http断点续传简单实现（java)

/* yf[1?{iVo  
**SiteFileFetch.java )gz]F_  
*/ _R^ZXtypd  
package NetFox; aeVd.`lxM  
import java.io.*; 1Q=L/keP  
import java.net.*; /oZvm  
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public class SiteFileFetch extends Thread { WZn"I&Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z0x^HDAeC  
long[] nStartPos; //开始位置 Lxn-M5RPQ  
long[] nEndPos; //结束位置 (/^?$~m"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S'`G7ht  
long nFileLength; //文件长度 ~$ Po3]{s  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 M;W&
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File tmpFile; //文件下载的临时信息 03AQB;.  
DataOutputStream output; //输出到文件的输出流 Xq_hC"s  
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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 0eKLp8;Lh
 
{ @NiLKcL#  
siteInfoBean = bean; L
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8QMMKOui\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <Qr*!-Kc6  
if(tmpFile.exists ()) ,gW$m
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{ @=}NMoNH  
bFirst = false; w#_7,*6]  
read_nPos(); qY!LzKM0  
} W4qnXD1n  
else ^$mCF%e8H  
{ 4`'Rm/)  
nStartPos = new long[bean.getNSplitter()]; dKP| TRd  
nEndPos = new long[bean.getNSplitter()]; 4uH} SG[  
} RameaFX8  
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} K47.zu  
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public void run() ?)[=>Kp  
{ Sj:c {jyJd  
//获得文件长度 GY5JPl  
//分割文件 \acGSW .c  
//实例FileSplitterFetch G^z>2P  
//启动FileSplitterFetch线程 Ted tmX$  
//等待子线程返回 APJFy@l}  
try{ vR pO0qG  
if(bFirst) xIV#}z0  
{ Y9 Bk$$#\  
nFileLength = getFileSize(); 1vAJ(O{-  
if(nFileLength == -1) fh66Gn,  
{ }A[5\V^D*  
System.err.println("File Length is not known!"); o.Bbb=*rZ  
} IGo5b-ds  
else if(nFileLength == -2) rWqr-"0S.  
{ il"pKQF  
System.err.println("File is not access!"); J9f]=1`  
} @HE?G  
else 1bDAi2 H  
{ 2f{a||  
for(int i=0;i<nStartPos.length;i++) ' QjJ^3A  
{ Su[(IMw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); **oDQwW]*  
} b7">IzAe  
for(int i=0;i<nEndPos.length-1;i++) b\kA  
{ fN21[Jv3  
nEndPos = nStartPos[i+1]; +bR|;b(v  
} Z0v&AD=  
nEndPos[nEndPos.length-1] = nFileLength; uJ fXe  
} t0?tXe.B  
} meXwmO  
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//启动子线程 2S4SG\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]r%fAmj  
for(int i=0;i<nStartPos.length;i++) b/\l\\$-  
{ )T&r770  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D'^%Q_;
u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m;TekJXm  
nStartPos,nEndPos,i); ??LE0i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R((KAl
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fileSplitterFetch.start(); i=hA. y`  
} NO/5pz}1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l<(jm{q?u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5zyd;y)|'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S!^I<#d K  
nEndPos = " + nFileLength); x^cJ~e2  
// fileSplitterFetch[nPos.length-1].start(); Fiw^twz5  
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//等待子线程结束 79k+R9m  
//int count = 0; P?jI:'u!R.  
//是否结束while循环 NF-@Q@  
boolean breakWhile = false; 4af^SZ)l  
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while(!bStop) )(c%QWz  
{ |TF6&$>d  
write_nPos(); -q nOq[  
Utility.sleep(500); cFq2 6(e  
breakWhile = true; \JCpwNT{P  
10GU2a$0"$  
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for(int i=0;i<nStartPos.length;i++) ~EvGNnTL  
{ 9Sa6v?sRor  
if(!fileSplitterFetch.bDownOver) xK5~9StP  
{ 7xO~v23oe  
breakWhile = false; )YZx]6\l)  
break; ^ ]+vtk  
} wS >S\,LV  
} [L ' >  
if(breakWhile) 6JRFYgI  
break; ivt~S  
v_pFI8Cz)  
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//count++; [l7n"gJ~  
//if(count>4) +Z=y/wY  
// siteStop(); f|3LeOyz  
} vfc,{F=Q  
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System.err.println("文件下载结束！"); o!c~"  
} 'TA !JB+  
catch(Exception e){e.printStackTrace ();} pTncx%!W5  
} kj
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//获得文件长度 )@=fGNDt  
public long getFileSize() [dqh-7  
{ ''q#zEf6  
int nFileLength = -1; L!`PM.:9  
try{ k%aJ%(  
URL url = new URL(siteInfoBean.getSSiteURL()); SO<9?uk.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hrXk7}9  
httpConnection.setRequestProperty("User-Agent","NetFox"); o]GZq..  
