http断点续传简单实现（java)

/* _X~xfmU  
**SiteFileFetch.java G4,.kK  
*/ AmX ~KK  
package NetFox; M=sGPPj  
import java.io.*;  (2dkmn  
import java.net.*; |H'wDw8  
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public class SiteFileFetch extends Thread { *EF`s~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _}l7f  
long[] nStartPos; //开始位置 X_(n  
long[] nEndPos; //结束位置 >/9Qgyc0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~mvD|$1z  
long nFileLength; //文件长度 a\xf\$Ym  
boolean bFirst = true; //是否第一次取文件 i{}Q5iy  
boolean bStop = false; //停止标志 T1A/>\Ns  
File tmpFile; //文件下载的临时信息 t $u.  
DataOutputStream output; //输出到文件的输出流 4p&YhV7j)o  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8S@"6TG`  
public SiteFileFetch(SiteInfoBean bean) throws IOException )E}eK-Yu  
{ blmY=/]  
siteInfoBean = bean; VX'G\Zz@h|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yUX<W'-Hev  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >8EmfjUoc  
if(tmpFile.exists ()) ^o[(F<q  
{ zC WN,K`  
bFirst = false; #RWmP$+#=  
read_nPos(); tWI%
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} c{\x<AwO  
else ;*>':-4  
{ 7D=gAMPvJ  
nStartPos = new long[bean.getNSplitter()]; im@c||
 
nEndPos = new long[bean.getNSplitter()]; WjF#YW\  
} xX\A&9m  
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} QV_Ep
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public void run() s%@HchZ 1  
{ AxiCpAS;J  
//获得文件长度 tybM3VA  
//分割文件 BF(Kaf;<t.  
//实例FileSplitterFetch PaBqv]  
//启动FileSplitterFetch线程 fK5iOj'Q  
//等待子线程返回 Rqun}v}  
try{ s AlOX`t  
if(bFirst) [OwrIL  
{ f4+}k GJN  
nFileLength = getFileSize(); zF_aJ+i:~  
if(nFileLength == -1) Dlx-mm_  
{ ^e:rRk7 &  
System.err.println("File Length is not known!"); n
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} K~jN"ev  
else if(nFileLength == -2) E)%r}4u>  
{ {p7b\=WB-  
System.err.println("File is not access!"); nm !H&#<  
} 3.D|xE]g  
else OIrr'uNH  
{ l~$Od jf  
for(int i=0;i<nStartPos.length;i++) #yR@.&P  
{ oU)HxV  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} ziG]BZ  
for(int i=0;i<nEndPos.length-1;i++) ~MZ.988:<  
{ Kz9h{Tu4  
nEndPos = nStartPos[i+1]; IK|W^hH\8  
} ZN-5W|' O  
nEndPos[nEndPos.length-1] = nFileLength; RLUH[[  
} ~n9-  
} 1" #W1im  
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//启动子线程 e(EXQP2P>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Jk=d5B  
for(int i=0;i<nStartPos.length;i++) E@S5|CM  
{ )jaNFJ 3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0?\d%J!"S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4e9'yi  
nStartPos,nEndPos,i); !_LRuqQ?"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TDj
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fileSplitterFetch.start(); vV /fTO  
} 6l?\iE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f*GdHUZ*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S0-/9h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", he1OLk  
nEndPos = " + nFileLength); *Q:EICDE7  
// fileSplitterFetch[nPos.length-1].start(); jthGNVZ  
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q NE(@at  
//等待子线程结束 2a[_^v $v  
//int count = 0; 2:D1<z6RQ  
//是否结束while循环
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boolean breakWhile = false; '3V?M;3|K  
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while(!bStop) 'X1fb:8m8  
{ `B71`  
write_nPos(); h?2:'Vu]  
Utility.sleep(500); Q.`O;D}x  
breakWhile = true; 09C[B+>h  
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for(int i=0;i<nStartPos.length;i++) } l4d/I  
{ _9Y7.5  
if(!fileSplitterFetch.bDownOver) B;mt11M  
{ @(Y+W2Iyy+  
breakWhile = false; @&E{ L  
break; }!0nb)kL  
} 
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} f3Cj
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if(breakWhile) %$.]g  
break; }Qo:;&"3  
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//count++; tr$~INe  
//if(count>4) f;PvXq<7"  
// siteStop(); 8I*
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} l~9P4 ,  
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System.err.println("文件下载结束！"); sVJwe\!  
} d)X6x-(  
catch(Exception e){e.printStackTrace ();} d %Z+.O  
} CUo %i/R  
"vnWq=E2  
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//获得文件长度 G~;hD-D~.  
public long getFileSize() L?gak@E  
{ *K1GX  
int nFileLength = -1; G>fJ)A  
try{ yxU??#v|g  
URL url = new URL(siteInfoBean.getSSiteURL()); -U/m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 09>lx$  
httpConnection.setRequestProperty("User-Agent","NetFox"); rM?ox  
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int responseCode=httpConnection.getResponseCode(); Q~p[jQ,4wZ  
if(responseCode>=400) ]C me)&hX  
{ umD[4aP~;  
processErrorCode(responseCode); A&~<qgBTp  
return -2; //-2 represent access is error <BNCo5*  
} P6cc8x9g(  
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String sHeader; q:D!@+U  
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for(int i=1;;i++) u LXV,  
{ kTLA["<m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !z.C}n5F  
//Utility.log(in.readLine()); }4n?k'_s?  
sHeader=httpConnection.getHeaderFieldKey(i); j4B|ktf  
if(sHeader!=null) ^YLpZoo  
{ }m6j6uAR6)  
if(sHeader.equals("Content-Length")) =<M7t*!  
{ ]%K 8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pWwB<F  
break; bl)iji`]  
} ~!w()v n  
} '"=Mw;p  
else m%hUvG| i  
break; q3s +?&  
} Q*+_%n1 /  
} 8VwByk8  
catch(IOException e){e.printStackTrace ();} `Oc`I9  
catch(Exception e){e.printStackTrace ();} A%G \ AT  
'
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Utility.log(nFileLength); aDik1Q  
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return nFileLength; ?*~Pgh >uL  
} .7HnWKUV
 
