http断点续传简单实现（java)

/* S " pI  
**SiteFileFetch.java it1/3y =]  
*/ {1~T]5  
package NetFox; usOx=^?=  
import java.io.*; [uR/M
 
import java.net.*; };S0 G!  
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public class SiteFileFetch extends Thread { kMxjS^fr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *Km7U-BG  
long[] nStartPos; //开始位置 w>979g  
long[] nEndPos; //结束位置 YV([2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8_Z/o5s  
long nFileLength; //文件长度 6E^~n  
boolean bFirst = true; //是否第一次取文件  `w<J25  
boolean bStop = false; //停止标志 ?+`xe{k  
File tmpFile; //文件下载的临时信息 \dkOK`)b  
DataOutputStream output; //输出到文件的输出流 Gi7RMql6Q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CAgaEJhX3  
public SiteFileFetch(SiteInfoBean bean) throws IOException kso*}u
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{ 8MZ$T3IM  
siteInfoBean = bean; (lWq[0^N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g}Qx`65:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4~|<`vqN  
if(tmpFile.exists ()) x-_vl 9P)  
{ cm@;*  
bFirst = false; %l$W*.j|;  
read_nPos(); 91d },Mq:  
} p;%<mUI  
else :
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{ "s_Z&  
nStartPos = new long[bean.getNSplitter()]; kGHC]Fb)  
nEndPos = new long[bean.getNSplitter()]; C-SLjJw  
} 5 9-!6;T  
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} P))^vUt~  
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public void run() w~+aW(2  
{ i_l+:/+G+  
//获得文件长度 M{KW@7j  
//分割文件 flnVYQe  
//实例FileSplitterFetch r@$ w*%  
//启动FileSplitterFetch线程 8cdsToF(e.  
//等待子线程返回 ][:rLs  
try{ ZkWL_ H)  
if(bFirst) 0I%: BT  
{ `ROG~0lN(  
nFileLength = getFileSize(); ]WL|~mG  
if(nFileLength == -1) h-XY4gq/  
{ I>n g`  
System.err.println("File Length is not known!"); &<1`O  
} F ?=9eISLJ  
else if(nFileLength == -2) BD*G1k_q  
{ $>w/
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System.err.println("File is not access!"); !j^&gRH  
} RKuqx:U  
else {
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{ >.DC!QV  
for(int i=0;i<nStartPos.length;i++) |wp,f%WK  
{ tT5pggml  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *g$i5!yM'  
} S; /. %
 
for(int i=0;i<nEndPos.length-1;i++) d3^7ag%  
{ aj8Rb&  
nEndPos = nStartPos[i+1]; wNDbHR  
} Ly #_?\bn  
nEndPos[nEndPos.length-1] = nFileLength; E1*QdCV2  
} nk@atK,38^  
} >^SEWZ_[  
9&  
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//启动子线程 4 I@p%g&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 92[a;a  
for(int i=0;i<nStartPos.length;i++) Oh; Jw
 
{ f[jNwb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8r:M*25  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HEY4$Lf(I  
nStartPos,nEndPos,i); |>1
hu1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;YH[G;aJ  
fileSplitterFetch.start(); A lwtmDa  
} ?F@%S3h.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f8n V=AQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {IM! Wb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kiUk4&1  
nEndPos = " + nFileLength); pIO4,VL;W  
// fileSplitterFetch[nPos.length-1].start(); T>d.#  
1FERmf? ?d  
(! KG)!  
//等待子线程结束 ;ojiJ?jU  
//int count = 0; Qvqqvk_tv  
//是否结束while循环 ` \ZqgX4  
boolean breakWhile = false;
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#kcSQ'  
while(!bStop) >k(MUmhX  
{ WUoOGbA `  
write_nPos(); &M[f&_"8Q  
Utility.sleep(500); Lp&k3?W  
breakWhile = true; !1Y&Y@ze  
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for(int i=0;i<nStartPos.length;i++) @WOM#Kc  
{ y8 E}2/  
if(!fileSplitterFetch.bDownOver) ?Rr2/W#F  
{ [EZYsOr.  
breakWhile = false; %&+59vq   
break; PLR0#).n  
} &|o$=Ad  
} 4IsG=7   
if(breakWhile) Fo|xzLm9*|  
break; w"zE_9I\  
=$^MQ\S0p  
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//count++; d8x%SQ!V  
//if(count>4) `8g7q 5  
// siteStop(); -_0?_Cb  
} 'Pd(\$ZY
 
