http断点续传简单实现（java)

/* {fW(e?8)  
**SiteFileFetch.java AC:cV='  
*/ ('BFy>@  
package NetFox; s_xWvx8?4.  
import java.io.*; _PUgK\  
import java.net.*; P0WI QG+  
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public class SiteFileFetch extends Thread { %QH "x`;  
bAS('R;4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean '_!j9A]g  
long[] nStartPos; //开始位置 Q[+&n*  
long[] nEndPos; //结束位置 <J" 7ufHSQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XG2&_u&  
long nFileLength; //文件长度 frV*
+  
boolean bFirst = true; //是否第一次取文件 ^|-*amh  
boolean bStop = false; //停止标志 X=$WsfN.h  
File tmpFile; //文件下载的临时信息 UZ#Yd|'PD  
DataOutputStream output; //输出到文件的输出流 0*0]RC5?  
c@H:?s!0R  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G Xx7/X  
public SiteFileFetch(SiteInfoBean bean) throws IOException )* 5R/oy,  
{ g#b[-)Qx  
siteInfoBean = bean; r:Uqtqxh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /;>U0~K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K8xwPoRL  
if(tmpFile.exists ()) G&8)5d[  
{ KZ_d..l*W  
bFirst = false; ,
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read_nPos(); L7oLV?k  
} jzCSxuZ7O  
else ]gI>ay"\QA  
{ 49. @Uzo  
nStartPos = new long[bean.getNSplitter()]; 1haNca_6,  
nEndPos = new long[bean.getNSplitter()]; <5rs~  
} #
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} P5 fp!YF  
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public void run() .u[hK  
{ e_m
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//获得文件长度 )c~1
s  
//分割文件 <k'JhMwN  
//实例FileSplitterFetch RW19I,d  
//启动FileSplitterFetch线程 IO/%X;Y_  
//等待子线程返回 9gFb=&1k  
try{ ;e~Z:;AR  
if(bFirst) i=
67  
{ 7g@P$e]  
nFileLength = getFileSize(); 2ZHeOKJ-  
if(nFileLength == -1) 3u]#Ra~5  
{ \Y;LbB8D  
System.err.println("File Length is not known!"); s>y=-7:N  
} Np$peT[  
else if(nFileLength == -2) *6uZ"4rb.  
{ zdY+?s)p  
System.err.println("File is not access!"); 0a<:.}  
} ?1%/G<  
else 8z,i/:  
{ N$u;Q(^  
for(int i=0;i<nStartPos.length;i++) 'nH/Z 84  
{ (Uk1Rt*h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eteq Mg}M  
} Vf?+->-?{  
for(int i=0;i<nEndPos.length-1;i++) cspO5S>#  
{
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nEndPos = nStartPos[i+1]; bpq2TgFj  
} Q.SLiI  
nEndPos[nEndPos.length-1] = nFileLength; 8j~:p!@  
} +)8,$1[p|  
} jY^wqQls  
88c-K{}3  
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//启动子线程 F3k]*pk8w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^(,qkq'u D  
for(int i=0;i<nStartPos.length;i++) L0ZgxG3:g  
{ l+# l\q%l  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9G)Sjn`AQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QiDf,$t|,  
nStartPos,nEndPos,i); WSA;p=_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a`SQcNBf*  
fileSplitterFetch.start(); S 6e<2G=O  
} o80?B~o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +RIG8w]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ziFg+i%
s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~lB im$o  
nEndPos = " + nFileLength); j9)WInYc:  
// fileSplitterFetch[nPos.length-1].start(); 9Z! j
 
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(dSf>p r2  
//等待子线程结束 G01J1Ll}  
//int count = 0;  XL@Y!  
