http断点续传简单实现（java)

/* o,=dm@j  
**SiteFileFetch.java 5=P*<Dnj  
*/ . AX6xc6  
package NetFox; Na_O:\x#  
import java.io.*; oF(|NS^  
import java.net.*; "A&HNkRz  
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-Sj|Y}  
public class SiteFileFetch extends Thread { .
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SiteInfoBean siteInfoBean = null; //文件信息Bean UoKXo*W2  
long[] nStartPos; //开始位置 k54Vh=p  
long[] nEndPos; //结束位置 P}mn2Hs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B}Sl1)E  
long nFileLength; //文件长度 F]^ZdJ2  
boolean bFirst = true; //是否第一次取文件 _.3O(?p,  
boolean bStop = false; //停止标志 ;TG<$4N  
File tmpFile; //文件下载的临时信息 $qh?$a  
DataOutputStream output; //输出到文件的输出流 G,h=5y9_J  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nn6&`$(Q~  
public SiteFileFetch(SiteInfoBean bean) throws IOException j43-YdCJ  
{ p>GxSE)
 
siteInfoBean = bean; 2 1]87$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W\JwEb9Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e2$k %c~  
if(tmpFile.exists ()) YCEdt>5PA  
{ KcNh3CR  
bFirst = false; UqaV9  
read_nPos(); x6B_5eF  
}  oN7JNMT  
else AH#klYK  
{ u}I\!-EX!v  
nStartPos = new long[bean.getNSplitter()]; q3-V_~5^/z  
nEndPos = new long[bean.getNSplitter()]; eNw9"X}g  
} Q
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} "]0sR  
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public void run() @80Z@Pj  
{ [<p7'n3x  
//获得文件长度 Pf?y!dK<  
//分割文件 *%wfR7G[B  
//实例FileSplitterFetch }hd:avze  
//启动FileSplitterFetch线程 a+Z95~*sZ"  
//等待子线程返回 ?Wz rv&E2  
try{ |T@\-8Ok  
if(bFirst) 98AX=%8  
{ bI?YNt,  
nFileLength = getFileSize(); OfSHZ;,  
if(nFileLength == -1) !R.*Vn[  
{ :;(zA_-  
System.err.println("File Length is not known!"); R"`7aa6  
} A$]&j5nh|  
else if(nFileLength == -2) lYq4f|5H}m  
{ }^np  
System.err.println("File is not access!"); ee|i  
} 2po>%Cp  
else kt*""&R  
{ xVn"xk  
for(int i=0;i<nStartPos.length;i++) 42wa9UL<Ka  
{ {Bb:S"7NX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #}Qzu~  
} "Wz#<! .r  
for(int i=0;i<nEndPos.length-1;i++) SuU_psF  
{ %@jL?u  
nEndPos = nStartPos[i+1]; DZI:zsf;5Q  
} v9qgfdBS5  
nEndPos[nEndPos.length-1] = nFileLength; NY`$D}Bi  
} udV.$N  
} DcQ[zdEz+  
2HemPth  
,#FK3;U  
//启动子线程 W+C@(}pt  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (!@ Q\P  
for(int i=0;i<nStartPos.length;i++) VdZmrq;?/  
{ &(]@L\A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q{?ku!cL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P~5[.6gW  
nStartPos,nEndPos,i); ,r-l^I3<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gw/imXL  
fileSplitterFetch.start(); 1j7sJ" *  
} YGj3W.eH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;QA`2$Ow  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); eKq`t.*Ft  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :q xd])-  
nEndPos = " + nFileLength); 0~5'O[NhF  
// fileSplitterFetch[nPos.length-1].start(); KAucSd`  
>(} I7  
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//等待子线程结束 RvQl{aL  
//int count = 0; &F*L=Ng  
//是否结束while循环 Ie[8Iot?bn  
boolean breakWhile = false; %$)[qa3  
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while(!bStop) py9HUyr5eZ  
{ $:#{Y;d  
write_nPos(); /=5YHq>  
Utility.sleep(500); %YI Xk1  
breakWhile = true; o<hT/ P  
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for(int i=0;i<nStartPos.length;i++) t_-1sWeA!  
{ L|7F%oR  
if(!fileSplitterFetch.bDownOver) a5v}w7vL
 
