http断点续传简单实现（java)

/* ;;ER"N  
**SiteFileFetch.java *ZGX-+{  
*/ N=OS\pz  
package NetFox; =?=)s  
import java.io.*; ^y:FjQC:  
import java.net.*; T?W[Z_D  
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public class SiteFileFetch extends Thread { `d75@0:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F0@Qgk]\  
long[] nStartPos; //开始位置 \n[ 392  
long[] nEndPos; //结束位置 ?k [%\jq{a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .CVUEK@Z4  
long nFileLength; //文件长度 k1wCa^*gc  
boolean bFirst = true; //是否第一次取文件 "e~k
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boolean bStop = false; //停止标志 S3SV.C:z>  
File tmpFile; //文件下载的临时信息 'I&|1I^  
DataOutputStream output; //输出到文件的输出流 ,`;jvY~Ec  
./#e1m?.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'dkXYtKCB  
public SiteFileFetch(SiteInfoBean bean) throws IOException #2h+dk$1  
{ Ds{{J5Um%  
siteInfoBean = bean; 
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XR|"dbZW.0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PKi_Zh.D  
if(tmpFile.exists ()) GtF2@\  
{ Z`rK\Bc  
bFirst = false; >4,{6<|  
read_nPos(); %PzQ\c  
} 'nMApPl  
else A
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{ p?;-!TUv  
nStartPos = new long[bean.getNSplitter()]; ;_iPm?Y
8  
nEndPos = new long[bean.getNSplitter()]; -<_7\09  
} ue@8voZhS/  
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} \@i=)dA  
=K:(&6f<t  
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public void run() sYI~dU2H  
{ QjLji+L  
//获得文件长度 p"KU7-BfvC  
//分割文件 O:1DOUYXs  
//实例FileSplitterFetch -PM)EGSk{  
//启动FileSplitterFetch线程 h}avX*Lx_  
//等待子线程返回 qtHfz"p  
try{ +O'vj  
if(bFirst) -n$ewV  
{ CD}Ns  
nFileLength = getFileSize(); Yb}w;F8(  
if(nFileLength == -1) 3wZ(+<4i  
{ i|%5  
System.err.println("File Length is not known!"); Kh)FyV  
} BBvZeG $Y  
else if(nFileLength == -2) L!gDFZr  
{ jPnO@H1  
System.err.println("File is not access!"); z!:'V]  
} y?>#t^  
else 27>a#vCT  
{ va5FxF*%  
for(int i=0;i<nStartPos.length;i++) _Fizgs  
{ \83sSw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a"QU:<-v  
} =O,JAR"ug  
for(int i=0;i<nEndPos.length-1;i++) R*yU<9Mm8  
{ Z v4<b  
nEndPos = nStartPos[i+1]; !h>D;k6 e  
} R uLvG+  
nEndPos[nEndPos.length-1] = nFileLength; }kE87x
'  
} J='W+=N  
} 0N{+y}/G  
i&A%"lOI9  
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//启动子线程 O6iCZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~s#e,Kav"  
for(int i=0;i<nStartPos.length;i++) X2gz6|WJ  
{ ^Gq5ig1rxy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8%[HYgd5)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B;!f<"a8  
nStartPos,nEndPos,i); +yWR#[`n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RZO5=L9E  
fileSplitterFetch.start(); t[EfOQ  
} &!jq!u$(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #.<V^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !%xP}{(7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '"'Btxz  
nEndPos = " + nFileLength); H] k'?;  
// fileSplitterFetch[nPos.length-1].start(); jJ~Y]dQi  
zE`R,:VI  
;
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//等待子线程结束 /)9W1U^B  
//int count = 0; ,)h)5o(?  
//是否结束while循环 B!bsTvX  
boolean breakWhile = false; B wC+o
v=  
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while(!bStop) 1zjaR4Tf  
{ Ax!Gu$K2o  
write_nPos(); kZVm
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Utility.sleep(500); z/1{OL  
breakWhile = true; EA|k5W*b  
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WH  
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for(int i=0;i<nStartPos.length;i++) |;u}sX1t9  
{ s-k_d<  
if(!fileSplitterFetch.bDownOver) z<p
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{ \cQ .|S  
breakWhile = false; R#(G%66   
break; 4DLq}v  
} zX kx7d8  
} "+|L_iuNQ  
if(breakWhile) s&'BM~WI  
break; !gH9ay  
~O;y?]U  
hazq#J!  
//count++; Pl+xH%U+?  
//if(count>4) 6:?rlh  
// siteStop(); )"`!AerJ  
} ~|lIC !q  
kIvvEh<L=  
<\@1Zz@ms  
System.err.println("文件下载结束！"); TfRGA(+#  
} ^Y04qeRd  
catch(Exception e){e.printStackTrace ();} Ht[{ryTxu  
} :?CQuEv-  
Y ?'tUV  
9<s4yZF@x  
//获得文件长度 ~]WVG@-  
public long getFileSize() -2i\G.,J  
{ 5HlWfD  
int nFileLength = -1; ksWSMxm  
try{ [vTMS2  
URL url = new URL(siteInfoBean.getSSiteURL()); q0O&UE)6Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lKKERO5+  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'r+PH*Mr  
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mm[SBiFO\  
int responseCode=httpConnection.getResponseCode(); otr>3a*'  
if(responseCode>=400) B@t'U=@7  
{ o }
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processErrorCode(responseCode); 6EJVD!#[K  
return -2; //-2 represent access is error ]Kdet"+  
} Q$ZHv_VLx  
V 0{tap}  
w([$@1]  
String sHeader; sR=/%pVN  
 k0H#:c}  
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y*;  
for(int i=1;;i++) P<;7j?  
{ ?KWj}|%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *'R#4@wmP  
//Utility.log(in.readLine()); A0xC,V~z  
sHeader=httpConnection.getHeaderFieldKey(i); ~kKrDL
W+  
if(sHeader!=null) x#8w6@iPQ  
{ hI|)u4q  
if(sHeader.equals("Content-Length")) $'"8QOnJ?k  
{ ~]uZy=P? 5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "5!BU&   
break; .g% Y@r)=5  
} vtxvS3   
} |L:Cn J  
else zAScRg$:?  
break; >V;,#5F_  
} qv+R:YYOq  
} {CUk1+  
catch(IOException e){e.printStackTrace ();} l1+[  
catch(Exception e){e.printStackTrace ();} 4]&<?"LSK  
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Utility.log(nFileLength); ?o[L7JI  
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. (`3JQ2s  
return nFileLength; lCb+{OB  
} y79qwM.  
c-CYdi@  
KN[d!}W:  
//保存下载信息（文件指针位置） 6C-YyI#s#  
private void write_nPos() 8_we: 9A  
{ (P@Y36j>N  
try{ or?%-)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X K>&$<5{  
output.writeInt(nStartPos.length); t\R; < x  
for(int i=0;i<nStartPos.length;i++) RiFw?Q+  
{ TbhH&kG)1  
// output.writeLong(nPos); ;+Yi.Q/\  
output.writeLong(fileSplitterFetch.nStartPos); MagMZR  
output.writeLong(fileSplitterFetch.nEndPos); G?hK9@ |v  
} h##WA=1QZ  
output.close(); U/w.M_S  
} O\beKBT;  
catch(IOException e){e.printStackTrace ();} 'ks{D(`  
catch(Exception e){e.printStackTrace ();} HKmcQM  
} (36K3=Qa  
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[CN$ScK,  
//读取保存的下载信息（文件指针位置） $3P`DJo  
private void read_nPos() eD;6okdP  
{ }e{qW  
try{ K|^wc$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xtfRrX^  
int nCount = input.readInt(); bEH de*q(  
nStartPos = new long[nCount]; 3y`F<&sA  
nEndPos = new long[nCount]; .y4&rF$n  
for(int i=0;i<nStartPos.length;i++) ?nFO:N<  
{ "mIgs9l$  
nStartPos = input.readLong(); BBL485`  
nEndPos = input.readLong(); pGWA\}'  
} N{joXHCu  
input.close(); .;I29yk\XS  
} ;;&F1@3tBa  
catch(IOException e){e.printStackTrace ();} y?z\L
 