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<A,G:&d~  
//保存下载信息（文件指针位置） : Jh  
private void write_nPos() W_zAAIY_Y  
{ _/)?GXwLn  
try{ UJ'}p&E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H...!c1M@  
output.writeInt(nStartPos.length); kXq*Jq  
for(int i=0;i<nStartPos.length;i++) I oz rZ  
{ VvO/  
// output.writeLong(nPos); -k19BDJ,W  
output.writeLong(fileSplitterFetch.nStartPos); +P~E54  
output.writeLong(fileSplitterFetch.nEndPos); @a1+  
} ?'_Q^O>  
output.close(); z5CWgN  
} #]yb;L  
catch(IOException e){e.printStackTrace ();} h%Nbx:vKk  
catch(Exception e){e.printStackTrace ();} hal3J  
} $cLtAo^W  
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//读取保存的下载信息（文件指针位置） l/BE~gdl  
private void read_nPos() %EuXL% B  
{ ?^F#}>C  
try{ 1f 0"z1
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r"a4;&mf  
int nCount = input.readInt(); ; b2)WM:  
nStartPos = new long[nCount]; 7^bO`  
nEndPos = new long[nCount]; w@
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for(int i=0;i<nStartPos.length;i++) 5@+8*Fdk  
{ UN&b]vg  
nStartPos = input.readLong(); f.gkGwNk  
nEndPos = input.readLong(); 7/;Xt&  
} ^ ,Bxq^'D  
input.close(); &/7AW(?  
} K/ q:aMq  
catch(IOException e){e.printStackTrace ();} ba?]eK  
catch(Exception e){e.printStackTrace ();} 13]sZ([B%|  
} )>)_>[  
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private void processErrorCode(int nErrorCode) Riq5Au?*)  
{ I3xx}^V  
System.err.println("Error Code : " + nErrorCode);
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} ,=tVa])  
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A$RN7#  
//停止文件下载 Ms*;?qtrR  
public void siteStop() *xs8/?  
{ DVYY1!j<  
bStop = true; ]?L?q2>&  
for(int i=0;i<nStartPos.length;i++) DTdL|x.{  
fileSplitterFetch.splitterStop(); _Y*: l7  
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} V#W(c_g
 
