http断点续传简单实现（java)

/* ))K3pKyb  
**SiteFileFetch.java j[.R|I|  
*/ >MauuL,.j  
package NetFox; 4'cdV0]  
import java.io.*; t"cGv32b  
import java.net.*; PeEC|&x  
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public class SiteFileFetch extends Thread { ogtKj"a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +ng8!k  
long[] nStartPos; //开始位置 {r?O>KDQf(  
long[] nEndPos; //结束位置 jSsbLa@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :,h47'0A  
long nFileLength; //文件长度 C4H M  
boolean bFirst = true; //是否第一次取文件 y)0r%=  
boolean bStop = false; //停止标志 vUk <z*  
File tmpFile; //文件下载的临时信息 5A g4o  
DataOutputStream output; //输出到文件的输出流 7q&Ru|T33  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zYvf}L&]h  
public SiteFileFetch(SiteInfoBean bean) throws IOException Uf}s6#  
{ U3}r.9/  
siteInfoBean = bean; u]lf~EE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R4.$9_ui  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OlL FuVR  
if(tmpFile.exists ()) ,B_Nz}\8  
{ hX#y7m  
bFirst = false; 66NJ&ac  
read_nPos(); Q=}p P*  
} 5 ?~ ?8Hi  
else d9^ uEz(  
{ -aK_
  
nStartPos = new long[bean.getNSplitter()]; ^oDCF  
nEndPos = new long[bean.getNSplitter()]; 'H+H4(  
} h;?=:(  
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} 9#Gz2u$  
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public void run() scZdDbL6+  
{ 4iMo&E<  
//获得文件长度 \Ld/'Z;w  
//分割文件 CT(VV6I\  
//实例FileSplitterFetch SEu1M}+E  
//启动FileSplitterFetch线程 \X1?,gV_  
//等待子线程返回 7VQ|3`!<  
try{ Sqw:U|h\FS  
if(bFirst) 2Hl0besm  
{ I-<U u2  
nFileLength = getFileSize(); T
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if(nFileLength == -1) :)hS-*P  
{ +0)s{?  
System.err.println("File Length is not known!"); \ t4:(Jp 3  
} Z3X/SQ'0  
else if(nFileLength == -2) y;aZMT.YI  
{ ,kS3Ioj  
System.err.println("File is not access!"); M+4>l\  
} fl%X>\i/7  
else "O@L IR7
 
{ o,}`4_N||  
for(int i=0;i<nStartPos.length;i++) ,v(K|P@  
{ Awy-kou[C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pD;'uEFBQ  
} AT*J '37  
for(int i=0;i<nEndPos.length-1;i++) 7L2$(
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{ |&!04~s;E  
nEndPos = nStartPos[i+1]; 0*G =~:  
} *q**,_?;  
nEndPos[nEndPos.length-1] = nFileLength; |e49F  
} u By[x 0  
} \[u7y. b  
cXP*?N4Cf  
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//启动子线程 {6}H}_(]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \o}m]v i  
for(int i=0;i<nStartPos.length;i++) Z{&dzc  
{ vw(X9xa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,c }R*\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )*6]m1  
nStartPos,nEndPos,i); od\-o:bS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a;@
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fileSplitterFetch.start(); 7tbM~+<0  
} ]rk8Jsg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y*ux7KO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C(/{53G(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m+&)eQ:  
nEndPos = " + nFileLength); ~\HGV+S!g}  
// fileSplitterFetch[nPos.length-1].start(); N_<wiwI<  
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//等待子线程结束 m][i-|@M  
//int count = 0; o!bIaeEaU  
//是否结束while循环 _4~'K?  
boolean breakWhile = false; Js{X33^Ju  
KYe@2 6   
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while(!bStop) Z]VmTB  
{ m3Ma2jLWC  
write_nPos(); !mX-g]4E  
Utility.sleep(500); 2GRL`.1  
breakWhile = true; uUy~
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for(int i=0;i<nStartPos.length;i++) ,e]|[,r#5  
{ uKOs
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if(!fileSplitterFetch.bDownOver) \Z~|ry0v{d  
{ Tw`n3y?  
breakWhile = false; G%Dhj)2}  
break; W.67};',  
} QY)hMo=|o8  
} PRTn~!Z0  
if(breakWhile) ePD~SO9*  
break; '+8`3['  
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<,:p?36  
//count++; "CH3\O\  
//if(count>4) u(kacQ7  
// siteStop(); ',>Pz+XKc  
} jPum2U_  
J]m[0g7O_  
],.1=iY  
System.err.println("文件下载结束！"); DAvF ND$=  
} ()cqax4  
catch(Exception e){e.printStackTrace ();} ON()2@Y4  
} gjbSB6[  
vZ0K1UTEXY  
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//获得文件长度 m@
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public long getFileSize() 8l<4OgoK  
{ 4nvi7  
int nFileLength = -1; %]U'   
try{ 
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URL url = new URL(siteInfoBean.getSSiteURL()); /);S?7u.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SO!|wag$  
httpConnection.setRequestProperty("User-Agent","NetFox"); "bhF`,V  
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int responseCode=httpConnection.getResponseCode(); 8x,{rSqq  
if(responseCode>=400) _
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{ agI"Kh]j?  
processErrorCode(responseCode); j o+-  
return -2; //-2 represent access is error 655OL)|cD6  
} IH2V.>h  
#?^%#"~4H  
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String sHeader; GE S_|[Q  
4lCEzWo[/  
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for(int i=1;;i++) :"im2J  
{ He1hgJ)N  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); VMZUJ2Yj/&  
//Utility.log(in.readLine()); <meQ  
sHeader=httpConnection.getHeaderFieldKey(i); p#QR^|7"  
if(sHeader!=null) X"sc'#G T  
{ B)v|A  
if(sHeader.equals("Content-Length")) `<oNEr+#  
{ CW+]Jv]"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ow3t2G  
break; K5"8zF)*  
} &;x*uG  
} kWZ@v+Mk3  
else o1k X`Eu  
break; #s}&  
} :svKE.7{  
} l.iT+T  
catch(IOException e){e.printStackTrace ();} Md5|
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catch(Exception e){e.printStackTrace ();} n)bbEXO  
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Utility.log(nFileLength); <Na .6P  
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return nFileLength; g^mnYg5
 