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}iiHr|l3  
System.err.println("文件下载结束！"); 0kDBE3i#  
} R: Z_g!h  
catch(Exception e){e.printStackTrace ();} >fs2kha  
} i
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//获得文件长度 lj[,|[X7`  
public long getFileSize() gK1g]Tc@G  
{ ?dq#e9  
int nFileLength = -1; ?=On%bh  
try{ M]rO;^;6?  
URL url = new URL(siteInfoBean.getSSiteURL()); W`)<vGn=Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gPXa>C  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2U$"=:Cf  
j,-C{ K  
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int responseCode=httpConnection.getResponseCode(); }*wLEa  
if(responseCode>=400) {^ec(EsO#  
{ 3YL l;TP_  
processErrorCode(responseCode); l|"6yB |  
return -2; //-2 represent access is error [M+tB"_  
} F:g=i}7  
c:4P%({  
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String sHeader; E`;;&V q-  
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for(int i=1;;i++) [c&B|h=>  
{ v}(6 <wnnS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '\7G@g?UZ  
//Utility.log(in.readLine()); tY/vL^mi  
sHeader=httpConnection.getHeaderFieldKey(i); QWO]`q`|  
if(sHeader!=null) L^J-("e_  
{ 1,t)3;o$  
if(sHeader.equals("Content-Length")) _M5%V>HO  
{ YZwaD b
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J7$_VP  
break; /@oLe[Mz$  
} Ib`-pRU;  
} #bnb': f  
else `wz[='yM  
break; %V_-%/3Z  
} `N87h"  
} 5
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catch(IOException e){e.printStackTrace ();} MZ4c{@Tg  
catch(Exception e){e.printStackTrace ();} .2:\:H~3  

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Utility.log(nFileLength); p.K*UP  
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return nFileLength;
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} eVz#7vqv  
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l?
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//保存下载信息（文件指针位置） '-
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private void write_nPos() gX @`X  
{ QfpuZEUK  
try{ Hh[Tw&J4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fb]S-z(  
output.writeInt(nStartPos.length); tjnPyaJEl  
for(int i=0;i<nStartPos.length;i++) a:rX9-**  
{ %5'6Tj  
// output.writeLong(nPos); Fwg^(;bL  
output.writeLong(fileSplitterFetch.nStartPos); t'qL[
r%?  
output.writeLong(fileSplitterFetch.nEndPos); /BA{O&Ro^  
} al^!,ykc  
output.close(); +OaUP*\Dd  
} /pH(WHT+/H  
catch(IOException e){e.printStackTrace ();} +%*&.@z_  
catch(Exception e){e.printStackTrace ();} ODw`E9  
} Xq#Y*lKVD  
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//读取保存的下载信息（文件指针位置） M4f;/`w  
private void read_nPos()  #@.-B,]  
{ !X^Ce)1K  
try{ cNK)5- U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nhT(P`6  
int nCount = input.readInt(); ).412I  
nStartPos = new long[nCount]; )r6EW`$  
nEndPos = new long[nCount]; PRu&3BP  
for(int i=0;i<nStartPos.length;i++) |CD"*[j]  
{ z}4L=KR\v  
nStartPos = input.readLong(); wTq{sW&  
nEndPos = input.readLong(); n.6
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} iAn'aW\TF  
input.close(); D)b}f`  
} ,^s0</ve  
catch(IOException e){e.printStackTrace ();} _r Y,}\  
catch(Exception e){e.printStackTrace ();} ;@mRo`D`  
} Gs0H@  
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private void processErrorCode(int nErrorCode) \}*k)$
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{ - xm{&0e)  
System.err.println("Error Code : " + nErrorCode); dbdM"z4  
} W#F Q,+0)  
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//停止文件下载 ~W0(1# i  
public void siteStop() [j,txe?n  
{ #&.
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bStop = true; &p(0K4:  
for(int i=0;i<nStartPos.length;i++) vRQOs0F;  
fileSplitterFetch.splitterStop(); K|S:{9Q  
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}%!tT\8  
} ^V*-1r1  
} w|Cx>8P8@  
//负责部分文件的抓取 "?}uQ5f  
**FileSplitterFetch.java K!z
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*/ kQ>^->w  
package NetFox; w!^~<{Kz  
k;yw#Af8  
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import java.io.*; R3.*dqo$  
import java.net.*; `8_z!)  
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public class FileSplitterFetch extends Thread { \Q$
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String sURL; //File URL k\r(=cex6  
long nStartPos; //File Snippet Start Position <
Bg8,;  
long nEndPos; //File Snippet End Position ;T+pu>)  
int nThreadID; //Thread's ID QfjN"25_  
boolean bDownOver = false; //Downing is over $0A~uDbs  
boolean bStop = false; //Stop identical E;Y;r"  
FileAccessI fileAccessI = null; //File Access interface T? ,P*l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \6I+K"  
{ %b2oiKSBx?  
this.sURL = sURL; e( X|3h|  
this.nStartPos = nStart; LaMLv<)k  
this.nEndPos = nEnd; +_l^ #?o,  
nThreadID = id; 9nSWE W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wBk@F5\<
 