} |WeLmy%9  
//负责部分文件的抓取 ,\5]n&T;r  
**FileSplitterFetch.java Vkex&?>v$  
*/ ^/HE_keY  
package NetFox; 7581G$@ym  
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import java.io.*; S<Q6b_D  
import java.net.*; J#CF SG
  
w
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public class FileSplitterFetch extends Thread { .1MXQLy  
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String sURL; //File URL =,I,K=+_x  
long nStartPos; //File Snippet Start Position vKDPg p<j  
long nEndPos; //File Snippet End Position 8oY0?|_Bx  
int nThreadID; //Thread's ID {S\cpCI`  
boolean bDownOver = false; //Downing is over C+}uH:I'L  
boolean bStop = false; //Stop identical Z{RgpVt  
FileAccessI fileAccessI = null; //File Access interface hNFMuv  
8|7fd|6~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException SDV} bN  
{ c
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this.sURL = sURL; u=#!je
 
this.nStartPos = nStart; C,-V>bx g  
this.nEndPos = nEnd; `c{i+  
nThreadID = id; c*!bT$]~\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w IT`OT6Q  
} lN1T\  
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public void run() k+-u4W  
{ 6R@ v>}  
while(nStartPos < nEndPos && !bStop) CQsVGn{x  
{ dvsOJj/b  
x&)
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try{ yq[C?N &N  
URL url = new URL(sURL); e&F,z=XJ}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ? Z8_(e0U  
httpConnection.setRequestProperty("User-Agent","NetFox"); av wU)6L  
String sProperty = "bytes="+nStartPos+"-"; 1kl4X3q6  
httpConnection.setRequestProperty("RANGE",sProperty); g9I2SdaJ  
Utility.log(sProperty); sBF>a|  
b
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InputStream input = httpConnection.getInputStream(); ~z>2`^Z"  
//logResponseHead(httpConnection); 05nG|  
? _[gs/i}  
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byte[] b = new byte[1024]; 5nqj  
int nRead; 50rq}-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uxVXnQQ  
{ yXrFH@3  
nStartPos += fileAccessI.write(b,0,nRead); Lc*i[J<s  
//if(nThreadID == 1) ^'
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u&bo32fc  
} u-j$
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Utility.log("Thread " + nThreadID + " is over!"); GC$Hp!H  
bDownOver = true; V'^s5  
//nPos = fileAccessI.write (b,0,nRead); .knRH^  
} 5`6@CRef  
catch(Exception e){e.printStackTrace ();} 2#6yO`?uo  
} b)$<aFl  
} E[2c`XFd8  
&OGY?[n  
v.\1-Q?  
//打印回应的头信息 bbiDY  
public void logResponseHead(HttpURLConnection con) $}W=O:L+D  
{ ;% !'K~  
for(int i=1;;i++) %S.R@C[3  
{ /$WEO[o  
String header=con.getHeaderFieldKey(i); +n^$4f  
if(header!=null) Y'bDEdeT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "=9L7.E)  
Utility.log(header+" : "+con.getHeaderField(header)); -UPdgZ_Vxz  
else OyZgg(iN  
break; G+^HZ4jg  
} 0l^-[jK)  
} @(Ou
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q+e'=0BHd:  
public void splitterStop() R(r89bTQ  
{ bNY_V;7Kw`  
bStop = true; ~;il{ym  
} *Yl9%x]3c  
"
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} LurBqr  
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N!/^s":  
/* z930Wi{@  
**FileAccess.java  ];Bh1  
*//文件访问(定位，写) WJ=eV8Uk  
package NetFox; Skp&W*Ai  
import java.io.*; [=7|LHjU  
#s)6u?N  
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public class FileAccessI implements Serializable{ vDv:3qN7(  
a0CmCv2#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ArbfA~jXB  
RandomAccessFile oSavedFile; cZZ-K?_  
long nPos; ISa2|v;M  
 9'\18_w  
/*`u(d2g  
public FileAccessI() throws IOException pDCQ?VW  
{ k[gO>UGB;  
this("",0); x<~ pqq8]  
} M{3He)&  
*Jmy:C<>  
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public FileAccessI(String sName,long nPos) throws IOException |.)oV;9  
{ V[5-A $ft  
oSavedFile = new RandomAccessFile(sName,"rw"); xWU0Ev)4U  
this.nPos = nPos; yO]Vex5)  
oSavedFile.seek(nPos); GFYAg  
} k3}|^/bHJ  
b Zn:q[7  
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public synchronized int write(byte[] b,int nStart,int nLen) xCEEv5(5  
{ i~MCY.F  
int n = -1; M`9qo8zCi  
try{ B'lWs;  
oSavedFile.write(b,nStart,nLen); co|jUDu>W  
n = nLen; @vCPX=c  
} 4=%Uv^M  
catch(IOException e) #78p#E  
{ .`)\GjDv  
e.printStackTrace (); m3+MRy5  
} fOdkzD,  
$[by)  
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return n; 0;#%KC,  
} SirjWYap  
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} |-e*^|  
