http断点续传简单实现（java)

/* C\*0621  
**SiteFileFetch.java 9 xFX"_J  
*/ [ub)`-6 u  
package NetFox; G%T<wKD<  
import java.io.*; k;HI-v  
import java.net.*; >iI_bcqF  
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public class SiteFileFetch extends Thread { \F<C$cys\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 70Ei<  
long[] nStartPos; //开始位置 ;W3c|5CE  
long[] nEndPos; //结束位置 uk3PoB^>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *
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long nFileLength; //文件长度 ki8Jl}dr  
boolean bFirst = true; //是否第一次取文件 ZBjb f_M:  
boolean bStop = false; //停止标志 tY60~@YO&  
File tmpFile; //文件下载的临时信息 ,PX7}//X^  
DataOutputStream output; //输出到文件的输出流 j#9n.i %h  
X + B=?|M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Hm_&``='  
public SiteFileFetch(SiteInfoBean bean) throws IOException :V#B]:Z9  
{ Bb7Vf7>  
siteInfoBean = bean; rrl{3
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o'ZW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 87hU#nVYh  
if(tmpFile.exists ()) sd |c/ayh~  
{ (n2=.9k!  
bFirst = false; }K
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read_nPos(); )Hqn  
} !lI1jb"
 
else z[0t%]7l  
{ 8zpTCae^=7  
nStartPos = new long[bean.getNSplitter()]; z*WQ=l2  
nEndPos = new long[bean.getNSplitter()]; 6g"qwWZp  
} nW]T-!  
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} ]GzfU'fOn|  
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public void run() V/J-zH&  
{ f1I/aRV:+  
//获得文件长度 2XV3f$,H  
//分割文件 CMYkxU  
//实例FileSplitterFetch 1P/4,D@  
//启动FileSplitterFetch线程 \5F {MBx !  
//等待子线程返回 ?8$h%Ov-  
try{ SOvo%L@  
if(bFirst) }1YQ?:@  
{ f:h<tlob  
nFileLength = getFileSize(); xUDXg*  
if(nFileLength == -1) DC=XPn/V  
{ ,>3|\4/Q  
System.err.println("File Length is not known!"); Y^'mBM#j  
} OyyE0  
else if(nFileLength == -2) D=~3N  
{ [?F]S:/i  
System.err.println("File is not access!"); h\*I*I8C  
} "=*  
else 9w$+Qc  
{ X1GM\*BE  
for(int i=0;i<nStartPos.length;i++) ^-
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{ [
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5}`e"X  
} VRz9;=m  
for(int i=0;i<nEndPos.length-1;i++) E=l^&[
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{ Ve4@^Jy;  
nEndPos = nStartPos[i+1]; 7
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} vkW]?::Cfd  
nEndPos[nEndPos.length-1] = nFileLength; X=pPkgW  
} GD }i=TK  
} Y!AQ7F  
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;Y`k-R:E6A  
//启动子线程 Ml9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (W_U<~`t  
for(int i=0;i<nStartPos.length;i++) G1/  
{ K?acRi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3+iQct[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \m1jV>q  
nStartPos,nEndPos,i); 4GqE%n+ta~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f}+8m .g2  
fileSplitterFetch.start(); bd3q207>  
} kB;!EuL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;.b^A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :faB7wduW;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !!UQ,yU  
nEndPos = " + nFileLength); <^wqN!/  
// fileSplitterFetch[nPos.length-1].start(); 'A9U[|  
Bhw|!Y&%  
 7VAet  
//等待子线程结束 ?K^~(D8(  
//int count = 0; 73kL>u  
//是否结束while循环 B;xGTl@8  
boolean breakWhile = false; ;U$EM+9  
[;hCwj#  
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while(!bStop) O,?aVgY  
{ >X-*Hu'U#  
write_nPos(); HU+zzTgI  
Utility.sleep(500); /a:L"7z  
breakWhile = true; :]^FTnO  
,N`D{H"F  
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for(int i=0;i<nStartPos.length;i++) TGu]6NzyZ  
{ 9aZ^m$tAt  
if(!fileSplitterFetch.bDownOver) UqZ#mKi  
{ d]w%zo,yr  
breakWhile = false; d3K-|  
break; ]~-
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} UIi`bbJ  
} y]TNjLpo$  
if(breakWhile) D!CuE7}  
break; _%$(D"^j  
g}]EIv{  
XN=Cq*3}  
//count++; U~w g'  
//if(count>4) MN22#G4j^w  
// siteStop(); m*^|9*dIC  
} 4JD 8w3u/  
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System.err.println("文件下载结束！"); %VCfcM}5I  
} 1xkU;no  
catch(Exception e){e.printStackTrace ();} #1C~i}J1  
} 9C{\=?e;  
n*oa J<o%  
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//获得文件长度 <XH

