http断点续传简单实现（java)

/* Gq]d:-7l  
**SiteFileFetch.java ; Zq/eiB  
*/  93w~.p  
package NetFox; 5()Fvae{k  
import java.io.*; k90B!kg  
import java.net.*;
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public class SiteFileFetch extends Thread { +Z+ExS<#z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ')nnWlK  
long[] nStartPos; //开始位置 ^Rmoz1d  
long[] nEndPos; //结束位置 ndOfbu;mf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4MX7=!E  
long nFileLength; //文件长度 x N`T  
boolean bFirst = true; //是否第一次取文件 $A?}a  
boolean bStop = false; //停止标志 u@D.i4U  
File tmpFile; //文件下载的临时信息 k!E"wJkpz  
DataOutputStream output; //输出到文件的输出流 .[f;(WR  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jzrt7p*k}  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6An{3"  
{ `$-lL"  
siteInfoBean = bean; Fp:3#Bh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :dDxxrs"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }[,3yfiX  
if(tmpFile.exists ()) ~n]N
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{ ?'2 v.5TQt  
bFirst = false; c)3O/`  
read_nPos(); ahp1!=Z-=  
} t:9 ZCu ay  
else },6*Y*?{  
{ k!13=Gh  
nStartPos = new long[bean.getNSplitter()]; fq Y1ggL  
nEndPos = new long[bean.getNSplitter()]; 3'@&c?Fye  
} pF='jj51  
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} #>q[oie1e  
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public void run() BkT-m'I?  
{ Opry`}5h  
//获得文件长度 CZfE |T~  
//分割文件 b"P&+c  
//实例FileSplitterFetch a4u^f5)@  
//启动FileSplitterFetch线程 s]bPV,"p  
//等待子线程返回 #PH#2/[  
try{ ]BfR.,,  
if(bFirst) {_as!5l  
{ b_ JWnh  
nFileLength = getFileSize(); bm6hZA|  
if(nFileLength == -1) <_f`$z  
{ f+^c@0que  
System.err.println("File Length is not known!"); xOM_R2Md  
} .Qk{5=l6P  
else if(nFileLength == -2) `]hCUaV   
{ =phiD&=  
System.err.println("File is not access!"); `5<1EGJsD  
} HPTHF  
else "GLYyC  
{ \^m.dIPdO  
for(int i=0;i<nStartPos.length;i++) LT(?#)D  
{ TMY{OI8a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &oc_a1R  
} 5U;nhDmM  
for(int i=0;i<nEndPos.length-1;i++) r./z,4A`  
{ #4q
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nEndPos = nStartPos[i+1]; gA"<MI'y  
} +{Gw9h"5g*  
nEndPos[nEndPos.length-1] = nFileLength; N&N 82OG  
} <O bHf`Q  
} M1gP R  
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//启动子线程 :o<N!*pT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H8<m9zDvl  
for(int i=0;i<nStartPos.length;i++) !?n50  
{ h=Oh9zsz8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }8 \|1@09  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J5-rp|  
nStartPos,nEndPos,i); F_ _H(}d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mf~
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fileSplitterFetch.start(); X,&xhSz
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} -sx-7LKi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VlV)$z_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <%/:w/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tPzM7 n|  
nEndPos = " + nFileLength); bCt_yR  
// fileSplitterFetch[nPos.length-1].start(); 6yp+h  
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//等待子线程结束 -P*xyI  
//int count = 0; 9g4QVo|  
//是否结束while循环 jvWI_Fto  
boolean breakWhile = false; LEA;dSf  
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8`DO[Z  
while(!bStop) pB[%:w/@l:  
{ Q{8qm<0g  
write_nPos(); SUo^c1)G  
Utility.sleep(500); rEg+i@~  
breakWhile = true; <gR`)YF7  
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for(int i=0;i<nStartPos.length;i++) V!H(;Tuuo  
{ |O%:P}6c  
if(!fileSplitterFetch.bDownOver) O<bDU0s{M  
{ %OuX`w=  
breakWhile = false; )2#vhMpdN  
break; .r(^h/IF  
} h1E 
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} 2[XltjO  
if(breakWhile) 0&f\7z  
break; ~DK F%}E  
}]tFz}E\  
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//count++; :mzCeX8 *  
//if(count>4) #fO*ROe  
// siteStop(); QZ?O;K1|y  
} Euqjxz  
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System.err.println("文件下载结束！"); zLo;.X[Y  
} KxGKA  
catch(Exception e){e.printStackTrace ();} m\/>C|f\  
} R9b
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//获得文件长度 <&KLo>B^  
public long getFileSize() /cM 5  
{ 
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int nFileLength = -1; U2VV[e)Z!  
