http断点续传简单实现（java)

/* T30fp  
**SiteFileFetch.java "= %"@"<)  
*/ 8rS;}Bt  
package NetFox; _eq$C=3Ta  
import java.io.*; #B
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import java.net.*; 41d+z>a]  
<z2.A/L  
6'N_bNW  
public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean HyWR&0J  
long[] nStartPos; //开始位置 '" %0UflJS  
long[] nEndPos; //结束位置 f42F@M(:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~
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long nFileLength; //文件长度 wG7>2
*(  
boolean bFirst = true; //是否第一次取文件 @:PMb Ub  
boolean bStop = false; //停止标志 :x[()J~N  
File tmpFile; //文件下载的临时信息 Ri`6X_xU  
DataOutputStream output; //输出到文件的输出流 Mb[4_D
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $.
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public SiteFileFetch(SiteInfoBean bean) throws IOException 5EVypw?]x  
{ hZ>m:es  
siteInfoBean = bean; KWjhkRK4]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g9JZ#BgZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <EgJm`V  
if(tmpFile.exists ()) {_*G"A 9  
{ "&f|<g5  
bFirst = false; \xggIW.^0  
read_nPos(); |;~2y>E  
} LXxQI(RO  
else p&Qm[!  
{ `
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nStartPos = new long[bean.getNSplitter()]; HH7WMYoKY  
nEndPos = new long[bean.getNSplitter()]; \db=]L=|  
} CC"
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} ?t6wozib2  
{*hvzS{1d  
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public void run() A'~mJO/  
{ [o(!/38"@=  
//获得文件长度 4XVwi<)  
//分割文件 9#hp]0S6  
//实例FileSplitterFetch |y0k}ed  
//启动FileSplitterFetch线程 65O 8?
I  
//等待子线程返回 fUY05OMZ  
try{ /%,aX[  
if(bFirst) s:xJ }Ll  
{ ke;=Vg|  
nFileLength = getFileSize(); Z:AB(c  
if(nFileLength == -1) f'5 6IT  
{ <Fx%P:d  
System.err.println("File Length is not known!"); W<#!He  
} <XDnAv0t  
else if(nFileLength == -2) ~/JS_>e#6P  
{ gfIS  
System.err.println("File is not access!"); Z&iW1  
} $G)HU6hF*  
else 6la'\l#  
{ u8>aO>(bVg  
for(int i=0;i<nStartPos.length;i++) u ynudO  
{ 1QD4
9)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6XZjZ*)W  
} H{N},B  
for(int i=0;i<nEndPos.length-1;i++) PknKzrEG:>  
{ 0L3
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nEndPos = nStartPos[i+1]; #T>?g5I  
} t}Td$K7  
nEndPos[nEndPos.length-1] = nFileLength; z?Z"*z  
} d(^HO~p  
} `<v$+mG  
Z}vDP^rf  
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//启动子线程 W*_c
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <N~9=g3  
for(int i=0;i<nStartPos.length;i++) j[\:#/J  
{ 6qTMHRI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T!9AEG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B?^~1Ua9Zv  
nStartPos,nEndPos,i); J;wB
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q=DMfJ"  
fileSplitterFetch.start(); l"`VvW[  
} rf@4
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jLMy27Cn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Pn9;&`t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |1A0YjOD  
nEndPos = " + nFileLength); D{\o*\TN  
// fileSplitterFetch[nPos.length-1].start(); |X XO0  
}xBO;  
zd$?2y8  
//等待子线程结束 Hu6Qr  
//int count = 0; WH39=)D%u  
//是否结束while循环 i g7|kl  
boolean breakWhile = false; E`q
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gSwHPm%zn  
d(RMD  
while(!bStop) f2o6GC_  
{ Y7qQ`|  
write_nPos(); 1c]{rO=taN  
Utility.sleep(500); u]O}Ub`  
breakWhile = true; GKF!GbGR@  
4 Cd5-I  
7_jt =sr  
for(int i=0;i<nStartPos.length;i++) n=~!x  
{ <{;'0> ToM  
if(!fileSplitterFetch.bDownOver) '4#NVXVQm  
{ >cmz JS  
breakWhile = false; &3"ODAp'  
break; *$R9'Yo}F  
} c1FSQ m81  
} _](y<O^9yO  
if(breakWhile) b5]<!~Fv:`  
break; T;{}bc&I  
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l4taD!WD/  
//count++; |k]]dP|:'  
//if(count>4) WwWOic2  
// siteStop(); os;94yd)  
} (7!pc  
toD!RE  
9SA%'  
System.err.println("文件下载结束！"); %r
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} OIw[sum2  
catch(Exception e){e.printStackTrace ();} bw/mF5AsW  
} qHyOaKMd  
a[j]f
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gn.)_  
//获得文件长度 6+ptL-Zt<  
public long getFileSize() c'VCCXe  
{ F|!=]A<  
int nFileLength = -1; 9mXmghoCO  
try{ vyWx{@  
URL url = new URL(siteInfoBean.getSSiteURL()); ALO/{:l(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _D{FQRU<YD  
httpConnection.setRequestProperty("User-Agent","NetFox"); t(PA+~sIp  
`.pd %\  
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int responseCode=httpConnection.getResponseCode(); SCMvq?9  
if(responseCode>=400) %q;y74  
{ V(LfFO{^>?  
