http断点续传简单实现（java)

/* &Ls0!dWC  
**SiteFileFetch.java ?>&8,p17  
*/ '!0CwZ 7  
package NetFox; jIl-}/2  
import java.io.*; x:2_FoQ  
import java.net.*; BgRiJFa.d[  
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public class SiteFileFetch extends Thread { r1\.Jz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zL|^5p`K  
long[] nStartPos; //开始位置 vr;7p[~  
long[] nEndPos; //结束位置 jzV#%O{`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V>%%2"
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long nFileLength; //文件长度 "Vh(%N`6  
boolean bFirst = true; //是否第一次取文件 LU]~d<i99  
boolean bStop = false; //停止标志 M|Se|*w  
File tmpFile; //文件下载的临时信息 "~;jFB8  
DataOutputStream output; //输出到文件的输出流 r[lHYO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J h"]iN  
public SiteFileFetch(SiteInfoBean bean) throws IOException <HD/&4$[  
{ K{iY
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siteInfoBean = bean; <(iOzn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #:yZJ
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nO/5X>A,Zw  
if(tmpFile.exists ()) <@yyx7  
{ vxgm0ZOMN  
bFirst = false; ~\^8 ^  
read_nPos(); yTEuf@  
} 7KEGTKfW  
else I2 Kb.`'!  
{ nMnc&8r  
nStartPos = new long[bean.getNSplitter()]; 9xz`
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nEndPos = new long[bean.getNSplitter()]; D^u{zZy@e  
} FlZ]R  
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} zf!c  
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public void run() gV7o eZ5  
{ q8D1MEBL`  
//获得文件长度 [brrziZ  
//分割文件 @!S$gTz  
//实例FileSplitterFetch EAI[J&c  
//启动FileSplitterFetch线程 +2g3%c0}  
//等待子线程返回 zPXd]jIwV  
try{ :JS}(  
if(bFirst) *vb)
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{ @Q^;qMy  
nFileLength = getFileSize(); #i,O "`4  
if(nFileLength == -1) v:>P;\]r9M  
{ 8 2qe|XD4p  
System.err.println("File Length is not known!"); f6#H@ X  
} p<jr&zVEc>  
else if(nFileLength == -2) UOu&sg*o2B  
{ '71btd1  
System.err.println("File is not access!"); J0K"WmW  
} H0HYb\TX?  
else `3OGCy  
{ Bb o*  
for(int i=0;i<nStartPos.length;i++) \Q$);:=qQ  
{ gXQ)\MY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); . FruI#99  
} o]Ki+ U  
for(int i=0;i<nEndPos.length-1;i++) V O
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{ PTP2QAt  
nEndPos = nStartPos[i+1]; D%A-& =  
} c[I,Sveq  
nEndPos[nEndPos.length-1] = nFileLength; e'6?iLpy  
} b-Hn=e_  
} =VU2#O  
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n&fV3[m`2  
//启动子线程 a$GKrc,z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cwroG#jGT  
for(int i=0;i<nStartPos.length;i++) %Xl@o  
{ 71%u|k8|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -FI1$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fwEi//1  
nStartPos,nEndPos,i); $CmTsnR1#y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (07d0<<[  
fileSplitterFetch.start(); "duJl-  
} {x:IsQZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x#^kv)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OrBFe *2y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c>g%oE  
nEndPos = " + nFileLength); W@tLT[}CG  
// fileSplitterFetch[nPos.length-1].start(); 6PH*]#PfoD  
)N/KQ[W  
7Tbkti;  
//等待子线程结束 F)@<ZE  
//int count = 0; \9p;md`  
//是否结束while循环 6yb<4@LOb  
boolean breakWhile = false; v^tKT&  
*/)gk=x8  
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while(!bStop) :q=OW1^k^  
{ 4Q>F4v`  
write_nPos(); -%.V0
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Utility.sleep(500); iH>djGhTh  
breakWhile = true; U*@_T3N  
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for(int i=0;i<nStartPos.length;i++) Go|65Z\`7M  
{ m+g>s&1H  
if(!fileSplitterFetch.bDownOver) epF>z   
{ d1
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breakWhile = false; Ba6xkEd  
break; UU/|s>F  
} 4pqZ!@45|  
} AMdS+(J  
if(breakWhile) hs4r5[  
break; *C BCQp[$  
7h2bL6Y88  
<c#[.{A}s  
//count++; zCrcCr  
//if(count>4) YO,ldsSz|r  
// siteStop(); s,Swlo7D!  