//是否结束while循环 4=]CAO=O  
boolean breakWhile = false; CH |A^!Zm  
K.A!?U=
 
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while(!bStop) zk)9tm;i{  
{ %<^B\|d'?  
write_nPos(); \SB~rz"A  
Utility.sleep(500); ]-  
breakWhile = true; ce/Z[B+d  
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for(int i=0;i<nStartPos.length;i++) %;5AF8#c  
{ FmU>q)  
if(!fileSplitterFetch.bDownOver) *.g0;\HF  
{ B o@B9/ABv  
breakWhile = false; }1EfyR  
break; UzLe#3MU  
} hAHZN^x&  
} X^L)5n+$X  
if(breakWhile) z$'_ =9yZ  
break; fC!]MhA"i  
1Ql\aO)  
>3R%GNw  
//count++; XhF7%KR  
//if(count>4) ppv/A4Kv  
// siteStop(); Fi8'3/q-^  
} `Qzga}`"]  
Vq7L:,N9  
9C-!I,  
System.err.println("文件下载结束！"); VUfV=&D-*g  
} eBZ^YY<*g  
catch(Exception e){e.printStackTrace ();} hdFIriE3  
} L2v j)(  
d,"?tip/SX  
eK
}AVz}k  
//获得文件长度 &<{=  
public long getFileSize() YuO-a$BP  
{ JXR_klx  
int nFileLength = -1; g.CUo:c  
try{ $`J'Y>`  
URL url = new URL(siteInfoBean.getSSiteURL()); C)2Waj}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JaC =\\B  
httpConnection.setRequestProperty("User-Agent","NetFox"); .gPE Qc+D  
#
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5  
int responseCode=httpConnection.getResponseCode(); idL6*%M  
if(responseCode>=400) ~b}@*fq  
{ 8FY.u{93  
processErrorCode(responseCode); c*+yJNm3>  
return -2; //-2 represent access is error }*+?1kv  
} 'BE &lW  
{Vz.| a[T  
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String sHeader; .]_Ye.}  
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for(int i=1;;i++) mp2J|!Lx  
{ -7_`6U2"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2l43/aCq  
//Utility.log(in.readLine()); UL0%oJ#  
sHeader=httpConnection.getHeaderFieldKey(i); ]e0yC  
if(sHeader!=null) z
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{ R(dVE\u  
if(sHeader.equals("Content-Length")) sS$"6  
{ w#v8a$tT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z
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break; Wb!"L`m  
} )wU.|9o]M  
} mmC&xZ5f  
else _C`cO  
break; F<8Rr#Z  
} yRQR@  
} 1i;-mYGaMn  
catch(IOException e){e.printStackTrace ();} i?R+Ul`Q  
catch(Exception e){e.printStackTrace ();} xpo<1Sr>S  
= ;sEi:HC  
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Utility.log(nFileLength); |1d;0*HIgX  
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return nFileLength; lWj|7  
} LM:|Kydp3  
K/;FP'.  
-!E))|A  
//保存下载信息（文件指针位置） g?V>+oMx  
private void write_nPos() nBs%k!RR  
{ qx0RCP /s  
try{ (yk^%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
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output.writeInt(nStartPos.length); u|m>h(O  
for(int i=0;i<nStartPos.length;i++)
A^+G w\  
{ fFD:E} >5  
// output.writeLong(nPos); / d S!  