} SJai<>k h  
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//保存下载信息（文件指针位置） JjC& io  
private void write_nPos() J=`2{ 'l  
{ Rk$  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); tbm/gOBw  
output.writeInt(nStartPos.length); +N>z|T<  
for(int i=0;i<nStartPos.length;i++) *~%QXNn`  
{ :|z.F+-/
 
// output.writeLong(nPos); =cwdl7N&I  
output.writeLong(fileSplitterFetch.nStartPos); ]fdxpqz  
output.writeLong(fileSplitterFetch.nEndPos); 25H=RTw  
} CU+H`-+"J  
output.close(); 86f8b{_e"  
} %8hx3N8>  
catch(IOException e){e.printStackTrace ();} PJn|  
catch(Exception e){e.printStackTrace ();} eelkK,4  
} c`agrS:P  
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//读取保存的下载信息（文件指针位置） twr-+rm2  
private void read_nPos() |e+r|i]  
{ 0/4"Jh$t  
try{ "">{8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i[O{M`Z%  
int nCount = input.readInt(); Wi"3kps q  
nStartPos = new long[nCount]; {+CBThC  
nEndPos = new long[nCount]; *a2-
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for(int i=0;i<nStartPos.length;i++) k+%c8w 9  
{ FE4P EBXvu  
nStartPos = input.readLong(); g}gOAN3.  
nEndPos = input.readLong(); ? \p,s-CR:  
} 6BY(Y(z  
input.close(); #J`MR05  
} @;b @O _  
catch(IOException e){e.printStackTrace ();} 9l
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catch(Exception e){e.printStackTrace ();} A2p]BW&  
} ?C`&*+
 
