http断点续传简单实现（java)

/* 0_"J>rMp  
**SiteFileFetch.java TmzEZ<} &7  
*/ Eg  w?  
package NetFox; 3TtnLay.k  
import java.io.*; /:U\U_j  
import java.net.*; *QAK9mc  
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public class SiteFileFetch extends Thread { ZL1[Khr,s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean uiDR}   
long[] nStartPos; //开始位置 n!3_%K0!r&  
long[] nEndPos; //结束位置 ,Y9lp)w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WnUYZ_+e!  
long nFileLength; //文件长度 (zgXhx_!D  
boolean bFirst = true; //是否第一次取文件 'H*S-d6V  
boolean bStop = false; //停止标志 bS* "C,b~s  
File tmpFile; //文件下载的临时信息 AbLOq@lrK  
DataOutputStream output; //输出到文件的输出流 LG&~#x  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a#j0N5<Nl  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]_F%{8|  
{ Xv=n+uo  
siteInfoBean = bean; <A"}Krq?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WI}P(!h\J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LA"`8  
if(tmpFile.exists ()) Et`z7Q*e  
{ ;wTl#\|w0  
bFirst = false; ?L{[84GSO  
read_nPos(); $]xe,}*Af  
} I.q nA  
else oh#6>|  
{ ,Qj7wFZ  
nStartPos = new long[bean.getNSplitter()]; Sn
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nEndPos = new long[bean.getNSplitter()]; qrm~=yU%  
} H$;K(,'  
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} GaM#a[p  
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public void run() 9s5CqB  
{ ldi'@
^  
//获得文件长度 ,C(")?4aJ  
//分割文件 ZqS'xN:k  
//实例FileSplitterFetch C x$|7J=O  
//启动FileSplitterFetch线程 N`8?bU7a}"  
//等待子线程返回 3D;\V&([  
try{ M,q'   
if(bFirst) }_gCWz-5?  
{ & UL(r  
nFileLength = getFileSize(); im4V6 f;%  
if(nFileLength == -1) rK}*Uwut  
{ ##1[/D(  
System.err.println("File Length is not known!"); \W}?4kz  
} Fgt/A#`fz  
else if(nFileLength == -2) <iJ->$  
{ b\dBt#mB!  
System.err.println("File is not access!"); Fu{[5uv  
} URX>(Y}g9^  
else )bw^!w)  
{ w*$nG$  
for(int i=0;i<nStartPos.length;i++) VU}UK$JN  
{ h^?[:XBeav  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tlI3jrgw  
} !)_80O1  
for(int i=0;i<nEndPos.length-1;i++) o&fAnpia=  
{ WLv( K_3Y  
nEndPos = nStartPos[i+1]; qRTxg%  
} Qh%7RGh_  
nEndPos[nEndPos.length-1] = nFileLength; uTBls8  
} o @~XX@5l  
} =>4>Z_q  
V,*YM  
]^/:Xsk$  
//启动子线程 vC&y:XMt,`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -:*PXu  
for(int i=0;i<nStartPos.length;i++) l4|bpR Cp  
{ Yf7n0Etd,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 86vk"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9%>H}7=  
nStartPos,nEndPos,i); gO gZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r-H~MisL  
fileSplitterFetch.start(); Z\6azhbI}  
} P/,7CfyPd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4US8B=jk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oT5?*3f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -gv@ .#N  
nEndPos = " + nFileLength); no)Sp
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// fileSplitterFetch[nPos.length-1].start(); }\OLBg/  
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//等待子线程结束 ()}O|JL:K  
//int count = 0; xJJlVP  
//是否结束while循环 y? )v-YGu  
boolean breakWhile = false; ?b^VEp.;}  
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while(!bStop) )PB&w%J  
{ {KdC51"Nv  
write_nPos(); QE=Cum  
Utility.sleep(500); *{)[:;  
breakWhile = true; E)NH6~  
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&
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for(int i=0;i<nStartPos.length;i++) Gxy>aS3  
{ MS_&;2  
if(!fileSplitterFetch.bDownOver) X+?*Tw!\  
{ B#B$w_z  
breakWhile = false; J55K+  
break; zTAt% w5  
} Haaungb"  
} <@A/`3_O)  
if(breakWhile) E)09M%fe  
break; cx1U6A+  
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//count++; |.*),t3 (w  
//if(count>4) gmj a2F,  
// siteStop(); c zL[W2l  
} zVGjXuNa  
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System.err.println("文件下载结束！"); \G#Qe*"'K  
} nyw,Fu  
catch(Exception e){e.printStackTrace ();} Zo-E0[9  
} ^.nvX{H8~=  
^ Gq2"rDM  
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//获得文件长度 l:z:tJ#(  
public long getFileSize() VahR nD  
{ 8r
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int nFileLength = -1; GWM2l?zOP  
try{ G|4vnIS  
URL url = new URL(siteInfoBean.getSSiteURL()); "of(,p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k#c BBrY  
httpConnection.setRequestProperty("User-Agent","NetFox"); {YcVeCq+N  
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int responseCode=httpConnection.getResponseCode(); OcQ_PE5\  
if(responseCode>=400) w>IkC+.?  
{ I{_St8  
processErrorCode(responseCode); y$r9Y!?s  
return -2; //-2 represent access is error -,TBUWg  
} m{JiF-=u  
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String sHeader; SV<*qz  
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for(int i=1;;i++) #h6(DuViKw  
{ ;}A#ws_CD_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]vXIj0:  
//Utility.log(in.readLine()); ]n _-
  
