http断点续传简单实现（java)

/* '%rn-|)  
**SiteFileFetch.java Dr(;A>?qG  
*/ Ra^c5hP:.E  
package NetFox; CPY|rV  
import java.io.*;
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import java.net.*; 2$2@?]|?  
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public class SiteFileFetch extends Thread { f{\[+>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean UIZ9"Da  
long[] nStartPos; //开始位置 .%\||1F<  
long[] nEndPos; //结束位置 46|LIc }  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X)c0y3hk  
long nFileLength; //文件长度 -:Juxh  
boolean bFirst = true; //是否第一次取文件 9`@}KnvB?  
boolean bStop = false; //停止标志 @)z?i  
File tmpFile; //文件下载的临时信息 e;"%h%'  
DataOutputStream output; //输出到文件的输出流 )IIWXN2A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _?bF;R  
public SiteFileFetch(SiteInfoBean bean) throws IOException EU Oa8Z  
{ YW8Odm  
siteInfoBean = bean;
8)b*q\O'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n2["Ln mO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Np.<&`p!  
if(tmpFile.exists ()) =~dXP  
{ K8QEHc:  
bFirst = false; g`"_+x'  
read_nPos(); M{Vi4ehOq  
} 3XUsw1,[  
else 9IacZ  
{ uw`J5TND  
nStartPos = new long[bean.getNSplitter()]; 1vq
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nEndPos = new long[bean.getNSplitter()]; w'mn O'%  
} 78]( ZYJV  
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} #,!/Cnqis  
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public void run() H~0B5Hl!F  
{ t-]~^s  
//获得文件长度 xp\6,Jyh  
//分割文件 h<!!r  
//实例FileSplitterFetch Dkg-y9  
//启动FileSplitterFetch线程 CzmB76zy.  
//等待子线程返回 Z22#lF\N  
try{ 
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if(bFirst) iTCY $)J  
{ P Qi=  
nFileLength = getFileSize(); o'YK\L!p  
if(nFileLength == -1) quq!Jswn  
{ 8ROZ]Xh,x  
System.err.println("File Length is not known!"); th{Ib@o  
} r#6djs1  
else if(nFileLength == -2) 4X>=UO``L  
{ LcHe5Bv%  
System.err.println("File is not access!"); Wr4Ob*2iD  
} 8J2UUVA`1  
else /86PqKU(P  
{ h]o{> |d9  
for(int i=0;i<nStartPos.length;i++) ^VjF W  
{ sz4;hSTy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >T^BD'z@'  
} O[9A}g2~  
for(int i=0;i<nEndPos.length-1;i++) ,sp((SF]1  
{ qa?0GTAS  
nEndPos = nStartPos[i+1]; V24FzQ?z:.  
} f!cYLU1e@  
nEndPos[nEndPos.length-1] = nFileLength; TF@k{_f  
} _Oc\hW  
} su~J:~q  
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mnq1WU;<  
//启动子线程 __-V_(/b,x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !L@a;L  
for(int i=0;i<nStartPos.length;i++) *1U"uJno  
{ D<bHRtP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C4eQ.ep  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /nNrvMtv  
nStartPos,nEndPos,i); 0?'v|5}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /f!ze|  
fileSplitterFetch.start(); L:UPS&)  
} Pbakw81!~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K5\;'.9M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /)XN^Jwa;m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2nB{oF-Z  
nEndPos = " + nFileLength); ?T8^tGD[  
// fileSplitterFetch[nPos.length-1].start(); -1]8f  
U#(#U0s*-  
%I%OHs  
//等待子线程结束 \7*"M y*  
//int count = 0; $HFimU,V=0  
//是否结束while循环 0JV|wd8j  
boolean breakWhile = false; 7)l+hZ  

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while(!bStop) b3+F~G-I"  
{ A04E <nr  
write_nPos(); PO]c&}/  
Utility.sleep(500);
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breakWhile = true; *|3G"B{w6  
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for(int i=0;i<nStartPos.length;i++) [^\HP]*Q{  
{ _4X3g%nXl  
if(!fileSplitterFetch.bDownOver) I8  
{ E:$r" oS  
breakWhile = false; OF1Qr bj  
break; j>|mpfU  
} ^ZDpG2(zk  
} QlH,-]N$L  
if(breakWhile) <U2Un 0T  
break; HD8*>p.  
