http断点续传简单实现（java)

/* (>dL  
**SiteFileFetch.java q\Z9.T+Qo  
*/ =HMuAUa.  
package NetFox; YW"nPZNPy~  
import java.io.*; nDNK}O~'  
import java.net.*; 'f6!a5qC  
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public class SiteFileFetch extends Thread { <O{G&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8,:lw3x1  
long[] nStartPos; //开始位置 Gn<e&|4>i}  
long[] nEndPos; //结束位置 pzU:AUW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'JAe=K H  
long nFileLength; //文件长度 l#]+I YD  
boolean bFirst = true; //是否第一次取文件 pH0MVu(W  
boolean bStop = false; //停止标志 v&`n}lS  
File tmpFile; //文件下载的临时信息 ^{-Z3Yxd  
DataOutputStream output; //输出到文件的输出流 s$/Z+"f(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +^a@U^V  
public SiteFileFetch(SiteInfoBean bean) throws IOException MU1T="N^+  
{ `[tYe<  
siteInfoBean = bean; QtOT'<2t]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RG-,<G`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ST\d-x  
if(tmpFile.exists ()) T"E%;'(cp)  
{ 3.%jet1  
bFirst = false; PH!rWR  
read_nPos(); C0L(ti;  
} yI's=Iu`  
else l+?sR<e?!  
{ 6Q`7>l.|?  
nStartPos = new long[bean.getNSplitter()]; 9A}n
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nEndPos = new long[bean.getNSplitter()]; 83Fmu/(  
} d^`n/"Ice  
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} !XY}\zKq  
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public void run() jDW$}^ 6  
{ {!"lHM%  
//获得文件长度 $"Nqto~  
//分割文件 S#|5&SR  
//实例FileSplitterFetch {|tMN,Z  
//启动FileSplitterFetch线程 $HV`bJ5!L*  
//等待子线程返回 U?ZxQj66}  
try{ `e5f69"  
if(bFirst) ^2mCF  
{ hle@= e/n  
nFileLength = getFileSize(); %UCu
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if(nFileLength == -1) Fw6x (j"  
{ pbqJtBBDDS  
System.err.println("File Length is not known!"); do@BJWo  
} @FuX^Q.[  
else if(nFileLength == -2) _?9|,  
{ +4K'KpFzZ  
System.err.println("File is not access!"); %X(|Z4dL  
} 5Veybchy "  
else {^Q1b.=  
{ >8DZj&j  
for(int i=0;i<nStartPos.length;i++) AHTQF#U^  
{ 200Fd8Ju  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0EUC8Ni  
} '>UQsAvm  
for(int i=0;i<nEndPos.length-1;i++) PL
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{ Yn-;+ 4 K  
nEndPos = nStartPos[i+1]; @.
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} fMZc_dsW9  
nEndPos[nEndPos.length-1] = nFileLength; g=kuM  
} L(3} H,t  
} 9jrlB0  
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-[>G@m:?e  
//启动子线程 5i&+.?(Z=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WSV% Oy3V  
for(int i=0;i<nStartPos.length;i++) ~`VD}{[,B  
{ =%d0MZD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W sDFui  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YXTd^M~@D  
nStartPos,nEndPos,i); [f-<M@id/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >^d+;~Q;  
fileSplitterFetch.start(); $lAhKpdlW  
} (\$=+' hy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F0+@FS0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bOdyrynh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %hb!1I  
nEndPos = " + nFileLength); RhumNP<M  
// fileSplitterFetch[nPos.length-1].start(); Ec|5'Kz]  
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//等待子线程结束 ?L6ACi`9  
//int count = 0; R>`TV(W`9  
//是否结束while循环 r!O4]j_3  
boolean breakWhile = false; ;O *o  
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|  
while(!bStop) !\N|$-M  
{ mX QVL.P\  
write_nPos(); iCZ1
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Utility.sleep(500); W8s/"  
breakWhile = true; h%(0|  
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for(int i=0;i<nStartPos.length;i++) Ed&M  
{ ;p2a .P  
if(!fileSplitterFetch.bDownOver) 4Awl  
{ j{;IiVHnR  
breakWhile = false; /? HLEX  
break; ryoD 1OE  
} e=EM07z  
} L9(!L$  
if(breakWhile) NW@guhK.  
