession() {
return getSession(false);
}
protected void writeSidToCookie(String sid) {
Cookie mycookies = new Cookie("terry", sid);
mycookies.setMaxAge(-1);
mycookies.setDomain("locahost");
mycookies.setPath("/");
response.addCookie(mycookies);
}
}

五、CacheHttpSession的实现：

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public class CacheHttpSession extends HttpSessionWrapper {
private String sid;
private RedisTemplate redisTemplate;
private StringRedisSerializer stringSerializer = new StringRedisSerializer();
public CacheHttpSession(HttpSession session,String sid,RedisTemplate redisTemplate) {
super(session);
this.sid = sid;
this.redisTemplate = redisTemplate;
}
@SuppressWarnings("unchecked")
@Override
public Enumeration<String> getAttributeNames() {
final byte[] key = stringSerializer.serialize(sid);
Object result = redisTemplate.execute(new RedisCallback<Object>() {
@Override
public Object doInRedis(RedisConnection connection)
throws DataAccessException {
Set<byte[]> set = connection.keys(key);
return set;
}
});
if(result != null) {
Set<byte[]> s = (Set<byte[]>)result;
Set<String> ss = new HashSet<String>();
for(byte[] b : s) {
ss.add(stringSerializer.deserialize(b));
}
Enumeration<String> en = new Vector(ss).elements();
return en;
}
return null;
}
@SuppressWarnings("unchecked")
@Override
public void setAttribute(String name, Object value) {
final byte[] key = stringSerializer.serialize(name);
final byte[] v = stringSerializer.serialize((String)value);
redisTemplate.execute(new RedisCallback<Object>() {
@Override
public Object doInRedis(RedisConnection connection)
throws DataAccessException {
connection.set(key, v);
return null;
}
});
}
@Override
public Object getAttribute(String name) {
final byte[] key = stringSerializer.serialize(name);
@SuppressWarnings("unchecked")
Object value = redisTemplate.execute(new RedisCallback<Object>() {
@Override
public Object doInRedis(RedisConnection connection)
throws DataAccessException {
return connection.get(key);
}
});
return value;
}
@Override
public String getId() {
return sid;
}
}

六、HttpSessionWrapper的实现：

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public class HttpSessionWrapper implements HttpSession {
private HttpSession session;
public HttpSessionWrapper(HttpSession session) {
this.session = session;
}
@Override
public long getCreationTime() {
return this.session.getCreationTime();
}
@Override
public String getId() {
return this.session.getId();
}
@Override
public long getLastAccessedTime() {
return this.session.getLastAccessedTime();
}
@Override
public ServletContext getServletContext() {
return this.session.getServletContext();
}
@Override
public void setMaxInactiveInterval(int interval) {
this.session.setMaxInactiveInterval(interval);
}
@Override
public int getMaxInactiveInterval() {
return this.session.getMaxInactiveInterval();
}
@Override
public HttpSessionContext getSessionContext() {
return this.session.getSessionContext();
}
@Override
public Object getAttribute(String name) {
return this.session.getAttribute(name);
}
@Override
public Object getValue(String name) {
return this.session.getValue(name);
}
@Override
public Enumeration<String> getAttributeNames() {
return this.session.getAttributeNames();
}
@Override
public String[] getValueNames() {
return this.session.getValueNames();
}
@Override
public void setAttribute(String name, Object value) {
this.session.setAttribute(name,value);
}
@Override
public void putValue(String name, Object value) {
this.session.putValue(name,value);
}
@Override
public void removeAttribute(String name) {
this.session.removeAttribute(name);
}
@Override
public void removeValue(String name) {
this.session.removeValue(name);
}
@Override
public void invalidate() {
this.session.invalidate();
}
@Override
public boolean isNew() {
return this.session.isNew();
}
}

以上代码就能把session保存到redis，当然这其中还有很多问题，比如sessionId的生成，session过去，对象序列化（测试为了方便统一用了string），等等很多问题。以后有时间再完善。

session保存到Redis简单实现

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