http断点续传简单实现（java)

/* ;W )Y OT  
**SiteFileFetch.java #powub  
*/ z]y.W`i   
package NetFox; ~8Fk(E_  
import java.io.*; ;\dBfP  
import java.net.*; Z9ZPr?C=  
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public class SiteFileFetch extends Thread { Lnl(2xD  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /N10   
long[] nStartPos; //开始位置 x_Y!5yg E  
long[] nEndPos; //结束位置 H [\o RId  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oG?Xk%7&\  
long nFileLength; //文件长度 _Kf%\xg  
boolean bFirst = true; //是否第一次取文件 9wUkh}s  
boolean bStop = false; //停止标志 <?.&^|kS  
File tmpFile; //文件下载的临时信息 ]IQ&>z}<  
DataOutputStream output; //输出到文件的输出流 YQvD|x  
V#$RR!X'  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A2Ed0|By  
public SiteFileFetch(SiteInfoBean bean) throws IOException ',@3>T**  
{ `:K
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siteInfoBean = bean; ibk6|pp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >Eto( y"q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K#d`Hyx  
if(tmpFile.exists ()) ;?iW%:_,  
{ %3-y[f  
bFirst = false; Np9<:GF1  
read_nPos(); zrgk]n;Pq  
} N/2T[s_&  
else dt]-,Y  
{ R4cM%l_#W  
nStartPos = new long[bean.getNSplitter()]; nPl?K
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nEndPos = new long[bean.getNSplitter()]; `i*E~'  
} &i6mW8l  
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} 19)i*\+  
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public void run() }B+C~@j  
{ j{A y\n(  
//获得文件长度 "Ac-tzhE  
//分割文件 DV-d(@`K  
//实例FileSplitterFetch %s|Ely)  
//启动FileSplitterFetch线程 X`>i&I]  
//等待子线程返回 E6ElNgL  
try{ hx%v+/  
if(bFirst) Rtl"Ub@HV  
{ (m/G(wg  
nFileLength = getFileSize(); `(V3:F("@  
if(nFileLength == -1) q"J]%zO  
{ sIGMA$EK  
System.err.println("File Length is not known!"); S`0(*A[W*  
} u|TeE\0  
else if(nFileLength == -2) %T%sGDCV  
{ IfAZn_  
System.err.println("File is not access!"); 9}<ile7^  
} <0&*9ZeD  
else xF'EiX~  
{ 24*XL,  
for(int i=0;i<nStartPos.length;i++) Yujiqi]J;  
{ IueFx u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )23H1  
} IY\5@PVZ  
for(int i=0;i<nEndPos.length-1;i++) "7F?@D$e  
{ BLiF 5  
nEndPos = nStartPos[i+1]; x*U)Y  
} />pI8 g<  
nEndPos[nEndPos.length-1] = nFileLength; _op}1   
} <)c)%'v  
} 9IfmW^0  
X *"i6*  
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//启动子线程 &.Qrs:U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {@{']Y  
for(int i=0;i<nStartPos.length;i++) Vaw+.sG`AP  
{ XJ| <?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7WS p($  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %RRNJf}z  
nStartPos,nEndPos,i); G@X% +$I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 051E6-  
fileSplitterFetch.start(); "_NN3lD)X  
} _9Te!gJ4_#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,i`,Oy(BI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,m|h<faZL
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u^I|T.w<r6  
nEndPos = " + nFileLength); j-}O0~Jz  
// fileSplitterFetch[nPos.length-1].start(); 29
] G^f>  
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//等待子线程结束 fxHH;hRfv  
//int count = 0; 0 ZKx<]!  
