http断点续传简单实现（java)

/* gvL*]U7  
**SiteFileFetch.java 4Lz[bI  
*/ jl>wvY||  
package NetFox; fu-,<m{  
import java.io.*; %*Vr}@BA)  
import java.net.*; ;Cjj_9e,:  
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public class SiteFileFetch extends Thread { ,f<J4U:Y  
# @7I  
1N5lI97j  
SiteInfoBean siteInfoBean = null; //文件信息Bean KP$AT}D  
long[] nStartPos; //开始位置 a4Z e!l(  
long[] nEndPos; //结束位置 ][YuJUK8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L>0Pur)[  
long nFileLength; //文件长度 =EU;%f  
boolean bFirst = true; //是否第一次取文件 !DHfw-1K  
boolean bStop = false; //停止标志 H^vA}F`  
File tmpFile; //文件下载的临时信息 +rhBC V  
DataOutputStream output; //输出到文件的输出流 kjXwVGK=P<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 73SH[
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public SiteFileFetch(SiteInfoBean bean) throws IOException {.DY\;Q  
{ ^+k= ;nl  
siteInfoBean = bean; bqaj~:}@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d<WNN1f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2]FRIy d  
if(tmpFile.exists ()) tCPK_Wws?Z  
{ "5?1S-Vl  
bFirst = false; _j*I\  
read_nPos(); xVN!w\0  
} 3Wx\Liw,  
else C@<gCMj,"  
{ #7}YSfm^6  
nStartPos = new long[bean.getNSplitter()]; xr7M#n  
nEndPos = new long[bean.getNSplitter()]; a`?Vc}&  
}  5PC:4  
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} `O;4b#!g  
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public void run() Q}a(vlZ  
{ Z%=A[`5]  
//获得文件长度 5w+&plIJ  
//分割文件 c~OvoTF,  
//实例FileSplitterFetch @D `j   
//启动FileSplitterFetch线程 PSX o"   
//等待子线程返回 nV`W0r(f'  
try{ y9=<q%Kc-  
if(bFirst) K8_\U0 K  
{ _}T )\o   
nFileLength = getFileSize(); |x>5T
}  
if(nFileLength == -1) ,|,kU0xXz  
{ ^L8:..+:  
System.err.println("File Length is not known!"); `U>2H4P  
} (v? rZv  
else if(nFileLength == -2) v"o@q2f_  
{ 3preBs#i  
System.err.println("File is not access!"); BMV\@Sg  
} |sP0z !)b  
else 6BM$u v4  
{ S1m5z,G  
for(int i=0;i<nStartPos.length;i++) s#")hMJQ  
{ D(&WEmm\B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F~bDg tN3  
} Kc#1H|'2N  
for(int i=0;i<nEndPos.length-1;i++) `R-?+76?  
{ U3UA  
nEndPos = nStartPos[i+1]; '#.D
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} tDfHO1pS  
nEndPos[nEndPos.length-1] = nFileLength; 475g-t2"@  
} ya,-Lt  
} h^''ue"  
W )Ps2  
i&DUlmt)f  
//启动子线程 J+N -+,,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N|ZGc{?  
for(int i=0;i<nStartPos.length;i++) eV}H  
{ 6\-u:dvGI?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Dk8@x8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Kxz|0l  
nStartPos,nEndPos,i); ~ tN/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P:3o}CB1I  
fileSplitterFetch.start(); r}:U'zlC{  
} -z se+]O`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UFUEY/q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a0Fq$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -%{+\x2  
nEndPos = " + nFileLength); 9U=6l]Np  
// fileSplitterFetch[nPos.length-1].start(); rq}xuSFI  
AEElaq.B  
v$5D&Tv  
//等待子线程结束 &FYv4J  
//int count = 0; eX!yIqAR  
//是否结束while循环 Ae"|a_>fMI  
boolean breakWhile = false; #uICHt3  
|B64%w>Y  
036QV M$  
while(!bStop) &fU48n1Uh  
{ "QD>:G;u  
write_nPos(); s'IB{lJ9  
Utility.sleep(500); !67xN?b  
breakWhile = true; sb?!U"v.'  