} }YhtUWz].  
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public void run() tAu4haa4;  
{ )~)*=u/  
while(nStartPos < nEndPos && !bStop) G[Lpe  
{ XMN:]!1J  
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try{ (oz$B0HO:  
URL url = new URL(sURL); 6X2PYJJZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uGU;Y'W)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y5q3T`xE  
String sProperty = "bytes="+nStartPos+"-"; SGc8^%-`  
httpConnection.setRequestProperty("RANGE",sProperty); Y.#:HRtg
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Utility.log(sProperty); p,g1eb|E  
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InputStream input = httpConnection.getInputStream(); 7Z,opc  
//logResponseHead(httpConnection); y@V_g'  
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byte[] b = new byte[1024]; ^ZD
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int nRead; n.oUVr=nX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @F*wg  
{ I751t  
nStartPos += fileAccessI.write(b,0,nRead); 9Z"+?bv/  
//if(nThreadID == 1) "Ml&[Oge  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ykg#{9+  
} bizTd  
#V02
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Utility.log("Thread " + nThreadID + " is over!"); `?(Bt|<>  
bDownOver = true; G2{O9  
//nPos = fileAccessI.write (b,0,nRead); SzDKByi  
} ?(6mVyIe  
catch(Exception e){e.printStackTrace ();} C#V ~Y  
} /Dtd#OAdr  
} MTGiAFE  
Ty(@+M~-  
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//打印回应的头信息 )jrT6x^IB  
public void logResponseHead(HttpURLConnection con) t+r:"bb  
{ V D?*h  
for(int i=1;;i++) Uh1NO&i.W  
{ ?']h%'Q  
String header=con.getHeaderFieldKey(i); /e}#' H   
if(header!=null) [k$*4u>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kUx&
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Utility.log(header+" : "+con.getHeaderField(header)); 3-Dt[0%{  
else w2O!M!1  
break; 98jN)Nl,oD  
} :p&!RI(l  
} W=B"Q qL  
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public void splitterStop() ,tH5e&=U01  
{ 6(|d|Si *c  
bStop = true; rx"s!y{!-  
} RR;AJ8wd  
`i +g{kE2M  
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} nz1'?_5  
)+")Sz3zx  
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/* m9}AG Rj  
**FileAccess.java ]j~"m
FAP  
*//文件访问(定位，写) y)c5u%(  
package NetFox; p}b/XnV$~  
import java.io.*; pg+[y<B  
wu9=N ^x  
 >YtdA  
public class FileAccessI implements Serializable{ $2DuB  
R #]jSiS  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )\;Z4x;]U  
RandomAccessFile oSavedFile; q*![AzFh  
long nPos; )QagS.L{z  
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public FileAccessI() throws IOException RyB~Lm`ZK%  
{ X;F?:Iw\  
this("",0); dUznxZB  
} V}o n|A  
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M~*u;v
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public FileAccessI(String sName,long nPos) throws IOException |IoB?^_h  
{ D0(xNhmKz  
oSavedFile = new RandomAccessFile(sName,"rw"); /"H`.LD.?  
this.nPos = nPos; w=h1pwY  
oSavedFile.seek(nPos); E@0
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} W>(/ bX  
./j,
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|wEN
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public synchronized int write(byte[] b,int nStart,int nLen) o'~5pS(wq  
{ ;|p$\26S)%  
int n = -1; g[>\4B9t  
try{ $N']TN  
oSavedFile.write(b,nStart,nLen); _qqr5NU  
n = nLen; F;lI+^}}  
} depYqYK7G  
catch(IOException e) <WXzh5D2  
{ +(D$9{y  
e.printStackTrace (); "1q>
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} $P7iRM]  
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return n; ;g_> ;tR/  
} G!8Z~CPF  
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} MC((M,3L  
b?4/#&z]  
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/* "
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**SiteInfoBean.java ]u-]'P  
*/ 9jp:k><\(c  
package NetFox; 3lLMu B+  
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public class SiteInfoBean { ]Fvm 7V  
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private String sSiteURL; //Site's URL Nfe>3uQK  
private String sFilePath; //Saved File's Path $I#q  
private String sFileName; //Saved File's Name 8;y&Pb~)  
private int nSplitter; //Count of Splited Downloading File rV({4cIe9R  
f\;65
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public SiteInfoBean() p_ Fy>j  
{//nSplitter的缺省值为5 ]Q "p\@\!  
//default value of nSplitter is 5 wi8Yl1p]!z  
this("","","",5); }~h'FHCC+  
} 6~#Ih)K  
HIGq%m=-x  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3'c\;1lhT  
{ M@P1,Y  
sSiteURL= sURL; gx03xPeu  
sFilePath = sPath; {:c]|^w6  
sFileName = sName; k+V6,V)my  
this.nSplitter = nSpiltter; FLoNE>q  
/!}'t  
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} 2#X4G~>#h  
n\I#CH0V  
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public String getSSiteURL() (qn2xrV  
{ ;v17K  
return sSiteURL; +6smsL~<#v  
} k"kJ_(  
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a"/#+=[  
public void setSSiteURL(String value) Y=Z1Tdxa|  
{ 'tN25$=V&W  
sSiteURL = value; iDl;!b&V.  
} AeIrr*~]B  
&)i|$J 2.  
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public String getSFilePath() sfr(/mp(  
{ n/QF2&X7)  
return sFilePath; RWgDD;&_[a  
} *xf._~E  
6b8;}],|  
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public void setSFilePath(String value) dk QaM@  
{ @4%L36k  
sFilePath = value; UL
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} x?x`oirh  
M >:]lpRK  
x\?;=@AW  
public String getSFileName() |o'Q62`%}  
{ KPSh#x&I  
return sFileName; oHM ]  
} $@\mpwANl  
rOW-0B+N  
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public void setSFileName(String value) l5Y/Ok0,  
{ nfb]VN~(  
sFileName = value; It_M@  
} L?_7bXoD
 
