http断点续传简单实现（java)

/* S-npJh 6  
**SiteFileFetch.java ]&qujH^Dd*  
*/ 'AE)&56  
package NetFox; r@H<@Vuc  
import java.io.*; ITRv^IlF  
import java.net.*; iQZgs@  
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public class SiteFileFetch extends Thread { ,Zb]3  
*;(
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+%=Ao6/#  
SiteInfoBean siteInfoBean = null; //文件信息Bean hJ>{`Tw  
long[] nStartPos; //开始位置 L=Fm:O'#2  
long[] nEndPos; //结束位置 # h]m8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h2zuPgz,  
long nFileLength; //文件长度 ,g#=pdX;  
boolean bFirst = true; //是否第一次取文件 =E8lpN'  
boolean bStop = false; //停止标志 g9H~\w  
File tmpFile; //文件下载的临时信息 vdYd~>w  
DataOutputStream output; //输出到文件的输出流 {%'(IJ|5z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B8'" ^a^&-  
public SiteFileFetch(SiteInfoBean bean) throws IOException i))S%!/r~  
{ MZB0vdx  
siteInfoBean = bean; f[HhLAVGK`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }L{en  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z"u4t.KpL  
if(tmpFile.exists ()) mZDrvTI'  
{ [7ZFxr\:!  
bFirst = false; =GTltFqI1  
read_nPos(); GNA:|x  
} Rgw\qOb  
else gXZ.je)NM  
{ d%
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nStartPos = new long[bean.getNSplitter()]; wLPL9  
nEndPos = new long[bean.getNSplitter()]; [iwn"e  
} [bIdhG  
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} :seo0w]  
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public void run() {j+w|;dZF  
{ Gmi4ffIb3  
//获得文件长度 ``)ys^V  
//分割文件 j8$
*$|  
//实例FileSplitterFetch 3<1Uq3Pa  
//启动FileSplitterFetch线程 w-2p'u['Z  
//等待子线程返回 n
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try{ Y'&A~/Adf  
if(bFirst) z*.
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{ #Sr_PEo _  
nFileLength = getFileSize(); -LJbx<'  
if(nFileLength == -1) I#zrz3WU  
{ %kS+n_*  
System.err.println("File Length is not known!"); U,yU-8z/  
} $(H%|Oyn  
else if(nFileLength == -2)
}
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{ ^I@1y}xi  
System.err.println("File is not access!"); mVg-z~44T  
} <LIL{g0eX  
else UJ1iXV[h"  
{ hW
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for(int i=0;i<nStartPos.length;i++) V~tq _  
{ DnS# cs~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); aB;syl{  
} ,o& &d.  
for(int i=0;i<nEndPos.length-1;i++) ^&MMtWR  
{  $J>GCY  
nEndPos = nStartPos[i+1]; acz8 H0cS  
} o;.PZi2k  
nEndPos[nEndPos.length-1] = nFileLength; d>*?C!xE  
} dFFJw[$8w  
} nR-`;lrF~  
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MU4/arXy  
//启动子线程 (|I:
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (ec?_N0=  
for(int i=0;i<nStartPos.length;i++) o_p#sdt"  
{ SH2|xn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r t@Jw]az  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fpJM)HU  
nStartPos,nEndPos,i); vyP3]+n
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w>>)3:Ytd  
fileSplitterFetch.start(); ml<X92Y  
} ,4zwd@&O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3`S|I_$(T"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?F1NZA[%t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G.OAzA13!t  
nEndPos = " + nFileLength); D]S@U>]M!  
// fileSplitterFetch[nPos.length-1].start(); 3JVENn9  
T&c0j(  
/L\
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//等待子线程结束 #;sUAR?]  
//int count = 0; D0Yl?LU3  
//是否结束while循环 ^AkVmsv;;  
boolean breakWhile = false; 0)`{]&  
DvCs 5  
#5-5N5-1  
while(!bStop) u@tJu'X  
{ YjN2 ,Xi  
write_nPos(); ! /;@kXN
 
Utility.sleep(500); Fk@A;22N  
breakWhile = true; i_Dv+^&zV  
/. GHR  
v!n\A}^:  
for(int i=0;i<nStartPos.length;i++) d0$dQg  
{ 23 j{bK  
if(!fileSplitterFetch.bDownOver) ~N2){0j4  
{ j&6'sg;n)  
breakWhile = false; 2`hc0 IE  
break; C` ?6`$Y  
} 86NAa6BW  
} k~Qb"6n2  
if(breakWhile) 7\m.xWX e  
break; sVtxh
]  
kY*3)KCp  
,S5tkTa  
//count++; z/6/   
//if(count>4) {U1 j@pKm  
// siteStop(); >Y=HP&A<  
} ~SgW+sDFu  
l!CWE  
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System.err.println("文件下载结束！"); 6X2>zUHR  
} gDE',)3Q,  
catch(Exception e){e.printStackTrace ();} _Mq0QQ42  
} W`_pjld  
vH/z|<  
:9un6A9JS  
//获得文件长度 =67dpQ'y  
public long getFileSize() |g<
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{ 5$Lo]H*  
int nFileLength = -1; M\O6~UFq!  
