http断点续传简单实现（java)

/* EEo+#  
**SiteFileFetch.java sIy$}_  
*/ l|up3A3)  
package NetFox; L+kS8D<  
import java.io.*; a0LX<}   
import java.net.*; "Q J-IRt&  
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public class SiteFileFetch extends Thread { /nmfp&@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $7bmUQ|  
long[] nStartPos; //开始位置 CKR9APkv  
long[] nEndPos; //结束位置 JR>B<{xB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .z4FuG,R  
long nFileLength; //文件长度 !*ucVv;  
boolean bFirst = true; //是否第一次取文件 )I$Mh@F  
boolean bStop = false; //停止标志 O0l;
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File tmpFile; //文件下载的临时信息 ixH7oWH#  
DataOutputStream output; //输出到文件的输出流 c]&VUWQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pxC5
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public SiteFileFetch(SiteInfoBean bean) throws IOException f 0#V^[%Q  
{ ^R$dG[Qf  
siteInfoBean = bean; j,-7J*A~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k %rP*b*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e/3hb)#;  
if(tmpFile.exists ()) #3$|PM7,_  
{ 0`thND)?O  
bFirst = false; ;Dgp !*v=  
read_nPos(); #P@r[VZ{6  
} Dm^kuTIG  
else f:0n-me  
{ ;5l|-&{@*  
nStartPos = new long[bean.getNSplitter()]; [eN{
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nEndPos = new long[bean.getNSplitter()]; 6qDD_:F  
} NNdS:(  
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} NEH$&%OV?  
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public void run() CUG<v3\  
{ tSYnc7  
//获得文件长度 M:$nL  
//分割文件 }.vy|^X  
//实例FileSplitterFetch ?n+\T'f!  
//启动FileSplitterFetch线程 `ouzeu9}  
//等待子线程返回 LN^8U  
try{ &40]sxm  
if(bFirst) b#U%aPH  
{ /km3L7L%R  
nFileLength = getFileSize(); *X-$* ~J0  
if(nFileLength == -1) ;CZcY] ol  
{ BYf"l8^,  
System.err.println("File Length is not known!"); 7EXmmB~>,  
} /{va<CL  
else if(nFileLength == -2) /0uinx  
{ iD`XD\.?  
System.err.println("File is not access!"); mTg
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} @$R a  
else ;$Jvqq|T  
{ q}i87a;m  
for(int i=0;i<nStartPos.length;i++) y^rg%RV  
{ #*/h
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z#O3s:`  
} hH/O2  
for(int i=0;i<nEndPos.length-1;i++) g <o;\\  
{ VLN3x.BY  
nEndPos = nStartPos[i+1]; g-}sVvM  
} hzb|:  
nEndPos[nEndPos.length-1] = nFileLength; ~
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} nSi
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} ZM?r1Z4  
}"Cn kg  
{@%(0d{n}  
//启动子线程 >cb gL%
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s`YuH <8  
for(int i=0;i<nStartPos.length;i++) F! e`i-xt  
{ TbVL71c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U'G`Q0n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QEKFuY<E+  
nStartPos,nEndPos,i); bl<7[J.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z;
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fileSplitterFetch.start(); . 6dT5x8u  
} ^ym{DSx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^aCYh[
=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gi>_>zStv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aO%FQ)BT  
nEndPos = " + nFileLength); V1`|j  
// fileSplitterFetch[nPos.length-1].start(); sQs5z~#51*  
zOdKB2_J7  
ZtoE=7K  
//等待子线程结束 du,-]fF  
//int count = 0; ^nF$<#a  
//是否结束while循环 jYz3(mM'J  
boolean breakWhile = false; dDbC0} x/  
eb\`)MI/  
<GRf%zJ  
while(!bStop) E;H(jVZ  
{ UD`Z;F  
write_nPos(); Kj 8 W  
Utility.sleep(500); f:5/y^M&  
breakWhile = true; *,*qv^  
Dt.Wb&V_w  
/nFw  
for(int i=0;i<nStartPos.length;i++) X)OP316yx  
{ Qu_T&  
if(!fileSplitterFetch.bDownOver) hp4(f W  
{ %Qz`SO8x?  