{ y7;i4::A\  
breakWhile = false; -gWqq7O  
break; 1@j0kTJ~m  
} !f\q0Gnl  
} "gcHcboU5$  
if(breakWhile) JP2zom  
break; vgc#IEx@  
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,  
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//count++; S}/?Lm}  
//if(count>4) Ye'=F  
// siteStop(); 7gLN
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}
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_
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System.err.println("文件下载结束！"); ;^9Ao>(?y  
} u}eqU%  
catch(Exception e){e.printStackTrace ();} E|(T(4;  
} ^^u{W|'CaH  
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//获得文件长度 6*] g)m  
public long getFileSize() Ue>;h9^  
{ 3;wAm/Z:Q  
int nFileLength = -1; dE<}X7J%  
try{ ^ |k7g  
URL url = new URL(siteInfoBean.getSSiteURL()); MeXzWLH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G@YX8!wU  
httpConnection.setRequestProperty("User-Agent","NetFox"); :x36^{7  
0Q81$% @<  
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int responseCode=httpConnection.getResponseCode(); Y:GSjq  
if(responseCode>=400) G:W4<w  
{ uSeRn@  
processErrorCode(responseCode); mE`OG8  
return -2; //-2 represent access is error ,]1oG=`3v  
} *SW.K{{  
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String sHeader; DAZzc :1Aj  
RoV^sbWFt  

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for(int i=1;;i++) WE_jT1^/  
{ ' }G!D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >/*wlY!E  
//Utility.log(in.readLine()); "|{3V:e>a  
sHeader=httpConnection.getHeaderFieldKey(i); *Y4h26  
if(sHeader!=null) svt%UE|_:$  
{ |'w_5?|4  
if(sHeader.equals("Content-Length")) AOT +4*)%  
{ mlIX>ss|7B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b)7uz>I  
break; tY?_#rc  
} 7MRu=Z.-b  
} 'S_kD! BO  
else c6IFt4)g  
break; !ke_?+8sY  
} 9.<dS  
} wYZ"fusT  
catch(IOException e){e.printStackTrace ();}  $D`~X`  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); 4WK@ap-~  
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return nFileLength;
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} HPc7Vo(  
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//保存下载信息（文件指针位置） Q.5C
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private void write_nPos() z93HTy9  
{ +f{CfWIKs  
try{ d3A= (/>D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6`sOhVD  
output.writeInt(nStartPos.length); B;SN}I  
for(int i=0;i<nStartPos.length;i++) bFivHms  
{ R5`"~qP-  
// output.writeLong(nPos); ]ne&`uO  
output.writeLong(fileSplitterFetch.nStartPos); /:]`TlAb,  
output.writeLong(fileSplitterFetch.nEndPos); OBGA~E;%  
} y
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output.close(); D`nW9i7  
} Ri$wt.b  
catch(IOException e){e.printStackTrace ();} "CYh"4]@rD  
catch(Exception e){e.printStackTrace ();} uZsm=('ww  
} @Y/PvS8!  
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a );>  
//读取保存的下载信息（文件指针位置） GF6c6TXF@  
private void read_nPos() +Eil:Jz  
{ y`"b%P)+T  
try{ zCrDbGvqF`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [ vU$zZ<  
int nCount = input.readInt(); ahagt9[,:F  
nStartPos = new long[nCount]; g8 (zvG;Y  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) L2s)B  
{ V K/;ohTTP  
nStartPos = input.readLong(); 7%p[n;-o&  
nEndPos = input.readLong(); 19)fN-0
Z  
} EleK*l  
input.close(); GarPnb  
} lO482l_t  
catch(IOException e){e.printStackTrace ();} >|<8QomD  
catch(Exception e){e.printStackTrace ();} F...>%N$  
} M8Y\1
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[.B)W);  
private void processErrorCode(int nErrorCode) \Q{@AC<?i  
{ ]9)pFL  
System.err.println("Error Code : " + nErrorCode); !cw<C*
 
} &$  F0  
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La?q>  
//停止文件下载 PaV[{CD  
public void siteStop() VE^NSkOa&  
{ @~fg[)7M  
bStop = true; v vlfL*f  
for(int i=0;i<nStartPos.length;i++) "^gZh3  
fileSplitterFetch.splitterStop(); RH ow%2D  
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l.1)%q&@^  
} xBU\$ToC  
} \(.&E`r  
//负责部分文件的抓取
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**FileSplitterFetch.java /dhx+K~  
*/ NKLGbH  
package NetFox; ?AP2Opsl  
rwFR5  
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import java.io.*; _)2.#L  
import java.net.*; UT [7 J  
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public class FileSplitterFetch extends Thread { ADA%$NhJ!  
a*CP1@O  
-'JTVfm.  
String sURL; //File URL +%X_+9bd  
long nStartPos; //File Snippet Start Position M! gX
4  
long nEndPos; //File Snippet End Position  ?1r@r  
int nThreadID; //Thread's ID \^;Gv%E  
boolean bDownOver = false; //Downing is over xC`Hm?kM  
boolean bStop = false; //Stop identical =nFT0];  
FileAccessI fileAccessI = null; //File Access interface Xn"n5=M  
n0U^gsD4J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q?8MKf[N  
{ v6oPAqj,r  
this.sURL = sURL; W)^:*z  
this.nStartPos = nStart; t2p/NIn  
this.nEndPos = nEnd; vQ+}rHf`[  
nThreadID = id; 3{Ze>yFE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dpZ7eJ  
} ,TOLr%+v~n  
"+_]N9%)  

