http断点续传简单实现（java)

/* <XagkD  
**SiteFileFetch.java j&pgq2Kl  
*/ .2P?1H
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package NetFox; wg1pt1 `  
import java.io.*; HlSuhbi'@  
import java.net.*; wm8x1+P  
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public class SiteFileFetch extends Thread { 1m)/_y~1 k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l!=WqIZ  
long[] nStartPos; //开始位置 ;R!
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long[] nEndPos; //结束位置 `IoX'|C[h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 zef,*dQY  
long nFileLength; //文件长度 &B4U
)  
boolean bFirst = true; //是否第一次取文件 w3Ohm7N[  
boolean bStop = false; //停止标志 ]>L]?Rm  
File tmpFile; //文件下载的临时信息 K5lp-F  
DataOutputStream output; //输出到文件的输出流 F%d"gF
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;^*!<F%t9R  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `Vi:r9|P  
public SiteFileFetch(SiteInfoBean bean) throws IOException NHF?73:  
{ @7=D]yu  
siteInfoBean = bean; YM|S<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J4g;~#_19  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "/fs%F  
if(tmpFile.exists ()) h;KK6*Z*$E  
{ S\ZAcz4  
bFirst = false; NLl~/smMS  
read_nPos(); ,Tl5@RN  
} .[fz x`  
else %}!}2s.A  
{ n4 @a`lN5g  
nStartPos = new long[bean.getNSplitter()]; DV\ei")  
nEndPos = new long[bean.getNSplitter()]; g8"7wf`0k  
} h12wk2@P/]  
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} `yZZP  
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public void run() m[j3s=Gr  
{ Z5L1^  
//获得文件长度 ELF`uWGE  
//分割文件 bl?%:qb.V  
//实例FileSplitterFetch )
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//启动FileSplitterFetch线程 }YP7x|  
//等待子线程返回 L"I] mQvd  
try{ ?ljod6  
if(bFirst) Ne7{{1  
{ ;x^,t@ xge  
nFileLength = getFileSize(); S\5k'ifh  
if(nFileLength == -1) +[/r^C  
{ NCFV
 
System.err.println("File Length is not known!"); >}{-!  
} Td1ba^J  
else if(nFileLength == -2) *v ^"4  
{ Sp,Q,Q4  
System.err.println("File is not access!"); %i>e  
} |S:!+[  
else xPup?oP >  
{ -0da"AB  
for(int i=0;i<nStartPos.length;i++) oB R(7U~0  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Zw][c7%  
} x,gE$dNzy  
for(int i=0;i<nEndPos.length-1;i++) u^zitW!X$  
{ 4E\ntufo  
nEndPos = nStartPos[i+1]; V55J[s*6!  
} =
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nEndPos[nEndPos.length-1] = nFileLength; q)ql]iH  
} ~h
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} m8j-lNu  
H#6^-6;/  
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//启动子线程 oz6+rM6MY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?_>^<1I1  
for(int i=0;i<nStartPos.length;i++) .00=U;H%`  
{ Jav2A6a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]}7rWs[|1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1bZiPG{  
nStartPos,nEndPos,i); |cGeL[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #S%Y;ilq  
fileSplitterFetch.start(); vj&5`  
} 4t Nvq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h+~df(S.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _G[I2]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *;e@t4  
nEndPos = " + nFileLength); ;c- ]bhBB  
// fileSplitterFetch[nPos.length-1].start(); 2{B(j&{  
5f'g3'  
|8c:+8  
//等待子线程结束 prEu9$:t  
//int count = 0; 8J3@VD.  
//是否结束while循环 V9j1j}  r  
boolean breakWhile = false; A1QI4.K  
3E}NiD\V}  
j8Q5d`  
while(!bStop) u] U)d$|  
{ 9jR[:[  
write_nPos(); 8$v zpu  
Utility.sleep(500); /;NE]{K  
breakWhile = true; Bd9hf`%2  
+lgF/y6  
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for(int i=0;i<nStartPos.length;i++) CQjZAv  
{ 4m~7 ~-h  
if(!fileSplitterFetch.bDownOver) 4:Xj-l^D  
{ "Z2Tc)  
breakWhile = false; vdT+,x`  
break; Rw}2*5#y  
} *e3L4 7"G  
} g"]<J&  
if(breakWhile) n!ZP?]FR  
break; uOl(-Zq@  
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//count++; 4Wla&yy  
//if(count>4) 1Y"35)CR)  
// siteStop(); K@jSr*\'  
} Vv]$\`d
#  
EARfbb"SG7  
,V33v<|wc  
System.err.println("文件下载结束！"); oB0 8  
} Xvu)  
catch(Exception e){e.printStackTrace ();} >{ECyh;  
} R] Disljq  
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I[=Wmxa?r  
//获得文件长度 lj EB  
public long getFileSize() 0Q$~
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{ Bn1L?>G  
int nFileLength = -1; B9LSxB  
try{ &$m=^  
URL url = new URL(siteInfoBean.getSSiteURL()); i0'Xy>l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U+.PuC[3  
httpConnection.setRequestProperty("User-Agent","NetFox"); .>kccLr:z  
t}]9VD9  
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int responseCode=httpConnection.getResponseCode(); >G<\1R  
if(responseCode>=400) Na. nA  
{ KP=D! l&q  
processErrorCode(responseCode); t&R!5^R  
return -2; //-2 represent access is error C|4
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} &@4.;u  
NWJcFj_  
Z[#I"-Q~:  
String sHeader; 'f-
  
