http断点续传简单实现（java)

/* HFqm6|  
**SiteFileFetch.java b9"jtRTdz  
*/ '*Almv{  
package NetFox; E7Ulnvd  
import java.io.*; g/&T[FOr  
import java.net.*; Cn_$l>  
<BW[1h1k5_  
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public class SiteFileFetch extends Thread { cS.-7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :aG#~-Q  
long[] nStartPos; //开始位置 af|5n><~A  
long[] nEndPos; //结束位置 suH&jE$x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :d8W+|1u  
long nFileLength; //文件长度 :iiw3#]  
boolean bFirst = true; //是否第一次取文件 qClHP)<  
boolean bStop = false; //停止标志 vfNAs>Xg"  
File tmpFile; //文件下载的临时信息 @VN&t:/l  
DataOutputStream output; //输出到文件的输出流 $HG}[XD?  
{} Bf  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NjE</Empb%  
public SiteFileFetch(SiteInfoBean bean) throws IOException }dxDtqb  
{ f,z P*  
siteInfoBean = bean; ?+c`]gO7N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \]9.zlB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D{v8q)5r  
if(tmpFile.exists ()) !WkIi^T  
{ "C?5f]T  
bFirst = false; ?%O3Oi Xz  
read_nPos(); E(Rh#+]Y5  
} ]MtFf6&  
else :y2p@#l#  
{ UwY-7Mmo  
nStartPos = new long[bean.getNSplitter()]; FA90`VOWYU  
nEndPos = new long[bean.getNSplitter()]; q@hp.(V  
} !TAp+b  
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} pbHsR^  
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public void run() 6+K_Z\  
{ $[@0^IJq=K  
//获得文件长度 QO{y/{
 
//分割文件 dz#5
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//实例FileSplitterFetch JM.XH7k  
//启动FileSplitterFetch线程 ExHAY|UA  
//等待子线程返回 iP3Z  
try{ K3GSOD>  
if(bFirst) i;PL\Er:tX  
{ lo&#(L+2  
nFileLength = getFileSize(); $mA5@O~C5\  
if(nFileLength == -1) :Zw@yt  
{ 7@%'wy&A  
System.err.println("File Length is not known!"); 02JL*  
} -m 5}#P89  
else if(nFileLength == -2) 9O,,m~B  
{ Fr
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System.err.println("File is not access!"); ~:sE:9$z  
} X7*`  
else J?:[$C5  
{ 7q9gngT1LA  
for(int i=0;i<nStartPos.length;i++) ;eB ~H[S/  
{ mjnUs-`W|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y\/gU8w/  
} }ZZ5].-a<D  
for(int i=0;i<nEndPos.length-1;i++) 1ywU@].6J]  
{ 0_<Nc/(P  
nEndPos = nStartPos[i+1];
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} S9Y[4*//  
nEndPos[nEndPos.length-1] = nFileLength; @y~P&HUN  
} P]<= ! F  
} 2C+(":=}  
T>]sQPg  
{0jI
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//启动子线程 &y_? rH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \ a-CN>  
for(int i=0;i<nStartPos.length;i++) o#i ]"  
{ 89eq[ |G_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0my9l;X   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .{rbw9  
nStartPos,nEndPos,i); M[
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cz.3|Lby  
fileSplitterFetch.start(); Uxl(96  
} 0'ZYO
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nX x=1*X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;( KMGir
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2>y:N.  
