hadoop学习笔记4：java实现hdfs -ls/-lsr
作业1：java代码实现hadoop fs -lsr的功能，调用FileSystem.listStatus(...)方法，显示结果，要求结果显示样式如hadoop fs -ls xxx的结果类似。
作业2：java 代码实现 hadoop fs -lsr 的功能
------上面两题的代码如下：
package
hdfs;
import
java.io.IOException;
import
java.net.URI;
import
java.net.URISyntaxException;
import
org.apache.commons.lang.time.DateFormatUtils;
import
org.apache.hadoop.conf.Configuration;
import
org.apache.hadoop.fs.FileStatus;
import
org.apache.hadoop.fs.FileSystem;
import
org.apache.hadoop.fs.Path;
public
class
TestFIleSystem {
public
static
void
main(String[] args)
throws
IOException,
URISyntaxException {
final
FileSystem fs = FileSystem.get(
new
URI(
"hdfs://chaoren1:9012"
),
new
Configuration());
FileStatus[] listStatus = fs.listStatus(
new
Path(
"/"
));
// java代码实现hadoop fs - lsr的功能，调用FileSystem.listStatus(...)方法，显示结果，要求结果显示样式如 hadoop fs -ls xxx的结果类似。
//ls (fs);
// java 代码实现 hadoop fs - lsr 的功能
lsr(fs, listStatus);
}
private
static
void
lsr(FileSystem fs, FileStatus[] listStatus)
throws
IOException {
for
(FileStatus fileStatus : listStatus) {
// 判断是否是文件夹
final
boolean
isdir = fileStatus.isDir();
final
String permission = fileStatus.getPermission().toString();
final
short
replication = fileStatus.getReplication();
final
String group = fileStatus.getGroup().toString();
final
String owner = fileStatus.getOwner().toString();
final
long
blockSize = fileStatus.getBlockSize();
final
String modificationTime = DateFormatUtils.format (
fileStatus.getModificationTime(),
"yyyy-MM-dd HH:mm:ss"
);
final
String path = fileStatus.getPath().toString();
final
String substringPath = path.substring(20, path.length());
System.
out
.println((isdir ?
"d"
:
"-"
)+ permission +
" "
+ (replication > 0 ? replication :
"-"
).toString() +
" "
+ owner +
" "
+ group +
" "
+ blockSize +
"\t\t"
+ modificationTime +
" "
+ substringPath);
if
(isdir) {
lsr(fs, fs.listStatus(fileStatus.getPath()));
}
}
}
private
static
void
ls(
final
FileSystem fs)
throws
IOException {
final
FileStatus[] listStatus = fs.listStatus(
new
Path(
"/"
));
for
(FileStatus fileStatus : listStatus) {
// 判断是否是文件夹
final
boolean
isdir = fileStatus.isDir();
final
String permission = fileStatus.getPermission().toString();
final
short
replication = fileStatus.getReplication();
final
String group = fileStatus.getGroup().toString();
final
String owner = fileStatus.getOwner().toString();
final
long
blockSize = fileStatus.getBlockSize();
final
String modificationTime = DateFormatUtils.format (
fileStatus.getModificationTime(),
"yyyy-MM-dd HH:mm:ss"
);
final
String path = fileStatus.getPath().toString();
final
String substringPath = path.substring(20, path.length());
System.
out
.println((isdir ?
"d"
:
"-"
) + permission +
" "
+ (replication > 0 ? replication :
"-"
).toString() +
" "
+ owner +
" "
+ group +
" "
+ blockSize +
"\t\t"
+ modificationTime +
" "
+ substringPath);
}
}
}
作业3： 从NameNode的源代码中找到NameNode是一个RPC Server的证据
(提示，只需要找到RPC.getServer的调用即可)
