http断点续传简单实现（java)

/* B=%cXW,  
**SiteFileFetch.java sw6]Bc  
*/ ~P 1(%FZ  
package NetFox; 'uGn1|Pvy  
import java.io.*; 3
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import java.net.*; %L.,:mtq)  
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public class SiteFileFetch extends Thread { PaP47>(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dms R>Q  
long[] nStartPos; //开始位置 |Kky+*  
long[] nEndPos; //结束位置 4.$<o/M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HUuL3lYka  
long nFileLength; //文件长度 *F1!=:&s  
boolean bFirst = true; //是否第一次取文件 {(U?)4@  
boolean bStop = false; //停止标志 8`Q8Mct$<  
File tmpFile; //文件下载的临时信息 a)^f`s^aa  
DataOutputStream output; //输出到文件的输出流 B4
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U=\ZeYK.  
public SiteFileFetch(SiteInfoBean bean) throws IOException |GM?4'2M.  
{ ><}FyK4C  
siteInfoBean = bean; &?f{.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'e_^s+l)a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L,*2tJcC<  
if(tmpFile.exists ()) tPIT+1.]z  
{ xgn@1.}G  
bFirst = false; OE]zC  
read_nPos(); NVU@m+m~  
}  Iz*'  
else jw?/@(AC6  
{ UX}ZE.cV  
nStartPos = new long[bean.getNSplitter()]; "
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nEndPos = new long[bean.getNSplitter()]; Vcz ExP  
} w{f!t8C*s  
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} 2~Z P[wr  
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public void run() 5
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{ S9S8T+  
//获得文件长度 .0kltnB  
//分割文件 K:gxGRE  
//实例FileSplitterFetch Vz6p^kMB  
//启动FileSplitterFetch线程 GGo)k1T|)  
//等待子线程返回 /)sA{q 4  
try{ |s`j=<rNQI  
if(bFirst) }u:@:}8K  
{ <^snS,06  
nFileLength = getFileSize(); \W=~@k  
if(nFileLength == -1) ~CIA6&  
{ wvBx]$SC  
System.err.println("File Length is not known!"); fDt#<f 4;  
} 6My=GByC  
else if(nFileLength == -2) bO]^TRai
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{ !#j y=A  
System.err.println("File is not access!"); &b8Dy=#  
} 2a8ZU{wjn  
else =># S7=  
{ 4+e9:r]  
for(int i=0;i<nStartPos.length;i++) ?$i`K|  
{ /yPFts_q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,~u5SR  
} N7Vv"o  
for(int i=0;i<nEndPos.length-1;i++) l5_RG,O0A  
{ 0h/gqlTK1  
nEndPos = nStartPos[i+1]; T;K@3]FbX  
} SxMmy  
nEndPos[nEndPos.length-1] = nFileLength; *yKw@@d+p  
} A:PQIcR;V  
} Wd#r-&!6j  
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//启动子线程 JJ`RF   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I4{uw ge  
for(int i=0;i<nStartPos.length;i++) Bd jo3eX  
{ *@/1]W  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), piKYO+;W'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &oI;^|  
nStartPos,nEndPos,i); KU#w%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mRU-M|  
fileSplitterFetch.start(); z+,l"#Vv  
} 8oiO:lyLSt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _^K)>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *'4+kj7>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %EkV-%o*  
nEndPos = " + nFileLength); pxP,cS  
// fileSplitterFetch[nPos.length-1].start(); Z-X(.Q  
bC*( ,n<'  
6-#<*Pg  
//等待子线程结束
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//int count = 0; *W,tq(%tQ  
//是否结束while循环 J&Ig%&/  
boolean breakWhile = false; g$bbm}6S  
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while(!bStop) lZ]x #v  
{ g(Q
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write_nPos(); q2 K@i*s  
Utility.sleep(500); ~,[-
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breakWhile = true; :U;n?Zu S  
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for(int i=0;i<nStartPos.length;i++) |R[@u=7s  
{ sjl(  
if(!fileSplitterFetch.bDownOver) Bh3N6j+$d  
{ $>Md]/I8  
breakWhile = false; Ilt!O^  
break; XgRrJ.  
} Wmri%  
} V&nTf100  
if(breakWhile) .m%/JquMFM  
break; L3}n(KAJj  
M~%~y`D^  
"<['W(  
//count++; vEQw`OC  
//if(count>4) qJV2x.!  
// siteStop(); v:/+OzY  
} JxI\ss?O  
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{l/j?1Dxq  
System.err.println("文件下载结束！"); C1w~z4Qp  
}  uP|Py.+  
catch(Exception e){e.printStackTrace ();} :yg:sU  
} |,!]]YO.V  
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//获得文件长度 v C,53g  
public long getFileSize() V9
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{ iA*^`NMaT  
int nFileLength = -1; 99W-sV  
try{ pc9m,?n  
URL url = new URL(siteInfoBean.getSSiteURL()); )@lZ~01~d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2?vjj:P+h  
httpConnection.setRequestProperty("User-Agent","NetFox"); #?=?<"*j  
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int responseCode=httpConnection.getResponseCode(); j"G1D-S:  
if(responseCode>=400) [I6(;lq2  
{ ~)J]`el,Q  
processErrorCode(responseCode); BpL7s ej7  
return -2; //-2 represent access is error |#_IAN  
} j}P x
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String sHeader; DJ&ni`  
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for(int i=1;;i++) ( X(61[Lu  
{ 5:S=gARz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >i&"{GZ  
//Utility.log(in.readLine()); [/Q .MmnL  
sHeader=httpConnection.getHeaderFieldKey(i); {WokH;a/
 