nEndPos = " + nFileLength); B%b_/F]e  
// fileSplitterFetch[nPos.length-1].start(); $iJnxqn  
6Dzs?P  
xUj2]Q>R+  
//等待子线程结束 ,nE&Me&#J  
//int count = 0; [yd6gH  
//是否结束while循环 D9,! %7i  
boolean breakWhile = false; 1Ii| {vR  
VO9f~>`(  
lBiovT  
while(!bStop) S%+R#A1  
{ %h*5xB]Tt  
write_nPos(); fPE?hG<x  
Utility.sleep(500); PNmF}"  
breakWhile = true; z>:U{!5k  
BvJ=iB<E  
m3?e]nL4W  
for(int i=0;i<nStartPos.length;i++) UX}*X`{  
{ =HPu{K$  
if(!fileSplitterFetch.bDownOver) Y+qus  
{ ,kE=TR.|  
breakWhile = false; C"No5r'K3  
break; 3:" &Z6t#  
} SQIdJG^:  
} @W)/\AZ3  
if(breakWhile) uHrb:X!q  
break; 51/sTx<Z}  
w{P6i<J  
C38XQLC  
//count++; &<{}8/x8(  
//if(count>4) Qi|?d7k0  
// siteStop(); Gbx";Y8  
} X8.y4{5  
GWh|FEqUbf  
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System.err.println("文件下载结束！"); (olLB  
} \!7*(&yly  
catch(Exception e){e.printStackTrace ();} nr<.YeJ  
} cl2ze  
kraVL%72  
tzmETRwG  
//获得文件长度 :'ihE\j  
public long getFileSize() .hgH9$\  
{ @dl<-  
int nFileLength = -1; 'M lXnHxt  
try{ #O><A&FrF`  
URL url = new URL(siteInfoBean.getSSiteURL()); J2=*-O:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lkN'uZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jbkt'Z(&J  
6,3}/hgWJ$  
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int responseCode=httpConnection.getResponseCode(); ,=x RoXYB}  
if(responseCode>=400) GGp{b>E+ #  
{ }eI`
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processErrorCode(responseCode); e-jw^   
return -2; //-2 represent access is error oM2|]ew)  
} n'Bmz  
O68bzi]  
)L|C'dJ<k`  
String sHeader; K^8@'#S  
#[Z<=i~C  
a
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for(int i=1;;i++) q'by
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{ V15q01bE#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d`UF0T  
//Utility.log(in.readLine()); #*+;B9
3)  
sHeader=httpConnection.getHeaderFieldKey(i); \A ;^ UxG  
if(sHeader!=null) iq,ah"L  
{ \?r$&K]4  
if(sHeader.equals("Content-Length")) \3L$I-]m  
{  sN;(/O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f>p; siR)  
break; o}d2N/T  
} QZ#3Bn%B5  
} L,O>6~9:^1  
else j1W bD7*8  
break; %C6|-?TAd  
} >y&[BB7S6  
} 3e#x)H/dr  
catch(IOException e){e.printStackTrace ();} $#F;xys  
catch(Exception e){e.printStackTrace ();} ]~$c~*0g  
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Utility.log(nFileLength); }<E sS  
/\6}SG;  
lkI8{  
return nFileLength; |}l@w+N3  
} PY[Sz=[  

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5hlJbWJa  
//保存下载信息（文件指针位置） 6(\q< fx  
private void write_nPos() "K9vm^xP  
{ wa9'2a1?  
try{ Sn;/;^@(\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C~3@M<X  
output.writeInt(nStartPos.length); E!:.G+SEl  
for(int i=0;i<nStartPos.length;i++)  "Nk`RsW  
{ @SX%? mk8G  
// output.writeLong(nPos); A}az m>  
output.writeLong(fileSplitterFetch.nStartPos); ]9bh+  
output.writeLong(fileSplitterFetch.nEndPos); %#[r_QQ^  
} |6\FI?  
output.close(); okd ``vG  
} >FK)p   
catch(IOException e){e.printStackTrace ();} Fm-q=3  
catch(Exception e){e.printStackTrace ();} PM#
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} |H3?ox*  
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//读取保存的下载信息（文件指针位置） TWl(\<&+)  
private void read_nPos() ~ wJ3AqNC?  
{ =R"Eb1  
try{ 6!gtve_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =Qjw.6@  
int nCount = input.readInt(); &r5&6p  
nStartPos = new long[nCount]; f4A4  
nEndPos = new long[nCount]; J?|K
#<%  
for(int i=0;i<nStartPos.length;i++) l,^i5t'  
{ V'f&JQA  
nStartPos = input.readLong(); cq@_*:~Or  
nEndPos = input.readLong(); U_N5~#9  
} O9Jx%tolF%  
input.close(); _k"&EW{ Ii  
} /: \VwH  
catch(IOException e){e.printStackTrace ();} T9U2j-lA?  