breakWhile = false; ;%alZ  
break; DG?\6Zh  
} TWEqv<c  
} ;@ X  
if(breakWhile) J*X.0&Toc  
break; J9.p8A^^2  
 eb@L
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z{L;)U B^  
//count++; zEfD{I  
//if(count>4) m0\}Cc  
// siteStop(); vPNZFi-(  
} K<JP9t6Qd  
|qDfFGYf  
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System.err.println("文件下载结束！"); L0  2~FT  
} 7=A9E]:  
catch(Exception e){e.printStackTrace ();}
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} c[lob{,  
Ki6.'#%7  
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//获得文件长度 >%dAqYi $  
public long getFileSize() ibs"Iv34  
{ no6]{qn=6  
int nFileLength = -1; F)kLlsp  
try{ <9tG_  
URL url = new URL(siteInfoBean.getSSiteURL()); vXQmEIm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H)aC'M^
 
httpConnection.setRequestProperty("User-Agent","NetFox"); @zF:{=+]+  
u!k<sd_8B  
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int responseCode=httpConnection.getResponseCode(); `1<3Hu_  
if(responseCode>=400) ,r
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{ -L?% o_  
processErrorCode(responseCode); 8z8SwWS?  
return -2; //-2 represent access is error
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} )}\@BtcjA]  
)ZyuF(C&  
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String sHeader; gD+t'qg$  
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c$:=d4t5$  
for(int i=1;;i++) Nw&}qSN  
{ (G%gVk]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s{J!^q  
//Utility.log(in.readLine()); WTv\HI2X !  
sHeader=httpConnection.getHeaderFieldKey(i); I jztj  
if(sHeader!=null) DLVs>?Y  
{ H6S vU  
if(sHeader.equals("Content-Length")) gs8@b5 RSb  
{ 9Sl|l.;!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XfK.Fj~-  
break; *Q120R  
} 8yz((?LrDh  
} &
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else '!h0![OH  
break; (DP9& b  
} MGyB8(  
} KXA)i5z  
catch(IOException e){e.printStackTrace ();} ::R00gd  
catch(Exception e){e.printStackTrace ();} [pFu ]^X  
7oLf5V1~  
}\L!;6oy  
Utility.log(nFileLength); yxWMatZ2  
=,8Eo"~\  
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return nFileLength; nEcd+7(  
} @&xaaqQ-  
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//保存下载信息（文件指针位置） o``>sBZOq  
private void write_nPos() /A))"D  
{ r
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try{ +ls*//R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AD%D ,l  
output.writeInt(nStartPos.length); Dzjt|U0ru9  
for(int i=0;i<nStartPos.length;i++) \j})Ku
l  
{ _u|FJTk  
// output.writeLong(nPos); {!eANm'  
output.writeLong(fileSplitterFetch.nStartPos); X<}o> 6|d  
output.writeLong(fileSplitterFetch.nEndPos); agU!D[M_G  
} :8-gm"awL5  
output.close(); KW7?: x  
} [gns8F#H\  
catch(IOException e){e.printStackTrace ();} Y0fO.k#C^  
catch(Exception e){e.printStackTrace ();} \pD=Lv9  
} QUZQY`'@  

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//读取保存的下载信息（文件指针位置） n$|c{2]=  
private void read_nPos() .0fh>kQ  
{ 9}jq`xSL  
try{ R~5*#r@f  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SM#S/|.]  
int nCount = input.readInt(); CndgfOF  
nStartPos = new long[nCount]; 27 145  
nEndPos = new long[nCount]; O][Nl^dl  
for(int i=0;i<nStartPos.length;i++) i$^B-  
{ Q$h:[_v  
nStartPos = input.readLong(); "3i80R\w`F  
nEndPos = input.readLong(); _X2EBpZp  
} fxoi<!|iGY  
input.close(); Ag4Ga?&8ec  
} -6~y$c&c  
catch(IOException e){e.printStackTrace ();} Z'*Z@u3  
catch(Exception e){e.printStackTrace ();} 7kX$wQZ_  
} !MJe+.  