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//count++; 7\EY&KI"0  
//if(count>4) i
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// siteStop(); m4'x>Z  
} #PA 9bM  
7;Vqr$9)  
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System.err.println("文件下载结束！"); rLI);!^-  
} }+GIrEDId  
catch(Exception e){e.printStackTrace ();} n]v,cfn/=<  
} *ZV=4[#bT  
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]Jx_bs
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//获得文件长度 =g$>]AE  
public long getFileSize() }/.GB5Ej  
{ [>LL  
int nFileLength = -1; sx@%3j  
try{ FYX"q-Z  
URL url = new URL(siteInfoBean.getSSiteURL()); c"`CvQO64  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _|s'0F/t  
httpConnection.setRequestProperty("User-Agent","NetFox"); 75*q^ui  
;Zw? tU  
h7o?z!  
int responseCode=httpConnection.getResponseCode(); .%x%(olf  
if(responseCode>=400) V-w{~  
{ Y]:Ch (Q  
processErrorCode(responseCode); |&AZ95v   
return -2; //-2 represent access is error 9"b =W@  
} 9{XV=a v  
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String sHeader; :a'[4w  
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for(int i=1;;i++) +`'>  
{ >4]y)df5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [^eQGv[S  
//Utility.log(in.readLine()); T6I$7F  
sHeader=httpConnection.getHeaderFieldKey(i); raB',Vp  
if(sHeader!=null) +`l)W`zX  
{ 2HF_kYZ  
if(sHeader.equals("Content-Length")) t-VU&.Y  
{ whh#J (  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @Avve8S  
break; d3tr9B  
} @$!rgLyL[  
} sJ5Ws%q  
else J6RzN'j  
break; ,^uQw/  
} Q> J9M`a  
} }C<$q  
catch(IOException e){e.printStackTrace ();} 9UE)4*5  
catch(Exception e){e.printStackTrace ();} 7~m[:Eg6[s  
v)%0`%nSR  
tDn:B$*}W,  
Utility.log(nFileLength); 1Y(NxC0P=g  
4)NbQ[  
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return nFileLength; S)=3%toS>  
} VrnZrQj<  
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#-8%g{  
//保存下载信息（文件指针位置） nIf~ds&TT  
private void write_nPos() cE+Y#jB  
{ qcGsx2  
try{ -DL"Yw}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); dd:vQOF;  
output.writeInt(nStartPos.length); ZXC_kmBN/  
for(int i=0;i<nStartPos.length;i++) k
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{ n'qWS/0U=  
// output.writeLong(nPos); BKk+<#Ti  
output.writeLong(fileSplitterFetch.nStartPos); vX<^x2~9(  
output.writeLong(fileSplitterFetch.nEndPos); ^:Fj+d  
} F-%Hw  
output.close(); -SUK[<=X  
} aXh~w<5F  
catch(IOException e){e.printStackTrace ();} )8*}-z  
catch(Exception e){e.printStackTrace ();} \"1%>O*  
} @cu#rWiG  
\/F*JPhy  
AfvIzsT0  
//读取保存的下载信息（文件指针位置） \%|%C  
private void read_nPos() sMgRpem;  
{ O 4'/C]B2  
try{ ky@ZEp=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =[nuesP'  
int nCount = input.readInt(); 8'#L+$O &N  
nStartPos = new long[nCount]; ErxvGB
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nEndPos = new long[nCount];  EHk$,bM  
for(int i=0;i<nStartPos.length;i++) 2"IDz01ne  
{ Q)2i{\GPVn  
nStartPos = input.readLong(); =buarxk  
nEndPos = input.readLong(); #MUY!  
} #T++5G  
input.close(); K8RV=3MBLD  
} l-$5CO  
catch(IOException e){e.printStackTrace ();} U<I
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catch(Exception e){e.printStackTrace ();} t 09-y  
} ?.^n,[2  
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private void processErrorCode(int nErrorCode) :pvB}RYD  
{ =d#(n M*  
System.err.println("Error Code : " + nErrorCode); [,sm]/Xlc  
} jr/IU=u*v  
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//停止文件下载 1xjWD30  
public void siteStop() z-_$P)[c  
{ ~Z' /b|x<3  
bStop = true; </!GU*  
for(int i=0;i<nStartPos.length;i++) E?
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fileSplitterFetch.splitterStop(); ^j7>Ul,  
*JF7
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} pU1miA '  
} ;e6L@)dp9  
//负责部分文件的抓取 >!
