http断点续传简单实现（java)

/* CIt@xi#I  
**SiteFileFetch.java jivGkIj!8  
*/ {NIE:MXX  
package NetFox; &W y9%  
import java.io.*; 2)`4(38  
import java.net.*; 0o!Egq_  
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[{-;cpM\  
public class SiteFileFetch extends Thread { K30{Fcb< h  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tw]Q5:6  
long[] nStartPos; //开始位置 ^X?3e1om  
long[] nEndPos; //结束位置 Y&b JKX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a/ Z\h{*  
long nFileLength; //文件长度 {Ve_u  
boolean bFirst = true; //是否第一次取文件 H|!|fo-Tx  
boolean bStop = false; //停止标志 pL'+sW  
File tmpFile; //文件下载的临时信息 OEgp!J  
DataOutputStream output; //输出到文件的输出流 "\Nn,3qp  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NHzhGg]  
public SiteFileFetch(SiteInfoBean bean) throws IOException IsiCHtY9  
{ X[iQ%Y$/n  
siteInfoBean = bean; .{#J2}+[_}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 20RISj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RC]-9gd3Q  
if(tmpFile.exists ())  Hn,;G`{  
{ ^&8xfI
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bFirst = false; w`K=J!5y2g  
read_nPos(); [Gb8o'  
} r`Cs

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else OM7EmMa;  
{ u"1Zv!  
nStartPos = new long[bean.getNSplitter()]; ^b`aO$  
nEndPos = new long[bean.getNSplitter()]; p#(5 ;  
} nJo6;_MI!  
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} Dj@7vM%_  
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public void run() r5\|%5=J  
{ ZncJ  
//获得文件长度 ?r-W , n  
//分割文件 rjW\tuZI  
//实例FileSplitterFetch 'e06QMp@  
//启动FileSplitterFetch线程 7^Q4?(A  
//等待子线程返回 c'~6 1HA<  
try{ UB1/0o  
if(bFirst)
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{ 2i_k$-  
nFileLength = getFileSize(); %Y//}  
if(nFileLength == -1) 1|Z!8:&pj  
{ .:=G=v=1  
System.err.println("File Length is not known!"); .+ g8zbD4  
} mX
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else if(nFileLength == -2) g O ;oM?|  
{ LL^WeD_Y  
System.err.println("File is not access!"); .a`(?pPr,  
} aqzIMOAf  
else aaM76;  
{ f& >[$zh  
for(int i=0;i<nStartPos.length;i++) 8!(09gW'>  
{ VsM~$ )  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "xKykSk  
} <^8&2wAkJ  
for(int i=0;i<nEndPos.length-1;i++) GY,HEe]2r  
{ &!5S'J%  
nEndPos = nStartPos[i+1]; 8%D 2G i  
} *Z,?VEO  
nEndPos[nEndPos.length-1] = nFileLength; NvqIYW  
} \_J;i[
  
} a8laPN  
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//启动子线程 YZ0Jei8+-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E2~&GkU.UN  
for(int i=0;i<nStartPos.length;i++) (W4H
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{ m]#oZVngy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tweku}D7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w5uOkz #  
nStartPos,nEndPos,i); 2Ub!wee  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,4tuWO)"  
fileSplitterFetch.start(); (Ld,<!eN0  
} 0<C]9[l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /f0*NNSat-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~dc~<hK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W2F*+M  
nEndPos = " + nFileLength); #XPY\n^k  
// fileSplitterFetch[nPos.length-1].start(); 7dbGUbT  
?(d<n   
oi:!YVc  
//等待子线程结束 6wY6*R  
//int count = 0; )eaEc9o>  
//是否结束while循环 :sL?jGk\
 
boolean breakWhile = false; `}Z`aK  
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while(!bStop) L6=`x
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{ ydm2'aV  
write_nPos(); U+FI^Xrt#  
Utility.sleep(500); _8I\!  