output.writeLong(fileSplitterFetch.nStartPos); QG\lXY,  
output.writeLong(fileSplitterFetch.nEndPos); k%w5V>]1  
} FC.d]XA%/d  
output.close(); ` aTkIo:ms  
} oY@4G)5  
catch(IOException e){e.printStackTrace ();} 9z9z
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catch(Exception e){e.printStackTrace ();} >Lo 0,b$  
} 8>.l4:`  
jg8j>"Vj>  
7Mxw0J  
//读取保存的下载信息（文件指针位置） /H+br_D9  
private void read_nPos() b#p)bcz!I  
{ B9`^JYT<  
try{ /E'cy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h?wNmLre  
int nCount = input.readInt(); ]=v_u9;  
nStartPos = new long[nCount]; Sbub|  
nEndPos = new long[nCount]; #W#GI"K  
for(int i=0;i<nStartPos.length;i++) O_8ERxj g]  
{ 
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nStartPos = input.readLong(); XE]YKJ?|k  
nEndPos = input.readLong(); reml|!F-)  
} Sfc0 ~1  
input.close(); wCiDvHF5+C  
} srfFJX7*  
catch(IOException e){e.printStackTrace ();} .5+*,+-  
catch(Exception e){e.printStackTrace ();} D8P<mIu}Y  
} `_Bvaej?,  
%lZ++?&^  
l,}{Y4\G  
private void processErrorCode(int nErrorCode) KE\p|Xi  
{ &.ZW1TxE8  
System.err.println("Error Code : " + nErrorCode); D$g|f[l  
} XHuY'\;-  
g]|K@sm  
n*-t =DF  
//停止文件下载 T^h;T{H2  
public void siteStop() hQ&S*f&='  
{ M0`nr}g  
bStop = true; & f7{3BK  
for(int i=0;i<nStartPos.length;i++) [.DSY[!8U  
fileSplitterFetch.splitterStop(); (A2x  
@xR7>-$0p  
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} 6zK8-V?9F  
} BCB"&:}  
//负责部分文件的抓取 zAEq)9Y"l'  
**FileSplitterFetch.java `<ITLT  
*/ 9"_JiX~3  
package NetFox; U,"lOG'  
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import java.io.*; XQ.czj  
import java.net.*; $Gb] K{e  
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public class FileSplitterFetch extends Thread { Ms5m.lX  
6U;pYWht  
FUzIuz 6  
String sURL; //File URL iorKS+w"  
long nStartPos; //File Snippet Start Position sZFIQ)b9  
long nEndPos; //File Snippet End Position ,j wU\xo`C  
int nThreadID; //Thread's ID >E^?<}E~.  
boolean bDownOver = false; //Downing is over <apsG7(7
 
boolean bStop = false; //Stop identical U#G[#sd> K  
FileAccessI fileAccessI = null; //File Access interface j"o`K}C  
J 2%^%5&0  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +7?p&-r)x  
{ mfOr+   
this.sURL = sURL; q[{q3-W  
this.nStartPos = nStart; /km^IH  
this.nEndPos = nEnd; s~Wjh7'  
nThreadID = id; {\22C `9t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B]dHMLzl  
} a9z|ef  
"UVqkw,vt  
DUf=\p6`f  
public void run() 6Uq@v8mh  
{ quc?]rb  
while(nStartPos < nEndPos && !bStop) B`OggdE  
{ 9Ue3
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1 GUF,A+_O  
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try{ a?6 r4u0  
URL url = new URL(sURL); sKIWr{D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b?7?iV4  
httpConnection.setRequestProperty("User-Agent","NetFox"); uy\<t  
String sProperty = "bytes="+nStartPos+"-"; T/G1v;]  
httpConnection.setRequestProperty("RANGE",sProperty); Mj |)KDL  
Utility.log(sProperty); B&A4-w v  
[dFxW6n  
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InputStream input = httpConnection.getInputStream(); Wq 7 c/|  
//logResponseHead(httpConnection); g#~jF  
rb%P30qc4  
9)l-5o:D  
byte[] b = new byte[1024]; A<^IG+Q,B7  
int nRead; /3:R{9S%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BDZB;DPb  
{ eKn&`\j6  
nStartPos += fileAccessI.write(b,0,nRead); W>eJGZ<  
//if(nThreadID == 1) b_-ESs]g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +<6L>ZAL  
} # 'G/&&<  
ug[|'tR8  
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Utility.log("Thread " + nThreadID + " is over!"); N kp>yVj  
bDownOver = true; @PuJre4!;L  
//nPos = fileAccessI.write (b,0,nRead); gT-'#K2qT  
} bs U$mtW  
catch(Exception e){e.printStackTrace ();} 1C+Y|p?KA  
} 6NJ"ty9Bp  
} |$Dt6{h  
h8>7si  
u7G@VZ Ux5  
//打印回应的头信息 6PT ,m  
public void logResponseHead(HttpURLConnection con) )hK5_]"lmj  
{ %KNnss}  
for(int i=1;;i++) kHd_q.  
