http断点续传简单实现（java)

/* _!E)a  
**SiteFileFetch.java s> JW
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*/ O^KIB%}fu  
package NetFox; ?k+>~k{}a  
import java.io.*; s}bv o  
import java.net.*; ,O`~ D~$  
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public class SiteFileFetch extends Thread { LW*v/`@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean < m/@_"  
long[] nStartPos; //开始位置 10{zF_9yx  
long[] nEndPos; //结束位置 )=%TIkeF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ##BfI`FJ  
long nFileLength; //文件长度 Ih^ziDcW  
boolean bFirst = true; //是否第一次取文件 Q<T+t0G\O-  
boolean bStop = false; //停止标志 ?V' zG&n@  
File tmpFile; //文件下载的临时信息 cA{7*=G?  
DataOutputStream output; //输出到文件的输出流 J1"16Uu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J3c8WS{:  
public SiteFileFetch(SiteInfoBean bean) throws IOException Zce/&  
{ l'twy$V4|~  
siteInfoBean = bean; a
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;%!]C0?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $HP<C>^Z8  
if(tmpFile.exists ()) yhh\?qqy  
{ z~Is E8  
bFirst = false; @ ('/NjTZ  
read_nPos(); CJe~>4BT  
} 4^_'LiX3[  
else ;3Z6K5z*f  
{ %JPBD]&M  
nStartPos = new long[bean.getNSplitter()]; x@? Y
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nEndPos = new long[bean.getNSplitter()]; =H;F{J"  
} !pxOhO
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} X{ f#kB]w  
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public void run() 36UUt!}p  
{ U5yBU9\G  
//获得文件长度 EGx
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//分割文件 =:_DXGW2H  
//实例FileSplitterFetch 9y?)Ga  
//启动FileSplitterFetch线程 odhcU5  
//等待子线程返回 lw=
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try{ q#\4/Dt  
if(bFirst) D+"
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{ v4vIcHDs  
nFileLength = getFileSize(); 'nN'bVl/  
if(nFileLength == -1) ;S+]Z!5LT  
{ x
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System.err.println("File Length is not known!"); u{5+hZ  
} xl ,(=L]  
else if(nFileLength == -2) 
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{ W]I+Rlv)U  
System.err.println("File is not access!"); Wgb L9'}B  
} I6Ga'5bV  
else W9:(P  
{ GD0Q`gWNe  
for(int i=0;i<nStartPos.length;i++) p mUG`8SY  
{ vbEO pYCS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1.I58(0~+  
} f"R'Q|7D  
for(int i=0;i<nEndPos.length-1;i++) 5+[ 3@  
{ +*Zjo&pc  
nEndPos = nStartPos[i+1]; 4WP@ F0@n3  
} ne 8rF.D  
nEndPos[nEndPos.length-1] = nFileLength; 6)yi^v  
} "=,IbC  
} )`K!XX$%  
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//启动子线程 FK~*X
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 65U&P5W  
for(int i=0;i<nStartPos.length;i++) Ru@ { b`  
{ -8Hv3J'=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ffR<G&"n~b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z!aU85y  
nStartPos,nEndPos,i); YK>?;U+|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }///k]_Sh  
fileSplitterFetch.start(); ){4!  