breakWhile = true; u?B9zt%$-m  
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for(int i=0;i<nStartPos.length;i++) mW&hUPRx  
{ r(VznKSx  
if(!fileSplitterFetch.bDownOver) >j$y@"+  
{ "|KhqV=?v  
breakWhile = false; (AI 4a+  
break; iu+r=sp  
} z+(V2?xcvt  
} J70r`   
if(breakWhile) |b'}.(/3i  
break; rZSD)I  
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8.m9 =+)8  
//count++; ]w;!x7bU(  
//if(count>4) 9 m`VIB  
// siteStop(); ]]^eIjg>a6  
} p]E\!/  
'BOMFp7c  
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System.err.println("文件下载结束！"); 2Mo oqJp  
} O; #qG/b1  
catch(Exception e){e.printStackTrace ();} Hru~Y}V  
} r(6$.zx  
a 0+W-#G  
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//获得文件长度 B9h'}460H  
public long getFileSize() 2{;~Bgd  
{ s5
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int nFileLength = -1; %;MM+xVVX  
try{ NA;OT7X[  
URL url = new URL(siteInfoBean.getSSiteURL()); sf5F$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &A!?:?3%O  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rw!wfh_+  
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int responseCode=httpConnection.getResponseCode(); F+Q(^Nk  
if(responseCode>=400) Sxzt|{  
{ '74*-yd  
processErrorCode(responseCode); *)u%KYGr  
return -2; //-2 represent access is error H05xt
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} %
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J-d>#'Wb|  
String sHeader; *1c1XN<7  
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for(int i=1;;i++) :F`-<x/  
{ c>.=;'2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `m+o^!SGe  
//Utility.log(in.readLine()); P?/Mrz   
sHeader=httpConnection.getHeaderFieldKey(i); TKs l.|  
if(sHeader!=null) bJ5 VlK67R  
{ GX0S9s  
if(sHeader.equals("Content-Length")) K$kI%eGZA  
{ dk>qTY+j5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `*-rz<G  
break; mGP&NOR0^y  
} >\4"k4d}  
} R8N*. [  
else Of.%rpgy  
break; bBg=X}9  
} 7Q>bJ Ek7  
} !si}m~K!_  
catch(IOException e){e.printStackTrace ();} 1.IEs:(;  
catch(Exception e){e.printStackTrace ();} He)
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Utility.log(nFileLength); Pe
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return nFileLength; y*H rv  
} HVH<S  
7v]9) W=y  
8d1r#sILI  
//保存下载信息（文件指针位置） , G9{:  
private void write_nPos() >eM>Y@8=  
{ N.F
//n  
try{ ]o2jSD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5-2#H?:U  
output.writeInt(nStartPos.length); MN<uIqG  
for(int i=0;i<nStartPos.length;i++) /v8yE9N_  
{ oxZXY]$y
 
// output.writeLong(nPos); kG>m(n  
output.writeLong(fileSplitterFetch.nStartPos); wrm ReT?  
output.writeLong(fileSplitterFetch.nEndPos); /ei(Q'pc[  
} 6xiCTs0@  
output.close(); O 4C}]E  
} n@_aTY  
catch(IOException e){e.printStackTrace ();} qW 2'?B3<  
catch(Exception e){e.printStackTrace ();} /7LAd_P6  
} +[Bl@RHe^  
$iMbtA5aQ  
8Os: SC@Q  
//读取保存的下载信息（文件指针位置） wn/Y5   
private void read_nPos() gn)>(MG  
{ aW*8t'm;m'  
try{ {n 4W3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^E]y >Y  
int nCount = input.readInt(); ;/ASl<t,  
nStartPos = new long[nCount]; OOZxs?pR  
nEndPos = new long[nCount]; s_#6^_  
for(int i=0;i<nStartPos.length;i++) a?1Ml>R6P  
{ 0dCg/wJx  
nStartPos = input.readLong(); p-f"4vH  
nEndPos = input.readLong(); 
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} D]'/5]~z<  
input.close(); rcUJOI  
} $A^OP{  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} GZzBATx  
} sh)[|?7
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private void processErrorCode(int nErrorCode) <~}NxY\5  
{ R "qt}4m  
System.err.println("Error Code : " + nErrorCode); H6Q!~o\"H  
} p(fL' J  
Uu0  
t{Wu5<F:  
//停止文件下载 )NmYgd~%  
public void siteStop() i%n9RuULh  
{ |31/*J!@z*  
bStop = true; UH`cWVLpr  
for(int i=0;i<nStartPos.length;i++) bx:j`5Uj`  
fileSplitterFetch.splitterStop(); w=k
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,;)_$%bHc  
} QC<O=<$Q[  
} CXh>'K  
//负责部分文件的抓取 w`
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**FileSplitterFetch.java o:PdPuZVR  
*/ L "5;<  
package NetFox; 
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g=e~YM85  
a\*_b2 ^n  
import java.io.*; (d*~Qpi{7  
import java.net.*; % 8P8h%%Z  
1 Szv4  
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public class FileSplitterFetch extends Thread { guk{3<d:Jy  
R 6 -RH7.  