N b3I%r  
~>#LOT `  
for(int i=1;;i++) O1?B{F/ e  
{ 1 [fo'M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ka2F!  
//Utility.log(in.readLine()); "u(S2'DW'(  
sHeader=httpConnection.getHeaderFieldKey(i); wTTTrk  
if(sHeader!=null) iN<(O7B;  
{ G-\<5]k]  
if(sHeader.equals("Content-Length")) [i(Cl}  
{ DC|xilP1O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9m\)\/V  
break; S9G8aea/  
} 0 &*P}U}Uc  
} m x3}m?W
Q  
else [as-3&5S  
break; oMh~5 W  
} 0\5M^:8i3  
} g|ql 5jW  
catch(IOException e){e.printStackTrace ();} FNz84qVIx'  
catch(Exception e){e.printStackTrace ();} YO@hE>  
n 5~=qQK2  
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Utility.log(nFileLength); <\, &:<  
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return nFileLength; +jq 2pFQ  
} :v#k&Uh3y  
W *YW6  
j6n2dMRvSE  
//保存下载信息（文件指针位置） #"Fg%36Zd  
private void write_nPos() 99F>n[5  
{ 4@
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try{ X$Q2m{dR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B;eW/#`  
output.writeInt(nStartPos.length); x8 f6,  
for(int i=0;i<nStartPos.length;i++) pNp^q/-yB  
{ J3H.%m!V  
// output.writeLong(nPos); KU+( YF$1
 