} zKfY0A R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %+@<T<>J<k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EIF"{,m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6cXZ3;a  
nEndPos = " + nFileLength); s9,Z}]Th  
// fileSplitterFetch[nPos.length-1].start(); Ou{VDE  
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//等待子线程结束 -{ES 36  
//int count = 0; FD/=uIXH2  
//是否结束while循环 @ \*Zq  
boolean breakWhile = false; IlZ$Jd  
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while(!bStop) y wmC>`0p  
{ [:8+ +#KD  
write_nPos(); E|y   
Utility.sleep(500); @#"6_{!j_X  
breakWhile = true; B-
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4 {+47=n  
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for(int i=0;i<nStartPos.length;i++) ^/)%s3  
{ b\p2yJ\  
if(!fileSplitterFetch.bDownOver) mD7kOOMY  
{ 3&zcdwPj  
breakWhile = false; ^00C"58A  
break; =>L2~>[  
} !+(H(,gI  
} =-]NAj\  
if(breakWhile) aSIoq}c(  
break; h/]));p  
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R%"'k<`#  
//count++; |LirjC4  
//if(count>4) <=%=,Yk  
// siteStop();  ?%*p!m  
} :kvQ3E0  
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System.err.println("文件下载结束！"); yM*_"z!L  
} Rbcu5.6  
catch(Exception e){e.printStackTrace ();} Jk57| )/  
} T@d4NF#  
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)!Zm*(  
//获得文件长度 lsU`~3nr  
public long getFileSize() { a_&L  
{ 2E0oLl[  
int nFileLength = -1; D~)bAPAD  
try{ 3x)jab  
URL url = new URL(siteInfoBean.getSSiteURL()); D!mx&O9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f1q0*
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httpConnection.setRequestProperty("User-Agent","NetFox"); \7G.anY  
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int responseCode=httpConnection.getResponseCode(); d 9]zB-A  
if(responseCode>=400) 9yp'-RKjw  
{ B#4'3Y-3  
processErrorCode(responseCode);  Y+Cv9U0  
return -2; //-2 represent access is error nnCz!:9p  
} '^(qlCI  
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String sHeader; =g?k`vp  
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for(int i=1;;i++) W8M(@* T  
{ Z<#h$XUA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Lc0=5]D  
//Utility.log(in.readLine()); ucFfxar"  
sHeader=httpConnection.getHeaderFieldKey(i); |}Z2YDwO/  
if(sHeader!=null) 4jW <*jM  
{ KgXu x-q  
if(sHeader.equals("Content-Length")) .f`KP!p.  
{ "Iacs s0;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jXIVR'n(  
break; \pXo~;E
\  
} *mn"GK6  
} 7=a e^GKo  
else _% i!LyG  
break; 0~e6\7={  
} (?ZS9&y}  
} 4ULdf|oP"  
catch(IOException e){e.printStackTrace ();} c|X}[  
catch(Exception e){e.printStackTrace ();} Q}#xfrprF  
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Utility.log(nFileLength); ~-'-<-  
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return nFileLength; :VE0eJ]J6  
} );{76  
;#=y5Q4  
'`j MNKn\  
//保存下载信息（文件指针位置） OV`li#H  
private void write_nPos() J:G{  
{ W&7(  
try{ goc; .~?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eQ<GNvm  
output.writeInt(nStartPos.length); yh{U!hG  
for(int i=0;i<nStartPos.length;i++) AsR}qqG  
{ Wz;@Rl|F  
// output.writeLong(nPos); l0eh}d  
output.writeLong(fileSplitterFetch.nStartPos); %`lLX/4~  
output.writeLong(fileSplitterFetch.nEndPos); >]kZ2gVt  
} MJU*Sq  
output.close(); 68~5Dx  
} Zi<(>@z2  
catch(IOException e){e.printStackTrace ();} DuIgFp  
catch(Exception e){e.printStackTrace ();} ~|{_Go{ Q  
} _O&P!hI  
37*2/N2  
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//读取保存的下载信息（文件指针位置） S 9;FD3  
private void read_nPos() Bnw^W_  
{ <DhuY/o  
try{ 2\CZ"a#[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]PB95%  
int nCount = input.readInt(); S$/SFB$)~W  
nStartPos = new long[nCount]; 60l!3o"p!  
nEndPos = new long[nCount]; MHS|gR.c  
for(int i=0;i<nStartPos.length;i++) 0O(Vyy  
{ (O/W`qo  
nStartPos = input.readLong(); oSl}A,aQ(  
nEndPos = input.readLong(); gi+FL_8CzU  
} !ZY1
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input.close(); @]L$eOV_  
} 3?TUt{3g  
catch(IOException e){e.printStackTrace ();} Eo@rrM:  
catch(Exception e){e.printStackTrace ();} t-Ble  
} t-SZBNb  
B/B`=%~5_^  
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private void processErrorCode(int nErrorCode) Nx!7sE*b$1  
{ n>,? V3ly  
System.err.println("Error Code : " + nErrorCode); f/{ClP.  
