http断点续传简单实现（java)

/* y2jw3R  
**SiteFileFetch.java MYjc6@=cR  
*/ ihwJBN>(  
package NetFox; `?N0?;  
import java.io.*; 0mUVa=)D  
import java.net.*; P[G>uA>Z1  
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public class SiteFileFetch extends Thread { MomHSvQ\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean yCN_vrH>  
long[] nStartPos; //开始位置 =(7nl#o  
long[] nEndPos; //结束位置 `q<W %'Tb$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X)~wB7_0G  
long nFileLength; //文件长度 zM=MFKhi ~  
boolean bFirst = true; //是否第一次取文件 =iKl<CqI$E  
boolean bStop = false; //停止标志 hF0,{v  
File tmpFile; //文件下载的临时信息 `wtso  
DataOutputStream output; //输出到文件的输出流 ;TWLo_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %2zmc%]r  
public SiteFileFetch(SiteInfoBean bean) throws IOException Qw'905;(  
{ =8?Kn@nMN  
siteInfoBean = bean; -%yrs6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I@9'd$YY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZzupK^5Z  
if(tmpFile.exists ()) m]AT-]*f  
{ 0(eaVi-%D  
bFirst = false; LO{Axf%  
read_nPos(); [#q>Aq$11  
} <8^x Mjc  
else s||" } l  
{ I8 :e`L  
nStartPos = new long[bean.getNSplitter()]; OA[e}Vn  
nEndPos = new long[bean.getNSplitter()]; v wEbGx  
} >UaQ7CRo  
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} (*9.GyK  
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public void run() 22CET9iCe  
{ ccHf+=  
//获得文件长度 |]*3
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//分割文件 8#7qHT;cx  
//实例FileSplitterFetch ",$_\l  
//启动FileSplitterFetch线程
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//等待子线程返回 ;2<5^hgk  
try{ m[B#k$  
if(bFirst) h= sNj  
{ lhGJ/By- -  
nFileLength = getFileSize(); Kp`{-dUf  
if(nFileLength == -1) (.ir"\k1(  
{ H;1@]|sH#  
System.err.println("File Length is not known!"); }xk(aM_  
} "=djo+y  
else if(nFileLength == -2) ZZY#.  
{ m\6/:~qWW  
System.err.println("File is not access!"); .AfZ5s]/F  
} Y[{:?i~9,  
else XQ#K1Z  
{ zjpZ] $  
for(int i=0;i<nStartPos.length;i++) ]`/>hH>+~9  
{ Eomfa:WL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t6
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} #-0e0  
for(int i=0;i<nEndPos.length-1;i++) Q^(CqQo!<  
{ mmTpF]t ?`  
nEndPos = nStartPos[i+1]; 'Gy`e-yB  
} 6"Uu;Q  
nEndPos[nEndPos.length-1] = nFileLength; 1q6)R/P  
} x-BU$bx5  
} +A| Bc~2!  
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//启动子线程 n{tc{LII/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'f5 8Jwql  
for(int i=0;i<nStartPos.length;i++) d:%b  
{ (` *BZ_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;4nY{)bD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %HUex 6!  
nStartPos,nEndPos,i); AV5={KK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H+Aidsn  
fileSplitterFetch.start(); ZZL@UO>:  
} `NTtw;%Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N<ux4tz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S*gm[ZLQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YmpaLZJ  
nEndPos = " + nFileLength); OADW;fj  
// fileSplitterFetch[nPos.length-1].start(); \B^NdG5Y  
F]t=5 -O<  
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//等待子线程结束 \KzH5?  
//int count = 0; cg o  
//是否结束while循环 ?J,,RK.  
boolean breakWhile = false; J.'%=q(Sb  
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while(!bStop) l4dG=x}M]  
{ `lQ;M?D  
write_nPos(); t0GJ$])  
Utility.sleep(500); Rj4C-X4=  
breakWhile = true; jFJ}sX9]  
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for(int i=0;i<nStartPos.length;i++) !^ad{#|X  
{ rwVp}H G  
if(!fileSplitterFetch.bDownOver) m[KmXPFht1  
{ nmts% u  
breakWhile = false; s2<[@@@q  
break; T=)qD2?  
} E3l*_b0  
} :o .+<_&  
if(breakWhile) #\`kg#&  
break; s5rD+g]E`  
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//count++; G<Eb~].1'  
//if(count>4) w#[cGaIB  
// siteStop(); S<-nlBs.  