sHeader=httpConnection.getHeaderFieldKey(i); PUltn}M  
if(sHeader!=null) `]LaX&u  
{ >BrxJw#M  
if(sHeader.equals("Content-Length")) E&{*{u4  
{ (e=ksah3>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s|pb0  
break; ~XsS00TL`G  
} Gqk"%irZ  
} HAf.LdnzS  
else ![7v_l\Q  
break; }(ay(  
} Te[[x
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} j /)cdP  
catch(IOException e){e.printStackTrace ();} Uf4QQ`c#  
catch(Exception e){e.printStackTrace ();} ?OZbns
~  
{;n
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Utility.log(nFileLength); wju~5  
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return nFileLength; JEdtj1v{O  
} (PsA[>F  
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//保存下载信息（文件指针位置） i#kRVua/  
private void write_nPos() c*RZbE9k  
{ K[~Wj8W0  
try{ $#]?\psf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qc[[@=S%  
output.writeInt(nStartPos.length); Yo| H`m,  
for(int i=0;i<nStartPos.length;i++) mH;Z_ME"  
{ iBp 71x65  
// output.writeLong(nPos); 2mu~hJ  
output.writeLong(fileSplitterFetch.nStartPos); $rFv(Qc^=  
output.writeLong(fileSplitterFetch.nEndPos); Wn0r[h5t  
} <Ks?g=K-  
output.close(); eb9qg.9Z  
} n 8AND0a1C  
catch(IOException e){e.printStackTrace ();} u%XFFt5  
catch(Exception e){e.printStackTrace ();} *9j9=N?  
} *uA?}XEfi  
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//读取保存的下载信息（文件指针位置） GVn
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private void read_nPos() Y0s^9?*  
{ 1Y}gki^F  
try{ "Y(S G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :vurU$
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int nCount = input.readInt(); ^3=8*Xr  
nStartPos = new long[nCount]; ;2L=WR%  
nEndPos = new long[nCount]; )@R:$l86  
for(int i=0;i<nStartPos.length;i++) }^`{YD  
{ Gk[P-%%b /  
nStartPos = input.readLong(); pxI*vgfN7  
nEndPos = input.readLong(); (g7nMrE$j  
} JGj_{|=:  
input.close(); <(BAws(X  
} ~{^A&#P  
catch(IOException e){e.printStackTrace ();} ei\X/Z*q%P  
catch(Exception e){e.printStackTrace ();} Ql
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} OQ+?nB  
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=_^g]?5i  
private void processErrorCode(int nErrorCode) ik8e  
{ `d OjCA_&  
System.err.println("Error Code : " + nErrorCode); hp,T(D|  
} g:[&]o} :9  
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]"/ *7NM  
//停止文件下载 RK rBHqh@  
public void siteStop() yt!K|g  
{ M\`6H8aLn  
bStop = true; #y>oCB`EM  
for(int i=0;i<nStartPos.length;i++) cgz'6q'T  
fileSplitterFetch.splitterStop(); h(G&X9*  
@Cz1rKU^l  
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} SCGQo.~,  
} jDXmre?  
//负责部分文件的抓取 _ORW'(:Z  
**FileSplitterFetch.java ^+GN8LUs  
*/ ?7G[`@^Y  
package NetFox; t:M>&r:BL  
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import java.io.*;  oK
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import java.net.*; QQ!,W':  
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public class FileSplitterFetch extends Thread { vm4]KEyrX  
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String sURL; //File URL xPb`CY7  
long nStartPos; //File Snippet Start Position w~Y#[GW  
long nEndPos; //File Snippet End Position ^'
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int nThreadID; //Thread's ID Q7}w
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boolean bDownOver = false; //Downing is over VJ=!0v  
boolean bStop = false; //Stop identical \ g0  
FileAccessI fileAccessI = null; //File Access interface "4"L"lJ   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?C $_?Qi  
{ J41ZQ  
this.sURL = sURL; 2l\Oufer"  
this.nStartPos = nStart; C y&L,  
this.nEndPos = nEnd; VFYJXR{  
nThreadID = id; GbL,k?ey  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8=2)I.   
} D~mGv1t"  
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public void run() }'@*Olj  
{ ~?L. n:wu  
while(nStartPos < nEndPos && !bStop) i,)kI  
{ F'*{Fk h  
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try{ a(J~:wgd  
URL url = new URL(sURL); oa9T3gQ?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |2
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httpConnection.setRequestProperty("User-Agent","NetFox"); LXK+W
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String sProperty = "bytes="+nStartPos+"-"; Sk1yend4  
httpConnection.setRequestProperty("RANGE",sProperty); V'6%G:?0a  
Utility.log(sProperty); G7),!Qol  
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InputStream input = httpConnection.getInputStream(); ^T<<F}@q  
//logResponseHead(httpConnection); #K4wO!
d  
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byte[] b = new byte[1024]; T %cN(0@  
int nRead; i^gzl_!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |5FyfDaFBX  
{ ^(6.M\Q  
nStartPos += fileAccessI.write(b,0,nRead); ml3]CcKn  
//if(nThreadID == 1) H7\EvIM=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;ga~ae=Fg  
} z{%G  
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Utility.log("Thread " + nThreadID + " is over!"); S&QZ"4jq  
bDownOver = true; goxgJOiB  
//nPos = fileAccessI.write (b,0,nRead); U|y+k`  
} w>!KUT  
catch(Exception e){e.printStackTrace ();} 0<P -`|X  
} '7E?|B0],  
} icnp^2P  
$:<KG&Br  
#=zh&`  
//打印回应的头信息 U9;AU]A  
public void logResponseHead(HttpURLConnection con) Uq[
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{ H>W A?4  
for(int i=1;;i++) p oNQ<ijK  
{ l$zM|Z1wR`  
String header=con.getHeaderFieldKey(i); +:^tppg  
if(header!=null) Q*lZ;~R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bx5X8D  
Utility.log(header+" : "+con.getHeaderField(header)); (IEtjv}D  
else 9cj:'KG)!  
break; \Hy~~Zh2  
} S(rA96n  
} /r]IY.  
PR.?"$!D{  
rt."P20T  
public void splitterStop() $_<,bC1[  
{ NB>fr#pb  
bStop = true; )TP7gLv=b  
} +=:CW'B5  
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3g} ]nj:N  
} :PjHsNp;^  
*%Q!22?6F  
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/* 2AU_<Hr6  
**FileAccess.java d7l0;yR&+  
*//文件访问(定位，写) PiM@iS  
package NetFox; r0hu?3u1?  
import java.io.*; xy[R9_V  
#,$d!l @  
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public class FileAccessI implements Serializable{ D[9eu>"'9M  
]X{LZYk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !R4`ihi1  
RandomAccessFile oSavedFile; &{"aD&  
long nPos; hPH=.rX  
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public FileAccessI() throws IOException Q7f\ 5QjT  
{ gP)g_K(e  
this("",0); DmPp&  
} K~C*4H:9  
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public FileAccessI(String sName,long nPos) throws IOException Rl-Sr  
{ @-)?2CH[8  
oSavedFile = new RandomAccessFile(sName,"rw"); >Ei_##
 
