http断点续传简单实现（java)

/* eP~
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**SiteFileFetch.java }#1.$a  
*/ | +;ZC y  
package NetFox; DG;u_6;JR  
import java.io.*; XtO..{qU  
import java.net.*; f
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public class SiteFileFetch extends Thread { .!~ysy  
a >fA-@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Mzg'$]N  
long[] nStartPos; //开始位置 |6d:k~p  
long[] nEndPos; //结束位置 /eHf8l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lSR\wz*Fk  
long nFileLength; //文件长度 L~ax`i1:"  
boolean bFirst = true; //是否第一次取文件 XF: wsC  
boolean bStop = false; //停止标志 &3/`cl[+  
File tmpFile; //文件下载的临时信息 Sp[9vlo8  
DataOutputStream output; //输出到文件的输出流 q5g_5^csM{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） il>+jVr  
public SiteFileFetch(SiteInfoBean bean) throws IOException }F1Asn  
{ .U(6])%;@  
siteInfoBean = bean; iY>xx~V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5V<6_o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9y\nO)\Tv  
if(tmpFile.exists ()) w8D8\`i!"  
{ _LF'0s*  
bFirst = false; pXNhU88  
read_nPos(); V.3#O^S  
} n^QDMyC;I  
else m@nGXl'!  
{ fyUW;dj
 
nStartPos = new long[bean.getNSplitter()]; qF3S\ C  
nEndPos = new long[bean.getNSplitter()]; gS(JgN  
} f]1 $`  
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} QqL?? p-S>  
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public void run() b5g^{bzwu  
{ *Iw19o-I  
//获得文件长度 ]Q^8 9?  
//分割文件 ])pX)(a  
//实例FileSplitterFetch -6 v?iiZr  
//启动FileSplitterFetch线程 lU|ltnU  
//等待子线程返回 ?Zv5iI  
try{ @uC
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if(bFirst) 3znhpHO)  
{ M/V"Ke"N  
nFileLength = getFileSize(); N+SA$wG  
if(nFileLength == -1) [9?
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{ !5+9~/;  
System.err.println("File Length is not known!"); PvUY Q>Kw  
} ~=wBF  
else if(nFileLength == -2) ,hK =x  
{ w}}+8mk[  
System.err.println("File is not access!"); tc;$7F ;  
} .*k!Zl*  
else ;2 o{6  
{ Qvny$sr
2  
for(int i=0;i<nStartPos.length;i++) hW,GsJ,  
{ ve#[LBOC8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dd=5`Bo9Yh  
} ]Gl_L7u`  
for(int i=0;i<nEndPos.length-1;i++) 3I?yRE
 