{ O_0|Q@  
String header=con.getHeaderFieldKey(i); L q8}z-
?  
if(header!=null) ~R-S$qizAC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Yo@>O98  
Utility.log(header+" : "+con.getHeaderField(header)); 1B=vrGq  
else /,$;xt-J35  
break; gbwKT`N*  
} DbJ:KQ!*  
} +o(t5O[G  
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_
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public void splitterStop() @i&LKr8  
{ Lx,"jA/  
bStop = true; l5Z=aW Q  
} 2NAGXWE  
cyA|6Ltg%  
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} }!\NdQs  
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/* 1;3oGuHj8  
**FileAccess.java [&t3xC,  
*//文件访问(定位，写) "C.'_H!Ex  
package NetFox; CCfuz
&  
import java.io.*; z*ZEw  
z %{>d#rw  
G& cm5  
public class FileAccessI implements Serializable{ G U~?S'{  
r4dG83qg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WGKN>nV  
RandomAccessFile oSavedFile; ][S<M24]Q  
long nPos; LgRx\*[C*  
"5%G[MB  
QKc3Q5)@j  
public FileAccessI() throws IOException X'.}#R1  
{ \$^z.  
this("",0); \lCr~D5  
} &}32X-~y  
m'Z233Nt"  
j]r
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public FileAccessI(String sName,long nPos) throws IOException >4}+\ Q`S  
{ Bka\0+  
oSavedFile = new RandomAccessFile(sName,"rw"); _X;^'mqf~  
this.nPos = nPos; &tw.]3  
oSavedFile.seek(nPos); r!V#@Md  
} U`K5 DZ~  
uzG<(Q pu  
1c~c_Cc4  
public synchronized int write(byte[] b,int nStart,int nLen) R"e~0WO  
{ SEXeK
2v  
int n = -1; a1M-F3  
try{ yk!,{Q?<$  
oSavedFile.write(b,nStart,nLen); 15VOQE5Fl`  
n = nLen; ps"crV-W  
} cKh
{ s  
catch(IOException e) f<9H#S:  
{ flIdL,  
e.printStackTrace (); iHr{ VQ  
} VF!?B>  
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return n; wfM$JYfI  
} @!'Pr$`  
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} IGEf*!  
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/* af\>+7x93  
**SiteInfoBean.java ;5=J'8f  
*/ "uN JQ0Y  
package NetFox; sI/Hcm  
\ lP c,8)  
oc?,8I[P5  
public class SiteInfoBean { Ge@./SGT  
d{hbgUSj  
\v9IbU*js  
private String sSiteURL; //Site's URL ~-GgVi*I  
private String sFilePath; //Saved File's Path *PMvA1eN=#  
private String sFileName; //Saved File's Name Mr<2I  
private int nSplitter; //Count of Splited Downloading File oaHg6
PT!  
