C++库的源代码位于：

这里提供一个直接对这些源文件进行编译的makefile，编译后将打包命名为libhdfs.a. makefile内容为：

CC = gcc
DEFINES = -DG_ARCH_X86_64

CFLAGS += -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT $(DEFINES)
CXXFLAGS += -pipe -O3 -D_REENTRANT $(DEFINES) -rdynamic

AR = ar cqs
LFLAGS = -rdynamic

OBJECTS = exception.o expect.o hdfs.o jni_helper.o native_mini_dfs.o

TARGET = libhdfs.a

#command, don't change
CHK_DIR_EXISTS= test -d
DEL_FILE = rm -f

first: all
####### Implicit rules

.SUFFIXES: .o .c .cpp .cc .cxx .C .cu

.cpp.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"

.cc.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"

.cxx.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"

.C.o:
$(CXX) -c $(CXXFLAGS) $(INCPATH) -o "$@" "$<"

.c.o:
$(CC) -c $(CFLAGS) $(INCPATH) -o "$@" "$<"

####### Build rules
all: $(AR)

$(AR): $(TARGET)

$(TARGET): $(OBJECTS)
$(AR) $(TARGET) $(OBJECTS)

clean:
-$(DEL_FILE) $(OBJECTS) $(TARGET)

保存好后，直接make. 编译信息如下：

gcc -c -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT -DG_ARCH_X86_64 -o "exception.o" "exception.c"
gcc -c -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT -DG_ARCH_X86_64 -o "expect.o" "expect.c"
gcc -c -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT -DG_ARCH_X86_64 -o "hdfs.o" "hdfs.c"
gcc -c -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT -DG_ARCH_X86_64 -o "jni_helper.o" "jni_helper.c"
gcc -c -fPIC -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -pipe -O3 -D_REENTRANT -DG_ARCH_X86_64 -o "native_mini_dfs.o" "native_mini_dfs.c"
ar cqs libhdfs.a exception.o expect.o hdfs.o jni_helper.o native_mini_dfs.o

接下来测试一下这个库能不能用。进入以下目录

hadoop-2.4.0-src/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test

找到测试源代码，对该文件夹中所有测试代码进行编译.这里再提供一个简单的makefile，内容如下：

LIBS = -L$(JAVA_HOME)/jre/lib/amd64/server/ -ljvm -L../ -lhdfs
INCPATH = -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/linux -I. -I..
all:
gcc -o hdfs_ops test_libhdfs_ops.c $(INCPATH) $(LIBS)
gcc -o hdfs_read test_libhdfs_read.c $(INCPATH) $(LIBS)
gcc -o hdfs_write test_libhdfs_write.c $(INCPATH) $(LIBS)
gcc -o hdfs_zerocopy test_libhdfs_zerocopy.c $(INCPATH) $(LIBS)

直接make,编译信息如下：

gcc -o hdfs_ops test_libhdfs_ops.c -I/d0/data/lichao/software/java/jdk1.7.0_55/include -I/d0/data/lichao/software/java/jdk1.7.0_55/include/linux -I. -I.. -L/d0/data/lichao/software/java/jdk1.7.0_55/jre/lib/amd64/server/ -ljvm -L../ -lhdfs
gcc -o hdfs_read test_libhdfs_read.c -I/d0/data/lichao/software/java/jdk1.7.0_55/include -I/d0/data/lichao/software/java/jdk1.7.0_55/include/linux -I. -I.. -L/d0/data/lichao/software/java/jdk1.7.0_55/jre/lib/amd64/server/ -ljvm -L../ -lhdfs
gcc -o hdfs_write test_libhdfs_write.c -I/d0/data/lichao/software/java/jdk1.7.0_55/include -I/d0/data/lichao/software/java/jdk1.7.0_55/include/linux -I. -I.. -L/d0/data/lichao/software/java/jdk1.7.0_55/jre/lib/amd64/server/ -ljvm -L../ -lhdfs
gcc -o hdfs_zerocopy test_libhdfs_zerocopy.c -I/d0/data/lichao/software/java/jdk1.7.0_55/include -I/d0/data/lichao/software/java/jdk1.7.0_55/include/linux -I. -I.. -L/d0/data/lichao/software/java/jdk1.7.0_55/jre/lib/amd64/server/ -ljvm -L../ -lhdfs

我们随便生成一个文件，包含1到10这10个数字，并加载到hdfs文件系统。

seq 1 10 > tmpfile
hadoop fs -mkdir /data
hadoop fs -put tmpfile /data
hadoop fs -cat /data/tmpfile
1
2
3
4
5
6
7
8
9
10

ok。现在运行生成的hdfs_read程序，测试一下hdfs的64位C++接口：

./hdfs_read /data/tmpfile 21 32

运行信息如下：

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
1
2
3
4
5
6
7
8
9
10

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