try{ B<(Pd  
URL url = new URL(siteInfoBean.getSSiteURL()); omNpE_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _w\Y{(k  
httpConnection.setRequestProperty("User-Agent","NetFox"); q"P5,:W  
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int responseCode=httpConnection.getResponseCode(); Ii,~HH  
if(responseCode>=400) q^)=F_QvG  
{ p1Y+
 
processErrorCode(responseCode); b{zAJ`|#[n  
return -2; //-2 represent access is error -3u@hp_  
} /rn"  
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String sHeader; Ng?apaIi@~  
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for(int i=1;;i++) n9N#&Q"7m  
{ PbbXi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +Gk! t]dy  
//Utility.log(in.readLine()); '2wXV;`  
sHeader=httpConnection.getHeaderFieldKey(i); ,}eRnl
\  
if(sHeader!=null) sM#!Xl;  
{ V h Z=,m  
if(sHeader.equals("Content-Length")) .WBI%ci  
{ ;Fx')  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j2< !z;2  
break; eo>/  
} dCa}
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} [q|?f?Zl  
else |\i:LG1  
break; V"w`!  
} -iY9GN89c  
} w> Tyk#7lw  
catch(IOException e){e.printStackTrace ();} IOSuaLH^  
catch(Exception e){e.printStackTrace ();} k&MlQ2'!<  
ox!|)^`$_  
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Utility.log(nFileLength); <$RS*n  
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return nFileLength; 9@$tiDV  
} *p""YEN  
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//保存下载信息（文件指针位置） >2]Eaw&W  
private void write_nPos() dE 3i=  
{ *37LN  
try{ "bHtf_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V}vl2o
  
output.writeInt(nStartPos.length); %GVEY  
for(int i=0;i<nStartPos.length;i++) [ c ~LY4:  
{ H.jLGe>  
// output.writeLong(nPos); [$hptQv  
output.writeLong(fileSplitterFetch.nStartPos); f28gE7Y\a  
output.writeLong(fileSplitterFetch.nEndPos); f?/|;Zo4  
} /Ki0+(4  
output.close(); @ChN_gd
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} DQ}_9?3  
catch(IOException e){e.printStackTrace ();} @4G.(zW  
catch(Exception e){e.printStackTrace ();} X{0ax.  
} }}kS~ w-#  
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//读取保存的下载信息（文件指针位置） 7yMieUF  
private void read_nPos() OVDMC4K2z!  
{ _7-"VoX  
try{ QVnO
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |#DC.Ga!  
int nCount = input.readInt(); O!#L#u53  
nStartPos = new long[nCount]; \SYPu,ZT  
nEndPos = new long[nCount]; <7vIh0  
for(int i=0;i<nStartPos.length;i++) &,m'sQ  
{ I><99cwFI  
nStartPos = input.readLong(); yRgDhA  
nEndPos = input.readLong(); W /~||s  
} w,M1`RsK  
input.close(); JxX jDYrU  
} o{ ,ba~$.w  
catch(IOException e){e.printStackTrace ();} R-g>W  
catch(Exception e){e.printStackTrace ();} !~Hafn-1  
} (hhdbf  
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private void processErrorCode(int nErrorCode) lU&`r:1>_  
{ "@c';".|  
System.err.println("Error Code : " + nErrorCode); ?#VP)A  
} y9V;IXhDc  
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//停止文件下载 q;1VF;<"vH  
public void siteStop() oiTMP`Y  
{ ]>VJ--fH  
bStop = true; RT.wTJS;  
for(int i=0;i<nStartPos.length;i++) WU+Jo@]y  
fileSplitterFetch.splitterStop(); |x _-I#H  
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} FT|/WZR  
} pO-s@"j]  
//负责部分文件的抓取 eHF(,JI  
**FileSplitterFetch.java ~
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*/ 1+16i=BF)  
package NetFox; 6T{o3wc;  
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import java.io.*; wzNt c)~i  
import java.net.*; bMK#^ZoH  
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public class FileSplitterFetch extends Thread { \,@Yl.,+  
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String sURL; //File URL \dp9@y[^  
long nStartPos; //File Snippet Start Position 'gk81@|  
long nEndPos; //File Snippet End Position zJy 89ib'  
int nThreadID; //Thread's ID 4'}_qAT  
boolean bDownOver = false; //Downing is over ijZydn  
boolean bStop = false; //Stop identical =u
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FileAccessI fileAccessI = null; //File Access interface ]AFM Y<mB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )"pxry4v7J  
{ ReHd~G9  
this.sURL = sURL; >'2w\Uk~:  
this.nStartPos = nStart; UgnsV*e&  
this.nEndPos = nEnd; W[1f]w3  
nThreadID = id; RAv RNd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (N~zJ.o  
} JEm?26n X  
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public void run() .qb_/#Bas  
{ <u x*r#a!d  
while(nStartPos < nEndPos && !bStop) {d?4;Kd  
{ |ZST Y}RXA  
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try{ ,/w852|ub  
URL url = new URL(sURL); g'}`FvADi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u]]5p[|S  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7fN&Q~.  