[qkc6sqo  
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for(int i=0;i<nStartPos.length;i++) HW#@e kh  
{ :_,3")-v  
if(!fileSplitterFetch.bDownOver) :C,}DyZy  
{ -pQ?ybQ  
breakWhile = false; -C!m#"P
DW  
break; giW9b_  
} I }8b]  
} 1\)lD(J\C  
if(breakWhile) Neii$  
break; _g,_G  
o&$lik  
BqdpJIr  
//count++; e+>$4Jq  
//if(count>4) n1PvZ~^3  
// siteStop(); yw89*:A6  
} *m`x/_y+  
M 8(w+h{  
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System.err.println("文件下载结束！"); \0&$n  
} q]SH
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catch(Exception e){e.printStackTrace ();} Z$6B}cz<  
} ];N/KHeZ  
PpF`0w=1%l  
|)*!&\Ch  
//获得文件长度 hFhC&2HN  
public long getFileSize() ,wv>
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{ hPCSAo!|  
int nFileLength = -1; #MiO4zXgd  
try{ C^,J6;'  
URL url = new URL(siteInfoBean.getSSiteURL()); }ov>b2H#<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y6MkaHW[m  
httpConnection.setRequestProperty("User-Agent","NetFox"); B+pLW/4l  
Wvl'O'R  
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int responseCode=httpConnection.getResponseCode(); &h=f  
if(responseCode>=400) fGe"1MfU  
{ W2M[w_~QE  
processErrorCode(responseCode); %dhrXK5  
return -2; //-2 represent access is error 1'dZ?`O  
} 5~E{bW$  

L%-ENk  
1Oak8 \G  
String sHeader; iQ
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>enP~uW[#  
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for(int i=1;;i++) ;<xPzf  
{ 7_rDNK@e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u bZ`Y$  
//Utility.log(in.readLine()); e:_[0#  
sHeader=httpConnection.getHeaderFieldKey(i); mmCGIX  
if(sHeader!=null) lTtc#  
{ C+mPl+}w  
if(sHeader.equals("Content-Length")) D}-HWJQA3  
{ $v"CQD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ![MtJo5  
break; :R$v7{1  
} MiF( &#  
} '
A1y~x#2B  
else N4{g[[ T  
break; A.r.tf}:  
} m2ph8KC  
} O(_f&a  
catch(IOException e){e.printStackTrace ();} fWF!%|L  
catch(Exception e){e.printStackTrace ();} F*NHy.Y  
(/t{z=  
vy>(?[  
Utility.log(nFileLength); h96<9L  
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return nFileLength; q 1u_r  
} >N}+O<Fc  
<xH! Yskc  
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//保存下载信息（文件指针位置） v`:!$U* H=  
private void write_nPos() .cmhi3o4  
{ 2(Yt`3Go(  
try{
'[HU!8F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n:H |=SF{  
output.writeInt(nStartPos.length); %z"$?Iv  
for(int i=0;i<nStartPos.length;i++) kb~ 9/)~g  
{ kY'C'9p  
// output.writeLong(nPos); hl DU.k  
output.writeLong(fileSplitterFetch.nStartPos); $d&7q5[  
output.writeLong(fileSplitterFetch.nEndPos); 9,"gXsvx(  
} &[yYgfs
p  
output.close(); >gn@NJ2N  
} 4]Gm4zO  
catch(IOException e){e.printStackTrace ();} -;i:bE  
catch(Exception e){e.printStackTrace ();} F>%,}Y~B:  
} 
2<V`  
gxC`Ml  
:z|$K^)7Z  
//读取保存的下载信息（文件指针位置） W4h]4X  
private void read_nPos() Z hCjY  
{ )_?HBTG  
try{ UCo<ie\V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b8$%=Xp  
int nCount = input.readInt(); 1WY$Vs  
nStartPos = new long[nCount]; VwXR,(  
nEndPos = new long[nCount]; 'l-VWqR-  
for(int i=0;i<nStartPos.length;i++) m&s;zQ  
{ gs~u8"B  
nStartPos = input.readLong(); piIG
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nEndPos = input.readLong(); (?.h<v1}  
} EvA8<o  
input.close(); " ;\EU4R  
} +hH7|:JQ  
catch(IOException e){e.printStackTrace ();} &@PAv5iNf  
catch(Exception e){e.printStackTrace ();} A!$sOp  
} j1ap,<\.k  
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s;tI?kR>%  
private void processErrorCode(int nErrorCode) DnF|wS  
{ u=(.}  
System.err.println("Error Code : " + nErrorCode); 4%<D\#  
} u}?{1B!  