output.writeLong(fileSplitterFetch.nStartPos); d@-wi%,^  
output.writeLong(fileSplitterFetch.nEndPos); YO)')&  
} LIr(mB"Y0  
output.close(); R]CZw;zS_  
} 3hc#FmLr2b  
catch(IOException e){e.printStackTrace ();} `6rrXU6|  
catch(Exception e){e.printStackTrace ();} .r~'(g{qt  
} TT|-aS0l(u  
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//读取保存的下载信息（文件指针位置） M$,Jg5Dc  
private void read_nPos() davvI$TA  
{ k?^%hO>[  
try{ ,q8(]n4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (-bRj#  
int nCount = input.readInt(); Jf
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nStartPos = new long[nCount]; -{!&/;Z  
nEndPos = new long[nCount]; (tJ91SBl  
for(int i=0;i<nStartPos.length;i++) Qn*6D  
{
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nStartPos = input.readLong(); DZJeup?Z  
nEndPos = input.readLong(); ^[en3aQ  
} 6/|U  
input.close(); c2/FHI0J;  
} rW[SU
:  
catch(IOException e){e.printStackTrace ();} DWu
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catch(Exception e){e.printStackTrace ();} ?#4+r_dP  
} (Ar?QwP9>  
~Y% : 3  
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private void processErrorCode(int nErrorCode) #xlZU  
{ /[0F6  
System.err.println("Error Code : " + nErrorCode); gC0;2  
} (%i!%{!]  
=h(7rU"Yz  
7k>zuzRyF  
//停止文件下载 Q5g,7ac8L  
public void siteStop() bpGzTU  
{ CP +4k.)*O  
bStop = true; Wt(Kd5k0'2  
for(int i=0;i<nStartPos.length;i++) ?;Un#6b  
fileSplitterFetch.splitterStop(); =Qyqfy*@D?  
:#Ty^-"]1  
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} 658\#x8|  
} p[u4,  
//负责部分文件的抓取 C+`xx('N9  
**FileSplitterFetch.java .
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*/ THJ 3-Ug  
package NetFox; Axf^
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C]/&vh7ta  
import java.io.*; FK6K6wU52m  
import java.net.*; Z
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rm
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public class FileSplitterFetch extends Thread { I:nI6gF  
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String sURL; //File URL !Pw$48cg  
long nStartPos; //File Snippet Start Position q=njKC  
long nEndPos; //File Snippet End Position "i&fp:E0  
int nThreadID; //Thread's ID |IAW{_9)U  
boolean bDownOver = false; //Downing is over +Jdm#n?_  
boolean bStop = false; //Stop identical Gp,'kw"I  
FileAccessI fileAccessI = null; //File Access interface /0 _zXQyV  
(oF-O{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =C#*!N73  
{ G&jZ\IV  
this.sURL = sURL; a/34WFC  
this.nStartPos = nStart; 9T$u+GX'  
this.nEndPos = nEnd; V#NtBreN  
nThreadID = id;  ER_ 3'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %0lf  
} VxkEez'|  
:Z[(A"dA  
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public void run() !j{CuA/  
{ iyc$)"w  
while(nStartPos < nEndPos && !bStop) O)`Gzx*ShU  
{ v[VC2D  
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try{ ?&6Q%IUW1  
URL url = new URL(sURL); J]dW1boT@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~?CS_B *  
httpConnection.setRequestProperty("User-Agent","NetFox"); *.o"ZVl  
String sProperty = "bytes="+nStartPos+"-"; 3+%nn+m  
httpConnection.setRequestProperty("RANGE",sProperty); z<i,D08|d  
Utility.log(sProperty); ;7L;  
3 &Sp@,  
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InputStream input = httpConnection.getInputStream(); $,@JYLC2  
//logResponseHead(httpConnection); y`6
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byte[] b = new byte[1024]; U:\p$hL9  
int nRead; BtzYA"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F*,5\s<  
{ mVt3W
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nStartPos += fileAccessI.write(b,0,nRead); ncj!KyU  
//if(nThreadID == 1) K_Re}\D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j$mz3Yk  
} 0X#+#[W  
&*A:[b\  
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Utility.log("Thread " + nThreadID + " is over!"); bLco:-G1E1  
bDownOver = true; ??j&i6sp  
//nPos = fileAccessI.write (b,0,nRead); k/@Tr
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} NZP7r;u  
catch(Exception e){e.printStackTrace ();} =-5[Hn%  
} M|H2kvl  
} 9OfU7_m  
9>;} /*:H  
ZL,8,;]  
//打印回应的头信息 [1U{ci&=p  
public void logResponseHead(HttpURLConnection con) y] y9'5_  
{ Hr&Ere8.4p  
for(int i=1;;i++) E?_ zZ2  
{ Wt:~
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String header=con.getHeaderFieldKey(i); +<{m45  
if(header!=null) sjn:O'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a5 bPEJ=I  
Utility.log(header+" : "+con.getHeaderField(header)); Cdmy.gx^  
else :]-$dEu&  
break; KGD'mByt"  
} [[X+P 0`r  
} %mu>-hac  
'-.
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public void splitterStop() h1*FPsc  
{ 5VZjDg?  
bStop = true; w&5/Zh[~~L  
} W "k|K:  
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} }#bZ8tm&  
GMw)*  
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/* &oEyixe  
**FileAccess.java fbV@=(y?  
*//文件访问(定位，写)
.`+yo0O:  
package NetFox; cWM:  
import java.io.*; 5NFRPGYX  
a%*_2#  
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public class FileAccessI implements Serializable{ z37Z%^  

-;/ Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \%4|t,en  
RandomAccessFile oSavedFile; h$/JGm5uDb  
long nPos; H?{MRe  
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public FileAccessI() throws IOException ]
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{
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this("",0); m1V-%kUI  
} $ 9=8@  
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public FileAccessI(String sName,long nPos) throws IOException !-,Ww[G>  
{ +A\V)  
oSavedFile = new RandomAccessFile(sName,"rw"); q:8\e  
this.nPos = nPos; K_&_z  
oSavedFile.seek(nPos); b5S7{"<V  
} 5*1#jiq  
61>f(?s  
N iISJWk6'  
public synchronized int write(byte[] b,int nStart,int nLen) `;/XK,m-  
{ uY]T:UVk
 