catch(Exception e){e.printStackTrace ();} l";'6;g  
} L-h$Z
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private void processErrorCode(int nErrorCode) 6Wf^0ok  
{ t#b0H)  
System.err.println("Error Code : " + nErrorCode); .p@N:)W6  
} j, u#K)7{T  
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`y!/F?o+!  
//停止文件下载 >-cfZ9{!  
public void siteStop() f~M8A.  
{  '3,\@4  
bStop = true; Ex(3D[WmMW  
for(int i=0;i<nStartPos.length;i++) \M+L3*W  
fileSplitterFetch.splitterStop(); xHkxc}h  
:pC;`iQ  
'Cg{_z.~c  
} lF4u{B9DM  
} i g71/'D  
//负责部分文件的抓取 X>l*v\F9  
**FileSplitterFetch.java G*n2Ii  
*/ j$@tK0P  
package NetFox; `rFAZcEj%  
mP}#Ccji?  
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import java.io.*; =,/D/v$m'2  
import java.net.*; #$1$T  
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public class FileSplitterFetch extends Thread { Wk7WK` >i  
#G;X' BN  
q~Jq/E"f  
String sURL; //File URL SS3-+<z  
long nStartPos; //File Snippet Start Position fC<m^%*zgA  
long nEndPos; //File Snippet End Position z@h~Vb&I  
int nThreadID; //Thread's ID s3QEi^~
 
