http断点续传简单实现（java)

/* nY<hfqof  
**SiteFileFetch.java ?(CMm%(8  
*/ SggS8$
a`  
package NetFox; fX2PteA0qX  
import java.io.*; S?_ ;$Cn  
import java.net.*; 3QrYH @7zx  
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public class SiteFileFetch extends Thread { T9+ ?A l  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >2l;KVm%  
long[] nStartPos; //开始位置 ]='E&=nc  
long[] nEndPos; //结束位置 {<- BU[H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O5Xu(q5+  
long nFileLength; //文件长度 =/rIXReY  
boolean bFirst = true; //是否第一次取文件 w(9.{zF|vQ  
boolean bStop = false; //停止标志 eOQUy
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File tmpFile; //文件下载的临时信息 j5:{H4?  
DataOutputStream output; //输出到文件的输出流 XK>/i}y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +)fl9>Mb  
public SiteFileFetch(SiteInfoBean bean) throws IOException ymBevL  
{ ``A=p<W  
siteInfoBean = bean; +`x8[A)-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !s]LWCX+|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QMfa~TH#p  
if(tmpFile.exists ()) [S/]Vk|4  
{ ]64mSB  
bFirst = false; *_z5Pa`A  
read_nPos(); NVMhbpX6  
} DT@6Q.  
else \@4_l?M  
{ 5"5D(  
nStartPos = new long[bean.getNSplitter()]; ( {H5k''  
nEndPos = new long[bean.getNSplitter()]; B;?"R  
}  (Ia}]q  
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wNW9xmS  
} \dbjh{  
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public void run() sSi1;9^o  
{ "}]1OL SV  
//获得文件长度 _n(NPFV  
//分割文件 Z2WAVSw  
//实例FileSplitterFetch _{o=I?+]  
//启动FileSplitterFetch线程 N(@'L43$V  
//等待子线程返回 M? oK@i  
try{ tqE LF  
if(bFirst) +xwz.:::  
{ p IXBJk  
nFileLength = getFileSize(); qDO4&NO  
if(nFileLength == -1)
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{ @#}9?>UV  
System.err.println("File Length is not known!"); vS:%(Y"!<  
} ;PJWd|3  
else if(nFileLength == -2) tqIz$84G  
{ #{GUu',?&  
System.err.println("File is not access!"); n< [np;\  
} %,GY&hTw  
else =/"Of  
{ \CL |=8[2  
for(int i=0;i<nStartPos.length;i++) cX@~Hk4=\  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); )kl| 5i  
} >UpTMEQ  
for(int i=0;i<nEndPos.length-1;i++) hFP$MFab  
{ vt[4"eU  
nEndPos = nStartPos[i+1]; 8h~v%aZ1  
} uRKCvsisX  
nEndPos[nEndPos.length-1] = nFileLength; A8hj"V47  
} sf]y\_zU  
} h%(dT/jPL)  
{>G\3|^D  
s@f4f__(]  
//启动子线程 0yXUVKq3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zbxd,|<|  
for(int i=0;i<nStartPos.length;i++) -Xkdu?6Eh  
{ 28-6(oG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @<\f[Znto  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y2j>lf?8  
nStartPos,nEndPos,i); <oPo?r|oM|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VY@uQ#&A  
fileSplitterFetch.start(); xmTa$tR+  
} N<:
5 r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *J?QXsg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d5]9FIj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y*O7lZuF%  
nEndPos = " + nFileLength); S)z jfJR  
// fileSplitterFetch[nPos.length-1].start(); ,:QG%Et  
[bJ/$A  
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//等待子线程结束 :KZI+  
//int count = 0; 7CABM  
//是否结束while循环 ^v3ytS  
boolean breakWhile = false; )ye[R^!}  
tsU.c"^n  
//:.k#}~B  
while(!bStop) h/`OG>./  
{ Oe^3YOR#j{  
write_nPos(); g||{Qmr=1  
Utility.sleep(500); SMk{159q&  
breakWhile = true; EKk~~PhW 8  
{.z2n>1J{T  
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for(int i=0;i<nStartPos.length;i++) |t|+pBB  
{ W{Ie(hf  
if(!fileSplitterFetch.bDownOver) 8^$}!9B~JZ  
{ D*`|MzlQ  
breakWhile = false; ;or(:Yoc-  
break; ^M  PU?k  
} 1okL]VrI  
} abW
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if(breakWhile) rZe"*$e  
break; OAR1u}  
!k||-Q&  
ME1lQ7E4B  
//count++; 06pLa3oi  
//if(count>4) t'_Hp},  
// siteStop(); P`5@$1CJ  
} Tm_AoZH  
