http断点续传简单实现（java)

/* %s :  
**SiteFileFetch.java m
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*/ jMWwu+w  
package NetFox; +U)|&1oa  
import java.io.*; ]9< 9F ?  
import java.net.*; UpseU8Wo  
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public class SiteFileFetch extends Thread { WJ8vHPSM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .-~%w  
long[] nStartPos; //开始位置 $#J
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long[] nEndPos; //结束位置 *]{I\rX
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f#Cdx"  
long nFileLength; //文件长度 <\>ak7m  
boolean bFirst = true; //是否第一次取文件 RYJc
>  
boolean bStop = false; //停止标志 SVWSO  
File tmpFile; //文件下载的临时信息 :O+b
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DataOutputStream output; //输出到文件的输出流 rkc%S5we  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sH,)e'0  
public SiteFileFetch(SiteInfoBean bean) throws IOException x Bw.M{  
{ V+~{a:8[pq  
siteInfoBean = bean; iwjl--)@K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m9w ;a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I%C:d#p  
if(tmpFile.exists ()) Bo\v-97  
{ ?F!J@Xn5  
bFirst = false; [#6Esy8|  
read_nPos(); F8;4Oj  
} s^R2jueR  
else E^W*'D  
{ RW[<e   
nStartPos = new long[bean.getNSplitter()]; \0T*msYQ  
nEndPos = new long[bean.getNSplitter()]; Xt*%"7yTp  
} iSLf:  
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} rWpfAE)!  
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public void run() WvzvGT=  
{ QGG(I7{-  
//获得文件长度 3CuoBb8  
//分割文件 @wJa33QT  
//实例FileSplitterFetch S,v>*AF  
//启动FileSplitterFetch线程 8B+^vF   
//等待子线程返回 _H<OfAO  
try{ J$*["y`+  
if(bFirst) }eFUw  
{ ?o5#Ve$-X  
nFileLength = getFileSize(); @@mW+16  
if(nFileLength == -1) vUx$[/<  
{ yzb&
  
System.err.println("File Length is not known!"); 6;XpLivP7  
} MJpTr5Vs  
else if(nFileLength == -2) ,,wx197XeD  
{ d6 EJn/  
System.err.println("File is not access!"); bO%ck-om!  
} UI|@5:J  
else
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{ <[l}^`IC^4  
for(int i=0;i<nStartPos.length;i++) ]JuB6o_L  
{ pFRnPOv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p&doQh
  
