我使用以下配置安装并配置了OpenLDAP服务器：
# Entry 1: dc=unixmen,dc=com
dn: dc=unixmen,dc=com
dc: unixmen
o: unixmen
objectclass: top
objectclass: dcObject
objectclass: organization
# Entry 2: cn=ServerAdmins,dc=unixmen,dc=com
dn: cn=ServerAdmins,dc=unixmen,dc=com
cn: ServerAdmins
gidnumber: 501
objectclass: posixGroup
objectclass: top
# Entry 3: cn=rcbandit,cn=ServerAdmins,dc=unixmen,dc=com
dn: cn=rcbandit,cn=ServerAdmins,dc=unixmen,dc=com
cn: rcbandit
gidnumber: 501
givenname: rcbandit
homedirectory: /home/users/rcbandit
objectclass: inetOrgPerson
objectclass: posixAccount
objectclass: top
sn: rcbandit
uid: rcbandit
uidnumber: 1000
userpassword: {MD5}2FeO34RYzgb7xbt2pYxcpA==
我测试了这个简单的Java LDAP客户端，以便通过发送用户名和密码来验证用户身份：
public class MainApp
{
public static String ldapHostUrl = null;
public static String ldapBindDN = null;
public static String ldapBindPwd = null;
public MainApp()
{
}
/**
* Generic method to obtain a reference to a DirContext
*/
public DirContext getDirContext() throws Exception
{
Hashtable<String, String> env = new Hashtable<String, String>(11);
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, getLdapHostUrl());
env.put(Context.SECURITY_AUTHENTICATION, "simple");
env.put(Context.SECURITY_PRINCIPAL, ldapBindDN);
env.put(Context.SECURITY_CREDENTIALS, ldapBindPwd);
DirContext ctx = new InitialDirContext(env);
return ctx;
}
/**
* Generic method to obtain a reference to the user ENV
*/
public static Hashtable<String, String> getUserEnv()
{
Hashtable<String, String> env = new Hashtable<String, String>(11);
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, getLdapHostUrl());
env.put(Context.SECURITY_AUTHENTICATION, "simple");
return env;
}
/**
*
* @param attributeName String - Standard ID (userID)
* @throws Exception -
*/
public void doFindEntries(String attributeValue, String attributeName, String searchBase) throws Exception
{
DirContext xctx = getDirContext();
SearchControls searchCons = getSimpleSearchControls();
String searchFilter = "(" + attributeName + "=" + attributeValue + ")";
// Search for objects with those matching attributes
NamingEnumeration<?> answer = xctx.search(searchBase, searchFilter, searchCons);
//formatResults(answer);
xctx.close();
}
public String getDN(String name, String ldapUserIDAttribute, String ldapBaseForusers) throws NamingException, Exception
{
String dn = null;
String searchFilter = "(" + ldapUserIDAttribute + "=" + name + ")";
SearchControls searchCons = getSimpleSearchControls();
searchCons.setReturningAttributes(new String[0]);
NamingEnumeration<?> results = getDirContext().search(ldapBaseForusers, searchFilter, searchCons);
int thisCount = 0;
if (results != null && results.hasMore())
{
if (thisCount > 0)
{
throw new NamingException("More than one Result was found!");
}
SearchResult si = (SearchResult) results.next();
dn = si.getNameInNamespace();
thisCount++;
}
return dn;
}
/**
* I am just lazy and hate to type.