{ !4F@ !.GG!  
nEndPos = nStartPos[i+1]; ;Xidv9
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} d{!zJ+n  
nEndPos[nEndPos.length-1] = nFileLength; J!rZskd  
} -'W:P'BG  
} 7({.kD6  
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"z.!h(Eq  
//启动子线程 y^p%/p%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 17Q* <iCs  
for(int i=0;i<nStartPos.length;i++) !/&~Feb  
{ tORDtMM9+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GmGq69]J*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n;b9f|&z  
nStartPos,nEndPos,i); 0g#?'sD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QqY42
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fileSplitterFetch.start(); 
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} DF#WQ8?$]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9DXu*}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]:^kw$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d@|j>Z  
nEndPos = " + nFileLength); '9wD+'c=A  
// fileSplitterFetch[nPos.length-1].start(); s|!b: Ms`  
>|T?87  
=7P; /EV  
//等待子线程结束 /=OSGIJzm  
//int count = 0; b!37:V\#}  
//是否结束while循环 X>jwjRK $  
boolean breakWhile = false; I^A01\p  
;rta#pRn  
4d'tK^X  
while(!bStop) tX*L_  
{ :kI x?cc  
write_nPos(); r3{o_w  
Utility.sleep(500); .yj=*N.  
breakWhile = true; w
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for(int i=0;i<nStartPos.length;i++) s.dn~|a  
{ Mz{ Rh+gS  
if(!fileSplitterFetch.bDownOver) m9>nvrQ  
{ 1J*wW# e  
breakWhile = false; {K0T%.G  
break; Iei4yDv ;  
} <F.Ol/'h  
} v:T` D  
if(breakWhile) &akMj@4;R  
break; f&cG;Y  
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:U[_V4?7  
//count++; $v oyXi`*  
//if(count>4) #XY]@V
\  
// siteStop(); +ow ^xiD  
} 
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System.err.println("文件下载结束！"); GRV9s9^  
} YL=k&QG  
catch(Exception e){e.printStackTrace ();} sBu"$"]  
} ;^8^L'7cr  
>`\*
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//获得文件长度 A07P$3>/W  
public long getFileSize() Pd;ClMa%  
{ EhUy7b,1_  
int nFileLength = -1; yaR;  
try{ ^{K8uN7  
URL url = new URL(siteInfoBean.getSSiteURL()); 7VXeu+-P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n)7icSc  
httpConnection.setRequestProperty("User-Agent","NetFox"); (MIw$)#^  
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qtH&]Suu,  
int responseCode=httpConnection.getResponseCode(); v(7A=/W_  
if(responseCode>=400) "AK3t' jF*  
{ 1DcarF  
processErrorCode(responseCode); Mqtp}<*@-  
return -2; //-2 represent access is error hw'2q9J|  
} &"h!SkX/  
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String sHeader; )IhY&?jk?  
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for(int i=1;;i++) oX4uRc7wR  
{ &P3vcB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xh/av[Q  
//Utility.log(in.readLine()); {LD8ie|x1`  
sHeader=httpConnection.getHeaderFieldKey(i); NGY I%:  
if(sHeader!=null) "\[>@_p h  
{ U}0/V c
26  
if(sHeader.equals("Content-Length")) \
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{ dZgfls  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G]1pGA;  
break; 5w1[KO#K|  
} [alXD_  
} m^.
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else >[@d&28b%  
break; @ 1A_eF  
} ?63JQ.;  
} vNSf:5H$  
catch(IOException e){e.printStackTrace ();} !?*!"S-Sl  
catch(Exception e){e.printStackTrace ();} [;Ac
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Utility.log(nFileLength); I}IW!K  
p ri{vveN@  
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return nFileLength; 'e64%t  
} oLMi vy4  
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//保存下载信息（文件指针位置） I7^X;Q F  
private void write_nPos() k&s7-yY  
{ V9_HC f  
try{ vqi$}=%n?W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X2YOD2<v  
output.writeInt(nStartPos.length); )"uG*}\?b  
for(int i=0;i<nStartPos.length;i++) <,4(3 >js  
{ veg!mY2&  
// output.writeLong(nPos); /$,=>  
output.writeLong(fileSplitterFetch.nStartPos); D#1~]d  
output.writeLong(fileSplitterFetch.nEndPos); 1T,PC?vr{  
} by[i"!RCu  
output.close(); i%4k5[f.:  
} i(iP}:3  
catch(IOException e){e.printStackTrace ();} ?(8%S
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catch(Exception e){e.printStackTrace ();} y?#J`o- O  
} B!ibE<7,  
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//读取保存的下载信息（文件指针位置） Z[S+L"0  
private void read_nPos() hyfnIb@~}  
{ PZRn6Tc  
try{ _C,@eu"9V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f\U&M,L\'  
int nCount = input.readInt(); @[lc0_b  
nStartPos = new long[nCount]; 7O{O')o!  
nEndPos = new long[nCount]; 89#0vG7m  
for(int i=0;i<nStartPos.length;i++) =e8L7_;  
{ E0^%|Mh]b  
nStartPos = input.readLong(); 3,L3C9V'  
nEndPos = input.readLong(); hUvuq,LH_  
} 65#:2,s  
input.close(); !LOors za  
} *3`oU\r  
catch(IOException e){e.printStackTrace ();} bTQa'y`3  
catch(Exception e){e.printStackTrace ();} "Lq|66  
} k+#l;<\2  
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private void processErrorCode(int nErrorCode) oXlxPN39  
{ f