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private void processErrorCode(int nErrorCode) s)-O{5;U  
{ pkEx.R)  
System.err.println("Error Code : " + nErrorCode); Y$<p_X,  
} pzFM#  
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8k9q@FSln  
//停止文件下载 4OTrMT$y  
public void siteStop() <6STw  
{ 4sM9~zC5  
bStop = true; %uQOAe55  
for(int i=0;i<nStartPos.length;i++) (4Ha'uqz  
fileSplitterFetch.splitterStop(); .:9XpKbt  
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} +&*Ybbhb  
} D^<5gRK?  
//负责部分文件的抓取 I/k/5  
**FileSplitterFetch.java |
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*/ myqQq
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package NetFox; v:zKn[;o  
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^"GDaM
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import java.io.*; Rxl/)H[Lc"  
import java.net.*; 6vr8rJ-  
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public class FileSplitterFetch extends Thread { 3hPp1wZd  
K0^Tg+U($p  
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String sURL; //File URL f=kt0  
long nStartPos; //File Snippet Start Position 
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long nEndPos; //File Snippet End Position P,*yuF|bk  
int nThreadID; //Thread's ID [{-5  
boolean bDownOver = false; //Downing is over wCw_aXqq  
boolean bStop = false; //Stop identical ^<`uyY))Q  
FileAccessI fileAccessI = null; //File Access interface 5]F4.sa  
HzZ.q2Zz%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >goG\y  
{ 9ohO-t$XkY  
this.sURL = sURL; ot; ]?M  
this.nStartPos = nStart; %h4|$  
this.nEndPos = nEnd; D22jWm2  
nThreadID = id; UYkuz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U`kO<ztk  
} gI{56Z  
Sp./*h\}  
"Ax#x  
public void run() p.RSH$]  
{ wY{!gQ  
while(nStartPos < nEndPos && !bStop) 6>F1!Q  
{ .,
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try{ <hB~|a<#  
URL url = new URL(sURL); G`R_kg9$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l
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httpConnection.setRequestProperty("User-Agent","NetFox"); 3}x6IM2  
String sProperty = "bytes="+nStartPos+"-"; $&KiN82,  
httpConnection.setRequestProperty("RANGE",sProperty); M <ccfU!  
Utility.log(sProperty); >gZ"^iW  
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InputStream input = httpConnection.getInputStream(); 4mwLlYZ  
//logResponseHead(httpConnection); }cd-BW  
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byte[] b = new byte[1024]; 4\iy{1{E,C  
int nRead; tr$d?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n{E9p3
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{ (Z#j^}G_
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nStartPos += fileAccessI.write(b,0,nRead); Hr!%L*h?  
//if(nThreadID == 1) 5Tiap8x+<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0khAi|PY  
} drd5oZ  
uYMH5Om+i  
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Utility.log("Thread " + nThreadID + " is over!"); =fcRH:B:  
bDownOver = true; 1pZ[rM'}  
//nPos = fileAccessI.write (b,0,nRead); qd@Fb*  
} Bt(U,nFB  
catch(Exception e){e.printStackTrace ();} (/gMtIw  
} )g[7XB/w  
} (F'?c1  
6;p"xC-  
*#c^.4$'  
//打印回应的头信息 M(#]NTr ~4  
public void logResponseHead(HttpURLConnection con) x4[ Fn3JL  
{ (k24j*1e$  
for(int i=1;;i++) &n9srs  
{ {IT;g9x  
String header=con.getHeaderFieldKey(i); 31{)~8  
if(header!=null) C)|#z/"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iuHs.k<z  
Utility.log(header+" : "+con.getHeaderField(header)); ?jHu,  
else v.{I^=  
break;
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} f\c%G=y  
} b_GAK  
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public void splitterStop() dZ"d`M>o6  
{ W0s3nio  
bStop = true; p^U#1c  
} aT}?-CUxx  
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{z*`* O@  
} 8Lh[>|~=  
-< }#ImTN  
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/* #}aBRKZf6  
**FileAccess.java ^_XV}&7Q  
*//文件访问(定位，写) QI{<q<  
package NetFox; 28=L9q   
import java.io.*; >|_B=<!99W  
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h f9yK6  
public class FileAccessI implements Serializable{ m"tke'a  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f<l.%B  
RandomAccessFile oSavedFile; (m&''yaH  
long nPos; :my@Oxx4@  
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public FileAccessI() throws IOException A]AM|2
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{ &T[BS;  
this("",0); $Y<(~E
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} T(iL#2^  
TDY =!  
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public FileAccessI(String sName,long nPos) throws IOException +8|r_z\A5a  
{ I oFtfb[  
oSavedFile = new RandomAccessFile(sName,"rw"); hnnPi  
this.nPos = nPos; brClYpp,h  
oSavedFile.seek(nPos); +e( (!  
} }I ^e:,{  
H`Ld,E2ex&  
r:9H>4m  
public synchronized int write(byte[] b,int nStart,int nLen) Wkc^?0p  
{ VO+3@d:  
int n = -1; hSfLNvK  
try{ C^!ej"  
oSavedFile.write(b,nStart,nLen); 0/0rWqg /  
n = nLen; 4Vrx9 sA1  
} kH>^3(Q\  
catch(IOException e) +d/^0^(D\5  
{ \X0wr%I  
e.printStackTrace (); kG|pM54:^  
} oLz9mqp2%  
}*R.>jQ+Y  
;+4X<)y*>  
return n; ?KtvXTy{m  
} {#J1D*?
$"  
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} aIABx!83>  
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/* 4Q FX  
**SiteInfoBean.java %QKRl5RM-  
*/ *r]Mn~3  
package NetFox; Ax"I$6n>  
t4CI+fqy  
rkC6-9V  
public class SiteInfoBean { P g1EE"N@  
1[r;  
{qkd63X  
private String sSiteURL; //Site's URL o
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private String sFilePath; //Saved File's Path Dt8wd,B  
private String sFileName; //Saved File's Name HRZ3}8Qj  
private int nSplitter; //Count of Splited Downloading File I\peO/w  
|? l6S
 