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public void run() nX5*pTfjL3  
{ #i ?@S$  
while(nStartPos < nEndPos && !bStop) I.R3?+tZ  
{ i0-!!  
& /-@R|  
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try{ 8)5n  
URL url = new URL(sURL); ="@W)"r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ms1G&NYP  
httpConnection.setRequestProperty("User-Agent","NetFox"); _I~TpH^1K  
String sProperty = "bytes="+nStartPos+"-"; &-<"HW  
httpConnection.setRequestProperty("RANGE",sProperty); L)8+/+  
Utility.log(sProperty); P)1@HDN==  
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+n,8o:fU:  
InputStream input = httpConnection.getInputStream();  3mWo`l  
//logResponseHead(httpConnection); >]:R{1h  
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byte[] b = new byte[1024]; W{ eu_  
int nRead; P7egT,Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ejgg.G ^  
{ vR,HCI  
nStartPos += fileAccessI.write(b,0,nRead); yel>-=Vn  
//if(nThreadID == 1) [2i+f<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bcM#KA  
} rO]C`bg  
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-
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Utility.log("Thread " + nThreadID + " is over!"); $nn~K  
bDownOver = true; T:)>Tcv}:  
//nPos = fileAccessI.write (b,0,nRead); =v:_N.Fh-c  
} QMtt:f]?i  
catch(Exception e){e.printStackTrace ();} `yQHPN0/  
} Hkg@M?(  
} `W]a @\EYA  
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/;OJ=x3i  
//打印回应的头信息 4T^M@+&|  
public void logResponseHead(HttpURLConnection con) m9L+|r  
{ So`xd *C!  
for(int i=1;;i++) T^sxR4F  
{ <ht>>  
String header=con.getHeaderFieldKey(i); }\823U %  
if(header!=null) n|,Es!8:o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Bs##3{ylu  
Utility.log(header+" : "+con.getHeaderField(header)); Q@$1!9m  
else aNqVs|H  
break; E32z(:7M  
} mceSUKI;L  
} V>['~|  
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public void splitterStop() qh2.N}lW  
{ R=e`QMq  
bStop = true; 0I#<-9&d-  
} CC)9Ks\  
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IcQ?^9%{  
} EXBfzK)a  
]$L[3qA.  
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/* ITsJjcYw  
**FileAccess.java &a|oJ'clz  
*//文件访问(定位，写) yjSN;3t71  
package NetFox; @?1%*/  
import java.io.*; ]!A;-m  
*,Re&N8  
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public class FileAccessI implements Serializable{ a6]!4  
"(xS  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \O0fo^+U,,  
RandomAccessFile oSavedFile; Olno9_'  
long nPos; <]9MgfAe  
t]` 2f3UO  
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public FileAccessI() throws IOException .U1dcL6  
{ .Gv~e!a8  
this("",0); RhJ<<T.2  
} `j(+Y  
{10ms_s  
*/\.-L{h  
public FileAccessI(String sName,long nPos) throws IOException 7d<v\=J
}  
{ t/$xzsoJZr  
oSavedFile = new RandomAccessFile(sName,"rw"); C{ti>'"V  
this.nPos = nPos; h49Q2`  
oSavedFile.seek(nPos); +/X'QB$R  
} J~}UG]j n  
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public synchronized int write(byte[] b,int nStart,int nLen) 7 dzE"m  
{ ]lo1Kw  
int n = -1; - VE#:&  
try{
xC{NIOYn'  
oSavedFile.write(b,nStart,nLen); 9=o b:  
n = nLen; Z\L@5.*ydE  
} %b?Pasf.  
catch(IOException e) Jt)~h,68  
{ "4`%NA  
e.printStackTrace (); K$ &wO.  
} |]q=D1/A  
{#%xq]r_  
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return n; y(dS1.5F  
} n,F00YR  
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} G4}q*&:k  
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/* #SYWAcTkO}  
**SiteInfoBean.java Q#N+5<]J)#  
*/ *p3P\ H^5  
package NetFox; d.AjH9 jg  
eTc`FXw`  
!7oy%{L  
public class SiteInfoBean { =F&RQ}$  
2X*<Fma3C  
=#tQIhX`  
private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path ddP,_.0  
private String sFileName; //Saved File's Name 4I*Mc%dD  
private int nSplitter; //Count of Splited Downloading File `k&K"jA7$  
P
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@"8QG^q8de  
public SiteInfoBean() &w0=/G/T=~  
{//nSplitter的缺省值为5 {wP|b@(1t  
//default value of nSplitter is 5 $at|1+bQ  
this("","","",5); "o3"1s>d{  
} %?hLo8  
ku?_/-ko]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QZr<=}
 