//是否结束while循环 {ROVvs`  
boolean breakWhile = false; Vv=. -&'  
|3"KK  
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while(!bStop) ~P**O~  
{ :{l_FY436  
write_nPos(); #r\4sVg  
Utility.sleep(500); .|fHy  
breakWhile = true; \V
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for(int i=0;i<nStartPos.length;i++) 2-EIE4
ds  
{ 5e^ChK0Q  
if(!fileSplitterFetch.bDownOver) D'DfJwA  
{ v$wIm,j  
breakWhile = false;  >Abdd  
break; <<5(0#y#  
} U$A]8NZ$S  
} ^k">A:E2  
if(breakWhile) :OT0yA=U  
break; d^ 8ZeC#  
u `6:5k  
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//count++; Cnh \%OW  
//if(count>4) X5$Iyis  
// siteStop(); xY(*.T9K  
} dkTX  
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System.err.println("文件下载结束！"); &B1WtW
 
} bK&+5t&  
catch(Exception e){e.printStackTrace ();} GGs}i1m  
} fr6fj  
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//获得文件长度 [waIi3Dv\  
public long getFileSize() `b7t4d*  
{ Iit;F  
int nFileLength = -1; ?IT*:A]E  
try{ U$z-e/  
URL url = new URL(siteInfoBean.getSSiteURL()); meO:@Z0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )Y{L&A  
httpConnection.setRequestProperty("User-Agent","NetFox"); +',S]Edx  
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int responseCode=httpConnection.getResponseCode();
.}~_a76  
if(responseCode>=400) v`Oc,  
{ c,+:i1IAy  
processErrorCode(responseCode); 'I6i,+D/q  
return -2; //-2 represent access is error z<XtS[ki
 
} )1`0PJoHE  
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String sHeader; $B5aje}i  
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for(int i=1;;i++) 00~mOK;1  
{ 9EibIOD^/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }N6.Uu5zI  
//Utility.log(in.readLine()); `7V]y-  
sHeader=httpConnection.getHeaderFieldKey(i); 56kI 5:  
if(sHeader!=null) kJT)r6  
{ ;"-&1qHN  
if(sHeader.equals("Content-Length")) ,(^*+G.i  
{ ope^~+c~\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); og>uj>H&  
break; R^e'}+Z  
} CU~PT.  
} MUwMb!Z.s  
else OcO3v'&  
break; iJ|uvPCE  
} Y|/ 8up  
} VS|2|n1<6  
catch(IOException e){e.printStackTrace ();} DIUjn;>k8  
catch(Exception e){e.printStackTrace ();} o,wUc"CE  
7mfS*aCb  
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Utility.log(nFileLength); f<6lf7qzC  
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return nFileLength; d0 /#nz  
} ll?X@S  
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//保存下载信息（文件指针位置） 
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private void write_nPos() U`s{Jm  
{ W(/h Vt  
try{ HLi%%"'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7o}J%z  
output.writeInt(nStartPos.length); JjS?  
for(int i=0;i<nStartPos.length;i++) cl/_JQ&  
{ hFBe,'3M  
// output.writeLong(nPos); ]
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output.writeLong(fileSplitterFetch.nStartPos); Vf1^4t  
output.writeLong(fileSplitterFetch.nEndPos); Yz93'HDB  
} 7IM@i>p%  
output.close();
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} pmYHUj #  
catch(IOException e){e.printStackTrace ();} 7cMv/g^h@  
catch(Exception e){e.printStackTrace ();} PTV:IzoW  
} 3irl (;v  
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//读取保存的下载信息（文件指针位置） Qe(
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private void read_nPos() m~ee/&T  
{ ygl0k \  
try{ PeEj&4k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *DhiN  
int nCount = input.readInt(); % %UE+u@J  
nStartPos = new long[nCount]; w@fi{H(R  
nEndPos = new long[nCount]; 7E!5G2XX~~  
for(int i=0;i<nStartPos.length;i++) Ilm^G}GB  
{ Ny)X+2Ae  
nStartPos = input.readLong(); lqpp)Cq  
nEndPos = input.readLong(); eh#(eua0/  
} 18:%~>.!  
input.close(); y1L,0 ]  
} lsNd_7k  
catch(IOException e){e.printStackTrace ();} 3"\lu?-E  
catch(Exception e){e.printStackTrace ();} @pU)_d!pJ  
} koi^l`B$  
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;i:d+!3XwC  
private void processErrorCode(int nErrorCode) , ++ `=o  
{ 0_t!T'jr7  
System.err.println("Error Code : " + nErrorCode); sCHJ&>m5-  
} y"wShAR  
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k  
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//停止文件下载 8}| (0mC  
public void siteStop() xKp4*[}m  
{ k|d+#u[Mj@  
bStop = true; VY\&8n}e(  
for(int i=0;i<nStartPos.length;i++) iAU@Yg`pt  
fileSplitterFetch.splitterStop(); V3j= Kf  
_:27]K:  
{Y9q[D'g.  
} |ZBI *  
} tIgN$BHR>  
//负责部分文件的抓取 Y:a]00&)#Y  
**FileSplitterFetch.java ]OzUGXxo~  
*/ 12LL48bi  
package NetFox; *;*r8[U}q  
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b  
import java.io.*; c!9nnTap  
import java.net.*; yz8jw:d^-  
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public class FileSplitterFetch extends Thread { 0"bcdG<}  
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String sURL; //File URL ixD)VcD-f  
long nStartPos; //File Snippet Start Position HA>OkA/  
long nEndPos; //File Snippet End Position W6/yn
 
int nThreadID; //Thread's ID Ek]'km!  
boolean bDownOver = false; //Downing is over CizX<Cr}  
boolean bStop = false; //Stop identical ~R92cH>L  
FileAccessI fileAccessI = null; //File Access interface e**qF=HCw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^.NU|NQi'  
{ 9;-p'C  
this.sURL = sURL; u:_,GQ )\  
this.nStartPos = nStart; U\*J9  
this.nEndPos = nEnd; s,&Z=zt0R  
nThreadID = id; JnM["Q=`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '(|ofJe!  