break; .eM A*C~n  
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//count++; BJ7m3[lz  
//if(count>4) &&{_T4  
// siteStop(); [[9XqD]  
} ao.v]6a  
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System.err.println("文件下载结束！"); P*sb@y>}O  
} <bxp/#6D  
catch(Exception e){e.printStackTrace ();} +UC-  
} A]"IQ-  
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//获得文件长度 @mrGG F  
public long getFileSize() LzJNQd'  
{ 9<S
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int nFileLength = -1; :p,DAt}  
try{ Zp*0%x!e  
URL url = new URL(siteInfoBean.getSSiteURL()); F B7.b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7Yd]#K{$  
httpConnection.setRequestProperty("User-Agent","NetFox"); {pW(@4U  
/ qo`vk A  
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int responseCode=httpConnection.getResponseCode(); # ~T KC|G  
if(responseCode>=400) k->cqtG  
{ 4m
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processErrorCode(responseCode); p(]o#$ 6[  
return -2; //-2 represent access is error 
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} ia}V8i  
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String sHeader; {QRrAi  
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for(int i=1;;i++) p6e9mSs  
{ U:o(%dk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L=."<,\  
//Utility.log(in.readLine()); $*[-kIy  
sHeader=httpConnection.getHeaderFieldKey(i); bp?4)C*R  
if(sHeader!=null) 7*&$-Hv  
{ #GT4/Ej}W  
if(sHeader.equals("Content-Length")) -v7O*xm"  
{ {]CO;5:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EzDQoN7Em  
break; V[N4 {c  
} V}UYr Va#9  
} l
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else />\6_kT  
break; K<Qy1y~[  
} >*aqYNft  
} 9F^rXY.  
catch(IOException e){e.printStackTrace ();} El)Wj
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catch(Exception e){e.printStackTrace ();} G*lkVQ6?  
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Utility.log(nFileLength); NN;'QiE  
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return nFileLength; ZhpbbS  
}
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l /\n7:  
//保存下载信息（文件指针位置） M;Dk$B{;R  
private void write_nPos() HQOz  
{ /Sag_[i  
try{ bAa+MB#A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^E3i]Oem  
output.writeInt(nStartPos.length); Y]R;>E5o|  
for(int i=0;i<nStartPos.length;i++) 3l8k O  
{ :>'4@{'  
// output.writeLong(nPos); n!K<g.tjW  
output.writeLong(fileSplitterFetch.nStartPos); {v>orP?  
output.writeLong(fileSplitterFetch.nEndPos); D7"RZF\)  
} YzD6S*wb  
output.close(); {KO+t7'Q  
} PLmf.hD\  
catch(IOException e){e.printStackTrace ();} v!
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catch(Exception e){e.printStackTrace ();} Q7b$j\;I  
} &7CAxU;i3  
5,<:|/r  
$ }D9)&f;  
//读取保存的下载信息（文件指针位置） yxt`  
private void read_nPos() CkJ\v%JAW  
{ c<gvUVHIxR  
try{ _PR><L_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OAhCW*B  
int nCount = input.readInt(); C3p/|{TP  
nStartPos = new long[nCount]; .%rB-vO:g  
nEndPos = new long[nCount]; ,:e##g~k  
for(int i=0;i<nStartPos.length;i++) If*t$f>y4N  
{ LgX"Qk&Ca  
nStartPos = input.readLong(); ^Q'^9M2)  
nEndPos = input.readLong(); A=5A8B1  
} jK{)gO  
input.close(); iEJY[P1  
} (3>Z NTm  
catch(IOException e){e.printStackTrace ();} OYsG#  
catch(Exception e){e.printStackTrace ();} v)a$;P%  
} 2Xt$KF,?  
