libhdfs的配置和使用

Posted 2021-01-14 cqdxwjd

测试环境：centos6.10，hadoop2.7.3，jdk1.8

测试代码：HDFSCSample.c

#include "hdfs.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {

    hdfsFS fs = hdfsConnect("default", 0);
    const char* writePath = "/tmp/testfile.txt";
    hdfsFile writeFile = hdfsOpenFile(fs, writePath, O_WRONLY |O_CREAT, 0, 0, 0);
    if(!writeFile) {
          fprintf(stderr, "Failed to open %s for writing!
", writePath);
          exit(-1);
    }
    char* buffer = "Hello, World!";
    tSize num_written_bytes = hdfsWrite(fs, writeFile, (void*)buffer, strlen(buffer)+1);
    if (hdfsFlush(fs, writeFile)) {
           fprintf(stderr, "Failed to ‘flush‘ %s
", writePath);
          exit(-1);
    }
    hdfsCloseFile(fs, writeFile);
}

编译脚本：

　　compile.sh

#!/bin/bash
export JAVA_HOME=/root/softs/jdk1.8.0_172
export HADOOP_HOME=/root/softs/hadoop-2.7.3/

gcc -I$HADOOP_HOME/include -L$HADOOP_HOME/lib/native -lhdfs -L$JAVA_HOME/jre/lib/amd64/server -ljvm HDFSCSample.c

执行命令：　

　　# chmod +x compile.sh

　　# ./compile.sh

执行脚本：

　　execute.sh

#!/bin/bash
export JAVA_HOME=/root/softs/jdk1.8.0_172
export HADOOP_HOME=/root/softs/hadoop-2.7.3/
export LD_LIBRARY_PATH=$HADOOP_HOME/lib/native:$JAVA_HOME/jre/lib/amd64/server/

CLASSPATH=./
for f in $HADOOP_HOME/share/hadoop/common/*.jar; do
  CLASSPATH=${CLASSPATH}:$f;
done
for f in $HADOOP_HOME/share/hadoop/common/lib/*.jar; do
  CLASSPATH=${CLASSPATH}:$f;
done
for f in $HADOOP_HOME/share/hadoop/hdfs/*.jar; do
  CLASSPATH=${CLASSPATH}:$f;
done
for f in $HADOOP_HOME/share/hadoop/hdfs/lib/*.jar; do
  CLASSPATH=${CLASSPATH}:$f;
done
export CLASSPATH=$CLASSPATH

./a.out

执行命令：

　　# chmod +x execute.sh

　　# ./execute.sh

打开/tmp/testFile.txt,可以看到里面写入了一条 Hello, World!