} CKX3t:HP0  
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//停止文件下载 SVPksr  
public void siteStop() j{@li1W@  
{ % @!hf!  
bStop = true; h<7@3Ur  
for(int i=0;i<nStartPos.length;i++) zrwzI+4  
fileSplitterFetch.splitterStop(); zuF]E+  
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} Fe2t[y:8h  
} ;8cTy8  
//负责部分文件的抓取 ek d[|g  
**FileSplitterFetch.java f||S?ns_  
*/ ~|ha91  
package NetFox; wdIJ?\/763  
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import java.io.*; fn8|@)J  
import java.net.*; w8F`RRHEE  
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public class FileSplitterFetch extends Thread { ^~s!*T)\  
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String sURL; //File URL 9 $^b^It  
long nStartPos; //File Snippet Start Position H%{k.#O  
long nEndPos; //File Snippet End Position :bkmm,%O  
int nThreadID; //Thread's ID -X-sykDm  
boolean bDownOver = false; //Downing is over J^zB5W,)  
boolean bStop = false; //Stop identical gI/(hp3ob  
FileAccessI fileAccessI = null; //File Access interface {uxTgX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <(1[n pS&+  
{ hb1eEn  
this.sURL = sURL; !1l~'/r  
this.nStartPos = nStart; I(b]V!mj:  
this.nEndPos = nEnd; :g{ybTSEe  
nThreadID = id; >b8-v~o{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m14'u GC  
} <VhD>4f{]  
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public void run() (^58$IW71  
{ zX6Q7Bc  
while(nStartPos < nEndPos && !bStop) 4r#4h4`y|  
{ [J55%N;#1  
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try{ whFJ]  
URL url = new URL(sURL); 4ZkaH(a1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z7k ku:9  
httpConnection.setRequestProperty("User-Agent","NetFox"); }taG/kE62  
String sProperty = "bytes="+nStartPos+"-"; lkJe7 +s  
httpConnection.setRequestProperty("RANGE",sProperty); 5=1Ml50  
Utility.log(sProperty); 4h T!D
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InputStream input = httpConnection.getInputStream(); EtQ:x$S_  
//logResponseHead(httpConnection); 24\^{3nOK  
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byte[] b = new byte[1024]; JD9
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int nRead; tD,I7%|@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TY?O$d2b3  
{ D5
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nStartPos += fileAccessI.write(b,0,nRead); -op)X>  
//if(nThreadID == 1) ?U =Mdw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >?.jN|  
} Lz!H@)-mr  
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Utility.log("Thread " + nThreadID + " is over!"); N$u: !  
bDownOver = true; V5gr-^E  
//nPos = fileAccessI.write (b,0,nRead); _>_"cKS  
} 6NQ`IC  
catch(Exception e){e.printStackTrace ();} 3E}j*lo  
} 3mL(xpT.8z  
} lHE \Z`  
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AEUR`.  
//打印回应的头信息 O^_CqT%  
public void logResponseHead(HttpURLConnection con) j}
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{ ^FZ9q  
for(int i=1;;i++) +^%)QH>9   
{ KL"_h`UW  
String header=con.getHeaderFieldKey(i); 6q,CEm  
if(header!=null) (px3o'lsh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S|?P#.=GX  
Utility.log(header+" : "+con.getHeaderField(header)); g'2}Y5m$`  
else @.,'A[D!K  
break; +wZ|g6vMct  
} =&~ K;=:  
} n*caP9B  
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public void splitterStop() R7c42L\QA  
{ D`U,T&@  
bStop = true; qCq?`0&#  
} 2iC BF-,  
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} ]C{N4Ni^Z  
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/* tH:?aP*2  
**FileAccess.java -![{Zb@  
*//文件访问(定位，写) V0n8fez b  
package NetFox; $QwzL/a  
import java.io.*; O2xqNQ`d  
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public class FileAccessI implements Serializable{ UG]x CkDS  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 99n;%W>  
RandomAccessFile oSavedFile; M0hR]4T  
long nPos; g!i45]6[Nw  
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public FileAccessI() throws IOException 5i'KGL  
{ "2 D{X  
this("",0); h;mOfF  
} '-#gQxIpD  
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public FileAccessI(String sName,long nPos) throws IOException =@nW;PUZ  
{ G0Z$p6z  
oSavedFile = new RandomAccessFile(sName,"rw"); s !II}'Je  
this.nPos = nPos; s"~,Zzy@j  
oSavedFile.seek(nPos); 4C3i  
} u,~+ho@  
^ '_Fd  
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public synchronized int write(byte[] b,int nStart,int nLen) ?OGs+G  
{ IvI;Q0E-3  
int n = -1; Z/:W.*u  
try{ ?.ofs}  
oSavedFile.write(b,nStart,nLen); \aN5:Yy  
n = nLen; p*JP='p  
} @P[%6 d  
catch(IOException e) F5{GMn;j  
{ rLbFaLeQ  
e.printStackTrace (); AP9\]qZ(7  
} m"
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return n; 9e&*++vf  
} mXu";?2  
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} 0:x+;R<P*w  
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/* \2Kl]G(w%y  
**SiteInfoBean.java aw7pr464  
*/ {@s6ly].  