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String sURL; //File URL bkS-[rW  
long nStartPos; //File Snippet Start Position h ;1D T  
long nEndPos; //File Snippet End Position _g%,/y 9y  
int nThreadID; //Thread's ID _<u>? Qt  
boolean bDownOver = false; //Downing is over #n.XOet<\  
boolean bStop = false; //Stop identical ",pd 9  
FileAccessI fileAccessI = null; //File Access interface *:"p*qV*  
4uE|$  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0aa&13!5  
{ \{.c0  
this.sURL = sURL; Vc!'=&*  
this.nStartPos = nStart; wxE'h~+  
this.nEndPos = nEnd; NX8. \Pf#  
nThreadID = id; >D_!d@Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q(jIqY1Hf  
} :aR_f`KMm  
k-I
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\[<8AV"E-'  
public void run() n'83P%x  
{ `{H!V~42  
while(nStartPos < nEndPos && !bStop) Ntlbn&lc;D  
{ i|!W;2KL5  
qlC4&82=Q  
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try{ Sz-TarTF  
URL url = new URL(sURL); D-Q54"^3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q.ZkQN+  
httpConnection.setRequestProperty("User-Agent","NetFox"); G2w0r,[  
String sProperty = "bytes="+nStartPos+"-"; -u~AY#*  
httpConnection.setRequestProperty("RANGE",sProperty); n!h952"  
Utility.log(sProperty); d,E2l~s  
#D^(dz*  
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InputStream input = httpConnection.getInputStream(); "0m\y+%8  
//logResponseHead(httpConnection); $GQ{Ai:VwF  
/>O.U?  
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byte[] b = new byte[1024]; M3s:B& /  
int nRead; ,U.|+i{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <~  ?LU^  
{ 4F,RlKHBl  
nStartPos += fileAccessI.write(b,0,nRead); ^%NjdZuDO  
//if(nThreadID == 1) [<.dOe7|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8gJg7RxL  
} LCMn9I  
p4@0Dz`Q  
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Utility.log("Thread " + nThreadID + " is over!"); ~ep^S^V+  
bDownOver = true;  t: 03  
//nPos = fileAccessI.write (b,0,nRead); vz^=o'  
} zKFiCP K  
catch(Exception e){e.printStackTrace ();} ntn ~=oL  
} nG7E j#1  
} <x1,4a~  
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"@L|Z6U(  
//打印回应的头信息 T1c&3  
public void logResponseHead(HttpURLConnection con) Q&vU|y  
{ K_-S`-eH  
for(int i=1;;i++) dG)}H_  
{ H,;9' *84  
String header=con.getHeaderFieldKey(i); , RU   
if(header!=null) pt%Y1<9Eh?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o"g<Vz  
Utility.log(header+" : "+con.getHeaderField(header)); 6c*QBzNL  
else +<'>~lDg  
break; dC?l%,W  
} ?3do-tTp  
} s[%@3bY!7  
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/gP"X1.  
public void splitterStop() UVD*GsBk  
{ 9,$ n6t;  
bStop = true; y-_IMu.J`  
} 4YA1~7R  
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!=]cASPGD  
} /U=?D(>x  
*/j[n$K>~`  
+K48c,gt?  
/* BP=<TRp.  
**FileAccess.java .2SD)<}(9  
*//文件访问(定位，写) aPHNX)  
package NetFox; 9n;6;K#  
import java.io.*; v K!vA-7  
wj\kx\+  
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public class FileAccessI implements Serializable{ 2[1lwV
  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >+Y@rj2  
RandomAccessFile oSavedFile; RC^k#+  
long nPos; yK w.69.  
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public FileAccessI() throws IOException ^`fqK4<  
{ ~\u
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this("",0); CUx[LZR7m  
} -|GX]jx(Y  
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public FileAccessI(String sName,long nPos) throws IOException AizLzR$OG  
{ JxlZ,FF$@  
oSavedFile = new RandomAccessFile(sName,"rw"); lz(}N7SLa  
this.nPos = nPos; )odz/\9n3c  
oSavedFile.seek(nPos); |\N))K-2D  
} ;& zBNj  
?;DzWCL~9  
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public synchronized int write(byte[] b,int nStart,int nLen) l:j>d^V*&x  
{ B1 xlWdm  
int n = -1; ?'^yw C`  
try{ U\6Ee-1#_  
oSavedFile.write(b,nStart,nLen); h-5] nL3  
n = nLen; `A$zLqz)Vm  
} T<U_Iq  
catch(IOException e) 2Jqr"|sw  
{ 66HxwY3a  
e.printStackTrace (); Nh+XlgXG  
} ~;I'.TW  
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return n; ]?s^{  
} s:^Xtox/  
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} Z"E2ZSa0  
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/* \+)AQ!E  
**SiteInfoBean.java %[fZ@!B  
*/ 0|FQIhVuY  
package NetFox; FIpJ>E"n  
$aj:\A0f  
}PzHtA,V  
public class SiteInfoBean { 'Xg9MS&  
,<fs+oi  
#<yKG\X?  