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int responseCode=httpConnection.getResponseCode(); 58eO|c(  
if(responseCode>=400) 9g.5:  
{ 1qm*#4x  
processErrorCode(responseCode); 9;L8%T (  
return -2; //-2 represent access is error K<50>uG  
} r8[)Ccv  
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String sHeader; NK:! U  
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for(int i=1;;i++) :-(qqC:  
{ %c8@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +jKu^f6  
//Utility.log(in.readLine()); PSyUC#;  
sHeader=httpConnection.getHeaderFieldKey(i); rfr]bq5  
if(sHeader!=null) 9w=[}<E  
{ k]2_vk^  
if(sHeader.equals("Content-Length")) MN:LL <  
{ E Q:6R|L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'q@vTM'-  
break; rD9:4W`^  
} |.-Muv  
} vskp1Wi(  
else upZf&4 I8  
break; zw iS%-F  
} <|w(Sn  
} d"Zyc(Jk  
catch(IOException e){e.printStackTrace ();} c: (nlYZ  
catch(Exception e){e.printStackTrace ();} #]Jg>  
}d5~w[  
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Utility.log(nFileLength); r@ !  
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return nFileLength; ofPv?_@  
} y! QYdf?  
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s=556  
//保存下载信息（文件指针位置） Py?Q::  
private void write_nPos() iJCv+p_f  
{ jvo^I$|2h  
try{ U"~W3vwJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jX^_(Kg  
output.writeInt(nStartPos.length); QbY@{"" `  
for(int i=0;i<nStartPos.length;i++) FPM l;0{  
{ Iv*u#]{t  
// output.writeLong(nPos); wzBI<0]z  
output.writeLong(fileSplitterFetch.nStartPos); QGE0pWL-a  
output.writeLong(fileSplitterFetch.nEndPos); 8# x7q>?  
} Iyb_5 UmpF  
output.close(); Sl@Ucc31  
} O=^/58(m  
catch(IOException e){e.printStackTrace ();} Jb-.x_Bf  
catch(Exception e){e.printStackTrace ();} >2X-98,  
} IaU%L6Q]  
& x_ #zN]  
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//读取保存的下载信息（文件指针位置） cH+ ~|3  
private void read_nPos() hML-zZ  
{ 0Q)YZ2  
try{ k|U2Mp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 
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int nCount = input.readInt(); yhs:.h  
nStartPos = new long[nCount]; OB*V4Yv  
nEndPos = new long[nCount]; {<?8Y  
for(int i=0;i<nStartPos.length;i++) .
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{ T)',}=  
nStartPos = input.readLong(); Ba**S8{/`  
nEndPos = input.readLong(); :\y' ?d- Q  
} JV_VM{w{K  
input.close(); f[ia0w5 m  
}  T;V!>W37  
catch(IOException e){e.printStackTrace ();} DgY !)cS  
catch(Exception e){e.printStackTrace ();} |"+Ufw^  
} `3@?)xa  
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private void processErrorCode(int nErrorCode) <1 ;pyw y  
{ *N"CV={No  
System.err.println("Error Code : " + nErrorCode); n=|%
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} C7DwA/$D  
<XN=v!2;  
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//停止文件下载 d`~~Ww1  
public void siteStop() 5}c8v2R:B  
{ bvZ:5M  
bStop = true; c] t@3m  
for(int i=0;i<nStartPos.length;i++) h_SkX@"/-  
fileSplitterFetch.splitterStop(); II!~"-WH  
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} TPak,h(1  
} ww #kc!'  