if(sHeader!=null) `Wc"Ix0  
{ ZiR },F/  
if(sHeader.equals("Content-Length")) ai,\'%N  
{ M$Sq3m`{!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k OYF]^uJ  
break; 8&[Lr o9  
} h"C7l#u  
} U&F1}P$fb  
else 2pr#qh8  
break; 7Iz%Jty  
} 0%x"Va~"z  
} p2m@0ou  
catch(IOException e){e.printStackTrace ();} "gt-bo.,  
catch(Exception e){e.printStackTrace ();} 6yn34'yw  
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Utility.log(nFileLength); #6g9@tE  
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return nFileLength; \\ZR~f!<  
} uGXN ciEp`  
:?uUh  
tW^oa  
//保存下载信息（文件指针位置） J\06j%d,  
private void write_nPos() ShP&ss  
{ X283.?  
try{ uUhqj.::<Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6[.#B!;9  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) $ ,:3I*}be  
{  w^Mj[v#  
// output.writeLong(nPos); ON,sN  
output.writeLong(fileSplitterFetch.nStartPos); z (1zth  
output.writeLong(fileSplitterFetch.nEndPos); dM-qd`
  
} 9+irf^D`O  
output.close(); OBnf5*eJ  
} f`;y "ba  
catch(IOException e){e.printStackTrace ();} i}tBB
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catch(Exception e){e.printStackTrace ();} ]VKM3[   
} tfKf*Um  
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//读取保存的下载信息（文件指针位置） Q>ZxJ!B<k  
private void read_nPos() kT-dQ32  
{ |2Krxi3*  
try{ %>];F~z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0 _n Pq  
int nCount = input.readInt(); (7X|W<xT  
nStartPos = new long[nCount]; +6zW(Ql/  
nEndPos = new long[nCount]; k?bIu  
for(int i=0;i<nStartPos.length;i++) 6%-RKQi  
{ L'Yg$9Vz  
nStartPos = input.readLong(); |]M|IX8 o  
nEndPos = input.readLong(); mp'Z.4  
} Yg<L pjq5X  
input.close(); Ri   
} OfE>8*RI4  
catch(IOException e){e.printStackTrace ();} Hto RN^9  
catch(Exception e){e.printStackTrace ();}
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} m}-*B1  
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private void processErrorCode(int nErrorCode) S^8C\ E  
{ VYR<x QA  
System.err.println("Error Code : " + nErrorCode); ]\JLlQ}#H  
} hR4\:s+[  
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aAbK{=/y_!  
//停止文件下载 &g.do?  
public void siteStop() }OsAO  
{ O|} p=ny  
bStop = true; ShIJ6LZ  
for(int i=0;i<nStartPos.length;i++) ?5IF;vk  
fileSplitterFetch.splitterStop(); ]Pp}=hcD  
p{vGc-zP.  
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} w=QlQ\  
} 1u~CNHm  
//负责部分文件的抓取 Vr^UEu.w?  
**FileSplitterFetch.java Vsj1!}X:  
*/ W?:e4:Q  
package NetFox; /&i6vWMhP  
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ke)}JU^"  
import java.io.*; 6(1S_b=a  
import java.net.*; ?Tlt(%f  
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public class FileSplitterFetch extends Thread { u*S-Pji,x  
/'l"Us},^!  
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String sURL; //File URL yg^ 4<A  
long nStartPos; //File Snippet Start Position X T<SR]  
long nEndPos; //File Snippet End Position "!B\c9q
 