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System.err.println("Error Code : " + nErrorCode); W#jZRviyq!  
} EH*ym#Y  
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//停止文件下载 yC 7Vb P  
public void siteStop() H]$=*(aje  
{  +iH30v  
bStop = true; Jhsv2,8 {  
for(int i=0;i<nStartPos.length;i++) q X%vRf0  
fileSplitterFetch.splitterStop(); n~)HfY  
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} "4ozlWx  
} s w.AfRQP  
//负责部分文件的抓取 EhIV(q9x  
**FileSplitterFetch.java seuN,jpt  
*/ Yl&tkSw46  
package NetFox; FfxX
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import java.io.*; 7}'A)C>J;  
import java.net.*; od}EM_  
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public class FileSplitterFetch extends Thread { Xm8Z+}i  
I51oG:6fR?  
J(EaE2  
String sURL; //File URL X(y  
long nStartPos; //File Snippet Start Position YF! &*6m  
long nEndPos; //File Snippet End Position JU'WiR bcb  
int nThreadID; //Thread's ID :Dk@?o@2;C  
boolean bDownOver = false; //Downing is over 9jMC|oE  
boolean bStop = false; //Stop identical  H\=LE  
FileAccessI fileAccessI = null; //File Access interface g>!:U6K  
2&gd"
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sArje(5Eo  
{ t8AkdSU0  
this.sURL = sURL; p<HTJ0  
this.nStartPos = nStart; NDRW  
this.nEndPos = nEnd; v;fJM5PA  
nThreadID = id; s~Lfi.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'n^2|"$sH  
} ;v,9v;T  
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public void run() %wt2F-u  
{ i5 L:L  
while(nStartPos < nEndPos && !bStop) ` /I bWu  
{ !f\?c7  
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try{ $bZu^d,  
URL url = new URL(sURL); oNuPP5d[]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \6SMn6a4  
httpConnection.setRequestProperty("User-Agent","NetFox"); PG6[lHmi  
String sProperty = "bytes="+nStartPos+"-"; X(GmiH /E  
httpConnection.setRequestProperty("RANGE",sProperty); C#Hcv*D  
Utility.log(sProperty); (!ZQ  
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|;A9A's  
InputStream input = httpConnection.getInputStream(); 9Hf*cQ  
//logResponseHead(httpConnection); cW)Oi^q%o2  
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byte[] b = new byte[1024]; t1e4H=d>  
int nRead; 5c:'>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IjG5X[@  
{ 1mJbQ#5  
nStartPos += fileAccessI.write(b,0,nRead); tS\=<T  
//if(nThreadID == 1) ZjU=~)O}H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GA|/7[I}  
} JsmbW|t^  
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E tJ~dL)  
Utility.log("Thread " + nThreadID + " is over!"); VLcyPM@"Q!  
bDownOver = true; !}>eo2$r^  
//nPos = fileAccessI.write (b,0,nRead); k
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} n$.1Wk"  
catch(Exception e){e.printStackTrace ();} gB]C&Q  
} |Du,UY/  
} >vlQ|/C  
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bK3B3r#$  
//打印回应的头信息 |}_gA  
public void logResponseHead(HttpURLConnection con) H1` rM^,%A  
{ H
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for(int i=1;;i++) [O^}rUqq  
{ 0TTIaa$  
String header=con.getHeaderFieldKey(i); CE~r4  
if(header!=null) f%2%T'Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hzaLx8L  
Utility.log(header+" : "+con.getHeaderField(header)); :3*`IB !  
else Ur^YG4(  
break; C/F@ ]_y  
} L)q`D2|'  
} Uh|TDuM  
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public void splitterStop() jEUx q%BH  
{ B-!guf rnY  
bStop = true; 8NnhT E  
} z>6.[Z(T  
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} ~6p5H}'H1  
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/* ~\2;i]|  
**FileAccess.java Ll,I-BQ9  
*//文件访问(定位，写) mHKJ  
package NetFox; t-_#Q bzE{  
import java.io.*; f,|QAj=a  
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public class FileAccessI implements Serializable{ $( S*GF$S  
y)P&]&"?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c8T/4hU MN  
RandomAccessFile oSavedFile; Truc[A.2Z  
long nPos; Zw+=ng.q?  
8pqs?L@W  
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public FileAccessI() throws IOException FtE90=$  
{ ^Sw2xT$p{j  
this("",0); \H^;'agA  
} )&>L !,z  
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public FileAccessI(String sName,long nPos) throws IOException Ddb-@YD&+0  
{ ?fV?|ZGZ
I  
oSavedFile = new RandomAccessFile(sName,"rw"); {o( * f  
this.nPos = nPos; G(3;;F7"  
oSavedFile.seek(nPos); )`^ /(YG  
} byafb+x  
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public synchronized int write(byte[] b,int nStart,int nLen) ]a M-p@  
{ ((qGh>*  
int n = -1; vTdUuj3N  
try{ sJOV2#r  
oSavedFile.write(b,nStart,nLen); B;V5x/  
n = nLen; ~Po<(A}`f  
} 4h;4!I|  
catch(IOException e) n,CD  
{ !:3^ hb  
e.printStackTrace (); M_Bu,<q^  
} Y17hOKc`  
8&%Cy'TIz4  
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return n; ZNi +Aw$u  
} teAukE=}  
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} m^Glc?g<  
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)9B:Y;>)  
/* FNC[59  
**SiteInfoBean.java 1eHe~p ,  
*/ i3P9sdTD  
package NetFox; Hs$'0:  
~q 7;8<U  

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public class SiteInfoBean { yPoSJzC=[  
gGEIK0\{  