?b]f$ 2  
?9*[\m?-  
//停止文件下载 %fh-x(4v  
public void siteStop() 5yroi@KT  
{ (YYwn@NGj  
bStop = true; Y)M-?|4  
for(int i=0;i<nStartPos.length;i++) w7<4D,hk  
fileSplitterFetch.splitterStop(); ZalL}?E ?  
 BfW@f  
=[gFa
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} $! g~pV  
} nyG5sWMpe  
//负责部分文件的抓取 q1/mp){  
**FileSplitterFetch.java ;Z,l};b  
*/ 8PG&/"K  
package NetFox; iX>)6)uJ  
q+lCA#Sx  
=Q!V6+}nY^  
import java.io.*; Jp~[Dm  
import java.net.*; DuC_uNJ  
~UsE"5  
,JJ1sf2A  
public class FileSplitterFetch extends Thread { 3b<;y%  
$^#q0Yx  
hXx:D3h  
String sURL; //File URL eHyIFoaC/  
long nStartPos; //File Snippet Start Position 1L3 $h0i  
long nEndPos; //File Snippet End Position 7TZ,bD_  
int nThreadID; //Thread's ID A5G@u}YS5  
boolean bDownOver = false; //Downing is over 48mTL+*  
boolean bStop = false; //Stop identical )Qo^Mz  
FileAccessI fileAccessI = null; //File Access interface EDA6b]  
.WGrzhsV  
GGGz7_s ?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (T.g""N~`  
{ 3C#Sr6  
this.sURL = sURL; T<mP.T,$!  
this.nStartPos = nStart; (%{!TJgZR  
this.nEndPos = nEnd; 2(Nf$?U@0  
nThreadID = id; hWr}Uui  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m;u:_4  
} s 8lfW6  
h-*h;Uyc  
+a'nP=e&  
public void run() $,1KD3;+]  
{ nA+gqY6 6|  
while(nStartPos < nEndPos && !bStop) 1]7v3m  
{ p4Xhs@.k  
"s\himoa  
z+Ej`$E{lD  
try{ {=P}c:iW  
URL url = new URL(sURL); iDlg>UYd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I"W
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httpConnection.setRequestProperty("User-Agent","NetFox"); kM(,8j  
String sProperty = "bytes="+nStartPos+"-"; qK&h$;~*y  
httpConnection.setRequestProperty("RANGE",sProperty); ^O3p:X4u  
Utility.log(sProperty); |b|bL 7nx  
U+@rLQ.-  

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InputStream input = httpConnection.getInputStream(); u9ue>I/  
//logResponseHead(httpConnection); PkF'#W%  
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%nj{eT  
byte[] b = new byte[1024]; <\?dPRw2>  
int nRead; z s[zB#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I$I',x5Z  
{ [}"m4+  
nStartPos += fileAccessI.write(b,0,nRead); XJ?zP=UK  
//if(nThreadID == 1) (gUxS.zU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oX6()FR  
} <A] Kg  
L^jhr>-";  
6 $+b2&V  
Utility.log("Thread " + nThreadID + " is over!"); ->&amPv
 
bDownOver = true; ztV%W6  
//nPos = fileAccessI.write (b,0,nRead); Bvz& p)(  
} >]?!9@#IH  
catch(Exception e){e.printStackTrace ();} u%nhQ%  
} U5H5QW+  
} ,<=_t{^  
;VPYWss  
B..> *Xb  
//打印回应的头信息 [vcSt5R=  
public void logResponseHead(HttpURLConnection con) 4,7W*mr3(  
{ 7iH%1f  
for(int i=1;;i++) #80r?,q  
{ ^xF-IA#ZeB  
String header=con.getHeaderFieldKey(i); OBZ:C!  