processErrorCode(responseCode); daSx^/$R  
return -2; //-2 represent access is error u^]Gc p  
} 0i8\Lu6  
#pW!(tfN^a  
~~"U[G1  
String sHeader; l'2vo=IQ  
FGc#_4SiL  
jG& 8`*|*  
for(int i=1;;i++) |cuKC \  
{ @~7au9.V=X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D8E^[w!  
//Utility.log(in.readLine()); !U2<\!_  
sHeader=httpConnection.getHeaderFieldKey(i); *&#M`
,#  
if(sHeader!=null) Si23w'T  
{ 9)=bBQyr:  
if(sHeader.equals("Content-Length")) _^RN$4.R>  
{ O#J7GbrHO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %$)Sz[=  
break; LB$0'dZU  
} zZ51jA9x  
} qJl DQc-  
else J%q)6&  
break; In:V.'D/>t  
} 0%HAa|L,,  
} &jg>X+;  
catch(IOException e){e.printStackTrace ();} n++

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catch(Exception e){e.printStackTrace ();} Unt]=S3u  
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Utility.log(nFileLength); &ID
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9|@5eN:N  
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return nFileLength; y9@j-m&  
} 5=9Eb  
>OjK0jiPf  
]JmE(Y1(1  
//保存下载信息（文件指针位置） I`g&>  
private void write_nPos() Q=[ IO,f  
{ HKOSS-`5  
try{ AhjCRYk+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g.8^ )u  
output.writeInt(nStartPos.length);  =mcQe^M  
for(int i=0;i<nStartPos.length;i++) n >E1\($  
{ *N{k#d/  
// output.writeLong(nPos); u!It';j  
output.writeLong(fileSplitterFetch.nStartPos); {Ngut  
output.writeLong(fileSplitterFetch.nEndPos); pxyFM@Z](  
} Ho&f[T(  
output.close(); S @!z'$&  
} "_BWUY  
catch(IOException e){e.printStackTrace ();} !VudZ]Sg  
catch(Exception e){e.printStackTrace ();} O\]{6+$fm!  
} ZN'B@E=p  
# M3d=  
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//读取保存的下载信息（文件指针位置） E2.!|u2  
private void read_nPos() $kR%G{j 4  
{ hQL@q7tUr  
try{ y6G6wk;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O_ $zK  
int nCount = input.readInt(); [z;}^3b  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; ]D2d=\  
for(int i=0;i<nStartPos.length;i++) DmB?.l-  
{ hS%oQ)zvE  
nStartPos = input.readLong(); lPA}06
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nEndPos = input.readLong(); _IxYnm`pc  
} Ib/e\+H\  
input.close(); z<yqQ[  
} 7o*~zDh@fH  
catch(IOException e){e.printStackTrace ();} /6x[C  
catch(Exception e){e.printStackTrace ();} PCc{0Rp\vk  
} D7B g!*  
iM8l,Os]<f  
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private void processErrorCode(int nErrorCode) fP
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{ =gd~rk9  
System.err.println("Error Code : " + nErrorCode); k%N$eO$  
} Vm I Afe  
?4W6TSW-'  
3Dj>U*fP  
//停止文件下载 mv/Nz?  
public void siteStop() 3|URlz  
{ @lh]?|*[  
bStop = true; i~4$V  
for(int i=0;i<nStartPos.length;i++) (ze
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fileSplitterFetch.splitterStop(); K)n058PO  
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} Mt~2&$>  
} pYUQSsqC  
//负责部分文件的抓取 @zt"Y~9i  
**FileSplitterFetch.java <hgfgk7<  
*/ }tH_Y
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package NetFox; cy2K#  
bK!uR&i^l  
hb)8
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import java.io.*;  [cfXcl  
import java.net.*; ,x[~|J!  