String sProperty = "bytes="+nStartPos+"-"; #g-*n@ 1  
httpConnection.setRequestProperty("RANGE",sProperty); PPj6QJ]R0  
Utility.log(sProperty); (Qh7bfd  
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InputStream input = httpConnection.getInputStream(); 0ez i?Um  
//logResponseHead(httpConnection); aoakTi!}  
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byte[] b = new byte[1024]; x^='pEt{  
int nRead; LjH&f 4mY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qV,
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{ y 8d`},  
nStartPos += fileAccessI.write(b,0,nRead); Zjp5\+hHV  
//if(nThreadID == 1) >QZt)<[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OB*Xb*HN  
} ax{-Qi7z-+  
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Utility.log("Thread " + nThreadID + " is over!"); :#W>S
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bDownOver = true; Hs4zJk  
//nPos = fileAccessI.write (b,0,nRead); ?%za:{  
} r"u(!
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catch(Exception e){e.printStackTrace ();} 'Qs3  
} !s[j1=y  
} 6(<~1{ X%  
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//打印回应的头信息 vRb(eg  
public void logResponseHead(HttpURLConnection con) tN'- qdm  
{ (;Q <@PZg  
for(int i=1;;i++) &6|^~(P?  
{ {HRxyAI!
 
String header=con.getHeaderFieldKey(i); dl7p1Cr  
if(header!=null) *F8uu.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a9@l8{)RX  
Utility.log(header+" : "+con.getHeaderField(header)); ".Deu|>  
else K3r>nGLBo  
break; dn)tP6qc/  
} H:{(CY?t  
} k+Ma_H`  
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public void splitterStop() ]N(zom_0d  
{ Dpp52UnTE  
bStop = true; T`'
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} d
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} I|3v&E1  
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/* _KkVI7a  
**FileAccess.java RJ@e5A6_  
*//文件访问(定位，写) |_xiG~  
package NetFox; G`9F.T_Z^)  
import java.io.*; IrwF B  
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public class FileAccessI implements Serializable{ LWb}) #E  
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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 milK3+N  
RandomAccessFile oSavedFile; |z7Crz  
long nPos; CIik@O*  
;,B@84'  
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public FileAccessI() throws IOException 1'U%7#;E  
{ p_40V%y^  
this("",0); "6NNId|Y  
} (zLIv9$  
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public FileAccessI(String sName,long nPos) throws IOException 2,e|,N"zN  
{ |xgCV@  
oSavedFile = new RandomAccessFile(sName,"rw"); 8H`l"  
this.nPos = nPos; qyBK\WqaP  
oSavedFile.seek(nPos); )J6b:W  
} 9B;Sk]y  
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public synchronized int write(byte[] b,int nStart,int nLen) JK8@J9(#  
{ (PrPH/$  
int n = -1; <ZvPtW  
try{ +U/"F|M  
oSavedFile.write(b,nStart,nLen); Lp]C![\>U  
n = nLen; (uK), *6B  
} -K'84 bZ  
catch(IOException e) p*&LEjaVM4  
{ :ktX7p~  
e.printStackTrace (); !/(}meZj  
} 
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return n; NizJq*V>  
} 98}vbl31j  
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} ? A#z~;X@  
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/*  p|8Fl  
**SiteInfoBean.java rHdP4:n  
*/ W
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package NetFox; |Gs-9+'y  
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public class SiteInfoBean { ! tP
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private String sSiteURL; //Site's URL [^=8k2  
private String sFilePath; //Saved File's Path `IRT w"  
private String sFileName; //Saved File's Name ?&nz  