{ )^H9C"7T  
sSiteURL= sURL; P;%QA+%7  
sFilePath = sPath; 05B+WJ1  
sFileName = sName; <&:&qngg  
this.nSplitter = nSpiltter;
w
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 ~C/KA6H  
} 4P!DrOB  
Fz&ilB  
M7R&J'SAY  
public String getSSiteURL() i[{] LiP  
{ io7U[#  
return sSiteURL; lzG;F]  
} K<6x4ha  
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public void setSSiteURL(String value) U!:!]DX(  
{ MuV0;K\  
sSiteURL = value; zL'IN)7MU  
} @z
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public String getSFilePath()  \t# 9zn>  
{ o?K|[gNi  
return sFilePath; h5rP]dbhXU  
} xg,]M/J  
eD{ @0&
 
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public void setSFilePath(String value) ef}E.Bl  
{ <ytKf<a%e  
sFilePath = value; lzs(i2pA  
} }u_EXP8M  
I"32[?0 (;  
VnSj:LUD  
public String getSFileName() (SsH uNt.  
{ (1AA;)`Kp  
return sFileName; $dTfvd  
} ;%7XU~<a  
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public void setSFileName(String value) ]Uu(OI<)  
{ .\~P -{Hd  
sFileName = value; M&djw`B  
} $wYuH9(  
zz 'dg-F  
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public int getNSplitter() >!Ap/{2  
{ {nPkb5xbW  
return nSplitter; w <#*O:  
} ?$J7%I@  
"T{~,'T  
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public void setNSplitter(int nCount) YR|(;B  
{ W?^8/1U  
nSplitter = nCount; _7=pw5[  
} -.b Io  
} <RoX|zJ
w  
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:!I)r$  
/* hINnb7o  
**Utility.java S:p.W=TAB  
*/ S< EB&P  
package NetFox; &ppE|[{  
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6VH90KAT  
public class Utility { D%jD8p  
9{O2B5u1  
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public Utility() ZVdsxo<  
{ (:.Q\!aZ1  
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} {t844La"  
z
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//线程睡眠 y wW-p.  
public static void sleep(int nSecond) 'a;ini  
{ gx!*O<|e4  
try{ I@3Q=14k%  
Thread.sleep(nSecond); o &BPG@n  
} T&9`?QD  
catch(Exception e) [c&2i`C  
{ D^66p8t  
e.printStackTrace (); /]ku$.mr\  
} -Wl)Lez@  
} 98ca[.ui  
Eyr5jXt%;  
//日志 La`h$=#`  
public static void log(String sMsg) p>k]C:h  
{ JQ*D  
System.err.println(sMsg); VDB$"T9#  
} wXc,FD$  
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o;ik Z*+*  
public static void log(int sMsg) '"oo;`g7  
{ sW;7m[o  
System.err.println(sMsg); s{yJ:WncI  
} % 2I  
} sS C?io  
jmkRP"ZnA  
n`P`yb\f$  
/* }C=Quy%Z<  
**TestMethod.java &(gm4bTg  
*/ riID,aut  
package NetFox; {UP'tXah  
y&7YJx  
0r1g$mKb  
public class TestMethod { ?#?e(mpo  
BRe{1i 6  
-r!42`S  
public TestMethod() LRWOBD  
{ ///xx/weblogic60b2_win.exe ^rL,&rk  
try{ S2ark,sp6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); TW>?h=
.z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YZ0en1ly  
SiteFileFetch fileFetch = new SiteFileFetch(bean); L*P_vCC  
fileFetch.start(); 8fnR1mWG  
} *%3oyWwCd  
catch(Exception e){e.printStackTrace ();} EY]a6@;  
5!~!j "q  
m)r]F#@/  
} +Z ><  
\[cH/{nt  
|H:<:*=6c  
public static void main(String[] args) UIn^_}jF`  
{ 8zAg;b[  
new TestMethod(); V7P6zAJy  
} .vK.XFZ8R  
} sv' Gt1&"Z  
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