} c'2ra/?k  
@jHio\/_  
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;  
System.err.println("文件下载结束！"); ~'3% Qr  
} je-s%kNlJ  
catch(Exception e){e.printStackTrace ();} Q1Ao65  
} l&B'.6XKs  
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//获得文件长度 WQx;tX  
public long getFileSize() KfNXX>'  
{ %u}sVRJ  
int nFileLength = -1; vknFtpx  
try{ @Hh"Y1B  
URL url = new URL(siteInfoBean.getSSiteURL()); ,)1e+EnV&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1*h7L<#|mQ  
httpConnection.setRequestProperty("User-Agent","NetFox");  6qlr+f  
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int responseCode=httpConnection.getResponseCode(); ;^]A
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if(responseCode>=400) =HHg:"  
{ _=5ZB_I  
processErrorCode(responseCode); Kdm5O@tq  
return -2; //-2 represent access is error &u-Bu;G.e  
} k 9rnT)YU  
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{9 O`/|  
String sHeader; +bW|Q>u  
@_3$(*n$~  
)v~]lk,
o  
for(int i=1;;i++) -e>)yM `i  
{ V-jL`(JF%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }c%y0)fL
 
//Utility.log(in.readLine()); ?C35   
sHeader=httpConnection.getHeaderFieldKey(i); T*yveo&j  
if(sHeader!=null) sA}R!  
{ e%6{P  
if(sHeader.equals("Content-Length")) 9 NQq=@  
{ MVZ>:G9:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kqw? X{  
break; QEa=!O  
} `x)bw  
} |m- `, we  
else g/p }r.  
break; VWt'Kx"  
} i:ZA{hA`c  
} Ah{pidUx  
catch(IOException e){e.printStackTrace ();} AW5g (  
catch(Exception e){e.printStackTrace ();} JxJntsn  
u,:`5*al{  
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Utility.log(nFileLength); IviQ)hp  
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return nFileLength; rrYp^xLa`  
} PqLqF5`S  
;NE/!!  
&Q>'U6"%  
//保存下载信息（文件指针位置） nD\os[ 3  
private void write_nPos() [dlH t;S  
{ .N&}<T[  
try{ _9|@nUD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G6{A[O[  
output.writeInt(nStartPos.length); RI3{>|*  
for(int i=0;i<nStartPos.length;i++) ;bX ~4O&v+  
{ shIi
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// output.writeLong(nPos); F t/ x5  
output.writeLong(fileSplitterFetch.nStartPos); s$x] fO  
output.writeLong(fileSplitterFetch.nEndPos); }TJ|d=  
} -i5g 8t'  
output.close();  **w~  
} y4We}/-<  
catch(IOException e){e.printStackTrace ();} H^;S}<pxW  
catch(Exception e){e.printStackTrace ();} U^BXCu1km  
} 2_n*u^X:_  
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//读取保存的下载信息（文件指针位置） <Cu?$  
private void read_nPos() e-3pg?M  
{ O&iYGREO  
try{ tkqBCKpDa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZM`P~N1?)g  
int nCount = input.readInt(); a9zph2o-  
nStartPos = new long[nCount]; eZ5}O0sfp  
nEndPos = new long[nCount]; T,2Dr;  
for(int i=0;i<nStartPos.length;i++) (!5}" fj  
{ DN':-PK  
nStartPos = input.readLong(); OKP_3Ns  
nEndPos = input.readLong(); ESjJHZoD(  
} cqL7dlhIl  
input.close(); {JCz^0DV  
} g*?+~0"`Y  
catch(IOException e){e.printStackTrace ();} =GKYroNM  
catch(Exception e){e.printStackTrace ();} GtJ*&=(  
} $1zeY6O  
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Q;ZHx.ye{  
private void processErrorCode(int nErrorCode) \}QuNwc  
{
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System.err.println("Error Code : " + nErrorCode); a& aPBv1  
} afiK!0col2  
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^(  
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//停止文件下载 y{Y+2}Dv/  
public void siteStop() 'ag6B(0Z  
{ dIa(</ }  
bStop = true; m4U+,|Fa  
for(int i=0;i<nStartPos.length;i++) WfT)CIKs  
fileSplitterFetch.splitterStop(); iSz@E&[X  
w[7.@%^[  
qvU$9cTY  
} 8<wuH#2<y  
} PT@e),{~o9  
//负责部分文件的抓取 f@Rpb}zg+C  
**FileSplitterFetch.java pebx#}]p-  
*/ \P~rg
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package NetFox; a$zm/  
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u~- fK'/!|  
import java.io.*; ?I2k6%a  
import java.net.*; acYoOW1G  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL O`[iz/7m  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position ~r>EF!U`h  
int nThreadID; //Thread's ID #ON#4WD?  