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private String sSiteURL; //Site's URL o5SQ1;`   
private String sFilePath; //Saved File's Path =G4u#t)  
private String sFileName; //Saved File's Name *1$
 
private int nSplitter; //Count of Splited Downloading File P_&p=${  
nM8[  
*GJ:+U&m[  
public SiteInfoBean() b!^@PIX  
{//nSplitter的缺省值为5 |NJ}F@t/5  
//default value of nSplitter is 5 a~opE!|m  
this("","","",5); w^Ag]HZN  
} 6Hk="$6K  
~>g+2]Bn>$  
-9d%+O~v6~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &?y7I Pp  
{ dw9Tf^V  
sSiteURL= sURL; +P
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sFilePath = sPath; {~'H  
sFileName = sName; &iBNO,v  
this.nSplitter = nSpiltter; !zR)D|w&  
w#9_eq|3  
X
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} 9 I{/zKq  
8Q=ZH=SQK  
:y1Bt+Fp  
public String getSSiteURL() '1-maM\r  
{ pawl|Z'Ez  
return sSiteURL; aClA{  
} g*J@[y;  
~x#vZ=]8  
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public void setSSiteURL(String value) |55dbL$w  
{ 64umul  
sSiteURL = value; +rc SL8C  
} Q|c|2byb  
i%F<AY\O)  
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public String getSFilePath() nQ-mmY>#  
{ `N'V#)Pi  
return sFilePath; ,[l
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} p0VUh!  
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50$W0L$  
public void setSFilePath(String value) + >nr.,qo3  
{ :o8MUXH$  
sFilePath = value; '!Wvqs  
} }`_(<H  
o\!qcoE2W  
#]Y*0Wzpfn  
public String getSFileName() T$P-<s  
{ 5JSrrpGr
 
return sFileName; x)oRSsv!Tr  
} :FHA]oec1  
Ej"u1F14J  
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public void setSFileName(String value) ue\t,*KYd  
{ |`0n"x7  
sFileName = value; pW|u P8#  
} tTuX\;G  
=J/FJb  
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public int getNSplitter() =;ICa~`C;  
{  3+U]?7t  
return nSplitter; G%:GeW  
} &%,DZA`  
+}JM&bfK  
J=H)JH3  
public void setNSplitter(int nCount) efOjTA%  
{ k\aK?(.RC7  
nSplitter = nCount; ahGT4d`)9  
} /XbW<dfl  
} c^9tYNn  
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{HrZ4xQnpV  
/* iqPBsIW  
**Utility.java *y]+dK&-  
*/ K{=PQ XSU  
package NetFox; RUo9eQIPD  
-LWK*q[J;*  
+B"0{>n}F  
public class Utility { ;rR/5d1!  
%!|O.xxRR  
nc?B6IV  
public Utility() lm0N5(XP  
{ Tv$sqVe9  
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} ^3~e/PKM  
| C+o;  
//线程睡眠 bw S*]!*  
public static void sleep(int nSecond) j-b*C2l  
{ DBgMC"_   
try{ n}nEcXb  
Thread.sleep(nSecond); `u_Qa  
} ?Bx./t><  
catch(Exception e) +%0z`E\?M#  
{ ',=g;  
e.printStackTrace (); \ |!\V  
} D4u%6R|F  
} 57I}RMT"  
p]T"|!d  
//日志 7Y( 5]A9=  
public static void log(String sMsg) {
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{ Lx[ ,Z,kD  
System.err.println(sMsg); v"O5u%P  
} (<c7<_-H  
`V!>J1x  
LKF/u` 0dP  
public static void log(int sMsg) Acm<-de  
{ =o7}]k7  
System.err.println(sMsg); [\e@_vY@OH  
} =xN= #  
} xge7r3i  
Dr#c)P~Wd  
T)iW`vZg8  
/* S
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**TestMethod.java tkKJh !Q7  
*/ {6
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package NetFox; rofNZ;nu  
q_fam,9  
}JgYCsF/f  
public class TestMethod { 8|g<X1H{M  
8y2+&#$  
dK9Zg,DZL  
public TestMethod() kLP0{A  
{ ///xx/weblogic60b2_win.exe UQ
?%|y*Kc  
try{ X$n(-65  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A[N{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0 p
uY"[c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HIvZQQW|  
fileFetch.start(); j}JZ  
} q6d~V]4:  
catch(Exception e){e.printStackTrace ();} ,FSrn~-j9  
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| A)\ :  
} b^CNVdo'  
L"(4R^]  

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public static void main(String[] args) D-p.kA3MJ  
{ 5Rv+zQ#GR  
new TestMethod(); N"7]R[*  
} t0E51Ic@  
} g_.^O$}  
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