int nThreadID; //Thread's ID gTQc=,3l3  
boolean bDownOver = false; //Downing is over jhJ'fI  
boolean bStop = false; //Stop identical FX  %(<M  
FileAccessI fileAccessI = null; //File Access interface v;sWI"Fv!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hh[@q
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{ @kPe/j/[1  
this.sURL = sURL; 1\X_B`xwD  
this.nStartPos = nStart; . #FJM2Xk  
this.nEndPos = nEnd; Y6[O s1  
nThreadID = id; m S4N%Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'Ul^V  
} lD#S:HX  
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public void run() edL sn>\*#  
{ ;)ku SH  
while(nStartPos < nEndPos && !bStop) ;L@p|]fu  
{ u*m|o8  
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j0~dJ#  
try{ )tv~N7  
URL url = new URL(sURL); =.]{OT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |Kq<}R  
httpConnection.setRequestProperty("User-Agent","NetFox"); aT~=<rEDy  
String sProperty = "bytes="+nStartPos+"-"; iOB*K)U1  
httpConnection.setRequestProperty("RANGE",sProperty); $Xr4=9(|7  
Utility.log(sProperty); { V$}qa{P  
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InputStream input = httpConnection.getInputStream(); W) ?s''WE;  
//logResponseHead(httpConnection); F|&
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byte[] b = new byte[1024]; )E*-  
int nRead; Kw =RqF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FM
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{ 1l s8h  
nStartPos += fileAccessI.write(b,0,nRead); ~hb;kc3  
//if(nThreadID == 1) 8 +mW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _/NPXDL  
} c{3P|O&.  
9hei8L:  
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Utility.log("Thread " + nThreadID + " is over!"); "9#hk3*GqX  
bDownOver = true; J6mUU3F9f  
//nPos = fileAccessI.write (b,0,nRead); HBm(l@#.  
} 2Mu3]2>  
catch(Exception e){e.printStackTrace ();} ;qs^+  
} >-j(
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} p+;;01Z+_  
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//打印回应的头信息 u/apnAW@M  
public void logResponseHead(HttpURLConnection con) ZmvtUma  
{ a/n~#5-  
for(int i=1;;i++) (\%J0kR3[  
{ }vd72PB  
String header=con.getHeaderFieldKey(i); lXRB"
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if(header!=null) MM*9Q`cB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E <N%  
Utility.log(header+" : "+con.getHeaderField(header)); T>irW(  
else cv_t2m
 
break; R(s[JH(&  
} W/.n R[!  
} I2gSgv%  
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 ]l}bk]  
public void splitterStop() wlDo(]mj=O  
{ #V.u[:mO  
bStop = true; U45-R-  
} P! P` MX  
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} *i"Mu00b  
p\}!uS4 (  
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/* #!>`$  
**FileAccess.java & j*Ylj}  
*//文件访问(定位，写) {KSy I#  
package NetFox; 1ZXRH;J40  
import java.io.*; X=? \A{Y  
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Ky*xAx:  
public class FileAccessI implements Serializable{ p7L6~IN  
Jw^h<z/Ux  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |!J_3*6$>*  
RandomAccessFile oSavedFile; 4'.]-u  
long nPos; ]d*O>Pm  