catch(Exception e){e.printStackTrace ();} yP1Y3Tga=  
} ]IbPWBX  
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private void processErrorCode(int nErrorCode) iA^+/Lt  
{
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System.err.println("Error Code : " + nErrorCode); c],frhmyd  
} b[&,%Sm+6  
vS24;:f  
*]E7}bqb  
//停止文件下载 #$vhC u<I  
public void siteStop() zw%n!wc_\  
{ $<>EwW  
bStop = true; %t5BB$y  
for(int i=0;i<nStartPos.length;i++) 8#d1}Y  
fileSplitterFetch.splitterStop(); GJ^]ER-K  
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8.;';[  
}
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} k,*#I<($  
//负责部分文件的抓取 afP&+ 5t@O  
**FileSplitterFetch.java ~&j`9jdOj  
*/
,;=( )-  
package NetFox; :hhE=A>X  
>$S,>d_k`  
rM >V=|9,  
import java.io.*; 1f pS"_}  
import java.net.*; +^&v5[$R  
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public class FileSplitterFetch extends Thread { `d|bH;w  
3!oQmG_T  
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String sURL; //File URL q[|`&6B  
long nStartPos; //File Snippet Start Position  ZV q  
long nEndPos; //File Snippet End Position n-b<vEZw#  
int nThreadID; //Thread's ID !{ESeBSCG  
boolean bDownOver = false; //Downing is over 0iZ9a/v  
boolean bStop = false; //Stop identical ks#Z~6+3  
FileAccessI fileAccessI = null; //File Access interface &pY G  
> v!c\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cV_IG}LJ  
{ (jE:Q2"  
this.sURL = sURL; yDyeP{  
this.nStartPos = nStart; b`W'M:$  
this.nEndPos = nEnd; Gxa.<E^k  
nThreadID = id; PUZXmnB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hYUV9k:  
} eW*ae;-  
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public void run() A{Htpm~  
{ aLk2#1$g  
while(nStartPos < nEndPos && !bStop) L%O8vn^3  
{ ^\kHEM|5v  
#M^Yh?~%w  
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try{ kmr 4cU5  
URL url = new URL(sURL); B{UoNm@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F4<2.V)#-  
httpConnection.setRequestProperty("User-Agent","NetFox"); d<'Yt|zt  
String sProperty = "bytes="+nStartPos+"-"; s
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httpConnection.setRequestProperty("RANGE",sProperty); 34^Cfh  
Utility.log(sProperty); cASHgm  
n9/0W%X>  
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InputStream input = httpConnection.getInputStream(); N_k6UA9  
//logResponseHead(httpConnection); J'c9577$  
!K~$-jlT  
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byte[] b = new byte[1024]; MVd 3*  
int nRead; khIa9Nm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?[B[ F  
{ N~J Eia%  
nStartPos += fileAccessI.write(b,0,nRead); ~[y+B0I3  
//if(nThreadID == 1) d@f2Vxe7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T>%ny\?tHW  
} xLK0~|_#!  
j4r,_lH^r  
p}7&x[fTLk  
Utility.log("Thread " + nThreadID + " is over!"); PM>
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bDownOver = true; W*`6ero  
//nPos = fileAccessI.write (b,0,nRead); iQ"F`C  
} F/>Pvq]  
catch(Exception e){e.printStackTrace ();} azc:C  
} 7O^ S.(  
} 8v
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//打印回应的头信息 %{abRBny  
public void logResponseHead(HttpURLConnection con) Z`c{LYP,y"  
{ -Ep6.v  
for(int i=1;;i++) }3y\cv0ct  
{ 4PM`hc  
String header=con.getHeaderFieldKey(i); qJt gnk|  
if(header!=null) lFY8^#@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gSYX@'Q!  
Utility.log(header+" : "+con.getHeaderField(header)); H5 hUY'O  
else  yE,o~O  
break; @0'|Uygn  
} ~GYtU9s5  
} ITlkw~'G  
;}'<`(f&nX  
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public void splitterStop() 3[Iw%% q  
{ TN`:T.B  
bStop = true; UdJV;T'rm  
} :q1r2&ne  
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} Q*(o;\s  
{2@96o2}  
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/* 'v  X"l  
**FileAccess.java a"aV&t  
*//文件访问(定位，写) G)7sXEe  
package NetFox; hGV/P94  
import java.io.*; `oBzt|f5  
ow[qpP[  
sc60:IxgI  
public class FileAccessI implements Serializable{ UXHFti/A<  
[=+/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g"Bv!9*H  
RandomAccessFile oSavedFile; d*L'`BBsp  
long nPos; .SN
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:TI1tJS~*  
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public FileAccessI() throws IOException |e&Kg~~C  
{ 9MxGyGz$  
this("",0); /$(D>KU  
} =C|^C  
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public FileAccessI(String sName,long nPos) throws IOException -S@:  
{ y e'5A   
oSavedFile = new RandomAccessFile(sName,"rw"); h# 8b#  
this.nPos = nPos; -;}Wm[  
oSavedFile.seek(nPos); kx[8#+P  
} s8Oz^5p(  
fp0Va!T(V  
qv6]YPP  