} `z`;eR2oX  
for(int i=0;i<nEndPos.length-1;i++) k r^#B^  
{ n8aiGnd=v  
nEndPos = nStartPos[i+1]; HTp
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} *]?YvY  
nEndPos[nEndPos.length-1] = nFileLength; }mZ*f y0t  
} >(KUYX?p  
} 4GA-dtyV&  
)?y"NVc*  
|sM#g1D@  
//启动子线程 [N+ruc?)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
* xXc$T  
for(int i=0;i<nStartPos.length;i++) vJ}  
{ vz5RS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m|FONQ,@D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8^i,M^f^{  
nStartPos,nEndPos,i); S9055`v5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )X$n'E  
fileSplitterFetch.start(); =DwH*U/YR  
} o;C)!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "z4E|s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yE{UV>ry  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4zbV' ]  
nEndPos = " + nFileLength); io_64K+K  
// fileSplitterFetch[nPos.length-1].start(); >&Lu0oHH  
iPNsEQ0We  
gipRVd*TA  
//等待子线程结束 baGI(Dk  
//int count = 0; k-0e#"B  
//是否结束while循环 uRhH_c-6C  
boolean breakWhile = false; NH6!|T  
czi!q1<vg  
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while(!bStop) s_kd@?=`x  
{ !gQ(1u|r  
write_nPos(); :$d3a"]  
Utility.sleep(500); >pHvBFa3G  
breakWhile = true; -q|M=6gOs  
c3-bn #  
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for(int i=0;i<nStartPos.length;i++) 5|z[%x~f  
{ $7g(-W  
if(!fileSplitterFetch.bDownOver) 6 VDF@V$E  
{ 'o9V0#$!  
breakWhile = false; Y:BrAa[  
break; K2v
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} {a%cU[q  
} v>l?d27R  
if(breakWhile) \?}.+v  
break; mt7:`-  
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//count++; Np_6ZUaqz  
//if(count>4) obGSc)?j  
// siteStop(); { )K(}~VD  
} Gl9
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"$9ZkADO  
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System.err.println("文件下载结束！"); l>q.BG  
} V^5 t~)#46  
catch(Exception e){e.printStackTrace ();} Cvy;O~)  
} Id1[}B-T  
/m:}rD  
2N#L'v@g=+  
//获得文件长度 tJ3s#q6  
public long getFileSize() 2Z|kf9  
{ |3@
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int nFileLength = -1; [r'M_foga*  
try{ B9\o:eY  
URL url = new URL(siteInfoBean.getSSiteURL()); $R4\jIewV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ktb.fhO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^jA}*YP  
#{sb>^BF  
H&+s&F{%  
int responseCode=httpConnection.getResponseCode(); \02e zG  
if(responseCode>=400) ~.tu#Y?  
{ K*[wr@)
u  
processErrorCode(responseCode); ['j,S<Bu~  
return -2; //-2 represent access is error oQO3:2
a  
} dno*Usx5d0  
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Ho|n\7$  
String sHeader; iqYc&}k,  
54&2SU$kx  
6!N&,I  
for(int i=1;;i++) *z~Y*Q0  
{ l7
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C:cu1Y9  
//Utility.log(in.readLine()); =?hlgQ  
sHeader=httpConnection.getHeaderFieldKey(i); #'oK
krl  
if(sHeader!=null) [g_@<?zg  
{ ]2'~e,"O  
if(sHeader.equals("Content-Length")) 4
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{ Zup?nP2GkT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F9" K  
break; ^,gKA\Wli  
} 5`Z#m:+u  
} 0fNBy^(K  
else IA'AA|v  
break; up?8Pq*  
} *V}}3Degh  
} 8wd2\J,]  
catch(IOException e){e.printStackTrace ();} va.wdk g  
catch(Exception e){e.printStackTrace ();} ),eiJblH  
$?YkgK  
oR }  
Utility.log(nFileLength); 2}AV_]]  
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return nFileLength; @lI/g  
} ORTM[cL  
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"%Ak[04'  
//保存下载信息（文件指针位置）  %JZIg!  
private void write_nPos() |r%P.f:y{X  
{ ~+Y;jAdU  
try{ $- L)>"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s*@.qN  
output.writeInt(nStartPos.length); w;"'l]W  
for(int i=0;i<nStartPos.length;i++) f&|SG
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{ 5P4>xv[  
// output.writeLong(nPos); CT : ac64  
output.writeLong(fileSplitterFetch.nStartPos); |bh:x{h  
output.writeLong(fileSplitterFetch.nEndPos); +}n]A^&I\E  
} i F Ab"VA  
output.close(); 5`J. ic  
} ,LvJ'N  
catch(IOException e){e.printStackTrace ();} @`yfft  
catch(Exception e){e.printStackTrace ();} C-7.Sa  
} `i
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]iPdAwc.1  
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//读取保存的下载信息（文件指针位置） ]pt @  
private void read_nPos() S@_GjCpn
 
{ ?@#<>7V  
try{ nC w1H kW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %K%z<R8  
int nCount = input.readInt(); c-,/qn/  
nStartPos = new long[nCount]; LQe<mZ<  
nEndPos = new long[nCount]; ]=/f`  
for(int i=0;i<nStartPos.length;i++) _Z%C{~,7)x  
{ 8LL);"$  
nStartPos = input.readLong(); wRKGJ
  
nEndPos = input.readLong(); +W}f0@#)<  
} l\eq/yg_  
input.close(); f%af.cR*  
} lL
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catch(IOException e){e.printStackTrace ();} #q-t!C%E  
catch(Exception e){e.printStackTrace ();} [|3 %~s|Sv  
} v1:5r  
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private void processErrorCode(int nErrorCode) SWu=n1J.?H  
{ 84k;d;  
System.err.println("Error Code : " + nErrorCode); Y9C]-zEv  
} zr
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//停止文件下载 &EMm<(.]a  
public void siteStop() JS4pJe\q  
{ |Q{l]D  
bStop = true; kmf4ax h1  
for(int i=0;i<nStartPos.length;i++) 8=$@azG  
fileSplitterFetch.splitterStop(); eI@O9<.&  
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} (Az^st/_  
} X(8]9  
//负责部分文件的抓取 2/GH5b(  
**FileSplitterFetch.java 4CDmq[AVS[  
*/ Qr/?tMALc  
package NetFox; `VHm,g2  
.w0?  
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import java.io.*; Y$N|p{Z  
import java.net.*; 9:P)@UF  
6ik6JL$AI  