} _zi|  
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public void run() E09:E  
{ iAIuxO  
while(nStartPos < nEndPos && !bStop) | h#u^v3  
{ W|63Ir67  
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try{ Z}Ft:7   
URL url = new URL(sURL); W v+?
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A{D];pE`  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fy-t T]Q9  
String sProperty = "bytes="+nStartPos+"-"; HRfYl,S,  
httpConnection.setRequestProperty("RANGE",sProperty); F@B]et7  
Utility.log(sProperty); ?+}_1x`  
'AS|ZRr/  
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InputStream input = httpConnection.getInputStream(); vnZC,J `  
//logResponseHead(httpConnection); U|Ta4W`k\  
[:SWi1cK2  
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byte[] b = new byte[1024]; ]|PiF+  
int nRead; _^%,x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n]o<S+z  
{ vT,AMja  
nStartPos += fileAccessI.write(b,0,nRead); x-&@wMqkc  
//if(nThreadID == 1) |H+UOEiv,p  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8NAON5.!  
} 5uj?#)N  
CN8Y\<Ar  
*mvlb (' &  
Utility.log("Thread " + nThreadID + " is over!"); t=W}SH  
bDownOver = true; mSl.mi(JiZ  
//nPos = fileAccessI.write (b,0,nRead); Trz@~d/[,n  
} ok\vQs(a  
catch(Exception e){e.printStackTrace ();} UhQj Qaa~  
} UJ')I`zuI  
} 9N3o-=  
>V8-i`  
a'yK~;+_9  
//打印回应的头信息 SbrecZ  
public void logResponseHead(HttpURLConnection con) )W _v:?A9  
{ 68C%B9.b'  
for(int i=1;;i++) |"CZ
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{ 5(Q%XQV*P  
String header=con.getHeaderFieldKey(i); y,,dCca  
if(header!=null) q ,]L$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zw S F^  
Utility.log(header+" : "+con.getHeaderField(header)); U$D65B4
=  
else ]Wlco
 
break; p}pjfG  
} eF-."1  
} !9VY|&fHe  
-3Z,EaG^  
1JG'%8}#8  
public void splitterStop() L2i_X@/  
{ ~YWQ2]  
bStop = true; nV/G8SeI  
} y'nK>)WG4  
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} 0gP}zM73  
ShP^A"Do  
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/* Zaf:fsj>  
**FileAccess.java jZkcBIK2  
*//文件访问(定位，写) FxWSV|Z  
package NetFox; [uN? ~lp\%  
import java.io.*; =ToyZm\  
q01wbO3-"  
w4{<n/"  
public class FileAccessI implements Serializable{ paE[rS\  
3J|F?M"N7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }?_?V&K|  
RandomAccessFile oSavedFile; 4-y:/8  
long nPos; z3m85F%dR  
u?<%q!  
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public FileAccessI() throws IOException k1Y?  
{ cO+qs[ BQ  
this("",0); bSi%2Onj  
} x,@B(9No  
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V]e8a"/[{  
public FileAccessI(String sName,long nPos) throws IOException Eib5  
{ s.QwSbw-g  
oSavedFile = new RandomAccessFile(sName,"rw"); d_E/8R_$L  
this.nPos = nPos; rCbDu&k]  
oSavedFile.seek(nPos); SaAFz&WRl  
} Q}K"24`=  
b;W3j  
&4x}ppX  
public synchronized int write(byte[] b,int nStart,int nLen) oC: {aK6\  
{ G+"t/?/  
int n = -1; /1V xc 6  
try{ :B5Fdp3  
oSavedFile.write(b,nStart,nLen); RVA(Q[ ;  
n = nLen; Val|n*%  
} Sc1 8dC0  
catch(IOException e) gpvYb7Of0  
{ kY|utoAP  
e.printStackTrace (); H.|#c^I  
} GxI!{oi2  
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return n; 17[3/m8a  
} p6]1w]*R  
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 vzs)[AD  
} 8f)
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0$)>D==  
/* 6azGhxh  
**SiteInfoBean.java 2Aazy'/  
*/ $=8 NED5  
package NetFox; j@U]'5EVB  
^Y>F|;M#  
[P=Jw:E  
public class SiteInfoBean { ~hnQUS`A  
9`A;U|~E@  
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private String sSiteURL; //Site's URL t?x<g<PJ4  
private String sFilePath; //Saved File's Path rq/yD,I,  
private String sFileName; //Saved File's Name r6MMCJ|G  
private int nSplitter; //Count of Splited Downloading File 3G)#5Lf<  
. y-D16V  
:Ij{s  
public SiteInfoBean() o WrKM  
{//nSplitter的缺省值为5 D3Ig>gKo?m  
//default value of nSplitter is 5 "$Z= %.3Q  
this("","","",5); Vod\a5c  
} dGYn4i2k?  