if(header!=null) 42,K

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//responseHeaders.put(header,httpConnection.getHeaderField(header)); jGOE CKP  
Utility.log(header+" : "+con.getHeaderField(header)); .\|}5J9W  
else gqACIXR  
break; a O(&<  
} Zs}EGC~&  
} ~{npG  
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@s~*>k#"#  
public void splitterStop() rJc=&'{&)N  
{ `:EU
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bStop = true; p|'Rm]&jb  
} 2I1CKA:7g  
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} _Wo(;'.  
~DUOL~E  
L ^{C4}x=  
/* 8DZ OPA  
**FileAccess.java (Ei} :6,}  
*//文件访问(定位，写) jI,?*n<  
package NetFox; hO4* X  
import java.io.*; Xa/]} B  
, @dhJ8/  
hZeF? G)L'  
public class FileAccessI implements Serializable{ z]R)Bh  
EJJW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -bQi4  
RandomAccessFile oSavedFile; VyxX5Lrj  
long nPos; n_46;lD  
BYWs\6vK  
6eAJ>9@x  
public FileAccessI() throws IOException WEk3 4crk  
{ 3"iJ/Hc}9  
this("",0); F]`_akE  
} x_.}C%  
wVtBH_>  
ue"e><c6:  
public FileAccessI(String sName,long nPos) throws IOException :N ]H"u9X  
{ Hrj@I?4  
oSavedFile = new RandomAccessFile(sName,"rw"); [HSN*LXe  
this.nPos = nPos; _XUDPC(*qz  
oSavedFile.seek(nPos); zc%HBZ3p  
} BZAF;j  
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m$bDWxm#e  
public synchronized int write(byte[] b,int nStart,int nLen) { ^ @c96&  
{ <l"rnM%  
int n = -1; \6K1Z!*;  
try{ u13v@<HGc  
oSavedFile.write(b,nStart,nLen); geEETb}+y  
n = nLen; "c0Nv8_G  
} QeipfK+me  
catch(IOException e) PBp+(o-  
{ QN OA66  
e.printStackTrace (); E8PlGQ~z{d  
} /faP@Q3kR  
2)47$eu  
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return n; "IKbb7x  
} -q}I; cH  
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} _Q6` Wp6m  
(`FY{]Wz!  
eCX
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/* b{hdEb  
**SiteInfoBean.java _/)HAw?k  
*/ \K(QE ~y'W  
package NetFox; rz]M}!>k  
1i:Q %E F  
/[#5<;  
public class SiteInfoBean { (GXFPEH8  
+a!uS0fIJi  
|FH|l#bu>  
private String sSiteURL; //Site's URL }ec3qZ@  
private String sFilePath; //Saved File's Path 7/GL@H  
private String sFileName; //Saved File's Name h$rk]UM/Q  
private int nSplitter; //Count of Splited Downloading File 0rj50$~$]  
vDp|9VY?  
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public SiteInfoBean()  njg\y  
{//nSplitter的缺省值为5 #5}v?  