sZPPS&KoP3  
;)5d wq  
System.err.println("文件下载结束！"); hv}rA,Yd  
} #wNksh/J^  
catch(Exception e){e.printStackTrace ();} EkEM|<GNd  
} AASw^A3p  
z*YkD"]B  
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//获得文件长度 AR]y p{NS  
public long getFileSize() K/+5$SjF  
{ K&9|0
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int nFileLength = -1; @ ILG3"  
try{ y;yXOE_  
URL url = new URL(siteInfoBean.getSSiteURL()); ^T)HRT-k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7tfMD(Q]e/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5 r"`c  
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int responseCode=httpConnection.getResponseCode(); F5wCl2I  
if(responseCode>=400) *|Q'?ty(x  
{ R(kr@hM
 
processErrorCode(responseCode); _,=A\C_b@  
return -2; //-2 represent access is error @~U: |h  
} 0V"r$7(}  
>1,.4)k%K  
)(9>r/bq  
String sHeader; ?&_ -,\t  
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Ji :2P*  
for(int i=1;;i++) x %L2eXL  
{ 1<fS&)^W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y!6B Gz  
//Utility.log(in.readLine()); ANc)igo  
sHeader=httpConnection.getHeaderFieldKey(i); yN5g]U.Q  
if(sHeader!=null) 4cRF3$amd  
{ $}jp=?,t  
if(sHeader.equals("Content-Length")) 'LpJ:Th  
{ tlV>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q'~kWmLf  
break; Ha1E /b]K  
} 84DneSpHsp  
} VtUe$ft  
else sczN0*w&C  
break; ,u#uk7V  
}  M
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} }\:3}'S.$  
catch(IOException e){e.printStackTrace ();} hq6fDR
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catch(Exception e){e.printStackTrace ();} 1Zx|
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aA-A>z  
4!i`9w$$"  
Utility.log(nFileLength); ^rfY9qMJr8  
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return nFileLength; \6-x~%xK  
} }tF/ca:XPQ  
Ds9pXgU(Z  
od{Y` .<  
//保存下载信息（文件指针位置） L)a8W   
private void write_nPos() OKNA36cU'  
{ YFv/t=`  
try{ nW3-)Q89  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yMq&9R9F  
output.writeInt(nStartPos.length); 8V>j-C  
for(int i=0;i<nStartPos.length;i++) .mn`/4  
{ b4Br!PL@G  
// output.writeLong(nPos); \{t#V ~  
output.writeLong(fileSplitterFetch.nStartPos); a*$to/^r  
output.writeLong(fileSplitterFetch.nEndPos); mvO!Y
 
} <{bQl L  
output.close(); )XmV3.rI  
} l~;H~h!h/  
catch(IOException e){e.printStackTrace ();} ];Z)=y,vM  
catch(Exception e){e.printStackTrace ();} <gF=$u|}3[  
} P9p:x6  
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//读取保存的下载信息（文件指针位置） 6v(}<2~  
private void read_nPos() 
9 
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{ p~6/+ap  
try{ 8W#/=X
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?:vp3f#  
int nCount = input.readInt(); 9un]}7^  
nStartPos = new long[nCount]; z}.y ?#  
nEndPos = new long[nCount]; j5,1`7\7B  
for(int i=0;i<nStartPos.length;i++) 
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{ veAg?N<c p  
nStartPos = input.readLong(); C8rD54A'M  
nEndPos = input.readLong(); /:3:Ky3  
} 0?KXQD  
input.close(); -G e5gQ=  
} n0F.Um  
catch(IOException e){e.printStackTrace ();} FRd!UqMXY  
catch(Exception e){e.printStackTrace ();} (+68s9XS7  
}
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Xf!@uS6<X  
NUbw]Y90~  
private void processErrorCode(int nErrorCode) u~[HC)4(0  
{ fuSfBtLPR#  
System.err.println("Error Code : " + nErrorCode); ^e:C{]S=  
} +%Q:  
,A`d!{]5  
$}V<Um  
//停止文件下载 zI$^yk-vn  
public void siteStop() &E0L7?l  
{ 6E/>]3~!  
bStop = true; dE19_KPm[j  
for(int i=0;i<nStartPos.length;i++) 5Ds/^fA  
fileSplitterFetch.splitterStop(); 0D/u`-  
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c[\ :^w^I6  
} 4YDK`:4I~  
} ~XN--4%Q  
//负责部分文件的抓取 =}>wxO  
**FileSplitterFetch.java uPKq<hBI  
*/ <_$]!Z6UR  
package NetFox; ?j;e/r.  