this.nPos = nPos; 4Yx?75/  
oSavedFile.seek(nPos); @R>J\>  
} a B%DIH,  
rT5dv3^MW!  
>*dqFZF  
public synchronized int write(byte[] b,int nStart,int nLen) t|d9EC]c(  
{ @ Al\:  
int n = -1; hesL$Z [  
try{ ,%yjEO  
oSavedFile.write(b,nStart,nLen); vA:1z$m  
n = nLen; X8p-VCkV  
} De\&r~bTW9  
catch(IOException e) Ll%[}C?~]?  
{ $^
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e.printStackTrace (); Xk
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} d\D.l^  
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"  
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return n; : xB<Rq  
}
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} j:\MrYt0H  
9:IVSD&"Rf  
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/* ]xfu@''  
**SiteInfoBean.java Tf<1Z{9  
*/ F
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package NetFox; Hq3"OMGq  
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public class SiteInfoBean { uI!rJc>TX  
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private String sSiteURL; //Site's URL nB WVG  
private String sFilePath; //Saved File's Path p,Qr9p3y  
private String sFileName; //Saved File's Name ab: yH ')  
private int nSplitter; //Count of Splited Downloading File 2D>WIOX  
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public SiteInfoBean() SBgBZm}%  
{//nSplitter的缺省值为5 3g`uLA X>u  
//default value of nSplitter is 5 ?ep93:j  
this("","","",5); lqT
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} 6DD"Asi+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %!mJnc%  
{ 0V@u]  
sSiteURL= sURL; Cq(dj^/~m  
sFilePath = sPath; Np$pz  
sFileName = sName; odD^xg"L  
this.nSplitter = nSpiltter; kG^DHEne  
9,sj,A1  
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}
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public String getSSiteURL() bx_`S#*N  
{ NiQ`,Q$B  
return sSiteURL; ?|s1Cuc  
} B\G?dmo  
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public void setSSiteURL(String value) F#*vJb)  
{ *$1M=$  
sSiteURL = value; u^8:/~8K  
} Y!N*J  
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public String getSFilePath() y0k*iS e  
{ )7l+\t  
return sFilePath;
jeXv)}  
} K[!OfP  
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public void setSFilePath(String value) !o1{. V9q  
{ =UE/GTbl  
sFilePath = value;  G?AZ%Yx  
} ze@NqCF  
(A|Gb2X  
@KfFtR-;  
public String getSFileName() =ZR9zL=h  
{ =Yg36J4[  
return sFileName; eKPxSN Z  
} z-$bce9*  
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public void setSFileName(String value) G0Q}
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{ aw&:$twbM  
sFileName = value; :8\!;!  
} ,K'>s<}
 