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private void processErrorCode(int nErrorCode) "`i:)Et  
{ D@\;@( |  
System.err.println("Error Code : " + nErrorCode); g;!@DVF$  
} ?X#/1X%u:  
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r2GK_$vd  
//停止文件下载 r -q3+c^+  
public void siteStop() z'o
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{ l/png:  
bStop = true; MYhx'[4[3  
for(int i=0;i<nStartPos.length;i++) xBRh!w  
fileSplitterFetch.splitterStop(); {`H<=h__  
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} $~,}yh;  
} <{cNgKd9
 
//负责部分文件的抓取 JYg% ~tW'  
**FileSplitterFetch.java 3 IWLBc  
*/ '-PMF~~S  
package NetFox; ?)' 2l6  
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import java.io.*; phgexAq  
import java.net.*; 6vgBqn[  
8@%mnyQ  
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public class FileSplitterFetch extends Thread { EY)Gi`lK  
hH1lgc  
EzIs@}  
String sURL; //File URL 2T@L{ql  
long nStartPos; //File Snippet Start Position 1O7]3&L@  
long nEndPos; //File Snippet End Position 0Ws;|Y
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int nThreadID; //Thread's ID :/v,r=Y9p  
boolean bDownOver = false; //Downing is over cZgMA8 F  
boolean bStop = false; //Stop identical 1X::0;3  
FileAccessI fileAccessI = null; //File Access interface 7k]RO  
l 70,Jo?78  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P1i*u0a  
{ ^}o7*  
this.sURL = sURL; %-# qO  
this.nStartPos = nStart; ;Rhb@]X  
this.nEndPos = nEnd; dCZ\ S91q  
nThreadID = id; #`La|a.-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 os1?6z~  
} <8rgtu!VU  
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public void run() ok`]:gf  
{ X%GD0h]X#  
while(nStartPos < nEndPos && !bStop) s!#HZK  
{ zb5N,!%r  
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try{ wqlcLIJPR  
URL url = new URL(sURL); IX<r5!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~^I\crx,U%  
httpConnection.setRequestProperty("User-Agent","NetFox"); jow7t\wk  
String sProperty = "bytes="+nStartPos+"-"; OGJ=VQA  
httpConnection.setRequestProperty("RANGE",sProperty); Y5og
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Utility.log(sProperty); iW|s|1mh3  
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E &7@#'l  
InputStream input = httpConnection.getInputStream();  c6Lif)4  
//logResponseHead(httpConnection); Q !9HA[Ly  
'lhP!E_)q  
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byte[] b = new byte[1024]; 7L=T]W  
int nRead; @iU%`=ziz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .3VK;au\\  
{ )Fqy%uR8  
nStartPos += fileAccessI.write(b,0,nRead); r8uqcKfU  
//if(nThreadID == 1) PSTu/^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t`"^7YFS>  
} -@''[m.*  
=-$!:W~  
OlMBMUR:  
Utility.log("Thread " + nThreadID + " is over!"); CQdBf3q  
bDownOver = true; tTotPPZf}  
//nPos = fileAccessI.write (b,0,nRead); YP[
LQ>  
} 'nRp}s1^[  
catch(Exception e){e.printStackTrace ();} NJZXs_%>$  
} n6b3E*  
} 6*ZU}xT  
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//打印回应的头信息 ,e9CJ~a  
public void logResponseHead(HttpURLConnection con) u8Y~_)\MA  
{
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for(int i=1;;i++) mCM|&u  
{ [2Iau1<@  
String header=con.getHeaderFieldKey(i); tbq|,"  
if(header!=null) Ko#4z%Yq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z!fdx|PUX  
Utility.log(header+" : "+con.getHeaderField(header)); u(W^Nou/+  
else c~P)4(udT  
break; W_^>MLq  
} ajW[eyX  
} nV'
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-#Np7/  
I(pb-oY3!I  
public void splitterStop() ?>sQF4 V"  
{ Dk6?Nwy"  
bStop = true; EMLx?JnP  
} mA&=q_gS  
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p ZtgIS(3  
} lLH$`Wnv  
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l '/N3&5  
/* 3[VWTq)D=  
**FileAccess.java [*<.?9n)or  
*//文件访问(定位，写) (vKI1^,  
package NetFox; A8J8u,u9  
import java.io.*; $,TGP+vH  
:/B:FY=  
_R)&k%i}  
public class FileAccessI implements Serializable{ q0Xoj__c!A  
_zq)0\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c4\C[$  
RandomAccessFile oSavedFile; MU|{g 5/ )  
long nPos; Ls]@icH0  
r*chL&7  
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public FileAccessI() throws IOException lzEb5mg  
{ W6vf=I@f  
this("",0); lWbZ=x_0  
} G]4OFz+  
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\^LWCp,C"  
public FileAccessI(String sName,long nPos) throws IOException r@iASITX  
{ u)v$JpNE  
oSavedFile = new RandomAccessFile(sName,"rw"); &pM'$}T*  
this.nPos = nPos; [B,'=,Hbs  
oSavedFile.seek(nPos); %swR:
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} <s_=-" il  
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public synchronized int write(byte[] b,int nStart,int nLen) ZRnL_z~  
{ pYt/378w  
int n = -1; QQFf5^  
try{ SG:bM7*1'  
oSavedFile.write(b,nStart,nLen); M ?*Tf&  
n = nLen; 34ha26\np  
} vIVr@1S  
catch(IOException e) 9x?B5Ap[  
{ }p=g*Zo*C;  
e.printStackTrace (); MAnp{  
} Q[uAIyv0  
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return n; D{cZxI  
} r,4lqar;E  
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} L]I3P|y_  
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&Yf",KcL*I  
/* \, 8p1$G  
**SiteInfoBean.java 'a#mViPTQ)  
*/ f"Vgefk  
package NetFox; DL{R|3{N  
 / +1{  
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public class SiteInfoBean { $"\O;dp7l  
1{
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path X\\7$  
private String sFileName; //Saved File's Name Q`A6(y/s?  