int n = -1; ]5)"gL%H`  
try{ .<.#aY;N  
oSavedFile.write(b,nStart,nLen); cmIT$?J  
n = nLen; WGMb8 /{$P  
} }^9paU  
catch(IOException e) I&\4C.\>  
{ AK;^9b-}q:  
e.printStackTrace (); y]^#$dK(z  
} F|*tNJU>  
=y<0UU  
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return n; {$|/|*  
} I=5dYq4 l  
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--A&TV  
} $P;UoqG<&  
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K"
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/* ;j!UY.i  
**SiteInfoBean.java 5{>>,pP&  
*/ fp tIc#4  
package NetFox; @(){/
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public class SiteInfoBean { RJwb@r<v  
b}}y=zO|$  
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private String sSiteURL; //Site's URL \OA L Or  
private String sFilePath; //Saved File's Path 1lsLG+Rpxi  
private String sFileName; //Saved File's Name O:,=xIXR  
private int nSplitter; //Count of Splited Downloading File s-%J5_d f  
sJv`fjf%8  
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public SiteInfoBean() ,(;5%+#n  
{//nSplitter的缺省值为5 %ZiK[e3G  
//default value of nSplitter is 5 Q.1XP  
this("","","",5); E|{m"RUOy  
} DyIV/  
-!~vA+jw1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3>M.]w6{  
{ }7Jp :.qk  
sSiteURL= sURL; 5;(0 $4I  
sFilePath = sPath; W}Zb~[,  
sFileName = sName; gwJ}]Tf  
this.nSplitter = nSpiltter; |@ *3^'  
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} 71*>L}H  
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public String getSSiteURL() ee^4KKsh\  
{ jr:drzr{I  
return sSiteURL; |eF.ZC)QWh  
} Az9J\V~"  

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public void setSSiteURL(String value) +[_gyLN<5b  
{ ?uig04@3  
sSiteURL = value; yi|:}K$  
} ET3,9+Gj  
=EWD |<  
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public String getSFilePath() F@EZ;[  
{ K#@
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return sFilePath; r_q~'r35_  
} F  "!`X#  
RPY6Wh|4  
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public void setSFilePath(String value) f}%sO  
{ 7BS/T  
sFilePath = value; <\p&jk?  
} ,[^o9u uB  
Xj(>.E{~H  
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public String getSFileName() .01TTK*  
{ .T{U^0 )  
return sFileName; pj+tjF6Np  
} B6uf;Yc  
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.jCk#@+  
public void setSFileName(String value) e_^KI  
{ t9]r  
sFileName = value; sZT VM9<)  
} bje'Oolc  

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public int getNSplitter() ?o@E1:aA  
{ sE}sE=\  
return nSplitter; ^&HI+M  
} h;jsH!  
oR77`  
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public void setNSplitter(int nCount) ~O8]3+U  
{ y^3,X_0  
nSplitter = nCount; R4yJ.f  
} -^0KE/  
} =qan%=0"h  
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/* oUCVd}wH  
**Utility.java :%pw`b, =V  
*/  eMztjN  
package NetFox; /1U,+g^O>  
aQC7V!v  
-)<JBs>  
public class Utility { ayHn_  
U24V55ZnI  
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public Utility() rC=f#YjR  
{ -B",&yTV  
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} Gl=@>Dc%  
&MBOAHhze  
//线程睡眠 I)qKS@  
public static void sleep(int nSecond) j^:b-:F  
{ A-}PpH~.Z  
try{ +ESX.Vel  
Thread.sleep(nSecond); !:&2+%  
} [@jp9D H  
catch(Exception e) @b4b{d5[  
{ zR_9D}  
e.printStackTrace (); ^o,y5,  
} ;H`=):U  
} Ti /;|lP@  
,80jMs  
//日志 3J23q  
public static void log(String sMsg) tPQ2kEW  
{ PsacXZNs\N  
System.err.println(sMsg);
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} ^a: Saq-}  
jp"XS  
bwv/{3G,Ys  
public static void log(int sMsg) vr5<LNCLQ  
{ (8+.#1!*  
System.err.println(sMsg); hrUm}@d  
} )WzGy~p8K  
} m/SJ4op$  
,%& LG],6  
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/* \>&@lA  
**TestMethod.java V7qCbd^>XJ  
*/ 1v+JCOy  
package NetFox; qQ3]E][/  
EY=\C$3J:  
y=y/d>=w  
public class TestMethod { ,K"r:)\  
{b\Y?t^>f  
=P@M&Yy'  
public TestMethod() ";%e~ =  
{ ///xx/weblogic60b2_win.exe eG a#$x?.  
try{ hlYS=cgY=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7R% PVgS4x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $sB48LJuU'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); My`josJ`Pb  
fileFetch.start(); $fq-wl-=  
} n3-GnVC][  
catch(Exception e){e.printStackTrace ();} 4+Li)A:4.  
p7?CeyZ-V  
k:&?$  
} N
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Off: ~  
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public static void main(String[] args) HY@kw>I  
{ 8,Q.t7v  
new TestMethod(); \rB/83[;u  
} U)IsTk~}O  
} 7zz(#  
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