try{ Tap=K|b ]  
URL url = new URL(siteInfoBean.getSSiteURL()); g /D@/AU1u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VP[
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httpConnection.setRequestProperty("User-Agent","NetFox"); XDs )  
;AMbo`YK[  
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int responseCode=httpConnection.getResponseCode(); q}gj.@Q"  
if(responseCode>=400) MDn+K#
p  
{ {* S8n09v  
processErrorCode(responseCode); vFz%#zk>  
return -2; //-2 represent access is error e=K2]Y Q{  
} V\Oe]w  
^%l~

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0!X;C!v;  
String sHeader; Y2709LWmP  
i bAZ*I  
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for(int i=1;;i++) ;d$PQi  
{ *fyC@fI>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vJ5`:4n"  
//Utility.log(in.readLine()); +p6cG\Gp  
sHeader=httpConnection.getHeaderFieldKey(i); (qd$wv^h  
if(sHeader!=null) NX7(;02  
{ w{uqy]  
if(sHeader.equals("Content-Length")) \l!^6G|c  
{ W:D'k^u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^9*FYV  
break; EWuuNf  
} *V+6409m  
} _/;k;$gDp  
else :Awnj!KNCc  
break; Vj?{T(K1[  
} YT7,=k_  
} E^uau=F  
catch(IOException e){e.printStackTrace ();} '}\{4Qst  
catch(Exception e){e.printStackTrace ();} "q@OMf  
lrSdFJ%  
{TT@Mkz_QC  
Utility.log(nFileLength); 6&/H XqP  
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b]S4\BBT  
return nFileLength;  .b] 32Ww  
} W+k`^A|@  
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w5*?P4P  
//保存下载信息（文件指针位置） me]O  
private void write_nPos() ghvF%-."1  
{ KV1zx(WI  
try{ }G^Bc4@b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0CXh|AU  
output.writeInt(nStartPos.length); X
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for(int i=0;i<nStartPos.length;i++) L~e\uP  
{ 2q}M1-^  
// output.writeLong(nPos); &_X6m0z  
output.writeLong(fileSplitterFetch.nStartPos); |lH~nU.*  
output.writeLong(fileSplitterFetch.nEndPos); 9^l[d<  
} &t)dE7u
5  
output.close(); c\GJfsVk  
} K07SbL7g!p  
catch(IOException e){e.printStackTrace ();} VYw vT0  
catch(Exception e){e.printStackTrace ();} ERxA79  
} ZUGuV@&-T  
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6GVj13Nr  
//读取保存的下载信息（文件指针位置） Gy{C*m7Q  
private void read_nPos() qc^u%  
{ {2kw*^,l  
try{ .#n1p:}[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0{|ib !  
int nCount = input.readInt(); ?^iX%   
nStartPos = new long[nCount]; z9mmZqhK\  
nEndPos = new long[nCount]; gs;3NW  
for(int i=0;i<nStartPos.length;i++) (lv|-Phc.  
{ RFF&-M]  
nStartPos = input.readLong(); Jp)>Wd  
nEndPos = input.readLong(); n]&/?6}  
} GRpS^%8i@  
input.close(); F@Bh>Vb  
} d;(&_;  
catch(IOException e){e.printStackTrace ();} O+Z[bis`  
catch(Exception e){e.printStackTrace ();} h
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} U" eP>HHp  
(QQ/I;  
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private void processErrorCode(int nErrorCode) EoLF7j<W  
{ }\5^$[p  
System.err.println("Error Code : " + nErrorCode); vn;_|NeSf  
} F 7+Gt Ed  
@}@`lv65}  
p"^^9'`=  
//停止文件下载 R03V+t=  
public void siteStop() Bv
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{ >o{(f  
bStop = true; F5Ce:+h  
for(int i=0;i<nStartPos.length;i++) YpQ/ )fSEV  
fileSplitterFetch.splitterStop(); zjd
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+gb2>fei&  
} l'YpSO~l7  
} @W3fKF9*R  
//负责部分文件的抓取 MsOO''o  
**FileSplitterFetch.java Ko%&~C_  
*/ T xRa&1  
package NetFox; Alh"G6  
b6=.6?H@4f  
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import java.io.*; IQ$l!)  