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/* |ITp$_S  
**SiteInfoBean.java sbjAZzrX2i  
*/ (/a2#iW  
package NetFox; q?nXhUD  
o )G'._  
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public class SiteInfoBean { +%OINMo.A  
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private String sSiteURL; //Site's URL !\'7j-6  
private String sFilePath; //Saved File's Path 'nz;|6uC  
private String sFileName; //Saved File's Name j\B]>PP5  
private int nSplitter; //Count of Splited Downloading File osoreo;V^  
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X
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public SiteInfoBean() X|TEeE c[L  
{//nSplitter的缺省值为5 9TIyY`2!  
//default value of nSplitter is 5 h3Nwxj~E  
this("","","",5); ms{:=L2$$  
} Kyt.[" p  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A[ 9 @:z  
{ W2D^%;mw  
sSiteURL= sURL;
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sFilePath = sPath; AON";&dLq-  
sFileName = sName; HgvgO\`]  
this.nSplitter = nSpiltter; gbsRf&4h  
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! @{rkp  
} 1P. W 34  
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public String getSSiteURL() nm'sub  
{ {>H#/I8si  
return sSiteURL; 6vbWe@#U/  
} nfJ|&'T  
>@KQ )p' `  
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public void setSSiteURL(String value) ?&I gD.  
{ q#:,6HDd  
sSiteURL = value; ZF"f.aV8)  
} WPygmti}Be  
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public String getSFilePath() 7-6Z\.-  
{ &$?e D{  
return sFilePath; u/Fa+S  
} 6&M $S$y  
*:J#[ET,  
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public void setSFilePath(String value) (#Z2  
{ ,],"tzKtE  
sFilePath = value; K QXw~g?  
} O<Qa1Ow7f  
7?-eR-  
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public String getSFileName() \HLI y  
{ 9!b,!#=  
return sFileName; (f#QETiV  
} .=~beTS'Vo  
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public void setSFileName(String value) /e1m1B  
{ gP"p7\ (  
sFileName = value; )X@Obg  
} @'C f<wns  
{Z 3t0F  
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public int getNSplitter() @[u!  
{ |:$D[=  
return nSplitter; y3F13 Z@%  
} 3v)v92;  
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9r-]@6;  
public void setNSplitter(int nCount) TC[_Ip
&  
{ lTJ1]7)  
nSplitter = nCount; o90SXa&l/  
} Qj5~ lX`W  
} }ddwL  
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/* h>-J
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**Utility.java 4d4le  
*/ OSk:njyC[  
package NetFox; lE:X~RO"~  
Ev* b  
#mlTN3   
public class Utility { AN7WMX  
LI_>fuv"8  
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public Utility() K-IXAdx  
{ NsJt=~  
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} mE(EyB<  
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//线程睡眠 Zs<}{`-  
public static void sleep(int nSecond) Bzn{~&i?W:  
{ LWHP31{R  
try{ 5%"$
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Thread.sleep(nSecond); ?z%@;&  
} 9 P_`IsVK  
catch(Exception e) hO(8v&ns3  
{ 
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e.printStackTrace (); _/bFt6  
} ^0"NcOzzxl  
} zqfv|3-!}  
Kdh(vNB>  
//日志 TJ[C,ic=D  
public static void log(String sMsg) Y,RED5]t  
{ v39`ct=e  
System.err.println(sMsg); ?(Q" y\  
} tt%Zwf  
r?
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public static void log(int sMsg) V2sWcV?  
{ !Rk1q&U5  
System.err.println(sMsg); y ,
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} `l@[8H%aw  
} "r @RDw
 
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/* A`<#}~A  
**TestMethod.java .o91^jt  
*/ mbxJS_P  
package NetFox; 95Bw;U3E  
1}#v<b$  
@?iLz7SPk  
public class TestMethod { P7QOlTQI  
n={}='  
\kcJF'JFA0  
public TestMethod() z_R^n#A~r  
{ ///xx/weblogic60b2_win.exe JL $6Fw;  
try{ fpf1^TZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ozH7c_ <  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~R/w~Kc!/A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $V-]DD%Y  
fileFetch.start(); r_p9YS@I  
} r9z_8#cR  
catch(Exception e){e.printStackTrace ();} 6~zR(HzV{  
,\!4A  
7IW:,=Zk8+  
} ;'l Hw]}O*  
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public static void main(String[] args) w]]`/`  
{ d=V4,:=S  
new TestMethod(); W[PZQCL}K)  
} :0IxnK(r&  
} _'<V<OjVM!  
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