} {?5iK1|}K  
8*@{}O##  
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System.err.println("文件下载结束！"); -F[@)$L  
} e).;;0  
catch(Exception e){e.printStackTrace ();} 6[4VbIBSI  
} gK9d `5  
\0d'y#Gp*  
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//获得文件长度 4k-A
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public long getFileSize() |5tZ*$nGa  
{ ~bxev/$d  
int nFileLength = -1; (nt`8 0  
try{ <y] 67:"<v  
URL url = new URL(siteInfoBean.getSSiteURL()); CDRbYO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O"+0 b|  
httpConnection.setRequestProperty("User-Agent","NetFox"); w\YS5!P,V  
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* l1*zaE  
int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) )\=
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{ U`i5B;k}-  
processErrorCode(responseCode); twq~.:<o  
return -2; //-2 represent access is error 8zD>t~N2C  
} wuA?t  
.Mb[j1L^  
^]nLE]M  
String sHeader; R-S<7Q3E0=  
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for(int i=1;;i++) At
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{ p@su:B2Rl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); > 0MP[  
//Utility.log(in.readLine()); 3W%6n-*
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sHeader=httpConnection.getHeaderFieldKey(i); 7TMq#Pb  
if(sHeader!=null) 1xW!j!A;  
{ i
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if(sHeader.equals("Content-Length")) ^w\22 Q  
{ + U5Q/g  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }q.D)'g_  
break; phuiLW{&  
} MO8}i?u=z  
} C~q
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else E]OexRJ^i  
break; iY,C0=n5Y  
} 112WryS  
} E+@Q u "W  
catch(IOException e){e.printStackTrace ();} #ODP+>-IjB  
catch(Exception e){e.printStackTrace ();} AygdAg'\  
5-|!mSd  
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Utility.log(nFileLength); @|a
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return nFileLength; Q"XDxa'7"  
} 9&eY<'MgP  
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//保存下载信息（文件指针位置） Jw;~$  
private void write_nPos() sN[}B{+  
{ i<^
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try{ 8!{*!|Xd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?'MkaG0g  
output.writeInt(nStartPos.length); nHdQe  
for(int i=0;i<nStartPos.length;i++) T7,]^ 1  
{ dw"Es;^  
// output.writeLong(nPos); =GX5T(P8k  
output.writeLong(fileSplitterFetch.nStartPos); =OHX5:Z  
output.writeLong(fileSplitterFetch.nEndPos); xaMDec V  
} 9Y:I)^ek  
output.close(); ka9@7IFM  
} =0g!Q  
catch(IOException e){e.printStackTrace ();} g-sNYd%?a  
catch(Exception e){e.printStackTrace ();} 4E^ ?}_$  
} m)tu~neM  
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//读取保存的下载信息（文件指针位置） @|b-X? `  
private void read_nPos() f*o  
{ k
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try{ zC2:c"E I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )zr*Ecz  
int nCount = input.readInt(); [Yt{h9  
nStartPos = new long[nCount]; BDI|z/~&  
nEndPos = new long[nCount]; E!9WZY  
for(int i=0;i<nStartPos.length;i++) r].n=455[  
{ FCEy1^u  
nStartPos = input.readLong(); "v1{  
nEndPos = input.readLong(); U]cXE1c>F  
} :0J`4  
input.close(); Q@W/~~N  
} su%(!XJQpg  
catch(IOException e){e.printStackTrace ();}
{18
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catch(Exception e){e.printStackTrace ();} E_ns4k#uG  
} 5#DMizv6  
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private void processErrorCode(int nErrorCode) _,J+b R+b  
{ VQ9A/DH/  
System.err.println("Error Code : " + nErrorCode); xi5"?*&Sb  
} <s9{o uZ  
CP7dn/  
#PkuCWm
6  
//停止文件下载 4IeCb?  