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public class FileSplitterFetch extends Thread { ZNDjk  
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String sURL; //File URL j4#S/:Q<7  
long nStartPos; //File Snippet Start Position 9m%+6#|  
long nEndPos; //File Snippet End Position "1Y DT-I"  
int nThreadID; //Thread's ID og*ti!Z  
boolean bDownOver = false; //Downing is over >T\^dHtz  
boolean bStop = false; //Stop identical 2aUE<@RU[  
FileAccessI fileAccessI = null; //File Access interface dA(+02U/.  
,LU|WXRB  
k/Ao?R=@gI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y5mk*Q#q  
{ WBD"
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this.sURL = sURL; >IZ$ .-  
this.nStartPos = nStart; `n`HwDo;i  
this.nEndPos = nEnd; ,!^;<UR:  
nThreadID = id; -e+im(2D=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {]7lh#M  
} P@Pe5H"o  
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public void run() A_.}-dzF  
{ e~6>8YO+7j  
while(nStartPos < nEndPos && !bStop) S<w?,Z  
{ Z
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~(.&nysZ-  
try{ GM0pHmC  
URL url = new URL(sURL); tRTJQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0\o5+  
httpConnection.setRequestProperty("User-Agent","NetFox"); _J_QB]t  
String sProperty = "bytes="+nStartPos+"-"; L^ U.h  
httpConnection.setRequestProperty("RANGE",sProperty); W)odaab7  
Utility.log(sProperty); u&o<>d
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InputStream input = httpConnection.getInputStream(); v 5&8C  
//logResponseHead(httpConnection); ,e*WJh8k[  
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byte[] b = new byte[1024]; .H86f !=  
int nRead; A] f^9F@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H+N6VVnO  
{ wJWofFz  
nStartPos += fileAccessI.write(b,0,nRead); Gnie|[3  
//if(nThreadID == 1) 9Om3<der  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6[a;83  
} 90a!_8o  
9H cxL  
ZBc8^QZ  
Utility.log("Thread " + nThreadID + " is over!"); +,4u1`c|$  
bDownOver = true; ^ `[T0X  
//nPos = fileAccessI.write (b,0,nRead); 42PA?^xPw  
} '#612iZo  
catch(Exception e){e.printStackTrace ();} A+"'8%o9}  
} Es1T{<G|w  
} *HQ>tvUh  
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//打印回应的头信息 mfgUf  
public void logResponseHead(HttpURLConnection con) lnrs4s Km  
{ Y\9zjewc  
for(int i=1;;i++) Rw`64L_
  
{ wG&rkg";#  
String header=con.getHeaderFieldKey(i); <im<0;i&e  
if(header!=null) 3'tq`t:SQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e,@5`aYHM@  
Utility.log(header+" : "+con.getHeaderField(header)); bxAHzOB(\  
else @`rC2-V  
break; uVZX53 ,g  
} jG/@kh*m  
} zIc_'Z,b  
8qv>C)~~
`  
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public void splitterStop() 7n'Ww=ttI  
{ %u*H
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bStop = true; G~zP&9N|  
} )1Z @}o 9  
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} wF{M"$am  
j k/-7
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/* Qs8Rb]%|  
**FileAccess.java b'(Hwc\ t  
*//文件访问(定位，写) ,o6,(jJU  
package NetFox; HurF4IsHk  
import java.io.*; nMH:7[x3  
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public class FileAccessI implements Serializable{ d'e\
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oSkvTK$&i  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G8Zl[8  
RandomAccessFile oSavedFile; _16r8r$V  
long nPos; D#d \1g  
'TDp%s*;  
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public FileAccessI() throws IOException $`"$ZI6[  
{ 8:"s3xaO3  
this("",0); md/NMC \  
} Z" dU$,n  
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l +#F
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public FileAccessI(String sName,long nPos) throws IOException E5t /-
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{ 7Q #A  
oSavedFile = new RandomAccessFile(sName,"rw"); k,jcLX
.  