p ~)\!  
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public FileAccessI() throws IOException 1pqYB]*u_  
{ X*a7`aL  
this("",0); *-'`Ea  
} oJZ0{^  
0ke1KKy/d  
#fFD|q  
public FileAccessI(String sName,long nPos) throws IOException qnzNJ_ `R  
{ Q'[~$~&`  
oSavedFile = new RandomAccessFile(sName,"rw"); ?sxf_0*  
this.nPos = nPos; I#xhmsF  
oSavedFile.seek(nPos); GYonb)F  
} +B7UGI  
dBHki*.u  
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public synchronized int write(byte[] b,int nStart,int nLen) 9lX[rBZ  
{ 9Dyw4'W.N  
int n = -1; NM1TFs2Y*  
try{ :~p_(rE  
oSavedFile.write(b,nStart,nLen); 6wb M$|yFj  
n = nLen; ^.M_1$-  
} w_YY~Af  
catch(IOException e) nZ`=Up p)  
{ z.W1Za  
e.printStackTrace (); 7KtgR=-Lb  
} 4-\4G"4  
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return n; Q
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} JV!}"[  
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} +PO& z!F  
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/* :$QwOz^N*  
**SiteInfoBean.java U27ja|W^  
*/ L~_zR>  
package NetFox; ~5Rh7   
'v@1_HHW\  
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public class SiteInfoBean { o#IWH;ck.  
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3iiOxg?j  
private String sSiteURL; //Site's URL 94XRf"^  
private String sFilePath; //Saved File's Path ) |hHbD^V  
private String sFileName; //Saved File's Name Uzk_ae  
private int nSplitter; //Count of Splited Downloading File cr{dl\Na  
hy:K) _   
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public SiteInfoBean() *kDV ^RBfq  
{//nSplitter的缺省值为5 <pUc( tPoz  
//default value of nSplitter is 5 j MA%`*r  
this("","","",5); _[ `"E'  
} 98WJ"f_ #  
!v3wl0  
,-BZsZ0~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yAc}4*;T/  
{ A3zNUad;  
sSiteURL= sURL; /zV0kW>N  
sFilePath = sPath; Rh7=,=u  
sFileName = sName; taOsC!Bp  
this.nSplitter = nSpiltter; ,I[A~  
xX
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} 5?|P
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public String getSSiteURL() FD}>}fLv  
{ g/,O51f'  
return sSiteURL; k_Edug~B  
} dk2o>jI4;  
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public void setSSiteURL(String value) upH%-)%'  
{ /XW,H0pR  
sSiteURL = value; 2qkC{klC^M  
} 4U:+iumy2  
>l5JwwG  
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public String getSFilePath() mH3{<^Z6  
{ >JhIRf  
return sFilePath; d>7bwG+k  
} 
g:c @
  
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public void setSFilePath(String value) jfrUOl'l  
{ 'w7{8^Z2  
sFilePath = value; {EupB?  
} B6vmBmN  
cl-i6[F  
}(XvI^K[^  
public String getSFileName() c[0$8F>  
{ z'X_s.9F  
return sFileName; :ui1]its4  
} N:/$N@"Ge  
**O4"+Xi8  
H\!u5o&}`  
public void setSFileName(String value) cjO,#W0&f  
{ [G|2m_  
sFileName = value; IN]bAd8"  
} j|WaWnl=  
mwTn}h3N  
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public int getNSplitter() E]Hl&t/}  
{ ss3fq}  
return nSplitter; wh:`4Yw  
} `\P:rn95;  
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public void setNSplitter(int nCount) p:ST$1 K  
{ tdr*>WL  
nSplitter = nCount;
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}
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} F]?$Q'U  
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7"JU)@ U]  
/* U>x2'B v  
**Utility.java .]H]H*wC  
*/ uf)W?`e~  
package NetFox; Lou4M  
.^.UJo;4G  
90aPIs-  
public class Utility { ^! ZjK-$A<  
cCV"(Oo[H|  
{Q(6 .0R  
public Utility() P[nWmY  
{ .Na>BR\F  
NV-9C$<n2!  
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} N<>dg  


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//线程睡眠 d8RpL{9\7  
public static void sleep(int nSecond) p go\(K0  
{ 8rp-Xi
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try{ iK%Rq  
Thread.sleep(nSecond); X0Oq lAw  
} )Y&De)=  
catch(Exception e) ZJ[ Uz_%W  
{ OEwfNZQ-  
e.printStackTrace (); BtHvfoT  
} JN KZ'9  
} F5<{-{Ky  
u\.sS|
$  
//日志 M<~F>(wxA  
public static void log(String sMsg) NxX1_d  
{ N[+dX_h  
System.err.println(sMsg); =;/h{ t  
} D
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MM8)yCI  
};!c]/,  
public static void log(int sMsg) B=c^ma
  
{ NJtB;  
System.err.println(sMsg); eu:_V+  
} ;W*$<~_  
} E0DEFB  
#*]= %-A  
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/* -<O:isB  
**TestMethod.java zuPH3Q
={  
*/ KnFbRhu[  
package NetFox; M{4_BQ4$  
G
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#dfW1@m  
public class TestMethod { y14@9<~9  
X0$_KPn  
Go67VqJr  
public TestMethod() TnaIRJ\B  
{ ///xx/weblogic60b2_win.exe aBC[(}Pb]  
try{  Fszk?0T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ha),N<'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >PJ-Z~O'   
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5k(#kyP  
fileFetch.start(); 68!fcK  
} E0pQRGPA  
catch(Exception e){e.printStackTrace ();} 5y'Yosy:  
-oo=IUk  
o_N02l4J)  
} Ji
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O9yQ9sl  
*Sf^()5C,  
public static void main(String[] args) VV4_  
{ >lW*%{|b$^  
new TestMethod(); C/Z"W@7#;  
} TatyD**(  
} }00e@a  
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