@Rj&9/\L  
dn$1OhN8M  
public SiteInfoBean() `"
H!=`  
{//nSplitter的缺省值为5 Me yQ`%  
//default value of nSplitter is 5 vi4u `  
this("","","",5); 2al%J%  
} !Y!Cv %  
@JT9utct  
ylLQKdcL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8/U
=~*`_  
{ 'I($IM  
sSiteURL= sURL; vvv~n
]S6  
sFilePath = sPath; T2Z;)e$m_  
sFileName = sName; ]G1{@r)  
this.nSplitter = nSpiltter; +Q If7=  
zAC   
9'o!9_j  
} cE/
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C&bw1`XJf  
public String getSSiteURL() 7_.z3Km:  
{ Z8(1QU,~2  
return sSiteURL; = PcmJG]  
} "BK'<j^q  
Q
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t]P[>{y  
public void setSSiteURL(String value) A@j;H|  
{ Um)0jT  
sSiteURL = value; '$ ~.x|  
} l2+qP{_4  
6%JKY
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@L {x;  
public String getSFilePath() +G"=1sxJ  
{ yrnB]$hf  
return sFilePath; {0q;:
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}  8;4vr@EV  
Pqo_+fL+  
S+R<wv,6  
public void setSFilePath(String value) vpFN{UfD  
{ j,80EhZ  
sFilePath = value; hc5M)0d  
} &}nU#)IX  
j.uN`cU!  
$B7<1{<=W  
public String getSFileName() 5UVQ48aT  
{ +[UFf3(ON  
return sFileName; wA+J49  
} @4B+<,i   
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!X(Lvt/  
public void setSFileName(String value) ;/N[tO?Q  
{ >>rW-&  
sFileName = value; ?t'ZX~k  
} 3q R@$pm  
MxuwEV|^  
ik+qx~+`Qv  
public int getNSplitter() lJi'%bOi  
{ 4-eb&
 
return nSplitter; 0L$v7
, 5  
} ZO2u[HSO>  
'
jZ2^  
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public void setNSplitter(int nCount) E8T4Nh_  
{ @b=tj
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nSplitter = nCount; c ^G\w+_  
} (?J6vK}S  
} Cc0`Ylx~(  
x1Q}B   
U u(ysN4`  
/* K$\az%NE  
**Utility.java jj0@ez{3  
*/ ;9q3FuR  
package NetFox; YPDc /  
?1xBhKq  
3P6pQm'.f  
public class Utility { F@kOj*5,[  
U#ueG  
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public Utility() 95_?F7}9  
{ ,ZJI]Q=!  
COOazXtW  
VCiJ]$`M  
} zid?yuP  
 @zEEX9U  
//线程睡眠 Y$--Hp4  
public static void sleep(int nSecond) c,Zs. kC  
{ "6~pTHT  
try{ U>(5J,G  
Thread.sleep(nSecond); 7OS\j>hb~  
} hQ i[7r($8  
catch(Exception e) y%|nE((  
{ &O#a==F!(  
e.printStackTrace (); yv9~  
} n]}+ :  
} UIvTC S  
n4 KiC!*i0  
//日志 ^LfCLI9Z  
public static void log(String sMsg) ~2 T_)l?  
{ G-G!c2o  
System.err.println(sMsg); Z_iu^Q  
} iv?'&IU
fK  
i6kW"5t  
iVd*62$@$  
public static void log(int sMsg) yrdJX  
{ +o?.<[>!GR  
System.err.println(sMsg); h.%VWsAO7  
} @\i6m]\X  
} HyiuU`  
VD,F?L!  
6.6~w\fR8  
/* si/F\NDT
 
**TestMethod.java T73oW/.0X?  
*/ r%xp^j}  
package NetFox; h76#HUBr!  
{dg3 qg~  
NO +j   
public class TestMethod { Uey.@2Q  
$e+@9LNK  
"}\2zub9  
public TestMethod() *GfGyOS(  
{ ///xx/weblogic60b2_win.exe Q#}} 1}Ja  
try{ (i|`PA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -vGyEd7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MKJ9PcVi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pCb@4nb  
fileFetch.start(); (gNI6;P;}  
} %\}|&z6  
catch(Exception e){e.printStackTrace ();} DHbLS3-  
j+*VP  
@!Il!+^3  
} teUCK(;23  
:
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29Kuq;6  
public static void main(String[] args) itm;,Sbg  
{ `kwyF27v]  
new TestMethod(); *na7/ysT<  
} ynw^nmM  
} E,xCfS)  
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