mPtZO*Fc  
EyD=q! ZVZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q77;ZPfs8  
{ jk; clwyz/  
sSiteURL= sURL; +,TRfP Fb  
sFilePath = sPath; @uqd.Q  
sFileName = sName; ?wiCQ6*$  
this.nSplitter = nSpiltter; b8`)y<7  
&
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<;eW=HT+uq  
} 1#V_Z^OL  
/7nb,!~~l  
G~^r)fm_  
public String getSSiteURL() fo*2:?K&  
{ H1pO!>M  
return sSiteURL; =)H.cuc  
} w(*vj  
'8RsN-w  
Bw)/DM]  
public void setSSiteURL(String value) F#,90F'  
{ 55nlg>j  
sSiteURL = value; KQaxvU)L  
} @w#-aGJO  
q1$N>;&  
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public String getSFilePath() uB]7G0g:  
{ ~:rl=o}  
return sFilePath; AW%#O\N  
} ?>D+ge  
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public void setSFilePath(String value) k2omJ$?v  
{ gq4Tb c oA  
sFilePath = value; =\&;Fi]  
} =V,mtT  
DbBcQ%  
~9a<0Mc?  
public String getSFileName() j\[dx^\=  
{ )0.kv2o.  
return sFileName; }>pknc?  
} 8O5s`qKMYT  
EA@.,7F  
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public void setSFileName(String value) xBThq?N?  
{ L:KF_W.I+  
sFileName = value; *)$Uvw E  
} >a!/QMh  
CTB~Yj@d+  
!1jBC.G1  
public int getNSplitter() Go`vfm"S  
{ e8>})  
return nSplitter; A2I9R;}  
} lLX4Gq1  
=57>!)  
oA7tEu   
public void setNSplitter(int nCount) :;RMo2Tl  
{ YFLZ%(  
nSplitter = nCount; s[RAHU  
} dc+>m,3$  
} 2.`\  
Fd%#78UEo}  
#5Qpu  
/* IA fcT!{  
**Utility.java 1*P~!2h  
*/ .wEd"A&j  
package NetFox; *<$*"p  
SXSgld2uS  

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public class Utility { bQzZy5,  
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)nC]5MXU  
public Utility() lZd(emH@  
{ P>y@kPi  
:(E@Gf  
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} A]_7}<<N  
NlA,'`,  
//线程睡眠 oM
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public static void sleep(int nSecond) 8 `v-<J  
{ n2"a{Ofhlf  
try{ gldAP:  
Thread.sleep(nSecond); AwCcK6N1  
} 6iry6wcHm  
catch(Exception e) Hc;[Cs0  
{ f$o_e90mu  
e.printStackTrace (); vz@A;t  
} 3<e=g)F  
} Yj<a" Gr4[  
k90YV(  
//日志 W-$Z(Z XL  
public static void log(String sMsg) ")1:F>  
{ DHg:8%3x  
System.err.println(sMsg); y B81f  
} Oz75V|D  
0G(/Wb"/  
U"~>jZKk  
public static void log(int sMsg) D5gFXEeh  
{ s-NX 
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System.err.println(sMsg); mtpeRVcF  
} T )&A2q  
} [@_Jj3`4  
Ucb F|vkI  
.y'>[  
/* 3xy<tqfr  
**TestMethod.java vJLK,[  
*/ s2a{>II6  
package NetFox; {Ea b j  
xf'V{9*  
"-E\[@/  
public class TestMethod { &.F4b~A7  
SjK  
,Y@Gyx!4  
public TestMethod() 4XL^D~V  
{ ///xx/weblogic60b2_win.exe oe ~'o'  
try{ :ffY6L+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i:dR\|B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JB\UKZXw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p0]=QH  
fileFetch.start(); mwO6g~@`  
} QDZWX`qw{  
catch(Exception e){e.printStackTrace ();} m%0p\Y-/  
\wmN  
0RzEY!9g+  
} M^A48u{,"  
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public static void main(String[] args) &L3M]  
{ "6A `
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new TestMethod(); "BAK !N$9  
} g9OY<w5s]  
} BqEI(c6  
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