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public class FileSplitterFetch extends Thread { 7Kn=[2J5k'  
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String sURL; //File URL i'a M#4V  
long nStartPos; //File Snippet Start Position 9J<KR#M  
long nEndPos; //File Snippet End Position Th-zMQ4  
int nThreadID; //Thread's ID {MIs%w.G  
boolean bDownOver = false; //Downing is over N@k:kI  
boolean bStop = false; //Stop identical U-k6ZV3&8  
FileAccessI fileAccessI = null; //File Access interface o;"!#Z 1SJ  
*d@}'De{8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ouj5NL  
{ ;$86.2S>B  
this.sURL = sURL; 9AS,-5;XQ  
this.nStartPos = nStart; ,7eN m>$  
this.nEndPos = nEnd; a+MC[aFr  
nThreadID = id; TiH(HW|:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $u>^A<TBN  
} U\51j  
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public void run() )xi|BqQz  
{ BV<LIrAS  
while(nStartPos < nEndPos && !bStop) B6
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{ ek.L(n,J|  
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eM8u
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try{ 5t0$nKah]  
URL url = new URL(sURL); Z";o{@p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wc(?ezn  
httpConnection.setRequestProperty("User-Agent","NetFox"); A M# '(k(  
String sProperty = "bytes="+nStartPos+"-"; ZM<1;!i  
httpConnection.setRequestProperty("RANGE",sProperty); z2-=fIr.h  
Utility.log(sProperty); @~zhAU!  
 ,5<-\"{]  
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InputStream input = httpConnection.getInputStream(); ~jJu*s$?  
//logResponseHead(httpConnection); gp;(M~we  
wjY3:S~  
<;=X7l+  
byte[] b = new byte[1024]; X\M0Q%8  
int nRead; #B54p@.}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F> ..eK  
{ WWD\EDnS  
nStartPos += fileAccessI.write(b,0,nRead); yfYAA*S!z  
//if(nThreadID == 1) BHa!jw_~o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r0_3`;H  
} +-5CM0*&  
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 ~B/|#o2  
Utility.log("Thread " + nThreadID + " is over!"); )5bhyzSZI  
bDownOver = true; R\6#J0&Y-  
//nPos = fileAccessI.write (b,0,nRead); Dj?95Z,r  
} 16xM
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catch(Exception e){e.printStackTrace ();} pp/Cn4"w  
} ,)%nLc  
} ytHa[U  
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//打印回应的头信息 `$Q $l  
public void logResponseHead(HttpURLConnection con) 24]O0K  
{ KrG$W/<tg  
for(int i=1;;i++) AM,@BnEcuT  
{ &EZ28k"x  
String header=con.getHeaderFieldKey(i); J1g `0XH  
if(header!=null) CI ~+(+q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zb3E-'
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Utility.log(header+" : "+con.getHeaderField(header)); ln9U>*<  
else ]l`?"X|^  
break; /Eu[7  
} `
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}
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) 3Eax_?Z  
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public void splitterStop() 3]/w3|y  
{ pl'n 0L<l  
bStop = true; V&[|%jm&  
} t4 $cMf  
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} cy%^P^M  
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/* -k")#1  
**FileAccess.java & Z*&&  
*//文件访问(定位，写) , En D3 |  
package NetFox; 
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import java.io.*; nTp?  
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OV^) N  
public class FileAccessI implements Serializable{ t d-EB&i\  
N'3Vt8o,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (hs[B4nV  
RandomAccessFile oSavedFile; V;Te =
4  
long nPos; m'@NF--#Oq  
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public FileAccessI() throws IOException gtqgf<mS  
{ ig)rK<@*[  
this("",0); -"#;U`.oh7  
} H~Hh$-z  
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public FileAccessI(String sName,long nPos) throws IOException ]t(;bD hT  
{ `pOiv&>  
oSavedFile = new RandomAccessFile(sName,"rw"); =;`+^  
this.nPos = nPos; c5nl!0XX  
oSavedFile.seek(nPos); VYMs`d[  
} vrLI`3n]  
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]  
public synchronized int write(byte[] b,int nStart,int nLen) xOp8[6Ga'  
{ T
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int n = -1; h,LwC9  
try{ ix [aS  
oSavedFile.write(b,nStart,nLen); %\Z{~(&-v  
n = nLen; uF/l,[0v  
} a}c.]zm]  
catch(IOException e) "at*G>+  
{ %nSLe~b  
e.printStackTrace (); &>XIK8*  
} 37Q9goMov  
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#"jEc*&=  
return n; ckHHD|  
} h}nceH0s3d  
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} Wz`MEyj  
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/* f,wB.MN  
**SiteInfoBean.java \'q 9,tP
 