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&IsQgS7R  
import java.io.*; =M'M/vKD  
import java.net.*; PLU8:H@X  
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public class FileSplitterFetch extends Thread { B!-hcn]y  
}/&Q\Sc
  
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String sURL; //File URL 59mNb:<  
long nStartPos; //File Snippet Start Position K~ ,|~  
long nEndPos; //File Snippet End Position ZycV?ob8}  
int nThreadID; //Thread's ID s3qWTdM  
boolean bDownOver = false; //Downing is over nfpkWyIu{  
boolean bStop = false; //Stop identical `q|&;wP.  
FileAccessI fileAccessI = null; //File Access interface mAMi-9  
**_`AM~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g?`g+:nug  
{ .w2QiJ  
this.sURL = sURL; Go~bQ2*'(/  
this.nStartPos = nStart; BC*vG=a  
this.nEndPos = nEnd; _nu,ks+  
nThreadID = id; :Mesh
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 D FDC'E  
} ^,u0kMG5l  
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public void run() Ay)q %:qx  
{ u>c\J|K_V  
while(nStartPos < nEndPos && !bStop) 9rXbv4{  
{ w}+#w8hu  
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try{ HDQhXw!!hc  
URL url = new URL(sURL); T'\B17 :*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !OWPwBm;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'F%4[3a$\n  
String sProperty = "bytes="+nStartPos+"-"; Z|;<:RKWY  
httpConnection.setRequestProperty("RANGE",sProperty); _svEPHU  
Utility.log(sProperty); h'VN& T,  
?_mcg8A@@*  
4w,=6|#  
InputStream input = httpConnection.getInputStream(); _Gs*4:  
//logResponseHead(httpConnection); @(>XSTh9  
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byte[] b = new byte[1024]; qu]ch&"?U  
int nRead; b`"E(S/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I)#=#eI*:  
{
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+  
nStartPos += fileAccessI.write(b,0,nRead); &:}e`u@5|  
//if(nThreadID == 1) L9tjHC]
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }OY]mAv-B  
} H.-jBFt}  
~RcI+jR)  
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Utility.log("Thread " + nThreadID + " is over!"); Rs+rlJq  
bDownOver = true; d"3S[_U  
//nPos = fileAccessI.write (b,0,nRead); tHNvb\MR$  
} jVP70c  
catch(Exception e){e.printStackTrace ();} *hVbjI$  
} GC?X>AC:  
} I9O9V[  
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//打印回应的头信息 f[,9WkC  
public void logResponseHead(HttpURLConnection con) vZV+24YWb  
{ 
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for(int i=1;;i++) D|8vS8p  
{ <viIpz2jh%  
String header=con.getHeaderFieldKey(i); u@|izRk  
if(header!=null) aE}1~`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); u\YH,  
Utility.log(header+" : "+con.getHeaderField(header));  V|=PaO  
else }e3M5LI1L  
break; .C^1.)  
} W{E22J}  
} fDc>E+,  
y*2R#jTA  
/dTy%hZC}  
public void splitterStop() `5 py6,  
{ (]7*Kq  
bStop = true; 3wXmX  
} >Gbj1>C}  
p:M#F:  
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} 1-Fg_G}|6  
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34VyR a  
/* -q7A\8C  
**FileAccess.java O+;0|4V%  
*//文件访问(定位，写) *S_e:^  
package NetFox; |\Nj  
import java.io.*; 216+ tX5Z  
M=[/v/M=  
c>fLSf  
public class FileAccessI implements Serializable{ xsK{nM6g  
%bf+Y7m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \RN,i]c-g/  
RandomAccessFile oSavedFile; -1Y9-nn[m  
long nPos; gyH'92
ck  
/x.TF'Z*  
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public FileAccessI() throws IOException ]2G5ng' @  
{ gr %8 O-n  
this("",0); I(BG%CO9  
} 51yIW*  
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public FileAccessI(String sName,long nPos) throws IOException zb9^ii$g  
{ h}xUZ:  
oSavedFile = new RandomAccessFile(sName,"rw"); #1R_* Uh  
this.nPos = nPos; }aYm86C]  
oSavedFile.seek(nPos); 9@AGx<S1  
} %VYQz)yW  
G)gf +
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8?] :>  
public synchronized int write(byte[] b,int nStart,int nLen) '$Jt
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{ eydVWVN  
int n = -1; ln.kEhQ3B  
try{ <'A>7M~h?*  
oSavedFile.write(b,nStart,nLen); C%d 4ItB >  
n = nLen; 7}bjJR "  
} ];Whvdnv  
catch(IOException e) JV'd!5P  
{ /=Ug}%.  
e.printStackTrace (); K#M h  
} g!n1]- 1  
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return n; =/=x"q+X  
} Ab7hW(/  
/uI/8>p(  
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} iU^ 4a  
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#oMbE<//"  
/* 992;~lBu  
**SiteInfoBean.java 9[DQ[bL  
*/ n
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package NetFox; ~\dpD  
>_M}l@1  
>V(>2eD'S  
public class SiteInfoBean { .jMm-vox}  
mFayU w  
]i*q*]x2u  
private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path #1Mk9sxo  
private String sFileName; //Saved File's Name EZ #UdK_  
private int nSplitter; //Count of Splited Downloading File Y0B
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:b>Z|7g?  