;ESuj'*t  
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private void processErrorCode(int nErrorCode) U%~L
){<V[  
{ [N-t6Z*  
System.err.println("Error Code : " + nErrorCode); e(NpX_8  
} )K0BH q7r  
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//停止文件下载 -%*w&',G  
public void siteStop() 0DFxVH_xN  
{ C/w!Y)nB=  
bStop = true; Xt!%W   
for(int i=0;i<nStartPos.length;i++) $O/@bh1@p  
fileSplitterFetch.splitterStop(); %;Dp~T`0  
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} dsh S+d  
} ]^63n/Twj  
//负责部分文件的抓取 2sOV3~bB  
**FileSplitterFetch.java V>`xTQG  
*/ vl'2O7  
package NetFox; %0z&k!P  
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6] ~g*]T  
import java.io.*; :$`"M#vMX  
import java.net.*; xgi/,Nk '  
f
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public class FileSplitterFetch extends Thread { $1h,<$5H  
b@yGa%Gz@  
T@ [
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String sURL; //File URL _Co*"hl>2  
long nStartPos; //File Snippet Start Position +s}"&IV%  
long nEndPos; //File Snippet End Position A{:PpYs  
int nThreadID; //Thread's ID )9L:^i6  
boolean bDownOver = false; //Downing is over BihXYux*  
boolean bStop = false; //Stop identical ~9OART='  
FileAccessI fileAccessI = null; //File Access interface X$L9kZ  
\Ami-<T  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jo.Sg:7&  
{ 0koC;(<n  
this.sURL = sURL; "Yo.]PU  
this.nStartPos = nStart; pL{h1^O}  
this.nEndPos = nEnd; J8T?=%?=  
nThreadID = id; EMDsi2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 W+&w'~M  
} ~ cKmf]  
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public void run() 26c,hPIeXY  
{ Wn(pz)+Y  
while(nStartPos < nEndPos && !bStop) 4&Q.6HkL  
{ O;u&>BMk  
u'o."J^&'  
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try{ Wgt[ACioN  
URL url = new URL(sURL); OIuEC7XM^C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C>d_a;pX  
httpConnection.setRequestProperty("User-Agent","NetFox"); z8SrZ#mg  
String sProperty = "bytes="+nStartPos+"-"; /mb?C/CI  
httpConnection.setRequestProperty("RANGE",sProperty); A{5^A)$  
Utility.log(sProperty); *20$u% z2  
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InputStream input = httpConnection.getInputStream(); Q)\~=/Lb  
//logResponseHead(httpConnection); ,~@Nhd~k  
5$,dpLbL  
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byte[] b = new byte[1024]; >i>%
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int nRead; jXBAo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r>=)Y32Q  
{ #PzRhanX  
nStartPos += fileAccessI.write(b,0,nRead); p nS{W \Q  
//if(nThreadID == 1) kvzGI>H:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E1U~ew  
} A8?uCkG  
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Utility.log("Thread " + nThreadID + " is over!"); CH6^;.  
bDownOver = true; fa7I6 i  
//nPos = fileAccessI.write (b,0,nRead); pNN6PsLt  
} n5Ad@Bg  
catch(Exception e){e.printStackTrace ();} [MmOPm}@  
} c:SA#.  
} 6R%Ra  
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jt?937{  
//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) =K6aiP$Ft  
{ [xF(t @p  
for(int i=1;;i++) qRXb9c  
{ }1ABrbc  
String header=con.getHeaderFieldKey(i); @S/jVXA  
if(header!=null) ;]* %w
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); f?_UT}n  
Utility.log(header+" : "+con.getHeaderField(header)); [ 7W@/qqv  
else gK{-eS  
break; ^f:oKKaAW;  
} L'dR;T[;  
} ,)u\G(N  
7V6gT}R  
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public void splitterStop() 'N?,UtG R  
{ >tfy\PY:  
bStop = true; %!5[3b'h  
} i1qhe?5  
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} TA=VfA B  
;VY0DAp{  
K,7IBv,B[  
/* /8\gT(@  
**FileAccess.java 1epj/bB&  
*//文件访问(定位，写) 9?xMsu-H  
package NetFox; ;aJBx  
import java.io.*; S&y(A0M  
 iw!kV  
l$ABOtM@  
public class FileAccessI implements Serializable{ ,J|8P{ZO  
VTOZ#*f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fVlTsc|e  
RandomAccessFile oSavedFile; n\f
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long nPos; s2-`}LL  
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{&_1/  
public FileAccessI() throws IOException ,/O,j SRk  
{ czMThm  
this("",0); ou;E@`h;x  
} n>d@}hyv  
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public FileAccessI(String sName,long nPos) throws IOException %?gh;? GD  
{ *Uvh;d{  
oSavedFile = new RandomAccessFile(sName,"rw"); H1`}3}"  
this.nPos = nPos; otQulL)T/  
oSavedFile.seek(nPos); ;A~efC^<  
} Tw|cgB  
> YHwWf-  
O s*B%,}  
public synchronized int write(byte[] b,int nStart,int nLen) h rL_. 4  