*
* @return
*/
public static SearchControls getSimpleSearchControls()
{
SearchControls searchControls = new SearchControls();
searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);
searchControls.setTimeLimit(30000);
return searchControls;
}
public static void testUserCredentials(String userFdn, String userPassword) throws NamingException
{
Hashtable<String, String> userEnv = getUserEnv();
userEnv.put(Context.SECURITY_PRINCIPAL, userFdn);
userEnv.put(Context.SECURITY_CREDENTIALS, userPassword);
DirContext userCtx = new InitialDirContext(userEnv);
}
/**
* Reads from console and works in Eclipse
*
* @param prompt
* @return
*/
private static String readLine(String prompt)
{
String line = null;
Console c = System.console();
if (c != null)
{
line = c.readLine(prompt);
}
else
{
System.out.print(prompt);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
try
{
line = bufferedReader.readLine();
}
catch (IOException e)
{
// Ignore
}
}
return line;
}
static String getLdapHostUrl()
{
return ldapHostUrl;
}
static void setLdapHostUrl(String ldapHostUrl)
{
ldapHostUrl = ldapHostUrl;
}
static String getLdapBindDN()
{
return ldapBindDN;
}
static void setLdapBindDN(String ldapBindDN)
{
ldapBindDN = ldapBindDN;
}
static String getLdapBindPwd()
{
return ldapBindPwd;
}
static void setLdapBindPwd(String ldapBindPwd)
{
ldapBindPwd = ldapBindPwd;
}
/**
* @param args
*/
public static void main(String[] args)
{
System.out.println("Performing LDAP Operations with the Following:");
MainApp ss = new MainApp();
MainApp.setLdapHostUrl("ldap://192.168.1.177:389");
MainApp.setLdapBindDN("cn=rcbandit,cn=ServerAdmins,dc=unixmen,dc=com");
MainApp.setLdapBindPwd("qwerty");
String ldapBaseForusers = "cn";
String ldapUserIDAttribute = "simple";
while (true)
{
String userFindValue = null;
String userFdn = null;
String userPassword = null;
// /Find a user
userFindValue = "rcbandit";
userPassword = "qwerty";
System.out.println("Return All Attributes for ALL users by: " + ldapUserIDAttribute + " = " + userFindValue);
try
{
ss.doFindEntries(userFindValue, ldapUserIDAttribute, ldapBaseForusers);
}
catch (javax.naming.PartialResultException e)
{
System.out.println("Find user DN by Name: Returned a PartialResultException\n" + e.getMessage());
}
catch (Exception e)
{
System.out.println("Find user DN by Name: FAILED\n" + e.getMessage());
}
System.out.println();
System.out.println("Find user DN by: " + ldapUserIDAttribute + " = " + userFindValue);
System.out.println("====================================================");
try
{
userFdn = ss.getDN(userFindValue, ldapUserIDAttribute, ldapBaseForusers);
System.out.println("DN: " + userFdn);
}
catch (NamingException e)
{
if (e instanceof javax.naming.PartialResultException)
{
// ignore
}
else
{
System.out.println("Find user DN by Name: Returned a PartialResultException\n" + e.getMessage());
}
}
catch (Exception e)
{
System.out.println("Find user DN by Name: FAILED\n" + e.getMessage());
}
System.out.println();
System.out.println("Test User's Credentials: ");
System.out.println("====================================================");
try
{
testUserCredentials(userFdn, userPassword);
System.out.println("Test User's Credentials: SUCCESS!");
}
catch (NamingException e)
{
System.err.println("Test User's Credentials: FAILED\n" + e.getMessage());
}
}// end while
}
}
运行代码时，我得到了这个结果：
Find user DN by: simple = rcbandit
====================================================
Find user DN by Name: FAILED
null
Test User's Credentials:
====================================================
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.javafx.main.Main.launchApp(Main.java:714)
at com.javafx.main.Main.main(Main.java:871)
Caused by: java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:514)
at dx57.ldapclient.MainApp.getUserEnv(MainApp.java:52)
at dx57.ldapclient.MainApp.testUserCredentials(MainApp.java:109)
at dx57.ldapclient.MainApp.main(MainApp.java:240)
... 6 more
你能帮我解决这个问题吗？
答案 0 :(得分：1)
我会说＆＃39; getLdapHostUrl（）＆＃39;返回null，但我也会说你真的被指控能够调试你自己的NPE，尤其是像这样的微不足道的NPE。至少我期待它。