public void siteStop() ot}erC2~  
{ 'ITq\1z  
bStop = true; yvd)pH<a2  
for(int i=0;i<nStartPos.length;i++) A=<7*E  
fileSplitterFetch.splitterStop(); P 45Ir
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 !VGG2N8  
} .&^
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} ,2M}qs"P7G  
//负责部分文件的抓取 Y(PCc}/\  
**FileSplitterFetch.java FLi'}C  
*/ QG5WsuT  
package NetFox; $[|(&8+7  
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import java.io.*; *9'3 `^l  
import java.net.*; (0 T!-hsP  

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public class FileSplitterFetch extends Thread {
~
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@Xo*TJB  
#mQ@4k9i  
String sURL; //File URL 94tfR$W;-  
long nStartPos; //File Snippet Start Position `zQuhD 8W  
long nEndPos; //File Snippet End Position a"jE\OZ{+s  
int nThreadID; //Thread's ID @v)Z>xv  
boolean bDownOver = false; //Downing is over & zDuh[j}  
boolean bStop = false; //Stop identical > 80{n8  
FileAccessI fileAccessI = null; //File Access interface ~c)&9'  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }*:3]  
{ ~,)jZ-fw  
this.sURL = sURL; :kgh~mx5LF  
this.nStartPos = nStart; ]_s3<&R  
this.nEndPos = nEnd; !l[;,l  
nThreadID = id; k|;a"56F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rq%]CsRY5  
} 7b"fpB  
7H Har'=T  
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public void run() Y
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{ NW\C
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while(nStartPos < nEndPos && !bStop) Fd9[Pe@?`  
{ *;A ;)'  
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try{ <pX?x3-'  
URL url = new URL(sURL); 0z=KnQx"4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); un "I  
String sProperty = "bytes="+nStartPos+"-"; (5$Ge$  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); K,S4  
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InputStream input = httpConnection.getInputStream(); kz=ho~ @  
//logResponseHead(httpConnection); "VaWZ*  
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byte[] b = new byte[1024]; #0AyC.\  
int nRead; 1<!P:@(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dk&F?B{6T  
{ w{tA{{  
nStartPos += fileAccessI.write(b,0,nRead); T!jh`;D+  
//if(nThreadID == 1) n.+*_c8k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %H\b5& _y  
} 1H-Wk  
P-X|qVNK1Z  
+^7cS6"L  
Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; Fyvo;1a  
//nPos = fileAccessI.write (b,0,nRead); Cmx<>7fN  
} ^wy  
catch(Exception e){e.printStackTrace ();} 1Ek3^TOv7  
} _9BL7W $;  
} "~Fg-{jM%  
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//打印回应的头信息 X;LYGJ{Xk  
public void logResponseHead(HttpURLConnection con) C^q|(G)  
{ MZ38=nJ  
for(int i=1;;i++) ~<k>07  
{  kF1$  
String header=con.getHeaderFieldKey(i); 6lzjaW5h  
if(header!=null) )?{<Tt@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Jxl'!8t  
Utility.log(header+" : "+con.getHeaderField(header)); O/eZ1YAC  
else .vHHw@  
break; %;&lVIU0  
} E$%v);u  
} 7~2_'YX>:  
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:^(y~q?  
public void splitterStop() hP:>!KJ  
{ Q7x[08TI  
bStop = true; 8cO?VH,nk  
} hT%fM3|,e  
@>2]zMFf  
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} .$~3RjM  
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/* EUSM4djL  
**FileAccess.java ]2u   
*//文件访问(定位，写) ";U~wZW_  
package NetFox; <^nS%hXEr  
import java.io.*; K2*rqg  
fDYTupKXH  
Sk EI51]  
public class FileAccessI implements Serializable{ 4lPO*:/  
OK4r)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8K2@[TE=5  
RandomAccessFile oSavedFile; W9l](Ow  
long nPos; 9{(q[C5m  
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public FileAccessI() throws IOException <5L99<E  
{
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this("",0); 0Fkr3x  
} <e! TF@  
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public FileAccessI(String sName,long nPos) throws IOException ]ovtH

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{ C'@I!m._i  
oSavedFile = new RandomAccessFile(sName,"rw"); 0J?443AY  
this.nPos = nPos; }alq~jY  
oSavedFile.seek(nPos); :Xy51p`.;]  
} OfrzmL<K  
q-CgXwU  
,#N}Ni:  
public synchronized int write(byte[] b,int nStart,int nLen) ~;6^n  
{ ")9^  
int n = -1; &@xm< A\S  
try{ LV ]10v6  
oSavedFile.write(b,nStart,nLen); gb!0%*  
n = nLen; 4,@jSr|I3i  
} CE{2\0Q  
catch(IOException e) 1 jLQij  
{ 5
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e.printStackTrace (); DI(XB6  
} w15a~\Qu  
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return n; J>+\a1{  
} N G vb]  
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} )Pubur %,  
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/* Vug[q=i  
**SiteInfoBean.java aj
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*/ 'A3*[e|OS  
package NetFox;
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public class SiteInfoBean { 3QXs
r<  
T+gH38!e  
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private String sSiteURL; //Site's URL DD  
private String sFilePath; //Saved File's Path 2zbn8tO  
private String sFileName; //Saved File's Name EqBTN07dZS  
private int nSplitter; //Count of Splited Downloading File KbciRRf!k  
g/FT6+&T.  