//default value of nSplitter is 5 QPJz~;V2  
this("","","",5); +o^sm'$  
} i :Sih"=  
Ul%D}(,  
%r >Y)@$Vt  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w^wh|'u^_@  
{ LGPPyKNx  
sSiteURL= sURL; kli)
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sFilePath = sPath; z{ MO~d9  
sFileName = sName; ewOR
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this.nSplitter = nSpiltter; 4oA9|}<FR  
66%4p%#b4  
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} Yi+$g  
h1jEulcMtq  
0>)F+QC  
public String getSSiteURL() JPGEE1!B{b  
{ ,R2;oF_  
return sSiteURL; U t'r^  
} ERZWK  
'7(oCab"_  
!@wG22iC4d  
public void setSSiteURL(String value) ~;P>}|6Y  
{ cOo@UU P  
sSiteURL = value; ZtH
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} _rjB.  
do&0m[x%  

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public String getSFilePath() f5dctDHP  
{ M&~cU{9c  
return sFilePath; >P[BwL]  
} fZF.eRP'  
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6V^KOG  
public void setSFilePath(String value) _l||69|.  
{ {H[3[  
sFilePath = value; hsZ}FLStJ  
} PuoN<9 #  
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A!.*
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public String getSFileName() m0_B[dw  
{ IM9P5?kJ ?  
return sFileName; 
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} EGIwqci:  
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A.
@
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public void setSFileName(String value) y&{ Z"+B5  
{ nk^-+olm  
sFileName = value; z}f;_NX  
}  &j_:VP  
rN5;W  
@!:_r5R~N  
public int getNSplitter() nps"nggk  
{ tF=Y3W+L  
return nSplitter; ^":Dk5gl  
} FST}:*dOe5  
!-Br?  
]`GDZw`  
public void setNSplitter(int nCount) t?404  
{ U)y~{E~c34  
nSplitter = nCount; ?~#{3b  
} I!uGI  
} ;?'=*+'>  
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/* AiE\PMF~{P  
**Utility.java <"rckPv_H  
*/ h<ULp&g  
package NetFox; sg!*%*XQ  
jYi{[**  
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public class Utility { 1[Ffl^\ARp  
zgR@-OtFZ  
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public Utility() zA?]AL(+YW  
{ q\gvX 76a  
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+HxL>\  
} ^S'tMT_  
B{+ Ra  
//线程睡眠 |L"!^Y#=D  
public static void sleep(int nSecond) 999E0A$dkv  
{ b 7%O[  
try{ b!ea(D!:  
Thread.sleep(nSecond); r=3knCEWK  
} j/9Uf|z-_  
catch(Exception e) u/8urxpy  
{ lC&B4zec  
e.printStackTrace (); Oor&1  
} =z$XqT.'  
} Qy+&N*k>  
zz+p6`   
//日志 ;Pi-H,1b  
public static void log(String sMsg) 30Z RKrW"~  
{ 8Qg,UX  
System.err.println(sMsg); )|@ H#kv?  
} [# '38  
0u'qu2mV  
+Eh^j3W  
public static void log(int sMsg) [Nn ?:5"
 
{ +#c3Y;JP  
System.err.println(sMsg); *Tt*\ O  
}
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}  `=h`:`  
_@47h86Q  
utvZ<zz`  
/* "x*5g*k  
**TestMethod.java 5z>kz/uxW  
*/ k'K&GF1B  
package NetFox; '`*{ig  
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public class TestMethod { ?5<Q+G0r  
UA
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x1}7c9nK  
public TestMethod() ]$>O--  
{ ///xx/weblogic60b2_win.exe !Bv"S0  
try{ v3i]z9`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U 
Ux]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2h6<'2'o1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <?UIux  
fileFetch.start(); KnC;j-j  
} /@
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catch(Exception e){e.printStackTrace ();}
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v){&g5djl  
f(h nomn  
} G Uf[Dz  
(1pxQ%yEA  
bnz2\C9^  
public static void main(String[] args) ]S6`",+)<f  
{ dT%$"sj5  
new TestMethod(); DUk&`BSJ  
} LH4!QDK-  
} -o8H_MR  
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