boolean bDownOver = false; //Downing is over "^rNr_  
boolean bStop = false; //Stop identical wyY*:{lZ  
FileAccessI fileAccessI = null; //File Access interface o'=VZT9  
_6LoVS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _j ;
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{ t&RruwN_;  
this.sURL = sURL; O!F]^'!  
this.nStartPos = nStart; *"9<TSU%m  
this.nEndPos = nEnd; _%pAlo_6  
nThreadID = id; 4<v;1   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 u<Xog$esu  
} H~fdbR  
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/L~m#HxWU  
public void run() hC<14  
{ H{zPft  
while(nStartPos < nEndPos && !bStop) :7b-$fm  
{ ;#QhQx  
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try{ *gqSWQ  
URL url = new URL(sURL); Pv){sYUh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j}WByaZ&  
httpConnection.setRequestProperty("User-Agent","NetFox"); h4`9Cfrq,  
String sProperty = "bytes="+nStartPos+"-"; tYe:z:7l?<  
httpConnection.setRequestProperty("RANGE",sProperty); kW-81  
Utility.log(sProperty); FC>d_=V  
#gv4  
{NQoS"  
InputStream input = httpConnection.getInputStream(); 49h0^;xlo:  
//logResponseHead(httpConnection); ef
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byte[] b = new byte[1024]; lOerrP6f(  
int nRead; bhg}-dto  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2{o10eL  
{ zhsx&  
nStartPos += fileAccessI.write(b,0,nRead); `deYi2z  
//if(nThreadID == 1) R]L2(' B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); []p"3i  
} a6nlt?1?D  
5Pke8K  
32>x^>G=>  
Utility.log("Thread " + nThreadID + " is over!"); _l&ucA
 
bDownOver = true; `wO}H
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//nPos = fileAccessI.write (b,0,nRead); 9([6d.`~  
} v59nw]'  
catch(Exception e){e.printStackTrace ();} ZKdh%8C  
} Sb"2Im>  
} |*\C{
b  
'}{?AUDx  
u-><}OVf~  
//打印回应的头信息 TOT PzB  
public void logResponseHead(HttpURLConnection con) S/Oxr%H  
{ ~@9zil41  
for(int i=1;;i++) >FFVY{F  
{ %$9bce-fcG  
String header=con.getHeaderFieldKey(i); <DmTj$  
if(header!=null) J r*"V`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <G
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Utility.log(header+" : "+con.getHeaderField(header)); JAP(|  
else jD9lz-Y@  
break; uxDLDA$;  
} a$}6:E  
} #PAU'u 3{/  
i21QJ6jPcI  
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public void splitterStop() Yj8&  
{ dY'Y5Th~  
bStop = true; JvJ;bFXD  
} Q[_Ni15  
J/kH%_ >Ir  
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} ^k72{ 3N(  
'
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c@OP5L>{  
/* A,<@m2  
**FileAccess.java ^H=o3#P~L  
*//文件访问(定位，写) hyu}}0:  
package NetFox; _*`q(dYcf  
import java.io.*; >q9{  
JDhwN<0R  
j|4tiv>  
public class FileAccessI implements Serializable{ |- OHve4A  
Xj,j0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 
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RandomAccessFile oSavedFile; yq6LH  
long nPos; ETelbj;0  
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n\>.T[$"  
public FileAccessI() throws IOException shK&2Noan  
{ \=g!$  
this("",0); %ck`0JZAP  
} wAz,vq=x  
78w4IICk  
-\,VGudM}  
public FileAccessI(String sName,long nPos) throws IOException gKQ@!UU8  
{ +]L)>$6  
oSavedFile = new RandomAccessFile(sName,"rw"); Pd],}/ZG-  
this.nPos = nPos; 9::YR;NY  
oSavedFile.seek(nPos); VjTAN=  
} Cyf]`*  
3@HIpQM3  
Pz {Ig  
public synchronized int write(byte[] b,int nStart,int nLen) n/-N;'2J  
{ {6tx,;r(F  
int n = -1; R=8
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try{ <P
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oSavedFile.write(b,nStart,nLen); Y_lCcu#O
A  
n = nLen; Wa/geQE1<  
} mxhW|}_-j  
catch(IOException e) yu_g
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{ +/_!P;I  
e.printStackTrace (); 4Q&mC"  
} opnkmM&[  
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,O9`X6rh'  
return n; UP*yeT,P,  
} u[J7Y  
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} P.1Qc)m4  
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/* f>4+,@G  
**SiteInfoBean.java L]NYYP-  
*/
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package NetFox; gQCC>8  
C=EhY+5  
8fEAY
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public class SiteInfoBean { c0hdLl;5  
JrxP,[qJG  
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private String sSiteURL; //Site's URL 1W7 iip,  
private String sFilePath; //Saved File's Path 6(sfpK'  
private String sFileName; //Saved File's Name ugRV5bUk  
private int nSplitter; //Count of Splited Downloading File  l58l  
[$H( CH`
 