public synchronized int write(byte[] b,int nStart,int nLen) Yo:&\a K[  
{ > R=YF*t  
int n = -1; Za w+  
try{ 7(H/|2;-d8  
oSavedFile.write(b,nStart,nLen); zeX?]@]Y  
n = nLen; yFG&Ir  
} P6Ei!t,>  
catch(IOException e) _qV_(TpS+  
{ @k
w=0  
e.printStackTrace (); [z\*Zg  
} o=ex{g(3  
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*RPI$0
 
return n; C$8=HM3  
} S:gP\Atf>  
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} ScEM#9T|  
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Ch3##-  
/* +xMDm_TGLA  
**SiteInfoBean.java 4"{q|~&=:$  
*/ D+OkD-8q  
package NetFox; Hogr#Sn2  
Y3?kj@T`i  
/=%4gWtr  
public class SiteInfoBean { lG2){){j  
n}2}4^  
&3rh{"^9  
private String sSiteURL; //Site's URL 52
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private String sFilePath; //Saved File's Path q+<TD#xoL  
private String sFileName; //Saved File's Name CXa$QSu>  
private int nSplitter; //Count of Splited Downloading File 6(.&y;  
V5=Injs*  
#C|iW@  
public SiteInfoBean() Ab2VF;z :  
{//nSplitter的缺省值为5 jsuQR  
//default value of nSplitter is 5 GFvOrRlP\  
this("","","",5); BzDS  
} t<4+CC2H  
akR*|iK#b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cng1k  
{ qu?D`29  
sSiteURL= sURL; }RXm=ArN  
sFilePath = sPath; "F=O   
sFileName = sName; m$]?Jq  
this.nSplitter = nSpiltter; !O*\|7A(  
VP[ J#TPU  
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} GZse8ng  
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public String getSSiteURL() %0L9)-R  
{ f)>=.sp  
return sSiteURL; =V(I  
} F;kNc:X`)  
hS<+=3 <M  
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public void setSSiteURL(String value) 0C7x1:  
{ yKi* 8N"e<  
sSiteURL = value; $cnIsyKWY  
} O.}{s;  
~i(X{^,3  
I U/gYFT  
public String getSFilePath() Ig~lD>dnr'  
{ p"w"/[8  
return sFilePath; $`mxOcBmQ  
} L9"V$MO  
0X.pI1jCO  
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public void setSFilePath(String value) }Dm-Ibdg(  
{ 6Wl+5 a6V
 
sFilePath = value; y^?7de}  
} )bXiw3'A  
,..&j
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}O-|b#Q  
public String getSFileName() m!V ?xGKJ  
{ uPhFBD7  
return sFileName; -r7*C:E  
} |#>\GU=!  
h@&&.S`B  
E)7vuWOO  
public void setSFileName(String value) unKi)v1  
{ nDhr;/"i  
sFileName = value; )%I2#Q"Nt-  
} \9N1:  
]yy10Pk[!  
Yj;KKgk  
public int getNSplitter() ],V_"\ATD  
{ ]c4?-Vq%u  
return nSplitter; 3 -Nwg9U  
} G(" S6u  
@i U@JE`C  
&NM.}f  
public void setNSplitter(int nCount) (e.?). e  
{ 2iO AUo+  
nSplitter = nCount; LQ(z~M0B  
} o`,|{K$H  
} GG<{n$h  
bk^W]<:z`  
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/*  3c#oK  
**Utility.java R9bsl.e  
*/ >
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package NetFox; 7/C,<$Ep  
lOB*M!8   
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public class Utility { %c:v70*h=  
j=c=Pe"?u  
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public Utility() /q[5-96c  
{ nz_=]PHO&  
]:H((rk  
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} GY%^!r  
ygI81\D  
//线程睡眠 H[oCI|k  
public static void sleep(int nSecond) vl}fC@%WRI  
{ gbf2ty  
try{ Z/ w}so  
Thread.sleep(nSecond); j<,Ho4v}_  
} i*ibx;s-  
catch(Exception e) R;y
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{ xbUL./uj  
e.printStackTrace (); Ei$?]~ &  
} \Dn47V{7-  
} 8nV#\J9  

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//日志 nrFuhW\r  
public static void log(String sMsg) s}1S6*Cr  
{ mE>v (JY  
System.err.println(sMsg); t 0 om
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} 8VWkUsOoI  
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[nYm-\M  
public static void log(int sMsg) C4,;l^?=%  
{ Nd;)V  
System.err.println(sMsg); Ire+r "am  
} An.Qi=Cv  
} aB
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k_,wa]ws$  
7NQ@q--3s  
/* [\_#n5  
**TestMethod.java BdMmeM2h  
*/ t%k1=Ow5i  
package NetFox; &gv{LJd5b  
Q:v9C ^7  
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public class TestMethod { H Z)an  
AcoU.tpP  
|Q|vCWel{  
public TestMethod() Bu{1^g:  
{ ///xx/weblogic60b2_win.exe 7^hwRZJ{  
try{ %C1*`"Jb&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <T^:`p/]4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d*cAm$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <+r<3ZBA  
fileFetch.start(); _T^+BUw  
} s*3p*zf  
catch(Exception e){e.printStackTrace ();} Nn:>c<[  
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~N!-4-~p  
} %~{G
*%:  
",Ge:\TR=  
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public static void main(String[] args) Vmb `%k20'  
{ 7[/1uI9U8K  
new TestMethod(); CHGV1X,  
} 97L|IZ s)  
} Pkq
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