private int nSplitter; //Count of Splited Downloading File +
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public SiteInfoBean() ^Jpd9KK  
{//nSplitter的缺省值为5 >)Z2bCe  
//default value of nSplitter is 5 4_:e+ ql  
this("","","",5); td$6:)  
} xENA:j?kF  
44{:UhJkx  
s ;Nu2aOp7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XUNgt(OGR'  
{ 5h^qtK  
sSiteURL= sURL; (9_e>2_  
sFilePath = sPath;  F%$Ws>l  
sFileName = sName; 00wH#_fm  
this.nSplitter = nSpiltter; ]Oh>ECA|D  
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} 7IW7'klkvD  
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public String getSSiteURL() p 8Hv7*  
{ Y tj>U  
return sSiteURL; ] r+I D  
} 2xBGs9_Y  
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public void setSSiteURL(String value) ^n5QKHD  
{ vjWgR9 4/{  
sSiteURL = value; g8@HAV^H  
} )tg*dE  
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public String getSFilePath() HY#("=9< h  
{ 8(K~QvE~  
return sFilePath; ]@]"bF!Dn  
} t$D[,$G9  
]>!_OCe&  
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public void setSFilePath(String value) .kDCcnm  
{ ]V\g$@  
sFilePath = value; 52Ffle8  
} $}
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?&^l8gE  
public String getSFileName() $k=rd#3  
{ l%w|f`B:  
return sFileName; Jq@LZ2^  
} .qP zd(<T7  
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!}m8]&  
public void setSFileName(String value) }E_zW.{!  
{ KDzI
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sFileName = value; 7cSvAX0Z.  
} 0drc^rj !  
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public int getNSplitter() BNLall  
{ Pl ,M>IQ  
return nSplitter; _+7f+eB  
} N#qoKY(#  
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public void setNSplitter(int nCount) O$\N]#  
{ wIPDeC4  
nSplitter = nCount; VJPPHJ[-  
} UcIR0BYa  
} ku=q:ryO  
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/* 7k3\_BHyb\  
**Utility.java ";%1sK  
*/ $x<-PN  
package NetFox; {GY$J<5=  
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;!Mg,jlQ  
public class Utility { ttxOP   
hTqJDP"&F  
Cr"hu;  
public Utility() svII =JB  
{ Xp@OIn  
{rr\hl-$  
E_#&L({|@  
} R2gax;  
m{"zFD/  
//线程睡眠 fe,CY5B{  
public static void sleep(int nSecond) x6]?}Q>>D
 
{ !ym5'h  
try{ ng\S%nA&J  
Thread.sleep(nSecond); U$%w"k7^(  
} Il[WXt<S  
catch(Exception e) $NSYQF%aO  
{ O5"80z38[  
e.printStackTrace (); VzNH%  
} r,\(Y@I  
} hy rJu{p  
pwQ."2x  
//日志 v?t+%|dzA  
public static void log(String sMsg) Msi
SC  
{ n%hnL$!z  
System.err.println(sMsg); vOU-bF%u  
} ekXHfA!i%  
l
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a$-ax[:\sm  
public static void log(int sMsg) _t7A'`Dh]  
{ g.qp _O  
System.err.println(sMsg); 23m+"4t  
} Obm\h*$  
} [\y>Gv%  
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/* {0~ p"%*  
**TestMethod.java  G%{jU'2  
*/ fzcT(y  
package NetFox; Xb {y*',  
q}lSnWY[[  
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public class TestMethod { yCVBG  
hvwr!(|W  
)XWL'':bF  
public TestMethod() :8FH{sqR  
{ ///xx/weblogic60b2_win.exe z%z$'m  
try{ +xa2e?A%L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YrX{,YtiX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6kk(FVX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sTONkd  
fileFetch.start(); 3FfS+q*3S  
} p_( NLJ%  
catch(Exception e){e.printStackTrace ();}  lwlR"Z  
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%$U+?lk}  
} {$JIR}4S  
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public static void main(String[] args) 6/)A6Tt  
{ x :s-\>RcA  
new TestMethod(); U-d&q>_@A  
} aE}u5L$#  
} {Ffr l(*  
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