Hadoop_07_HDFS???Java API ??????

Posted 2020-11-18

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??????Java API?????????HDFS

1.Windows?????????????????????

????????????Hadoop????????????Hadoop?????????????????????HADOOP_HOME??????????????????

???????????????HADOOP_HOME/lib???HADOOP_HOME/bin?????????path??????

2.??????bin??????

????????????????????????Hadoop???????????????bin???????????????Windows????????????Hadoop???bin?????????

??????????????????????????????????????????hadoop-2.6.1???bin??????????????????https://pan.baidu.com/s/1P50N60Qb16zuZxSwPq6HaA??????

??????????????????????????????http://blog.csdn.net/mrbcy/article/details/55806809 ???????????????????????????????????????????????????

3.Eclipse?????????jar?????????

???????????????jar??????????????????

• hadoop/share/hadoop/common/hadoop-common-2.6.4.jar
• hadoop/share/hadoop/common/lib/*.jar
• hadoop/share/hadoop/hdfs/hadoop-hdfs-2.6.4.jar
• hadoop/share/hadoop/hdfs/lib/*.jar

4.?????????????????????HDFS????????????

4.1.??????????????????HADOOP_HOME??????????????????

package cn.bigdata.hdfs;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.junit.Before;
import org.junit.Test;
/**
 * ??????????????????HDFS?????????????????????????????????
 * ??????????????????hdfs?????????api??????jvm??????????????????????????????????????????????????????-DHADOOP_USER_NAME=root
 * ???????????????????????????fs????????????????????????????????????
 */

public class HdfsCientDemo {
    private FileSystem fs  = null;
    Configuration conf = null;
    @Before
    public void inin() throws IOException, InterruptedException, URISyntaxException{
        Configuration conf = new Configuration();
        //??????????????????????????????????????????????????????,??????????????????????????????,nameNode???????????????hdfs://shizhan2:9000
        fs = FileSystem.get(new URI("hdfs://shizhan2:9000"),conf,"root");
    }
    
    //????????????
    @Test
    public void testUpload() throws Exception{
        fs.copyFromLocalFile(new Path("c:/regist.log"), new Path("/regist-copy.log"));
        fs.close();
    }
}

?????????????????????????????????

4.2.????????????????????????bin??????????????????

 

???  @Test
    public void testDownload() throws Exception {
        fs.copyToLocalFile(false, new Path("/regist-copy.log"), new Path("D:/"), false);
        fs.close();
    }

 

4.3.????????????????????????bin??????????????????

??????