//负责部分文件的抓取 C\B4Uu6q  
**FileSplitterFetch.java j-.Y!$a%6  
*/ |qz%6w=  
package NetFox; f8`dJ5i  
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import java.io.*; ZY@ntV?  
import java.net.*; P(/eVD#v  
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public class FileSplitterFetch extends Thread { `uH7~ r^  
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String sURL; //File URL iq[IZdza  
long nStartPos; //File Snippet Start Position xc\zRsY`  
long nEndPos; //File Snippet End Position d325Cw?  
int nThreadID; //Thread's ID vm'ZA7f6  
boolean bDownOver = false; //Downing is over D/GE-lq  
boolean bStop = false; //Stop identical RBBmGZ  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F=e-jKogK  
{ v+8Ybq  
this.sURL = sURL; h9#)Eo  
this.nStartPos = nStart; z^z`{B  
this.nEndPos = nEnd; /,UnT(/k(  
nThreadID = id; P.
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~QDM .5  
} Hmt2~>FI[  
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-
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public void run() #sDb611}#  
{ qmt9J?$k  
while(nStartPos < nEndPos && !bStop) v(!:HK0oeT  
{ YRFz]  
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try{ bI8uw|c  
URL url = new URL(sURL); 7 )rL<+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0H]{,mVs  
httpConnection.setRequestProperty("User-Agent","NetFox"); a@d 15CN  
String sProperty = "bytes="+nStartPos+"-"; 9dBxCdpu  
httpConnection.setRequestProperty("RANGE",sProperty); ,&qC R sw  
Utility.log(sProperty); eZN"t~\rX  
"H<us?r{  
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InputStream input = httpConnection.getInputStream(); PMV,*`"9"A  
//logResponseHead(httpConnection); RtzSe$O  
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byte[] b = new byte[1024]; $LFL4Q  
int nRead; %yu =,J j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $Ery&rX.  
{ ovBmo2W/  
nStartPos += fileAccessI.write(b,0,nRead); xLDD;Qm,  
//if(nThreadID == 1) g\ vT7x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r$}C<a[U  
} q$mc{F($D  

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Utility.log("Thread " + nThreadID + " is over!"); G3%Ju=  
bDownOver = true; _]pu"hZz4  
//nPos = fileAccessI.write (b,0,nRead); P(TBFu  
} XclTyUGoK+  
catch(Exception e){e.printStackTrace ();} ;}"Eqq:  
} aR/?YKA  
} \r[u>7I  
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//打印回应的头信息 6/Xs}[iJ  
public void logResponseHead(HttpURLConnection con) ,3y9yJQa*#  
{ Z>Mv$F"p:  
for(int i=1;;i++) UNff&E-  
{ |=m.eU  
String header=con.getHeaderFieldKey(i); 9S*"={}%  
if(header!=null) _gI1rXI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C5,fX-2Q  
Utility.log(header+" : "+con.getHeaderField(header)); \'4~@  
else bAGKi.  
break; G9 O6Fi  
} ow.!4kx{d  
} *^~ =/:  
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public void splitterStop() 4]ni-u0*  
{ E<[ s+iX  
bStop = true;
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} *_
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kzDN(_<1  

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} e12QYoh  

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/* bYnq,JRA  
**FileAccess.java $2?AJ/2r$b  
*//文件访问(定位，写) 0!_?\)X  
package NetFox; #e|o"R;/`  
import java.io.*; 2 HEU  
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public class FileAccessI implements Serializable{ 2!Dz
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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 nQjpJ /=  
RandomAccessFile oSavedFile; '\tI|  
long nPos; cR/Nl pX  
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public FileAccessI() throws IOException !m+Pd.4TaB  
{ >|E]
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this("",0); 5M0Q'"`F:  
} L(VFzPkY%  
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public FileAccessI(String sName,long nPos) throws IOException  D}98ZKi  
{ 30!DraW8  
oSavedFile = new RandomAccessFile(sName,"rw"); (WyNO QO'  
this.nPos = nPos; e~N&?^M  
oSavedFile.seek(nPos); -AdDPWn  
} /I=|;FGq  
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public synchronized int write(byte[] b,int nStart,int nLen) &*=!B9OBI  
{ U]=yCEb8p  
int n = -1; z'EQdQ)  
try{ %N*[{j= ^  
oSavedFile.write(b,nStart,nLen); i[!|0U`p  
n = nLen; J rx^  
} ,Vhve'=*2  
catch(IOException e) u ]e-IYH  
{ &Q883A J  
e.printStackTrace (); w\bwa!3Y  
} N}?|ik
 