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public long getFileSize() "n3i(sZ  
{ ;5.o;|w?!  
int nFileLength = -1; 6!3Jr  
try{ I:qfB2tL)O  
URL url = new URL(siteInfoBean.getSSiteURL()); n6a*|rE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T"GuE[?a  
httpConnection.setRequestProperty("User-Agent","NetFox"); joN}N}U  
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int responseCode=httpConnection.getResponseCode(); ;Q]j"1c  
if(responseCode>=400) %YaUc{.%  
{ ^3-Wxn9&  
processErrorCode(responseCode); iZy
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return -2; //-2 represent access is error L8~nx}UP5
 
} O&:0mpRZ  
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String sHeader; _uO#0 )l  
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for(int i=1;;i++) >Ufjmm${  
{ ; -R
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_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y"uFlHN&i  
//Utility.log(in.readLine()); Jb~-)n2  
sHeader=httpConnection.getHeaderFieldKey(i); E00zf3Jgv'  
if(sHeader!=null) UEq;}4Bo  
{ I>27
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if(sHeader.equals("Content-Length")) >t"]gQHtx  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !k&~|_$0@  
break; [LonY
49  
} axY-Vj
 
} Hr$oT=x[  
else LaZF=<w(  
break; k:4?3zJI  
} bmAgB}Ior  
} sK:,c5^  
catch(IOException e){e.printStackTrace ();} t#y  
catch(Exception e){e.printStackTrace ();} xX'Uq_Jv  
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Utility.log(nFileLength); r<oI4px  
{/BEO=8q2  
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return nFileLength; 0;)6ZU  
} z#!xqIg0  
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v.1= TBh  
//保存下载信息（文件指针位置） (oxe\Qk  
private void write_nPos() 'D-#,X C  
{ &F}1\6{fL  
try{ 6QRfju'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =3=KoH/'  
output.writeInt(nStartPos.length); zJMKgw,i*  
for(int i=0;i<nStartPos.length;i++) l\^q7cXG  
{ LeW.uh3.  
// output.writeLong(nPos); e![Q1!r  
output.writeLong(fileSplitterFetch.nStartPos); lq@Vb{Z  
output.writeLong(fileSplitterFetch.nEndPos); AEwb'  
} 4(4JQ(5  
output.close(); =tcPYYD  
} *eXO?6f%s^  
catch(IOException e){e.printStackTrace ();} $UjSP  
catch(Exception e){e.printStackTrace ();} 2LYd # !i  
} ZZC= 7FB  
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//读取保存的下载信息（文件指针位置） YeJ95\jf  
private void read_nPos() g]xZ^M+  
{ ~,e!t.339  
try{ t%z7#}9$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IQ{Xj3;?y  
int nCount = input.readInt(); V8&/O)}o  
nStartPos = new long[nCount]; L1QQU  
nEndPos = new long[nCount]; bT-G<h*M  
for(int i=0;i<nStartPos.length;i++) (?\ZN+V)  
{ gE=~.P[Z
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nStartPos = input.readLong(); fnnwe2aso  
nEndPos = input.readLong(); vP}K(' (  
} oQ;f`JC^  
input.close(); /^[)JbgB  
} ):78GVp  
catch(IOException e){e.printStackTrace ();} 5 J|;RtcR  
catch(Exception e){e.printStackTrace ();} gSj-~kP  
} CHpDzG>]4  
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private void processErrorCode(int nErrorCode) %Y Rg1UKY  
{ *Kzs(O  
System.err.println("Error Code : " + nErrorCode); @@|E1'c7  
} s*CKFEb#  
)+t5G>yKK  
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//停止文件下载 !P Gow  
public void siteStop() G^m
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{ z3*G(,  
bStop = true; C6"!'6 W  
for(int i=0;i<nStartPos.length;i++) w78Ius,  
fileSplitterFetch.splitterStop(); &<Gq-IN  
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} RO.(k!J .  
} vWkKNB  
//负责部分文件的抓取 "(efd~.]  
**FileSplitterFetch.java x#8=drh.:C  
*/ ,t+ATaOF  
package NetFox; r3j8[&B"  
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import java.io.*;
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import java.net.*; aY:(0en]&  