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**FileSplitterFetch.java 'Lh nl3  
*/ 6'Q*SO;1gh  
package NetFox; lQ&J2H<
w  
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import java.io.*; c!N#nt_<  
import java.net.*; 7n]ukqZ  
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public class FileSplitterFetch extends Thread { z&y
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String sURL; //File URL |f1RhB  
long nStartPos; //File Snippet Start Position i?861Hu  
long nEndPos; //File Snippet End Position Ffig0K+`  
int nThreadID; //Thread's ID (L`IL e*  
boolean bDownOver = false; //Downing is over UJ><B"  
boolean bStop = false; //Stop identical -ufaV#  
FileAccessI fileAccessI = null; //File Access interface 'LYN{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M[P1hFuna  
{ .rQcg.8/B  
this.sURL = sURL; N?IdaVLj  
this.nStartPos = nStart; }Z)YK}_1  
this.nEndPos = nEnd; Q w)U  
nThreadID = id; w5=<}1`St  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )JY#8,{w  
} d2fiPI7lg  
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public void run() q);oO\<  
{ 0{/
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while(nStartPos < nEndPos && !bStop) WO$8j2!~#  
{ F`>qg2wO  
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= u&dU'@q  
try{ f9t+x+ Z  
URL url = new URL(sURL); I#;.;%u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3gYtu-1  
httpConnection.setRequestProperty("User-Agent","NetFox"); <?h(Dchq  
String sProperty = "bytes="+nStartPos+"-"; ~:*V'/2k  
httpConnection.setRequestProperty("RANGE",sProperty); #vc!SI  
Utility.log(sProperty); MzF,is  
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InputStream input = httpConnection.getInputStream(); F^&@[k7WW  
//logResponseHead(httpConnection); DABV}@K"  
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byte[] b = new byte[1024]; i!eY"|o  
int nRead; / 2MhP=
,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) WBR# Ux  
{ "n{JH9sA:  
nStartPos += fileAccessI.write(b,0,nRead); l!": s:/'  
//if(nThreadID == 1) bl{W{?QI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }!"Cvu  
} (
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#)s +I2  
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Utility.log("Thread " + nThreadID + " is over!"); 8! /ue.T  
bDownOver = true; Zzmo7kFx3  
//nPos = fileAccessI.write (b,0,nRead); 7!;zkou  
} V P(JV  
catch(Exception e){e.printStackTrace ();} 7Kpv fyL{  
} 2InM(p7j~K  
} u+c2 m  
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Mm!;+bM%  
//打印回应的头信息 op3a*KG  
public void logResponseHead(HttpURLConnection con) uQKo2B0  
{ QcX&q%*0  
for(int i=1;;i++) wbI1~/  
{ AmJdZs|/  
String header=con.getHeaderFieldKey(i); J+wnrGoK  
if(header!=null) `l %,4qR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {REGoe=W%  
Utility.log(header+" : "+con.getHeaderField(header)); >h.HW  
else rr>6;  
break; K5z<n0X ~  
} OTNI@jQ)  
} _Ud!tK*H  
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public void splitterStop() w|NId,#f  
{ 0QyL}y2  
bStop = true; *;Cpz[N  
} 3J8M0W  
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} 2`A[<S  
RL H!f1cta  
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/* Fl*<N  
**FileAccess.java nWhf  
*//文件访问(定位，写) hZWkw{c  
package NetFox; eU.C<Tv:8  
import java.io.*; 2B
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}}bMq.Q'  
=J]M#6N0  
public class FileAccessI implements Serializable{ 9W-1P}e,  
8"p rWAN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |:,`dQfw  
RandomAccessFile oSavedFile; /lhk} y^  
long nPos; 4J?\JcGs  
/2MZ
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public FileAccessI() throws IOException tY:,9eh7B  
{ _xBhMu2f  
this("",0); Aj
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} LBmXy8'T`  
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public FileAccessI(String sName,long nPos) throws IOException KTwP.!<v  
{ GkI{7GD:z  
oSavedFile = new RandomAccessFile(sName,"rw"); s3'kzwX  
this.nPos = nPos; Fc=6*.hy  
oSavedFile.seek(nPos); :^`Wrc
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}
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4,?beA  
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public synchronized int write(byte[] b,int nStart,int nLen) Bwu?DK  
{ IkxoW:L  
int n = -1; `$FB[Z} &  
try{ DghqSL^s  
oSavedFile.write(b,nStart,nLen); =NSunW!  
n = nLen; d(Hqj#`-31  
} 0f
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catch(IOException e) (:h&c6'S)b  
{ =W>a~e]/  
e.printStackTrace (); <fA}_BH%]  
} ltMcEv-d0  
= uepg@J  
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return n; if3z Fh  
} B\l0kiNT  
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} U??OiKVZ+  
`:jF%3ks+0  
THB[(3q  
/* zU!d(ge.E  
**SiteInfoBean.java 7!)VOD8Z  
*/ PYzTKjw  
package NetFox; cr?ZXu
_  
[xQ.qZ[h&  
9[lk=1.qN  
public class SiteInfoBean { pbIVj3-lY  
&>R:oYN  
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private String sSiteURL; //Site's URL 7|"$YV'DM  
private String sFilePath; //Saved File's Path JbMp /  
private String sFileName; //Saved File's Name 8Qj1%Ri:U  
private int nSplitter; //Count of Splited Downloading File )@!T_#  
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public SiteInfoBean() }mI0D>n  
{//nSplitter的缺省值为5 >6IUle>z  
//default value of nSplitter is 5 51*[Ibx  
this("","","",5); t2|0no  
} /ge
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O
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AJ3Byb=.  