M'vXyb%$1  
public SiteInfoBean() LA
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{//nSplitter的缺省值为5 A1 b6Zt  
//default value of nSplitter is 5 X)Ocn`
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this("","","",5); ~Gwas0eNa  
} rcW#6VZ=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B~e7w 4  
{ U(8I
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sSiteURL= sURL; Wd1 IX^7C%  
sFilePath = sPath; L1:}bH\y  
sFileName = sName;  *X0K2|  
this.nSplitter = nSpiltter; %Ln?dF+  
d`<#}-nh  
2/UI>@By  
} P@-R5GK  

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public String getSSiteURL() ,at-ci\'  
{ <"{+  
return sSiteURL; 5auL<Pq  
} }]Qmt5'NI  
>DkN+S  
~c9vdK  
public void setSSiteURL(String value) E^'C"6  
{ ^JiaR)#r  
sSiteURL = value; ByC1I.B`  
} WJBW:2=;  
(#C
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public String getSFilePath() 6Lav.x\W  
{ )3+xsnv  
return sFilePath; m]  EDuW  
} {lTR/  
H,/~=d: ^  
/{49I,  
public void setSFilePath(String value) e=YO.HT  
{ gE-lM/w  
sFilePath = value; {Nzmb|&  
} mJ7`.  
/0X0#+kn  

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public String getSFileName() 5Q2T
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{ <7@mg/T  
return sFileName; x Q@&W
;  
} p]X!g  
4Q&Xb <  
g%Th_=qy  
public void setSFileName(String value) qT&S  
{ kJVM3F%  
sFileName = value; zlC^  
} la!1[VeL  
0W!VV=j<}  
VGkW3Nt0  
public int getNSplitter() Xd90n>4S  
{ l;"ub^AH  
return nSplitter; >MBn2(\B;  
}
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7H/!rx  
rHA/  
public void setNSplitter(int nCount) v3iDh8.__  
{ (UbR%A|v;  
nSplitter = nCount; Q-H=wJ4R  
} ./aZ

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} Q;{D8 #!  
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:8p2Jxm  
/* 5)/4)0  
**Utility.java c"oQ/x  
*/ ]l9,t5Y  
package NetFox; s\F EA"w/  
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bw<~R2[  
public class Utility { LRfFn^FPM  
/It.>1~2@  
FE^?U%:u@  
public Utility() D0,o
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{ }bj,&c  
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} &kmd<  
>TH-Q[  
//线程睡眠 c +"O\j'  
public static void sleep(int nSecond) {VrAh*#h  
{ Vj9`[1}1Z  
try{ ~7eUt^SD;  
Thread.sleep(nSecond); qHcY 2LV  
} q?gQ  
catch(Exception e) J~nJpUyP*  
{ $! fz~  
e.printStackTrace (); AVdd?Ew  
} r5X BcG(2  
} c@"i?  
X(0:zb,#G*  
//日志 h}c6+@w&-  
public static void log(String sMsg) @$N*lrM2  
{
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System.err.println(sMsg); V2<k0@y  
} 0t/z"  
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PN)TX~}  
public static void log(int sMsg) 4w3V!K8  
{ ]h`E4B  
System.err.println(sMsg); Z_hBd['!  
} 2#Q"@  
} l[!C-Tq  
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FSXKH{Z  
/* &p(*i@Ms  
**TestMethod.java qH}62DP3  
*/ R`<{W(J;r  
package NetFox; Fg}5V,  
FB^dp}  
{0m[:af&  
public class TestMethod { E<fwl1<88  
n"Z,-./m  
?\/dfK:!  
public TestMethod() ^b/q|(Nu&  
{ ///xx/weblogic60b2_win.exe V!
aC#^  
try{ VG*=)8{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [fJFH^&?hr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lqf#,J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 83O^e&Bt  
fileFetch.start(); hPCSLJ  
} #,|_d>p:  
catch(Exception e){e.printStackTrace ();} O(WMTa'%  
=kZwB*7  
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} P\G C8KV]  

q;He:vX  
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public static void main(String[] args) ~{]m8a/ `6  
{ 28ov+s~1+-  
new TestMethod(); V'BZ=.=  
} ^.$r1/U  
} @kg
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