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public SiteInfoBean() eV
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{//nSplitter的缺省值为5 XR<g~&h  
//default value of nSplitter is 5 ml)\RL  
this("","","",5); @o1#J`rv  
} hAds15 %C  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y"8,jm  
{ Z:<w
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sSiteURL= sURL; (["V( $  
sFilePath = sPath; \|B\7a'4  
sFileName = sName; YUTh*`1k<  
this.nSplitter = nSpiltter; Gf
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XL;WU8>  
j4`+RS+q  
} M+j*5wNy  
b?!S$Sxz  
FI$ -."F  
public String getSSiteURL() x|c_(  
{ R?#=^$7U  
return sSiteURL;  V_
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} tnBCO%uG  
]Nssn\X7  
VV54$a  
public void setSSiteURL(String value) @KHY8y7  
{ /<-=1XJI  
sSiteURL = value; rR/{Yx4  
} P0sAq7"  
\"L0d1DK)  
Eg}U.ss^  
public String getSFilePath() OZz!8-|wE  
{ <dVJV?i;  
return sFilePath; )J+A2>  
} 5G`fVsb  
z yp3+|  
0S&J=2D!  
public void setSFilePath(String value) 2AMb-&po&f  
{ `|v/qk7 ^?  
sFilePath = value; _ShWCU-~Z  
} 'qG-
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B~@Gfb>`'  
\L}7.fkb8  
public String getSFileName() ;n|%W,b-  
{ !g)rp`?  
return sFileName; =:6B`,~C  
} LCzeE7x  
.RAyi>\e  
L ed{#+  
public void setSFileName(String value)  n6Uf>5  
{ #Hu##x|  
sFileName = value; ;1nXJ{jKw  
} iCh8e>+  
ZPq.|6&  
l7VTuVGUJ  
public int getNSplitter() bT T>  
{ 8<C@I/  
return nSplitter; )Td{}vbIh  
} ;XjXv'  
<Uf`'X\e6  
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public void setNSplitter(int nCount) 2DJg__("  
{ u#^l9/tl  
nSplitter = nCount; ,mi7WW9  
} l.Ev]G/5  
} /Qef[$!(  
9(z) ^G  
ME]89 T&  
/* qR?}i,_  
**Utility.java um_J%v6ER  
*/ *f>\X[wN  
package NetFox; J:ka@2>|  
41+WIa L  
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public class Utility { |42;171  
S+wT}_BQ  
dw5"}-D  
public Utility() GQd[7j[sh  
{ XIZN9/;  
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} >#l:
]T  
_~C1M&b(X3  
//线程睡眠 L+ XAbL)  
public static void sleep(int nSecond) &
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{ B)L0hi  
try{ Vky]In=  
Thread.sleep(nSecond); mEi(DW)(  
}
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catch(Exception e) <%m1+%mA.  
{ r@vt.t0#  
e.printStackTrace (); Kn=EDtg  
} PUZcb+%]h  
} e?B}^Dk0i  
ZnzO
]  
//日志 CxJ3u  
public static void log(String sMsg) JsuI&v  
{ /BQqg08@L  
System.err.println(sMsg); |mRlP5  
} ePJ_O~c  
4pQf*l8e  
Mlo,F1'?>  
public static void log(int sMsg) HQ7g0:-^a>  
{ l:JVt`A4?  
System.err.println(sMsg); @H4]Gp ]  
} yFb"
2  
} i\b^}m8c.N  
-vT{D$&1  
){'<67dK  
/* _(8#  
**TestMethod.java _Z9d.-  
*/ :3 Hz!iZM  
package NetFox; L*,
h=#x(  
|%ZJN{!R  
6_
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public class TestMethod { Y~{<Hs  
0!ZaR6  
3BD&;.<r  
public TestMethod() "a~r'+'<  
{ ///xx/weblogic60b2_win.exe
P!IA;i  
try{ '\op$t/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jXALL8[c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s5mJ -  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;]m;p,$  
fileFetch.start(); m;{HlDez  
} ^gp]tAf  
catch(Exception e){e.printStackTrace ();} )8#-IXxp  
UF-'(  
}[UH1+`L  
} ~?fl8RF\  
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public static void main(String[] args) 6Y,&q|K  
{ 26k~Z}  
new TestMethod(); DeNWh2  
} =P9rOK=  
} I(7iD. ^:  
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