CDH开启kerberos后，HDFS连接的Java——API参数配置

    大数据平台的安全认证Kerberos是一个比较麻烦的东西，但往往为了平台的安全需要开启，开启后使用JavaAPI操作HDFS，需要进行用户登陆认证。

   1. 首先需要开启CDH的kerberos，开启Kerberos可以参考_CDH配置kerberos_。

   2.开启后，下载 krb5.conf、hdfs-site.xml（hdfs的配置文件）和认证用户的.keytab文件

   3.下面贴出来测试使用的代码

import org.apache.commons.io.filefilter.FileFileFilter;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.log4j.Logger;

/**
 * @Description: HDFS的操作类
 * @author: WH
 * @date: 2016-8-8 下午7:13:11
 */
public class HdfsService {

	// 日志
	private static Logger log =Logger.getLogger(HdfsService.class);
	private static Configuration conf = null;

	public String defaultAddress = "webhdfs://10.134.161.108:50070/";//设置hdfs的连接方式为webhdfs，通过HTTP访问hdfs
	
	
	private HdfsService() {
		// TODO Auto-generated method stub
		conf = new Configuration();
		System.setProperty("java.security.krb5.conf","C:/Users/user/Desktop/pwmx/krb5.conf");//设置kerberos配置信息
		conf.set("fs.defaultFS", defaultAddress);//namenode地址
		conf.set("fs.hdfs.impl",org.apache.hadoop.hdfs.DistributedFileSystem.class.getName());
		conf.set("fs.file.impl",org.apache.hadoop.fs.LocalFileSystem.class.getName());
		conf.set("fs.webhdfs.impl",org.apache.hadoop.hdfs.web.WebHdfsFileSystem.class.getName());
		conf.setBoolean("hadoop.security.authentication",true);
		conf.set("hadoop.security.authentication","kerberos");
		conf.set("dfs.namenode.kerberos.principal","hdfs/[email protected]");//hdfs-site.xml中配置信息
		conf.set("dfs.datanode.kerberos.principal","hdfs/[email protected]");//hdfs-site.xml中配置信息
		UserGroupInformation.setConfiguration(conf);
		try {
			UserGroupInformation.loginUserFromKeytab("YJ100001","C:/Users/user/Desktop/pwmx/YJ100001.keytab");//kerberos 认证
			UserGroupInformation.getLoginUser();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	/**
	 * @param path
	 * @return
	 * @throws IOException
	 */
	public boolean exits(String path) throws Exception {
		
		FileSystem fs = FileSystem.get(conf);
		return fs.exists(new Path(path));
	}

	

	public static void main(String[] args){
		HdfsService hd = new HdfsService();
		try {
			System.out.println(hd.exits("/"));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}



}