boolean bDownOver = false; //Downing is over e8ULf~I  
boolean bStop = false; //Stop identical 4&oXy,8LC  
FileAccessI fileAccessI = null; //File Access interface zJuRth)(,  
ua$k^m7m5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~ACP%QM=  
{ "wF ?Hamz  
this.sURL = sURL; ZO%fS'n  
this.nStartPos = nStart; 3Zaq#uA  
this.nEndPos = nEnd; )+w/\~@  
nThreadID = id; @!":(@3[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $d2kHT  
} l~fh_IV1  
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public void run() M2;%1^  
{
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while(nStartPos < nEndPos && !bStop) N /sEec  
{ ~tg1N^]
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try{ 'NT#
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URL url = new URL(sURL); pcRF:~TE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 42Aje  
httpConnection.setRequestProperty("User-Agent","NetFox"); d s|8lz,  
String sProperty = "bytes="+nStartPos+"-"; d7W%zg\T
 
httpConnection.setRequestProperty("RANGE",sProperty); 9Qt)m fqM  
Utility.log(sProperty);
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/'&.aGW4%  
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InputStream input = httpConnection.getInputStream(); JHvFIo   
//logResponseHead(httpConnection); W>p\O9BG  
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byte[] b = new byte[1024]; '^Pq(b~  
int nRead; u;+%Qh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lSn5=^]q  
{ ov\Ct%]  
nStartPos += fileAccessI.write(b,0,nRead); y\F`B0#$  
//if(nThreadID == 1) dr|| !{\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vQ:x%=]  
} -@%t"8  
\3%W_vU_  
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Utility.log("Thread " + nThreadID + " is over!"); 9USrg
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bDownOver = true; z6p#fsD  
//nPos = fileAccessI.write (b,0,nRead); 8s QQK.N(  
} 6PiEa(  
catch(Exception e){e.printStackTrace ();} 2-8YSHlh  
} "NxOOLL  
} R&NpdW N  
@ \!KF*v  
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//打印回应的头信息 e.h~[^zg  
public void logResponseHead(HttpURLConnection con) kjx>  
{ P7}t lHX  
for(int i=1;;i++) Q8 -3RgAw  
{ >oe4mW  
String header=con.getHeaderFieldKey(i); !-KCFMvT  
if(header!=null) j?=VtVP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t G]N*%@  
Utility.log(header+" : "+con.getHeaderField(header)); 3b<: :t  
else $X`bm*  
break; ~q{\;  
} $RpFxi  
} d "2wO[  
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public void splitterStop() *f{7  
{ \$'R+k-57;  
bStop = true; VxNXd?  
} 1d`cTaQ-  
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} J(4g4?  
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/* ya#RII']  
**FileAccess.java E\ tL
 
*//文件访问(定位，写) iM8sX B  
package NetFox; 'CgV0&@  
import java.io.*; $Ru&>D#stK  
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public class FileAccessI implements Serializable{ Pv~:gP  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5~QhX22  
RandomAccessFile oSavedFile; -=5EbNPwG  
long nPos; lHcA j{6  
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public FileAccessI() throws IOException w"1x=+  
{ XJc ,uj7  
this("",0); f`,
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} k; ;viT  
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public FileAccessI(String sName,long nPos) throws IOException  e#1.T  
{ w~]T<^fW~  
oSavedFile = new RandomAccessFile(sName,"rw"); r5[4h'f  
this.nPos = nPos; P:qz2Hw  
oSavedFile.seek(nPos); JwB"\&'1ZS  
} #,TELzUVE  
5} G:D  
7_KXD#  
public synchronized int write(byte[] b,int nStart,int nLen) EsTB(9c?  
{ z{=v)F5y  
int n = -1; =MxpH+spI  
try{ iKhH^V%j  
oSavedFile.write(b,nStart,nLen); drI\iae{^  
n = nLen; lY8`5Uz  
} ?,>5[Ha^?  
catch(IOException e) 7k'gt/#up  
{ O:._
W<  
e.printStackTrace (); `0rRKlbj4  
} iy}xICt  
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return n; /kRAt^4!  
} dZD
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} 7E\g &R.  
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v  
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/* xp^ 7#`MJ?  
