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LDAP作为一种普遍使用的认证服务，可以通过模拟登录的方式来监测服务的可用性。今天写了一个服务来轮询模拟LDAP登录，下面是主要的代码。

LDAP的原理是先用一个admin用户去认证，认证通过后，使用应登录的用户的用户名及密码去登录。

1.常量设置

public class Constants { /** * LDAP服务端地址URL(端口默认389) */public static final String ldapURL= "ldap://xxx.xxx.xxx.xxx/";/** * LDAP根 */public static final String ldapBasedn= "ou=ldaptest,dc=ldaptest,dc=com";/** * LDAP登陆账号(注：特殊字符\需要进行转义) */public static final String ldapPrincipal= "ldapadmin";/** * LDAP登陆密码 */public static final String ldapCredentials= "ldappassword";/** * LDAP查询Filter  
#arg在代码中可替换为实际查找用户的用户账号 */public static final String ldapFilter= "(&(objectClass=user)(sAMAccountName=#arg))";     }

package com.system.ldap;import java.io.FileWriter;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Hashtable;import javax.naming.Context;import javax.naming.NamingEnumeration;import javax.naming.NamingException;import javax.naming.directory.SearchControls;import javax.naming.directory.SearchResult;import javax.naming.ldap.Control;import javax.naming.ldap.InitialLdapContext;import javax.naming.ldap.LdapContext;public class LDAPAuthentication implements   Runnable    {    private final String BASEDN = Constants.ldapBasedn;    private final String FACTORY = "com.sun.jndi.ldap.LdapCtxFactory";    private LdapContext ctx = null;    private final Control[] connCtls = null;    //private Log log = null;	public void LDAP_connect(){		Hashtable
   
     env = new Hashtable
    
     ();        env.put(Context.INITIAL_CONTEXT_FACTORY, FACTORY);        env.put(Context.PROVIDER_URL, Constants.ldapURL);        env.put(Context.SECURITY_AUTHENTICATION, "simple");        env.put(Context.SECURITY_PRINCIPAL, Constants.ldapPrincipal);        env.put(Context.SECURITY_CREDENTIALS, Constants.ldapCredentials);        try {        	            ctx = new InitialLdapContext(env, connCtls);            wirte("认证LDAP服务器(" + Constants.ldapURL + ")成功!");        } catch (javax.naming.AuthenticationException e) {        	wirte("认证LDAP服务器(" + Constants.ldapURL + ")失败,原因:"+e.toString());            //throw new Exception();        } catch (Exception e) {        	wirte("认证LDAP服务器(" + Constants.ldapURL + ")失败,原因 :"+e.toString());        }	}   		public static void wirte(String msg){				FileWriter fileWriter;		try {						SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");						fileWriter = new FileWriter("D:\\log\\ldap.log",true);			String s = new String( "["+sf.format(new Date())+"]"+msg);			fileWriter.write("\r\n");			fileWriter.write(s);  	        fileWriter.close(); 		} catch (IOException e) {			// TODO Auto-generated catch block			e.printStackTrace();		}           	}	private String getUserDN(String uid) {        try {            String userDN = "";            SearchControls constraints = new SearchControls();            constraints.setSearchScope(SearchControls.SUBTREE_SCOPE);            // 查找用户DN            NamingEnumeration
     
       en = ctx.search(BASEDN, Constants.ldapFilter.replace("#arg", uid), constraints);            while (en != null && en.hasMoreElements()) {                Object obj = en.nextElement();                if (obj instanceof SearchResult) {                    SearchResult si = (SearchResult) obj;                    userDN += si.getName();                    userDN += "," + BASEDN;                    System.out.println(userDN);                    wirte("查找到用户" + uid + "的DN信息：" + userDN);                } else {                }            }            return userDN;        } catch (NamingException e) {        	wirte("查找用户DN时错误!");        	wirte("原因:" + e);            return null;        } catch (Exception e1) {            return null;        }    }	public boolean authenricate(String UID, String password) {        //是否成功        boolean valide = false;        try {            //连接            LDAP_connect();             String userDN = getUserDN(UID);            if (userDN != null && userDN != "") {                // 如果需要加密SHA-1                // password = SHA1.shaBase64(password);                ctx.addToEnvironment(Context.SECURITY_PRINCIPAL, userDN);                ctx.addToEnvironment(Context.SECURITY_CREDENTIALS, password);                ctx.reconnect(connCtls);                System.out.println(userDN + " 验证通过");                wirte("LDAP用户验证成功！");                valide = true;            } else {                wirte("未找到" + UID + "用户信息！");                valide = false;            }        } catch (NamingException e) {            wirte("用户信息认证失败！password:" + password);            valide = false;        } catch (Exception e) {            //创建连接失败            valide = false;        } finally {            // 关闭连接            closeLdapContext();            wirte("close ldap connection");        }        return valide;    }		private void closeLdapContext() {        if (ctx != null) {            try {                ctx.close();            } catch (NamingException e) {            	wirte("关闭LDAP连接错误，错误原因："+e);            }        }    }	@Override	public void run() {		// TODO Auto-generated method stub		while (true) { 			try {				Thread.sleep(1000);				LDAPAuthentication ldap = new LDAPAuthentication();		        if (ldap.authenricate("ldapuser", "ldappassword") == true) {		            System.out.println("该用户认证成功");		            wirte("该用户认证成功");		        }			} catch (InterruptedException e) {				// TODO Auto-generated catch block				e.printStackTrace();			}		}	}}
     
    
   

使用线程轮询的方式不停地调用认证方法

public class TestLDAP {	/**	 * @param args	 */	public static void main(String[] args) {    	LDAPAuthentication Authentication=new LDAPAuthentication();    	Thread t1 =new Thread(Authentication);    	t1.start();    }}

线程每轮询一次打印一次日志到文件，可以通过日志跟踪认证服务的正常状态。

5.扩展阅读

1) LDAP

http://baike.baidu.com/link?url=e59cBqJmOebBv1FnOUnDFDjAyIoLlmP2Gpg1npNF0b9FaoVO3YgAUppILHp7CPqQdDYC4w33DXxe_yIboMjb5_

2) LDAP概念和原理

http://blog.sina.com.cn/s/blog_6151984a0100ey3z.html

3）LDAP认证基本原理

http://www.edu.cn/sfrz_9956/20120608/t20120608_788018_1.shtml

转载地址：http://vlsbb.baihongyu.com/