public SiteInfoBean() Wq)'0U;{$  
{//nSplitter的缺省值为5 A{h hnrr8  
//default value of nSplitter is 5 , >Y.!  
this("","","",5); _yjM_ALjo  
} L*tXy>&b.  
kN9S;o@)  
X@+:O-$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &n<jpMB  
{ a#H=dIj  
sSiteURL= sURL; Ary$,3X2  
sFilePath = sPath; Td[w<m+p<P  
sFileName = sName; ..FUg"sSO  
this.nSplitter = nSpiltter; F$r8hj`  
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} L:YsAv  
!~UI~-i'  
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public String getSSiteURL() xmKa8']x  
{ yG&kP:k<  
return sSiteURL; S "oUE_>  
} <6/XE@"  
>0 !J]gK  
4\pA^%73  
public void setSSiteURL(String value) d1e'!y}R5  
{ &o"Hb=k<  
sSiteURL = value; }=A6Jv(j  
} T.ub!,Y  
$Fz/&;KX!  
([|5(Omd\  
public String getSFilePath() +^YV>;  
{ _if&a'  
return sFilePath; ?y<n^`  
} &Wd,l$P<O  
2?t(%uf]  
e::5|6x  
public void setSFilePath(String value) 
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{ #!#V!^ o  
sFilePath = value; 4NR,"l)  
} miS+MK"  
{J})f>x<xM  
%>I!mD"X\  
public String getSFileName() !P@u4FCs  
{  p<*-B  
return sFileName; 1)_f9GR  
} 
TG?;o/  
?P`wLS^;  
D\({]oj]  
public void setSFileName(String value) >[|:cz  
{ #*S/Sh?Q  
sFileName = value; 1bzPBi  
} L*FmJ{Yf  
gY0*u+LF  
|Q9S$l]  
public int getNSplitter() 6FEtq,;0w  
{ 4n3QW%#  
return nSplitter; 2IjqTL  
} hN\E8"To  
w41#?VC/  
hph 3kfR  
public void setNSplitter(int nCount) Jq6p5jr"  
{ O.rk!&N  
nSplitter = nCount; v@>hjie  
} P]Gsc  
} *\VQ%_wg  
o\|dm."f  
Dj!J 4uD  
/* :@:R4Ac  
**Utility.java =m}{g/Bk  
*/ AL|fL  
package NetFox; Fg#*rzA  
pbqa  
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public class Utility { BOwkC;Q[  
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Q]6nW[@j'  
public Utility() =Rb,`%  
{ -^#Ix;%  
)_j.0a  
|:!0`p{R  
} [*}[W6 3v  
z[t$[Qg
 
//线程睡眠 `n^jU92  
public static void sleep(int nSecond) boN)C?"^h  
{ 6Ir ?@O1'!  
try{ +e?ixvl
d  
Thread.sleep(nSecond); ' J-(v  
} 6 Dg[b  
catch(Exception e) :~T:&;q0  
{ QyHUuG|g  
e.printStackTrace (); d+&V^qLJ  
} XLmbpEh  
} ir]uFOj  
(Mtc&+n{  
//日志 U Ciq'^,  
public static void log(String sMsg) i(c2NPbX  
{ 3[V|C=u0  
System.err.println(sMsg); E0)v;yRcw  
} /@wm?ft6Gk  
t#P)KcWOt  
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public static void log(int sMsg) }*R"yp  
{ |Cen5s W&  
System.err.println(sMsg); dvL'>'g  
} " g_\W  
} 'm2,7]  
}VFSF/\^  
B]Zsn`n  
/* RsV<*s  
**TestMethod.java MI@ RdXkY  
*/ f ~Fus  
package NetFox; 4uu*&B  
_aDx('  
_OrE{  
public class TestMethod { XkK16aLE  
2XI%4  
X`aED\#\h  
public TestMethod() IvO3*{k,  
{ ///xx/weblogic60b2_win.exe &pmJ:WO,h  
try{ 3[e@mcO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); { j/w3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {K|{a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9Q.j <  
fileFetch.start(); fe0 Y^vW  
} Yb6\+}th  
catch(Exception e){e.printStackTrace ();} mWGT (`|~/  
6g.@I!j E  
J`x9XWYw  
} lO) B/N&  
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public static void main(String[] args) 
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{ ILVbbC`D  
new TestMethod(); %idnm  
} hT Xc0  
} Ec[:6}  
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