**SiteInfoBean.java l|q%%W0  
*/ oqYt/4^Q  
package NetFox; [S0mY["  
{[P!$ /  
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public class SiteInfoBean { %J!NL0x_  
,rai%T/rL  
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private String sSiteURL; //Site's URL , D"]y~~I5  
private String sFilePath; //Saved File's Path c0ZaFJ  
private String sFileName; //Saved File's Name MMd.0JuaO  
private int nSplitter; //Count of Splited Downloading File qnXTNs ?b  
M)O[j}N  
({ k7#1 h8  
public SiteInfoBean() &a6,ln:P  
{//nSplitter的缺省值为5 S3y246|4  
//default value of nSplitter is 5 `ET& VV  
this("","","",5); RG}}Oh="v  
} `tVy_/3(9  
5\'AD^{  
~},W8\C>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,Xtj;@~-  
{ eGvOA\y:  
sSiteURL= sURL; BIj   
sFilePath = sPath; 7n&yv
9"  
sFileName = sName; V|: qow:F  
this.nSplitter = nSpiltter; H=<LutnZ  
mNDuwDd$S  
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} = F<:}Tx)C  
+|&0fGv;d9  
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public String getSSiteURL() o;J;k_[MX  
{ t9` Ed>a  
return sSiteURL; -_>.f(1  
} &<0ZUI |S3  
l
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~kb{K;  
public void setSSiteURL(String value) qqvF-mDN  
{ eaAPKx  
sSiteURL = value; niWx^gKb$  
} ,YB1 y)x  
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public String getSFilePath() qm%nIU \*  
{ >r}Vf9 5[N  
return sFilePath; *eGM7o*\X  
} 1exfCm  
vgThK9{m;  
ti9}*8  
public void setSFilePath(String value) W[|[;{  
{ Ue7 6py9  
sFilePath = value; <|H?gfM  
} L|\Diap  
~:Mm<*lL%  
N`1r;%5  
public String getSFileName()  Zi4d]  
{ :-Wv>V\t  
return sFileName; *s\sa+2al  
} 1JeJxzv>C  
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public void setSFileName(String value) jVYH;B%%z  
{ MGybGbd  
sFileName = value; t?3BCm$Mi  
} D9o*8h2$  
5\S&)ZA@  
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public int getNSplitter() y<M]dd$  
{ jONjt(&N  
return nSplitter; =l,#iYJP8  
} oEIqA  
$?f]ZyZr.  
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public void setNSplitter(int nCount) oMc1:=EG  
{ v{koKQ'Y()  
nSplitter = nCount; WG%2<Q^  
} VDiOO  
} \h#9oPy  
C #aFc01B  
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/* ]l&'k23~p  
**Utility.java s=U\_koyH  
*/ e5OVq ,  
package NetFox; gjZx8oIoP  
3EOyq^I%  
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public class Utility { 'tuBuYD\  
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public Utility() |j# ^@R  
{ pVz*ZQ[]  
{(0I
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} 5rN7':(H!%  
k=|K|  
//线程睡眠 ?Cc :)  
public static void sleep(int nSecond) 3):?ZCw7y  
{ +7Rt{C,  
try{ iAHZ0Du  
Thread.sleep(nSecond); W5X7FEW  
} 6sy,A~e  
catch(Exception e) .hne)K%={y  
{ hgwn> p:S#  
e.printStackTrace (); oG\>--  
} K0 QH?F  
} |*1xrM:v~  
@ExLh9  
//日志 5"uNj<.V  
public static void log(String sMsg) OPLl*bnf  
{ s9 &)Fv-#V  
System.err.println(sMsg); <M305BH  
} g/B\ObY  
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'}CN?f|.  
public static void log(int sMsg) 1VGpq-4*j  
{ RUqO!s~#rY  
System.err.println(sMsg); *?p ^6vO  
} r;'i<t{P  
} G ~A$jStm
 
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l-
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/* W7$s5G,  
**TestMethod.java "R8.P/ 3  
*/ [bsXF#  
package NetFox; P*7S3Td  
#1B}-PGCm  
R qnWtE  
public class TestMethod { %6N)G!P  
blUY.{NN3  
"A]?M<R  
public TestMethod() CuIqh BW!  
{ ///xx/weblogic60b2_win.exe ~z&0qQ  
try{ ;eP_;N5+J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^]i" H|(x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <o~t$TH  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); [#IBYJ.6  
} IeH^Wm&^  
catch(Exception e){e.printStackTrace ();} `|&\e_"DE  
s:3aRQ%  
)dqR<)  
} 7:z>+AM[r  
' 4,y  
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public static void main(String[] args) *B%y`cj|  
{ zf`5>h|  
new TestMethod(); -Sx0qi'%  
} o T:j:n  
} 1k$2LQ  
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