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public int getNSplitter() Y_tLSOD#/  
{ veIR)i@dx  
return nSplitter; %xF j;U?  
} (&HAjB  

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rH Et]Xa  
public void setNSplitter(int nCount) FKRO0%M4}Z  
{ #}*w &y  
nSplitter = nCount; ,#:*dl  
} 6;6a.iZ  
} qkVGa%^  
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/* o=@0Bd8  
**Utility.java t\Pn67t  
*/ nm5zX,  
package NetFox; zO8`xrN!  
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d*Q:[RUf,  
public class Utility { itClCEOA  
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public Utility() H<T9$7Yr%r  
{ {C3AxK0  
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} tl9=u-D13@  
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//线程睡眠 y"q7Gx*^j  
public static void sleep(int nSecond) \9k$pC+l  
{ l`=).k
  
try{ 65X31vU  
Thread.sleep(nSecond); v|uY\Z  
} tVVnQX  
catch(Exception e) |:yQOq|  
{ k.=67L  
e.printStackTrace (); a Mp*Ap  
} B^g+_;  
} banie{ e  
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//日志 F[m"eEX  
public static void log(String sMsg) .I\)1kjX  
{ m| 8%%E}d  
System.err.println(sMsg); tKg\qbY&
 
} bL*;6TzRK  
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public static void log(int sMsg) 0w^\sf%s  
{ ZK,}3b{  
System.err.println(sMsg); M7z>ugk"  
}
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} .Rl58]x~  
l*
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/LMb~Hy,  
/* k<W n  
**TestMethod.java ;4.D%  
*/ <K4`GT"n  
package NetFox; rx`G*k{X  
DC
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public class TestMethod { :(tSL{FO  
q)JG_Y.p  
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public TestMethod() sX53(|?*  
{ ///xx/weblogic60b2_win.exe hCRW0 I  
try{ pl62mp!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  /;LteBoY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mw}obblR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JHpoW}7QB  
fileFetch.start(); pL`snVz  
}
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catch(Exception e){e.printStackTrace ();} 7s:`]V%  
}gi>Z  
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} *]G&pmMs  
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public static void main(String[] args) $$C5Q;7w!  
{  v|+}>g  
new TestMethod(); VuTH"br6  
} K@xp
!  
} m(JFlO  
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