this.nPos = nPos; ePiZHqIsv/  
oSavedFile.seek(nPos); c^}DBvG,  
} 4siq  
23P7%\  
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public synchronized int write(byte[] b,int nStart,int nLen) \&^U9=uq  
{ p)*x7~3e  
int n = -1; OT}P0 ~4s  
try{  J?qikE&  
oSavedFile.write(b,nStart,nLen); !'kr:r}gg  
n = nLen; ;^ YpQP  
} }n?D#Pk,  
catch(IOException e) ]oyWJ#8  
{ >$;,1N $bd  
e.printStackTrace (); PS`F  
} J
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kQO5sX$;  
return n; QzV%m0  
} ZEG~ek=jM  
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} SBamgc  
:hDv^D?3  
$qM&iI-l0  
/* 8l>YpS*S^  
**SiteInfoBean.java
9K=K,6 b  
*/ /Ca M(^W   
package NetFox; 4'H)h'#C  
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public class SiteInfoBean { \N)!]jq  
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private String sSiteURL; //Site's URL P B{7u  
private String sFilePath; //Saved File's Path XPMvAZL  
private String sFileName; //Saved File's Name *I`Eb7 ^  
private int nSplitter; //Count of Splited Downloading File FQ]5W |e  
@4P_Yfn  
+D M,+{}  
public SiteInfoBean() !1`f84
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{//nSplitter的缺省值为5 P&AaD!Qn  
//default value of nSplitter is 5 j`_tb
 
this("","","",5); <E7y:%L[Go  
} ~!'T!g%C  
jN!sLW  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^2"w5F  
{ %WtF\p  
sSiteURL= sURL;
x=V3_HI/}  
sFilePath = sPath; >*]B4Q  
sFileName = sName; P$
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this.nSplitter = nSpiltter; &IkHP/  
.Iv`B:4  
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} rz5@E  
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public String getSSiteURL() [m9=e-KS$Q  
{ fILD
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return sSiteURL; %TzdpQp"  
} K#dG'/M|Pb  
@mEB=X(-l=  
{hx=6"@  
public void setSSiteURL(String value) j]6YLM@5$  
{ gflO0$i  
sSiteURL = value; p I@!2c:}  
} j +Ro?  
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public String getSFilePath() [V41 Gk  
{ l/56;f\IA  
return sFilePath; a-9sc6@  
} W7.QK/@  
l:s
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public void setSFilePath(String value) (^^}Ke{J  
{ oC(.u?  
sFilePath = value; `&SBp }W}  
} <Mf(2`T  
^PowL:  
}*vO&J@z  
public String getSFileName() _sF Ad`  
{ 0#/Pc`zC  
return sFileName; cfPQcB>A  
} C.+:FY.H  
mW
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*NQsD C.J^  
public void setSFileName(String value) g3\13<  
{ -@/!u9l  
sFileName = value; r1.OLn?C  
} O @{<?[  
S|T*-?|  
&;$- &;  
public int getNSplitter() >!#or- C  
{ Ej'N!d.  
return nSplitter; 6KKQ)DNu_  
} ]?~[!&h  
$H1igYc  
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public void setNSplitter(int nCount) BV]$= e'  
{ wQ\bGBks  
nSplitter = nCount; =[`gfw  
} -
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} .$ 5*v  
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/* y(jd$GM|  
**Utility.java Klqte*!  
*/ wK  Je^7  
package NetFox; [)nU?l  
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public class Utility { 2yA+zJ 46B  
8<Ex`  
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public Utility() Q=#!wWVP  
{ jQpG7H  
cDh\$7'b  
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} wyv%c/WlS  
]}nX$xy  
//线程睡眠 /UiB1-*b  
public static void sleep(int nSecond) iI!g1  
{ YG>6;g)Zm  
try{ 0<]]q[pr  
Thread.sleep(nSecond); -d6PXf5  
} ]0;,M  
catch(Exception e) wO"ezQ  
{ =+VI{~.|}  
e.printStackTrace (); &_$xMM,X  
} D?r% Y  
} $TavvO%#  
'o-J)+oa  
//日志 UUxP4  
public static void log(String sMsg) ,~7+r#q7  
{ .KF(_ 92  
System.err.println(sMsg); 'z">4{5  
} XC\'8hL:  
~JohcU}d  
]H=P(Z-  
public static void log(int sMsg) \-I)dMm[  
{ 'd9cCQ}  
System.err.println(sMsg); M[KYt"v  
} txy'7t  
} T$s)aM  
/{nZI_v#  
n]bxG8~t  
/* q%wF=<W  
**TestMethod.java *AA78G|  
*/ <W88;d33r=  
package NetFox; |p":s3K"Hy  
u9%AK g}~  
^uIKwql  
public class TestMethod { 30L/-+r1  
d(
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"gq_^&  
public TestMethod() k1M?6TW&  
{ ///xx/weblogic60b2_win.exe 5C"A*Fg?;  
try{ 
vmT6^G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); szD BfGd%j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UJGmaE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dlo4Wy  
fileFetch.start(); rYk   
} f`_6X~
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catch(Exception e){e.printStackTrace ();} $ iU~p  
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} @!s(Zkpev  
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public static void main(String[] args) z;[Z'_B  
{ DqlspT  
new TestMethod(); -vBk,;^>  
} %~YQlN  
} LQ=Fck~[r  
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