private int nSplitter; //Count of Splited Downloading File @*(4dt:V  
OP%?dh]  
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public SiteInfoBean() OR4!YVVQ  
{//nSplitter的缺省值为5 j
)by}}  
//default value of nSplitter is 5 J R$r!hX  
this("","","",5); %ucjMa>t  
} EB!daZH,  
(?3[3w~  
SdJ/4&{ !  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X3wX`V}

  
{ 'e@=^FC  
sSiteURL= sURL; _dU8'H  
sFilePath = sPath; x6;j<m5Mjx  
sFileName = sName; g?G+dnl/8  
this.nSplitter = nSpiltter; J#Z5^)$  
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} KKEN'-3  
nX^1$')gp  
l?8)6z#Zl  
public String getSSiteURL()  f:wd&V  
{ c0ez/q1S  
return sSiteURL; bA@P}M)X  
} e;VIL 2|  
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s+Q;pRZW{  
public void setSSiteURL(String value) aDL*W@1S  
{ *hdC?m._  
sSiteURL = value; C4\,z\Q  
} F[Q!d6  
(qBvoLkF9N  
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public String getSFilePath() @hif$  
{ LA%bq_>f  
return sFilePath; VK:8 Nk_y  
} AIRr{Y  
1J}8sG2`  
y(a!YicA?  
public void setSFilePath(String value) eV7u*d?  
{ ;%!B[+ut"  
sFilePath = value; DCQ^fZ/  
} *5VXyt2  
%gd(wzco  
mC[UXN/  
public String getSFileName() -*a?<ES`  
{ MCc$TttaVz  
return sFileName; @5VV|Wt=  
} "D][e'  
6!q#x[A  
^qvZ XS  
public void setSFileName(String value) Uxu\u0*  
{ E9}{1A  
sFileName = value; 8VQ 24r  
} x
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jS<_ )  
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public int getNSplitter() ]zfG~^.  
{
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return nSplitter; Vj?DA5W`'  
} +&|S'7&{  
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dy>!KO  
public void setNSplitter(int nCount) 
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{ 'h1b1,b~  
nSplitter = nCount; T=Z.TG|lIx  
} XfYC7-e9c  
} j&R+2%  
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Te,$M3|  
/* 9QC.TG@  
**Utility.java -&2B@]
]  
*/ 'gso'&Uaj  
package NetFox; uz30_aH  
sEc;!L  
%^]?5a!  
public class Utility { As&vFt P  
++-{]wB3=.  
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public Utility() %A/_5;PZ/  
{ 1|r,dE2k9  
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@Xp~2@I=ls  
} tBATZ0nK`Q  
Gi2$B76<  
//线程睡眠 zDTv\3rZ4X  
public static void sleep(int nSecond) xdvh-%A4  
{ 3
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try{ :4gLjzL  
Thread.sleep(nSecond); bM,1f/^  
} M~Ttb29{  
catch(Exception e) Cq)IayD@  
{ Ro(Zmk\t  
e.printStackTrace (); jE2}p-2Q0  
} kgdT7  
} R(Kk{
c:-@  
^' M>r(t  
//日志 q`NXJf=sc  
public static void log(String sMsg) {'En\e  
{ Q
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System.err.println(sMsg); aGZi9O7G}  
} nC1zzFFJ  
Y?J"wdWJNB  
/4\wn?f  
public static void log(int sMsg) 7R4z}2F2  
{ mEyK1h1G@  
System.err.println(sMsg); K14^JAdY/  
} M=qb^~ l
 
} 1 rs&74-  
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/* -s|8<A||"  
**TestMethod.java J(4"S o_  
*/ d?AlI  
package NetFox; Sq\(pfvo  
NEt1[2X%  
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public class TestMethod { wr(*?p]R  
=Z
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a, Q#Dk  
public TestMethod() ZK;zm  
{ ///xx/weblogic60b2_win.exe jHXwOJq %  
try{ 'y]\-T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~S,p?I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zaTb~#c_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @yd4$Mv8%  
fileFetch.start(); ]?O2:X  
} @Jm7^;9/  
catch(Exception e){e.printStackTrace ();} )a@k]#)Skm  
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} Yim<>. !  
>_OYhgs1w  
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public static void main(String[] args) 3>E%e!D%  
{ &k-Vcrcz  
new TestMethod(); W[EKD 7  
} 9O{b]=>wq  
} l3Njq^T  
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