{ cIK4sOTJ&  
sSiteURL= sURL; _1WA:7$C  
sFilePath = sPath; .Yz^r?3t  
sFileName = sName; /zr)9LQY0  
this.nSplitter = nSpiltter; _a_T`fE&de  
;ZMIYFXRqh  
P{Q$(rOe  
} *i!t&s  
1u(n[<WtT_  
{Z Ld_VGW  
public String getSSiteURL() Hw62'%  
{ k![H;}W  
return sSiteURL; Z|)1ftcC  
} {~G~=sC$  
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l-x-
 
public void setSSiteURL(String value) |CQ0{1R1  
{ ]86*k%A  
sSiteURL = value; H\a\xCP3  
} :)kHXOb.  
_::ssnG3jT  
@hrIu"
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public String getSFilePath() ikb77?.  
{ \((5Sd  
return sFilePath; B@ msGb C  
} tCA0H\';  
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public void setSFilePath(String value) }([}A`@  
{ BWB}bq  
sFilePath = value; %c%`<y<~L  
} ZCM
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8@RJ>  
LvZ',u}  
public String getSFileName() $@L2zl1  
{ WMWUP ZsGS  
return sFileName; fvV"H{V,  
} >;VZB/d  
Y^;izM}  
/s+S\ djk  
public void setSFileName(String value) -"^xg"  
{ xVN!w\0  
sFileName = value; 3Wx\Liw,  
} C@<gCMj,"  
6Ypc]ym=J  
] ;CJ6gM~  
public int getNSplitter() <
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{ koE]\B2A6  
return nSplitter; d>Nh<PqH6  
} >+>N/`BG  
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m`]d`%Ex  
public void setNSplitter(int nCount) o02G:!gB  
{ mAJ'>^`^  
nSplitter = nCount; Kb1@+  
} r:4]:NKCi  
} YD{N)v  
?{5}3abB`  
X|QokAR{$>  
/* WT3g31  
**Utility.java X\i;j!;d  
*/ S/RChg_L5  
package NetFox; (Jk[%_b>_  
JZE@W-2  
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public class Utility { ;18u02z^  
/Ei e5p  
|2rOV&@l9  
public Utility() v"o@q2f_  
{ 3preBs#i  
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} ]&`
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]mgpd}Y  
//线程睡眠 ASr@5uFR  
public static void sleep(int nSecond) AN|f:259  
{ %L wq.  
try{ 'op_GW  
Thread.sleep(nSecond); ]<c\+9  
} V7O7"Q^q  
catch(Exception e) :Gx5vo  
{ W/~q%\M {  
e.printStackTrace (); )UVekkq>Q  
} i->G{_gH  
} !@y/{~Gu  
#^$_3AY  
//日志 F2EX7Crj  
public static void log(String sMsg) ?32i
1F!  
{ >J)4e~9EJ2  
System.err.println(sMsg); 'iDkAmvD  
} U\-.u3/  
z^WY5~?  
_#{qDG=  
public static void log(int sMsg) XdOntP*a  
{ WW!-,d{{@  
System.err.println(sMsg); DZEq(>mn  
} 
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} % I2JS  
gFfKK`)}D'  
\ Z5160  
/* peOoZdJd  
**TestMethod.java 5P 5Tgk  
*/ cR*~JwC:  
package NetFox; q9a6s{,  
sOS^  
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public class TestMethod { &FYv4J  
`~41>mM%  
&!M6{O=~  
public TestMethod() Rtl1eJ-  
{ ///xx/weblogic60b2_win.exe JeA_mtSQ|  
try{ K]|hkp&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bqx2lQf,_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); raU_Z[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "QD>:G;u  
fileFetch.start(); S;%k?O7v  
} Z5EII[=$o  
catch(Exception e){e.printStackTrace ();} T1x67 b u  
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} bT|-G2g7Z  
vGI)c&C>  
=wD&hDn4  
public static void main(String[] args) kXlI*h  
{ \|M[W~
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new TestMethod(); z3>4 xn{  
} ap
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} Pj{I}4P`  
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