package NetFox; $
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"AIS6%,  
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public class SiteInfoBean { R^.c  
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private String sSiteURL; //Site's URL S-brV\v7  
private String sFilePath; //Saved File's Path buHUBn[3)  
private String sFileName; //Saved File's Name \_+Af`  
private int nSplitter; //Count of Splited Downloading File 7j"B-k#  
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public SiteInfoBean() Eb8z`@p  
{//nSplitter的缺省值为5 5KssfI a  
//default value of nSplitter is 5 luz
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this("","","",5); !m9g\8tE  
} ul"Z% 1]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fJi?~[5<  
{ t2qWB[r  
sSiteURL= sURL; :k~ p=ko  
sFilePath = sPath; w!Z,3Yc)  
sFileName = sName; /|<0,ozoJ  
this.nSplitter = nSpiltter; @2\UjEo~  
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} Kn\$\?u  
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public String getSSiteURL() OW8TiM mK  
{ ; d}  
return sSiteURL; <q|eG\01S  
} XsMETl"Av4  
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public void setSSiteURL(String value) X<H+Z2d  
{ ~>}7+p ?;  
sSiteURL = value; Ll^9,G"Tt  
} <a2Kc '  
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public String getSFilePath() MO79FNH2\  
{ v2mqM5Z  
return sFilePath; jF5oc  
} L/O:V^1  
1:"ZS ]i  
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public void setSFilePath(String value) AOCiIPw  
{ dr4m}v.  
sFilePath = value; o4&#,m+:  
} [_p&,$z8[  
DzY`O@D[  
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public String getSFileName() yMf["AvG  
{ _\FA}d@N  
return sFileName; y;HJ"5.Mw  
} 4$v08zZ  
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public void setSFileName(String value) R=HcSRTkA  
{ vu)V:y  
sFileName = value; jyjK~!0  
} h,'m*@Eg  
}sGH}n<9*  
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public int getNSplitter() _NM=9cWd  
{ "gi 1{  
return nSplitter; 5LxzET"P  
} cUr'mb  
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public void setNSplitter(int nCount) U^$l$"~"  
{ LpSd/_^b  
nSplitter = nCount; %:.00F([r  
} a7l-kG=R;  
} $RV'DQO  
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/* C`C$i>X7^  
**Utility.java ]i:O+t/U  
*/ &k {1N.  
package NetFox; Yy8%vDdJO  
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public class Utility { `LCxxpHi|  
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}U7><I  
public Utility() 8I=migaxP  
{ |;P9S
  
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} \~
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_}wy|T&7k&  
//线程睡眠 o@G <[X|ke  
public static void sleep(int nSecond) _&6&sp<n  
{ d[I}+%{[  
try{ BM]sW:-v  
Thread.sleep(nSecond); FA;uu
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} lO0 PZnW9  
catch(Exception e) kculHIa\.  
{ |JH1?n  
e.printStackTrace (); p)=Fi}#D\  
} Y
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} bi[gyl#  
c>RS~/Y  
//日志 ~*h` ?A0  
public static void log(String sMsg) h+h`0(z  
{ p,+$7f1S  
System.err.println(sMsg); bPtbU:G  
} QA&BNG  
8z,|N#  
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public static void log(int sMsg) @[4Tdf  
{ )fz<n$3|$#  
System.err.println(sMsg); CzZmC]5  
} 38T2IN  
} cB9`U4<  
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/* y2eeE CS]  
**TestMethod.java Awad!_VdHS  
*/ n.$wW =  
package NetFox; C.$`HGv  
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public class TestMethod { "b"Q0"w  
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public TestMethod() T6ajWUw  
{ ///xx/weblogic60b2_win.exe "!6 Ax-'  
try{ X}v]iX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RWi~34r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~h{
v^}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3N,
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fileFetch.start(); IU`&h2KZ.  
} ApYri|^r  
catch(Exception e){e.printStackTrace ();} qE`  
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} L 59q\_|  
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public static void main(String[] args) gs_nUgcA  
{ r9@Q="J_)  
new TestMethod(); GJY7vS^#  
} ?B2 T'}
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} ^\uj&K6l  
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