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public class FileSplitterFetch extends Thread { 6$6NVq  
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String sURL; //File URL *Ra")(RnDK  
long nStartPos; //File Snippet Start Position n&C9f9S  
long nEndPos; //File Snippet End Position zRJy3/>  
int nThreadID; //Thread's ID k(qQvn  
boolean bDownOver = false; //Downing is over Wq9s[)F"Z  
boolean bStop = false; //Stop identical ?^ErrlI_  
FileAccessI fileAccessI = null; //File Access interface #P9VX5Tg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =h_gj >  
{ &\X;t|  
this.sURL = sURL; {H+?DMh  
this.nStartPos = nStart; BkZ%0rw%  
this.nEndPos = nEnd; KncoIw  
nThreadID = id; 'j)eqoj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `2fuV]FW  
} E7h}0DX  
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 yY| .  
public void run() 3QHZC0AY  
{ &V:dcJ^Q  
while(nStartPos < nEndPos && !bStop) ]czy8n$+  
{ )[K3p{4  
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#] GM#.  
try{ UKJY.W!w4  
URL url = new URL(sURL); Q]7Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2DC#PX)i  
httpConnection.setRequestProperty("User-Agent","NetFox"); `P5"5N\h  
String sProperty = "bytes="+nStartPos+"-"; .~U9*5d  
httpConnection.setRequestProperty("RANGE",sProperty); l46F3C|  
Utility.log(sProperty); 0/gcSW b  
;Pa(nUE@  
*=7[Ip<X  
InputStream input = httpConnection.getInputStream(); ~/x42|t  
//logResponseHead(httpConnection); /< :;^B  
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byte[] b = new byte[1024]; VxFy[rP  
int nRead; ``<1Lo@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^"l$p,P+  
{ Qm.kXlsDI  
nStartPos += fileAccessI.write(b,0,nRead); 0\#Q;Z2  
//if(nThreadID == 1) @ tIB'|O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `@eH4}L*  
} ( 7?%Hg  
fA8
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Utility.log("Thread " + nThreadID + " is over!"); 9vbh5xX   
bDownOver = true; 7xc<vl#:q7  
//nPos = fileAccessI.write (b,0,nRead); Xdq, =;  
} *YtNt5u  
catch(Exception e){e.printStackTrace ();}  B~NC  
} ~/U0S.C  
} dc>y7$2  
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//打印回应的头信息 :65HMWy.  
public void logResponseHead(HttpURLConnection con) f$>orVm%.  
{ m#nxw  
for(int i=1;;i++) cBI)?  
{ %8L<KJd  
String header=con.getHeaderFieldKey(i); 0uz"}v)  
if(header!=null) Rpk`fxAO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `
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Utility.log(header+" : "+con.getHeaderField(header)); Ds87#/Yfv  
else rxK0<pWJhx  
break; QC4T=E]`j  
} Vi#im`@  
} '| }
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_o.Z`]  
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public void splitterStop() ]K7 64}  
{  /Xz4q!Ul  
bStop = true; +*J4q5;E[?  
} c2^7"`  
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} I{zE73  
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/* MI(i%$R-A  
**FileAccess.java 5G!U'.gr  
*//文件访问(定位，写) f4S@lyYF  
package NetFox; {{3H\ rR  
import java.io.*; S7a6ntei  
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public class FileAccessI implements Serializable{ kkB
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @'*#]YU8  
RandomAccessFile oSavedFile; CLfb`rF  
long nPos; !)3s <{k#  
cf'}*$[S  
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public FileAccessI() throws IOException UWp8I)p!\O  
{ l _O~v?  
this("",0); DH9?2)aR  
} ~Ls I<
z  
-^H5z+"^  
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public FileAccessI(String sName,long nPos) throws IOException xD#I&.  
{ o'7ju~0L  
oSavedFile = new RandomAccessFile(sName,"rw"); ;CMC`h9,  
this.nPos = nPos; 23$hwr&G\  
oSavedFile.seek(nPos); |u"R(7N*  
}  #>jH[Q  
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public synchronized int write(byte[] b,int nStart,int nLen) pMp9O/u%  
{ 3Z