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return n; L,[Q/$S8  
} ny5P*yWEh  
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}
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/* yV(#z2|  
**SiteInfoBean.java &<VU}c^!  
*/ gwoe1:F:J  
package NetFox; *#T: _  
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public class SiteInfoBean { R^l0Bu]X  
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private String sSiteURL; //Site's URL Qr$'Q7  
private String sFilePath; //Saved File's Path e*7O!Z=O  
private String sFileName; //Saved File's Name vB8$Qx\J  
private int nSplitter; //Count of Splited Downloading File ,|A^ <R`  
SGWb*grt  
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public SiteInfoBean() 8G:/f3B=  
{//nSplitter的缺省值为5 msBoInhI  
//default value of nSplitter is 5 MzIDeZ  
this("","","",5); EN!C5/M{&  
} 41
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5whW>T  
{ pU7;!u:c4%  
sSiteURL= sURL; v`A)GnNiN  
sFilePath = sPath; |OH*c3~r  
sFileName = sName; rmX*s}B  
this.nSplitter = nSpiltter; Hd~g\  
}dkXRce*  
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} )p\`H;7*V4  
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public String getSSiteURL() os/h~,=  
{ fsL9d}  
return sSiteURL; @+b$43^  
} Msqqjhoy  
9\Jc7[b  
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public void setSSiteURL(String value) 4z<c8 E8  
{ xMjhC;i{  
sSiteURL = value; ]Dq6
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} !85bpQ.  
b Hr^_ogN  
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public String getSFilePath() $${I[2R)  
{ Z@zo~*o  
return sFilePath; v"k ?e  
} ^*Za
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public void setSFilePath(String value) w6vbYPCN  
{ KuJ)alD;1  
sFilePath = value; }4C_r'd6  
}  S_P&Fv  
<
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public String getSFileName() 6Z_V,LD9L  
{ ]Y[N=
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return sFileName; :nIMZRJ_!E  
} h#YO;m2wd  
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public void setSFileName(String value) KhR3$|fH<  
{ ",/6bs#$  
sFileName = value; 4S26TgY  
} )L b` 4B  
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public int getNSplitter() @[r[l#4yUi  
{ Ey=2zo^F  
return nSplitter; f;'*((  
} *u+DAg'&  
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public void setNSplitter(int nCount) YiZk|K_  
{ m9[ 7"I  
nSplitter = nCount; nah?V" ?Y  
} ,WyEwc]  
} IW\^-LI.  
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/* ljbAfd  
**Utility.java 1V2]@VQF  
*/ |=q~X}DA  
package NetFox; M(C">L]8  
);!ND%  
\TP$2i%W  
public class Utility { 7i"b\{5  
V(`
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_#{*I(l  
public Utility() ~R|9|k  
{ Tt
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} 'l'3&.{Yfk  
:ts3_-cr  
//线程睡眠 xT>9ZZcE  
public static void sleep(int nSecond) V|YQhd0kv  
{ 89M'klZ   
try{ Q/|.=:~FO  
Thread.sleep(nSecond); ZUI6VM  
} Htgo=7!?\3  
catch(Exception e) YrL(4Nt8  
{ UBL{3s^"  
e.printStackTrace (); Z1fY' f  
} ()aCE^C  
} U`6|K$@  
e=&~6bs1U  
//日志 ~xqiasE#K  
public static void log(String sMsg) &PJ;B)b  
{ !.UE}^TV  
System.err.println(sMsg); $`lWW6>P  
} |^1g*fy?  
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}#s{."  
public static void log(int sMsg) Rw'}>?k]  
{ 8&EJ.CQ  
System.err.println(sMsg); 3k'Bje?9~  
} sywuS  
} y`oj\  
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/* =w3A{h"^  
**TestMethod.java ^iONC&r  
*/ ]njNSn  
package NetFox; IR$
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aL:|Dr3SX  
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public class TestMethod { !H\;X`W|~D  
# `^nmC/F  
1@Jp3wW  
public TestMethod() M-t9M~  
{ ///xx/weblogic60b2_win.exe ,P9F*;Dj  
try{ l
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Pm%xX~H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /0\g!29l<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?kR1T0lKkE  
fileFetch.start(); 3zB'AG3b  
} WVR/0l&bU  
catch(Exception e){e.printStackTrace ();} a{xJ#_/6  
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} tMw65Xei6b  
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public static void main(String[] args) X$UK;O  
{ ?3~t%Q`  
new TestMethod(); CT'4.  
} "73*0'm  
} S$
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