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public SiteInfoBean() _I}rQfPJ  
{//nSplitter的缺省值为5 xtP=/B/  
//default value of nSplitter is 5 5Pu
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this("","","",5); )
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} t(F] -[  
4*aNdh[t.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8ncgTCH:  
{ %l8nTcL_?  
sSiteURL= sURL; $>mTPNF  
sFilePath = sPath; 8GD!]t#  
sFileName = sName; ]VS$ ?wD  
this.nSplitter = nSpiltter; =\l7k<  
; 
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} Uv"GG: K_  
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public String getSSiteURL() N}2xt)JZz  
{ Fl^}tC  
return sSiteURL; Y8yRQzu  
} !.ot&EbE
 
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public void setSSiteURL(String value) dQ
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{ &]2z)&a  
sSiteURL = value; 4SqZV  
} e!(0y)*  
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=7c1l77z  
public String getSFilePath() : *Nvy={c  
{ hA81(JWG  
return sFilePath; r&|-6OQZZ  
} VIxt;yE  
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?"no~(EB  
public void setSFilePath(String value) @Pc]qu  
{ l&d 6G0  
sFilePath = value; g(0 |p6R  
} O}!L;?  
=*YK6  
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public String getSFileName() KR6*)?c`  
{ YJ`[$0mam  
return sFileName; wxg`[c$:  
} LyB$~wZx~@  
&!{wbm@  
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public void setSFileName(String value) PIuk]&L^  
{ 1;l&ck-Gg/  
sFileName = value; ZL`G<Mo;.  
} ul e]eRAG  
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Ha\q}~_  
public int getNSplitter() {q1&4U~'>O  
{ S4]xxc  
return nSplitter; u|=G#y;3  
} eYurg6Ob~  
)CzWq}:  
{37DrSOa  
public void setNSplitter(int nCount) S< <xlW  
{  8IH&=3  
nSplitter = nCount; gkuI!=  
} Mc9P(5Bf
  
} <)zh2UI  
B
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y  
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/* S#X$QD  
**Utility.java 2oAPJUPOJ  
*/ l|ZwZix
 
package NetFox; cK>5!2b  
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7;C9V`  
public class Utility { <v"C`cga  
Wx&AY"J  
8kih81tx"U  
public Utility() qphN  
{ I~qS6#%r  
Fz16m7.  
8=7u,t  
} ,LXuU8sB  
&tKs t,UR8  
//线程睡眠 <}%>a@  
public static void sleep(int nSecond) ^6+P&MxM  
{ MjG=6.J|`  
try{ Y$EqBN  
Thread.sleep(nSecond); RC8{QgaI  
} 2|o6~m<pE  
catch(Exception e) A==P?,RG  
{ >#R<*?*D}  
e.printStackTrace (); qqSk*oH~  
} T IPb ]  
} uG3t%CmN  
A0M)*9 f  
//日志 g!7/iKj:  
public static void log(String sMsg) DT(A~U<y  
{ v|jBRKU99  
System.err.println(sMsg); E`>-+~ZUsk  
} O!sZMGF$p  
]?^m;~MQZ  
(]>c8;o#b  
public static void log(int sMsg) q:-8W[_
 
{ $qy%Q]  
System.err.println(sMsg); [S":~3^B6  
} >E?626*  
} )KR9alf3  
!5 %c`4  
_p7c<$;  
/* p[&'*
"o!/  
**TestMethod.java GS~jNZx  
*/ %Md;=,a:6  
package NetFox; Cdiu*#f  
m$A|Sx&sG$  
?D\6CsNp(2  
public class TestMethod { VbK| VON[  
}MrRsvN  
S'V0c%'QQV  
public TestMethod() 8:-[wl/@  
{ ///xx/weblogic60b2_win.exe J}KATpHs  
try{ w*Sl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?`,UW;Br6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A;w,m{9<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'HkV_d[li  
fileFetch.start(); eUVE8pZl  
} F)lDK.  
catch(Exception e){e.printStackTrace ();} rjQV;kX>  
&~G>pvZ  
\x)T_]Gcm  
} 3Zdkf]Gh  
>va#PFHA  
lW?}jzuo  
public static void main(String[] args) &iL"=\#  
{  {Rjj  
new TestMethod(); s{KwO+UW  
} 6I72;e^!  
} ,S:LhgSP  
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