private String sSiteURL; //Site's URL jNW/Biy4u  
private String sFilePath; //Saved File's Path TlJ'pG 4^  
private String sFileName; //Saved File's Name +kT o$_Wkz  
private int nSplitter; //Count of Splited Downloading File 7QHrb'c  
o.])5i_HV  
2Y%E.){  
public SiteInfoBean() J pKCux  
{//nSplitter的缺省值为5 L[lS >4eN  
//default value of nSplitter is 5 ?]0bR]}y  
this("","","",5); B2,JfKk/  
} b#:!b  
/y-8dgv0a  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YH{FTVOt{C  
{ J;Eg"8x]  
sSiteURL= sURL; sF1j
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sFilePath = sPath; Q&e*[l2M6  
sFileName = sName; >0I\w$L  
this.nSplitter = nSpiltter; :6W* ;<o  
>{#QS"J#  
y-o54e$4Cq  
} VP:9&?>G  
[\.@,Y0j  
7z3YzQ=Kg  
public String getSSiteURL() C^ Oy.s  
{ N@R?<a  
return sSiteURL; +EM^  
} |.LE`  
?xtP\~  
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public void setSSiteURL(String value) V)cL
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{ `<* tp@  
sSiteURL = value; U46Z~B  
} ]/odp/jm  
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public String getSFilePath() SaA-Krn  
{ |\SwZTr  
return sFilePath; lM[FT=M  
} 1^y^b{  
)%~<EJ*&Z  
$J]o\~Z J  
public void setSFilePath(String value) yQquGu  
{ >?GCH(eW%  
sFilePath = value; L+NrU+:=C  
} ]gDX~]f[  
O8 5)^  
Y$ '6p."=  
public String getSFileName() o7v,:e:  
{ B-[qS;PY%  
return sFileName; P30|TU+B  
} pFwhvw  
CF/8d6}Vf  
w>6cc#>q  
public void setSFileName(String value) q 1+{MPJ  
{ 4_h?E:sBb  
sFileName = value; KNqs=:i  
} X>ck.}F  
'%[r9w  
EGK7)O'W  
public int getNSplitter() Yk yB  
{ fi';Mb3B3  
return nSplitter; 48n7<M;I  
} N6%M+R/Q  
7^DN8g"&\  
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public void setNSplitter(int nCount) >d$Sh`a6  
{ gtRs||  
nSplitter = nCount; z#\YA]1  
} ]xN)>A2  
} GaLQ/V2R  
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9M1UkS$`@  
/* Mt%=z9OLq9  
**Utility.java lAo S 9w  
*/ 3V@!}@y,F6  
package NetFox; 6}GcMhU<r  
.X{U\{c|a  
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public class Utility { (zIIC"~5  
f"0?_cG{%  
OQh4MN#$  
public Utility() (sx,Ol  
{ (GbZt{.  
]?(_}""1  
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} </9@RO  
0i/!nke.  
//线程睡眠 D:Fi/JY~  
public static void sleep(int nSecond) \* SEj&9  
{ i|QL6e*0  
try{ = K3NKPUI  
Thread.sleep(nSecond); 8 J;\Z  
} 6:qh%ZR  
catch(Exception e) U$ 22r b  
{ tqicyNL  
e.printStackTrace (); 7q'T,'[  
} 0M5m8  
} Fm
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0p1~!X=I  
//日志 Q(h/C!rKe  
public static void log(String sMsg) M3c  
{ 8&UwnEk<  
System.err.println(sMsg); ($[)Tcq*~  
} Y@Ti2bI`v  
B%/N{i*Z  
@&GfCg5Cb  
public static void log(int sMsg) 29r(Y  
{ Wt
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System.err.println(sMsg); GKa_
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} Eg 8rgiU  
} o1)8?h  
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/* IHvrx:7  
**TestMethod.java CyD)=e{  
*/ X!!3>`|  
package NetFox; fm&pxQjg  
6;#Rd|  
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public class TestMethod { % n~ 'UA  
)_\q)t"=  
vDcYz,  
public TestMethod() JFh_3r'  
{ ///xx/weblogic60b2_win.exe KIYs[0*k  
try{ #Iwxt3K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #Hi$squJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bf{c4YiF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |}naI_Qudv  
fileFetch.start(); !\/J|~XZ  
} p@jwHlX  
catch(Exception e){e.printStackTrace ();} @szr '&\%A  
J0,;F9<C#X  
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} fe!{vrS  
ayh=@7*  
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public static void main(String[] args) ^2-t|E=  
{ t$-!1jq  
new TestMethod(); ,8Q&X~$rY  
} g0>Q* x  
} 98LyzF9  
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