import java.net.*; xQs2)  
2%g)0[1  
Te?UQX7Z}M  
public class FileSplitterFetch extends Thread { b;\qF&T  
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@ ?y(\>  
String sURL; //File URL 6L@g]f|Y@  
long nStartPos; //File Snippet Start Position =!3G,qV  
long nEndPos; //File Snippet End Position r.M8#YL  
int nThreadID; //Thread's ID {UT>> *C  
boolean bDownOver = false; //Downing is over p1t9s N,  
boolean bStop = false; //Stop identical "El$Sat`  
FileAccessI fileAccessI = null; //File Access interface +=I_3Wtth  
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u  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C`OdMM>D  
{ TL@_m^SM  
this.sURL = sURL; K1RTAFf /  
this.nStartPos = nStart; 2!/*I:  
this.nEndPos = nEnd; SZJ~ktXC-V  
nThreadID = id; Y<Y5HI"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \XwXs5"G  
} rly3f  
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public void run() a
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{ !!f)w!wW  
while(nStartPos < nEndPos && !bStop) @;x|+@r  
{ ,c_[`q\  
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try{ J'tc5Ip!}V  
URL url = new URL(sURL); A"`62  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h$|K vS  
httpConnection.setRequestProperty("User-Agent","NetFox"); xin<.)!E  
String sProperty = "bytes="+nStartPos+"-"; (A`/3Aq+  
httpConnection.setRequestProperty("RANGE",sProperty); 4A0R07"  
Utility.log(sProperty); e#L/  
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InputStream input = httpConnection.getInputStream(); 0[}"b(O{  
//logResponseHead(httpConnection); Md'd=Y_0  
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byte[] b = new byte[1024]; ch,<4E/c[R  
int nRead; c:"*MM RC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l){l*~5zl2  
{ 7~TE=t  
nStartPos += fileAccessI.write(b,0,nRead); t6_6Bl:  
//if(nThreadID == 1) ?1}1uJMj-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j['Z|Am"l  
} pgT{#[=>  
&!JX  
{6'5K U*RH  
Utility.log("Thread " + nThreadID + " is over!"); 2Xk(3J!!'a  
bDownOver = true; F>&Q5Kl R  
//nPos = fileAccessI.write (b,0,nRead); Oa\!5Pw1  
} KZeRbq2jJ  
catch(Exception e){e.printStackTrace ();} \p1H" A  
} 20;M
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} DIodQkF  
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//打印回应的头信息 0iqa]Am  
public void logResponseHead(HttpURLConnection con) G\tTwX4  
{ 
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for(int i=1;;i++) "?lirOD  
{ yi%A*q~MT  
String header=con.getHeaderFieldKey(i); #B:J7&@fn  
if(header!=null) K^?yD   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bmna*!l^M  
Utility.log(header+" : "+con.getHeaderField(header)); V| z|H$-  
else 3JEH sYxs  
break; ya{vR* '~  
} MzYTEe&-L  
} K$(&Qx}  
3WS`,}  
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public void splitterStop() sLzcTGa2:z  
{ z^I"{eT8  
bStop = true; Qpiv,n  
} wcP0PfY  
~ C6<75  
9+h9]
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} ]oP2T:A  
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/* VkhZt7]K}B  
**FileAccess.java u*{hXR-"  
*//文件访问(定位，写) <M=U @  
package NetFox; cH'*J/  
import java.io.*; F%bv vw*(  
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public class FileAccessI implements Serializable{ d /&aC#'B  
u-Ct-0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vlIet$k  
RandomAccessFile oSavedFile; rX%#Q\
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long nPos; Qbfm*JP~  
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public FileAccessI() throws IOException ~-lIOQ.v  
{ *RUB`tEL  
this("",0); ?2OT:/I,  
} ##BMh!  