{ oxN~(H)/ #  
int n = -1; `N8?F3>
 
try{ C-Q]f
 
oSavedFile.write(b,nStart,nLen); >7yOu!l  
n = nLen; >syQDB  
} D^+#RR'#,  
catch(IOException e) 86bl'FdKS  
{ s8,N9o[.~P  
e.printStackTrace (); [42vO  
} P`JO6O:&  
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return n; Z x9oj  
} g3r4>SA  
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} u)]]9G _8  
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/* XUf]gQu3=  
**SiteInfoBean.java vYT%e:8)q  
*/ Nqih LUv  
package NetFox; E'|@hL-jn  
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.G"UM>.}d  
public class SiteInfoBean { GtQ$`~r  
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c  
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private String sSiteURL; //Site's URL %1E:rw@
 
private String sFilePath; //Saved File's Path 0/".2(\}T  
private String sFileName; //Saved File's Name bVEt?E*+  
private int nSplitter; //Count of Splited Downloading File Tk[`kmb  
y6.Q\=  
?W l=F/  
public SiteInfoBean() >"^H"K/T  
{//nSplitter的缺省值为5 ?.&]4z([  
//default value of nSplitter is 5 >Ux5UD  
this("","","",5); L B:wo.X  
} U#=Q`  
$vlc@]~d`&  
_wa1R+`_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H{Zfbb  
{ ES~ykE  
sSiteURL= sURL; %
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sFilePath = sPath; &&Sl0(6x[T  
sFileName = sName; {VWX?Mm  
this.nSplitter = nSpiltter; YQU
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ET;=o+\d  
d,r%LjNI  
} {-28%  
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public String getSSiteURL() !{
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{ d|UK=B^x  
return sSiteURL; wYTF:Ou^5~  
} 7O3\  
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[I*BEJ;W'  
public void setSSiteURL(String value) .Rq|F  
{ Jf<+VJ>t  
sSiteURL = value; (A.%q1h  
} -]1
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public String getSFilePath() ekB
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{ JJL#Y  
return sFilePath; FKU$HQw*  
} ^j1?LB  
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public void setSFilePath(String value) S|U/m m  
{ bL`O k  
sFilePath = value; p4k*vuu>  
} ISy\g`d`C  
(h
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public String getSFileName() <^}{sdOyu  
{ VH&6Tm1  
return sFileName; V,=V   
} $7q'Be@{  
\IZfp=On  
K2J DG.<  
public void setSFileName(String value) 6PETIs  
{ /aa'ryl_%  
sFileName = value; @/6cEiC+r\  
} Go>_4)jy  
k(>hboR5n  
!b<c*J?f  
public int getNSplitter() !o.l:Mr  
{ *M*:3v 0  
return nSplitter; ZU%7m_zO  
} (/J$2V5-  
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D]nVhOg|  
public void setNSplitter(int nCount) ejYJOTT{^  
{ ADoxma@  
nSplitter = nCount; oi4tj.!J  
} HbWl:yU  
} D{~mJDUzK  
9o7E/wP  
Rn={:u4  
/* Hd(|fc{2  
**Utility.java MqXN,n+`k  
*/ SooSOOAx[  
package NetFox; Z/=x(I0  
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public class Utility { (dO, +~  
,@2d<d]  
>SA?lG8f%  
public Utility() E]PHO\f-m}  
{ 7T \}nX1  
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YnZV.&4{  
} !@E=\Sm8EV  
RH+3x7l  
//线程睡眠 7o?6Pv%HJC  
public static void sleep(int nSecond) fDo )~t*~  
{ `PI,tmv!  
try{ WZ}c)r*R  
Thread.sleep(nSecond);
"qEHK;  
} SJhcmx+  
catch(Exception e) mO$]f4}  
{ &E.ckWf  
e.printStackTrace (); z@hlN3dg  
} _iBNy   
} i>gbT+*E!  
GJW>8*&&(  
//日志 Hf P2o5-  
public static void log(String sMsg) >U@7xeK  
{ A@^e4\  
System.err.println(sMsg); /I~iUND"G  
} @A(*&PU>j  
HpI[Af}l  
SEm3T4dfzf  
public static void log(int sMsg) @$ E&H`da  
{ aML?$_6  
System.err.println(sMsg); qG.HJD  
} <TmMUA)`}  
} 3QSP](W-(  
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/* b!VaEK  
**TestMethod.java 9j458Yd4*  
*/ tiJY$YqA  
package NetFox; >jU.R;H5  
.L'>1H
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ks=jv:  
public class TestMethod { _1[5~Pnh  
nunTTE,iq%  
X&sXss<fO%  
public TestMethod() h%MjVuLn  
{ ///xx/weblogic60b2_win.exe " SkTVqm  
try{ ?.#?h>MS{s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M{$EJS\d=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d*ch.((-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YUdCrb9F  
fileFetch.start(); 8:c[_3w  
} _+%RbJ~H  
catch(Exception e){e.printStackTrace ();} VYj hU?I  
*"#62U6  
FCxLL"))  
} 9:N@+;|T  
F)KUup)gc  
9u";%5 4  
public static void main(String[] args) d
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{ g+h)s!$sB  
new TestMethod(); D}59fWz@  
} U-(2;F)  
} o*H j E  
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