*/ `%SFu  
package NetFox; {R5Q{]dK3  
wz}
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xxLD8?@e7  
public class SiteInfoBean { FFQ=<(Ki  
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<DxUqCE  
private String sSiteURL; //Site's URL :<=A1>&8  
private String sFilePath; //Saved File's Path
U ]Ek5p  
private String sFileName; //Saved File's Name eZ'J,;  
private int nSplitter; //Count of Splited Downloading File s,!+wHv_8  
?ey!wcv~  
]>M{Qn*  
public SiteInfoBean() tsaf|xe  
{//nSplitter的缺省值为5 ^rO3B?_  
//default value of nSplitter is 5 0pYO-@E  
this("","","",5); 2m7Z:b  
} .'.#bH9K  
cy%JJ)sf  
_ +q.R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;nW#Dn9  
{ z%Pbs[*C  
sSiteURL= sURL; $d? N("L  
sFilePath = sPath; Y]!8Ymuww@  
sFileName = sName; -!zyit5B  
this.nSplitter = nSpiltter; e@}zp  
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=B-a]?lM  
} yqi=9NB  
~<!b}Hv  
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public String getSSiteURL() \3a(8Em  
{ 'mx_]b^O  
return sSiteURL; U{6i5;F#H  
} c((^l&  
Vj(}'h-c\  
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public void setSSiteURL(String value) d}#G~O+y3v  
{ @62QDlt;
 
sSiteURL = value; HIM>%   
} Wyh   
-b'93_ZTu:  
>U?HXu/TJr  
public String getSFilePath() P4@<`Eb  
{ hYOUuC  
return sFilePath; tu{y  
} yyCx;  
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"  
public void setSFilePath(String value) wju2xM
 
{ 9,g &EnvG  
sFilePath = value; I[E/)R{\  
} IWbW=0IsS  
|a/1mUxQ&  
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public String getSFileName() "9mJ$us  
{ gwHNz5 a*V  
return sFileName; TNs;#Q  
} WPLM*]6  
>5G2!Ns'  
$#E?`At{I  
public void setSFileName(String value) CDOqdBQ  
{ N4y$$.uv2  
sFileName = value; M8j%bmd(,  
} $$QbcnOf$  
2\ 3}y(  
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public int getNSplitter() Pt<lHfd  
{ 5R6@A?vr  
return nSplitter; ETQ.A< v  
} H
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(5AgI7I,  
public void setNSplitter(int nCount) V0yQ  
{ &Xw{%Rg  
nSplitter = nCount; 5T]GyftFV  
}
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} ^3`CP4DT  
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7/^`y')  
/* 5@_c<   
**Utility.java 5<1,`Bq@  
*/ =+@IpXj  
package NetFox; 5\1C@d  
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public class Utility { 2x3'm  
ai/VbV'|  
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public Utility() XHq8p[F  
{ @H'pvFLK?  
Q5R7se_  
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} '&_<!Nv3  
'&~A  
//线程睡眠 sR%,l  
public static void sleep(int nSecond) 8'c_&\kdv  
{
-4:L[.2  
try{ 8GC(?#Kb  
Thread.sleep(nSecond); 5|zISK%zHS  
} "b6ZAgx
v  
catch(Exception e) VeT\I.K[  
{ %) -5'l<  
e.printStackTrace ();  ^"Y5V5
 
} K&{*sa r  
} 3'(w6V  
@r.u8e)l  
//日志 ,]ALyWGuX  
public static void log(String sMsg) fG;(&Dx  
{ 'MEO?]Tf.^  
System.err.println(sMsg); ?V|t7^+:  
} k:D;C3vJd  
q!l[^t|;  
==d@0`  
public static void log(int sMsg) G[U'-a}I  
{ Vj.5b0/(  
System.err.println(sMsg); y~jKytq^@  
} 4BSSJ@z  
} wr\d5j  
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&^-quzlZ  
/* K>H_q@-?f  
**TestMethod.java X2#;1 ku  
*/ /mST<{(_G\  
package NetFox; 4%5H<:V7  
n ETm"  
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public class TestMethod { YE#OAfj~  

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^s'ozCk 0  
public TestMethod() 0q%=Vs~@g  
{ ///xx/weblogic60b2_win.exe _J}vPm  
try{ ii%n:0+zm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v5i?4?-Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P<iS7Ys+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^:0NKq\  
fileFetch.start(); x+h7OvW{  
} H^s@qh)L  
catch(Exception e){e.printStackTrace ();} >j]*=&,7  
Q7PqN1jTE  
%;,D:Tv=&  
} |0Kj0u8T  
; *G[3kk  
TI-#\v9  
public static void main(String[] args) -B\`O*Q  
{ @nN+F,phx  
new TestMethod(); h 9V9.'  
} a.F6!?  
} /wIev1Z!Y  
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