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qqQnL[`)C  
public FileAccessI(String sName,long nPos) throws IOException FyJI@PZdI-  
{ Mkko1T=6  
oSavedFile = new RandomAccessFile(sName,"rw"); !(F+~,  
this.nPos = nPos; UP 1Y3  
oSavedFile.seek(nPos); W"AWhi{h  
} 2:MB u5**  
3X*;.'#Z  
f( hK>H  
public synchronized int write(byte[] b,int nStart,int nLen) jii2gtu'U  
{ X_+`7yCi"x  
int n = -1; .\X/o!xC  
try{ BqP:]  
oSavedFile.write(b,nStart,nLen); Hx2UDHF  
n = nLen; ;#78`x2  
} < Upn~tH  
catch(IOException e) Q{b ZD*  
{ f[.RAHjk  
e.printStackTrace (); pZ+zm6\$  
} %>Z=#1h/a  
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return n; {z|0Y&>[=  
} 2W|4
 
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} s2_j@k?%  
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5|NM]8^^0[  
/* l Vo](#W  
**SiteInfoBean.java ]o$Kh$~5  
*/ FT/H~|Z>  
package NetFox; Dd<gYPC  
idvEE
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public class SiteInfoBean { b.47KJzt  
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private String sSiteURL; //Site's URL 4o9#B:N]J  
private String sFilePath; //Saved File's Path hz<kR@k}  
private String sFileName; //Saved File's Name hUSr1jlA  
private int nSplitter; //Count of Splited Downloading File eT[,k[#q  
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dE_BV=H{  
public SiteInfoBean() ~e{Ag
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{//nSplitter的缺省值为5 .Di+G-#aEs  
//default value of nSplitter is 5 RR{]^g51  
this("","","",5); '`T.K<  
} 
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^TVy:5Ag  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 50rCW)[#  
{ '|':W6m,  
sSiteURL= sURL; YTL [z:k}  
sFilePath = sPath; I"#jSazk  
sFileName = sName; [X
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this.nSplitter = nSpiltter; =+T{!+|6P  
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} ,(N&%  
(03m%\  
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public String getSSiteURL() !ceuljd]  
{ LDBxw  
return sSiteURL; [ 8N1tZ{`  
} "}*P9-%  
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?CAP8_  
public void setSSiteURL(String value) Jh{(xGA  
{ ^TVica  
sSiteURL = value; #E5Sc\,  
} x@m"[u  
;Y?7|G97*S  
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public String getSFilePath() R)Wv
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{ %N|7<n<S  
return sFilePath; }%| (G[  
} yb*SD!  
7 '2E-#^  
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public void setSFilePath(String value) Mto3Ryic!  
{ W>wIcUP<<  
sFilePath = value; %LXk9K^]e  
} t&mw@bj  
(=CV")tF  
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public String getSFileName() llhJ,wD  
{ (
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return sFileName; 6NZ3(   
} [ k^6#TQcn  
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 8yOzD  
public void setSFileName(String value) /jC0[%~jV  
{ kFHqQsaG  
sFileName = value; /e|`mu%  
} 1FjA  
]r$S{<  
N
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public int getNSplitter() w)&]k#r  
{ |D$U{5}Mv  
return nSplitter; ZUQ1\Iw  
} ~ I]kY%  
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_;
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public void setNSplitter(int nCount) 7{D+\i  
{ o83HR[
 
nSplitter = nCount; i'L7t!f}o  
}  M)Yu^  
} 5L42'gJ  
W
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|m"2B]"@  
/* =NSLx2:T  
**Utility.java ?%JH4I2  
*/ qK:
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package NetFox; Um9!<G=;  
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public class Utility { r1}OlVbK  
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public Utility() {p9y{$  
{ #8R\J[9  
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} BpDf4
)|  
k^C;"awh  
//线程睡眠 .',ikez  
public static void sleep(int nSecond) Fng":28o  
{ 4L^KR_h/  
try{ bV@53_)N2  
Thread.sleep(nSecond); ,`P,))  
} X z2IAiAs'  
catch(Exception e) 6}L[7~1  
{ +C/K@:p  
e.printStackTrace (); _t:rWC"X  
} ^gw_Up<e6  
} >LgV[D#=&o  
UI<'T3b  
//日志 hs2f
3;)  
public static void log(String sMsg) (vz)GrH>  
{ d7It}7@9  
System.err.println(sMsg); W2%(a0p  
} VpWax]'  
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[9z<*@$-  
public static void log(int sMsg)  _"%d9B  
{ ^KF  
System.err.println(sMsg); Nq9Qsia&  
} |I^\|5  
} I =qd\  
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R|$=Pfg~4  
/*
}&y>g0$@  
**TestMethod.java Z:,HB]&;9  
*/ >P>.j+o/  
package NetFox; (
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9V.)=*0hp  
k#JFDw\  
public class TestMethod { S?OK
@UEJ  
mXz-#Go(  
$Fc*^8$ryC  
public TestMethod() 42Gr0+Mb  
{ ///xx/weblogic60b2_win.exe ? RB~%^c!  
try{ ]B3 0d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MZ=U} &F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }UXj|SY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _UjAct]6  
fileFetch.start(); u<!!%C~+=  
} <C+:hsS=  
catch(Exception e){e.printStackTrace ();} {8@?9Z9R{  
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udp&U+L  
} un W{ZfEC  
p tv  
6:-qL}  
public static void main(String[] args) @r+ErFI  
{ P6i4Dr  
new TestMethod(); GQ2&D}zh  
} PLFM[t/  
} j:) (`  
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