: FAH\  
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public int getNSplitter() /wQL  
{ ]DFXPV  
return nSplitter; U,/6;}  
} eLwTaW !C  
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public void setNSplitter(int nCount) * v8Ts  
{ Z'pQ^MO  
nSplitter = nCount; )oo~m\`  
} 3qHQX?a  
} h9$ Fx  
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/* GZ!|}$8  
**Utility.java 0,*%vG?Q  
*/ qP!eJ6[Nh"  
package NetFox; P ]N [y  
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public class Utility { 3>
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public Utility() 8pM>Co!  
{ L+B?~_*  
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} d lH$yub  
iK;dU2h  
//线程睡眠 +&tgJ07A  
public static void sleep(int nSecond) Q8p&
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{ U]qav
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try{ 78n=nHS  
Thread.sleep(nSecond); 2^~<("+w  
} (-
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catch(Exception e)  R7oj#  
{ x+? 9C  
e.printStackTrace (); 1rw0sAuGy  
} W]<$0  
} K.tlo^#^B[  
y<W8Q<9  
//日志 kI*(V[i  
public static void log(String sMsg) *VSel4;\t  
{ 3zuF{Q2P<  
System.err.println(sMsg); @e~]t}fH  
} 
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,O=a*%0rt  
public static void log(int sMsg) \8uo{#cL8  
{ KHKS$D  
System.err.println(sMsg); !=Y;h[J.p  
} ~Y=@$!Uq  
} XA0(f*  
0X..e$'  
3HG;!D~m;  
/* y-?>*fNo  
**TestMethod.java 2J;`m_oP  
*/ Kj=gm .  
package NetFox; mOll5O7VW  
fbrp#G71y  

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public class TestMethod { :(3|HTz  
lw8"'0  
(J$\-a7<f  
public TestMethod() z^* '@  
{ ///xx/weblogic60b2_win.exe <dA8 '7^  
try{ Eu@
5L9A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |YJCWFbs8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;S
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SiteFileFetch fileFetch = new SiteFileFetch(bean); >Dm8m[76  
fileFetch.start(); q)u2Y]  
} @b&84Gn2 r  
catch(Exception e){e.printStackTrace ();} 78#!Q.#
#  
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# jYpVc{]  
} !Gs} tiMH  

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public static void main(String[] args) R U"/2i  
{ V|Tud  
new TestMethod(); ]*"s\ix  
} XY7Qa!>7j  
} Ar9nBJ`  
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