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int n = -1; htYrv5q=M  
try{ j{R|]SjW2H  
oSavedFile.write(b,nStart,nLen); |/^aLj^u  
n = nLen; 1vs>2` DLa  
} WlQ=CRY  
catch(IOException e) Kw0V4UF  
{ 0~b6wuFl  
e.printStackTrace (); !7`=rT&  
} j' KobyX<  
hS{ *l9v7  
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return n; @Q\$dneY  
} zXPJ;^Xxa  
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} ;9p5YxD  
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/* &IEBZB\/+&  
**SiteInfoBean.java T{4fa^c2J  
*/ q
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package NetFox; DgT.Lku?  
$;i$k2n:  
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public class SiteInfoBean { Usf"K*A  
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private String sSiteURL; //Site's URL uU(G_E ?  
private String sFilePath; //Saved File's Path :
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private String sFileName; //Saved File's Name tD7C7m  
private int nSplitter; //Count of Splited Downloading File 8^/Ek<Qb|  
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public SiteInfoBean() h"1"h.  
{//nSplitter的缺省值为5 *!]Epb  
//default value of nSplitter is 5 199hQxib:  
this("","","",5); _2X6
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} 8wpwJs&V  
@~#79B"9&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EXW 6yXLV  
{ wJos'aTmE  
sSiteURL= sURL; k3/JQ]'D  
sFilePath = sPath; [^d6cMEOlc  
sFileName = sName; ok%a|Zz+]  
this.nSplitter = nSpiltter; 2}`Vc{\  
zNr_W[  
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} />^`*e_  
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6 ,pZRc  
public String getSSiteURL() N<Z)b!o%u  
{ 1Q&WoJLfR  
return sSiteURL; t:"=]zUU  
} {`Fx~w;i  
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*VC4s`<  
public void setSSiteURL(String value) Hu9-<upc&  
{ sx(l  
sSiteURL = value; z^!A/a[[!  
} j&[3Be'pQ  
|
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!/Bw,y ri<  
public String getSFilePath() K!-&Zv  
{ %YvSHh;c  
return sFilePath; *4hOCQ[  
} \p@nH%@v  
}Cmj(k`~  
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public void setSFilePath(String value) 'tV"^KQHI  
{ dJQ }{,+6  
sFilePath = value; mWN1Q<vn,l  
} *@G(3 n  
0'%+X|  
cfC;eRgq~  
public String getSFileName() g3|Y$/J7P  
{ ^E<~zO=Z  
return sFileName; )0n29  
} *`g-gk  
Z\*5:a]  
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public void setSFileName(String value) ??\*D9rCn  
{ iUxDEt[t*  
sFileName = value; fD\^M{5f  
} ^aD
/ .  
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=hugnX<9  
public int getNSplitter() 3<jAp#bE  
{ 1fO2)$Y  
return nSplitter; fUp
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} }/7.+yD  
CFkW@\]  
fbHW
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public void setNSplitter(int nCount) ]U#[\ Z  
{ "S B%02  
nSplitter = nCount; *fQ?A|l!x  
} @;m@Luk  
} A4#3O5kij  
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/* "u Of~e"  
**Utility.java JI+KS  
*/ ^
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package NetFox; wv7p,9Z[  
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public class Utility { +B`'P9Zk@  
z,}c?BP  
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public Utility() tyn?o  
{ qL%.5OCn(  
c#\ah}]Vo  
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} X ]pR,\B  

)8x:x7?  
//线程睡眠 .y %pGi  
public static void sleep(int nSecond) M9(ez7Z  
{ {.aK{ V  
try{ W2F+^  
Thread.sleep(nSecond); Nh1e1m?  
} 0okO+Q
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catch(Exception e) ;B|^2i1Wi  
{ #uD)0zdw  
e.printStackTrace (); e9z$+h  
} G!!-+n<  
} #RR:3ZPZC  
HsjELbH  
//日志 p@cfY]<7  
public static void log(String sMsg) 5eiZs  
{ q9>Ls-k  
System.err.println(sMsg); b!4N)t>gl  
} ;PfeP;z  
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bk\dy7  
public static void log(int sMsg) ]^yV`Z8  
{ GZ/pz+)i&  
System.err.println(sMsg); y+ 6`| h_  
} _XH4;uGg  
} eD*?q7  
_"?c9  
};|!Lhl+  
/* *<`7|BH3  
**TestMethod.java vHs>ba$"  
*/ 0%;N9\  
package NetFox; Cbgj@4H  
F:[7^GQZ{  
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public class TestMethod { N`,7FI}  
HZQDe&  
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public TestMethod() _L&n&y1+%  
{ ///xx/weblogic60b2_win.exe IZ4W_NN  
try{ ONjC(7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rmY,v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wphe%Of  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ewb*?In  
fileFetch.start(); ntrY =Y  
} 8Zcol$XS'  
catch(Exception e){e.printStackTrace ();} M(n<Iu4^_  
fnVW/23  
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} ( GFgt_  
+G*"jI8W  
V+qFT3?-  
public static void main(String[] args) y;,=ajrF  
{ EzzTJ>  
new TestMethod(); ]4Nvh\/P9  
} ?8Hn{3X  
} ]%gp?9wy  
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