http断点续传简单实现（java)

/* U)jUq_LX  
**SiteFileFetch.java ^t.W|teD  
*/ ~2}Pl)  
package NetFox; %5</d5.  
import java.io.*; "Tbnxx]J  
import java.net.*; X
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public class SiteFileFetch extends Thread { x/TGp?\g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e$l6gY  
long[] nStartPos; //开始位置 =v-2@=NJ`K  
long[] nEndPos; //结束位置 <bmLy_":  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QX0Y>&$)  
long nFileLength; //文件长度 Ub)I66  
boolean bFirst = true; //是否第一次取文件 ?T*";_o,B  
boolean bStop = false; //停止标志 &~~s6   
File tmpFile; //文件下载的临时信息 I@Z)<5Zf  
DataOutputStream output; //输出到文件的输出流 /)#8)"`nT  
hb^!LtF#Y  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?X_V#8JK  
public SiteFileFetch(SiteInfoBean bean) throws IOException # mT]j""  
{ hY8#b)l~lu  
siteInfoBean = bean; WYIw5jzC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u}jrfKdE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +$pJ5+v  
if(tmpFile.exists ()) *Zkss   
{ 5{l1A(b  
bFirst = false; =Sxol>?t  
read_nPos(); 'F_}xMU  
} 'Ji+c  
else ,seFkG@1  
{ >Q2). E  
nStartPos = new long[bean.getNSplitter()]; "DckwtG:%  
nEndPos = new long[bean.getNSplitter()]; J/Q|uRpmqr  
} #ooc)),  
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} 1L[S*X  
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public void run() hZuYdV{'h  
{ \C/z%Hf7-  
//获得文件长度 "{F;M{h$},  
//分割文件 &BgU:R,  
//实例FileSplitterFetch 1%eLs=u?  
//启动FileSplitterFetch线程 Zoow*`b|$U  
//等待子线程返回 _T~H[&Hl  
try{ L>nO:`>h  
if(bFirst) 2LhE]O(_"  
{ BX$hAQ(6Q  
nFileLength = getFileSize(); [X|OrRA  
if(nFileLength == -1) t<lyg0f  
{ Zr"dOj$Jf  
System.err.println("File Length is not known!"); E^syrEz  
} TNci.']  
else if(nFileLength == -2) M[,^KJ!  
{ SJ(9rhB5*.  
System.err.println("File is not access!"); cdsQ3o  
} nHU3%%%cU  
else lIl9ypikg  
{ r}@< K  
for(int i=0;i<nStartPos.length;i++)
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{ vs*I7<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); '%Dg{ zL  
} @7|)RSBQz  
for(int i=0;i<nEndPos.length-1;i++) '%O\E{h  
{ oZvG3_H4.  
nEndPos = nStartPos[i+1]; qS82/e)7  
} [NR1d-Wg  
nEndPos[nEndPos.length-1] = nFileLength; riEqW}{  
} :eLLDp<  
} K!b>TICa:  
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"GBUQ}  
//启动子线程 g{&PrE'e9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d.1Q~&`  
for(int i=0;i<nStartPos.length;i++) V
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{ `R ]&F$i(E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Sh47c4{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RA~_
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nStartPos,nEndPos,i); :O#gJob-%s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %w%zv2d  
fileSplitterFetch.start(); lMPbLF%_  
} pb=HVjW<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T/3;NXe6E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dW6Q)Rfi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l?N`V2SuR  
nEndPos = " + nFileLength); Jz2q\42q  
// fileSplitterFetch[nPos.length-1].start(); `}n0=E  
M%77u=m  
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//等待子线程结束 B)(w%\M4^  
//int count = 0; c{ZqQtfM  
//是否结束while循环 n/:Z{  
boolean breakWhile = false;  2fbvU  
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while(!bStop) @u7%B}q7:  
{ 5"]aZMua  
write_nPos(); RH1U_gp4 ]  
Utility.sleep(500); LE Jlo%M  
breakWhile = true; EzwF`3RjK  
@#J H=-06  
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for(int i=0;i<nStartPos.length;i++) eq7C]i rH  
{ H==X0  
if(!fileSplitterFetch.bDownOver) jR}*bIzv  
{ <:H  
breakWhile = false; SlM>";C\  
break; | H5Ync[s  
} agGgJ@  
} J#_\+G i  
if(breakWhile) Gf!t< =T   
break; XP3QBq  
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//count++; WIhIEU7/  
//if(count>4) 3
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// siteStop(); * ,|)~$=>  
} }"!6Xm  
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System.err.println("文件下载结束！"); Tm'lN5}&9  
} kjQIagw  
catch(Exception e){e.printStackTrace ();} +<vqkc  
} "@F*$JGT y  
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//获得文件长度 ?^F*"+qI  
public long getFileSize() q>wa#1X)  
{ U<#$w{d:  
int nFileLength = -1; YLr%vnO*NS  
try{ j=zU7wz)D  
URL url = new URL(siteInfoBean.getSSiteURL()); ~QQEHx\4zZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xV }:M  
httpConnection.setRequestProperty("User-Agent","NetFox"); H"kc^G+(R"  
x|P<F2L  
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int responseCode=httpConnection.getResponseCode(); 7l4InR]  
if(responseCode>=400) woC FN1W  
{ aH~x7N6!  
processErrorCode(responseCode); q|de*~@-P  
return -2; //-2 represent access is error e%5'(V-y,  
} F5om-tzy  
?kG#qt]Q5  
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String sHeader; |R:v<  
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for(int i=1;;i++) /;]B1T7  
{ h|Teh-@A5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pfT`WT  
//Utility.log(in.readLine()); `i_L?C7  
sHeader=httpConnection.getHeaderFieldKey(i); '/n%}=a=  
if(sHeader!=null) %$!R]B)  
{ JXD?a.vy^q  
if(sHeader.equals("Content-Length")) 8kn]_6:3i  
{ J_((o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u:qD*zOq  
break; ;^*+:e  
} zN8&M<mTl  
} n+A'XBHk  
else _sCJ3ZJ  
break; F"HI>t)>  
} cVv4gQD\  
} u"
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catch(IOException e){e.printStackTrace ();} Ke;X3j ]`  
catch(Exception e){e.printStackTrace ();} GhfUCW%  
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Utility.log(nFileLength); `!>dbR&1  
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return nFileLength; fuIv,lDA  
} | 9\7xT  
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//保存下载信息（文件指针位置） ,oi`BOh  
private void write_nPos() \i;~~;D  
{ lXL7q?,9  
try{ TF iM[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {dr&46$p  
output.writeInt(nStartPos.length); <:yq~?  
for(int i=0;i<nStartPos.length;i++) .8uwg@yD  
{ _XO)`D~  
// output.writeLong(nPos); 7)6Yfa]I%  
output.writeLong(fileSplitterFetch.nStartPos); F~rYjAFTi  
output.writeLong(fileSplitterFetch.nEndPos); pGcx jm  
} ^*UfCoj9Z  
output.close(); ;h(;(  
} G]NtX4'4  
catch(IOException e){e.printStackTrace ();} A(@gv8e[H^  
catch(Exception e){e.printStackTrace ();} D``NQ`>A  
} "VVR#H}{  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() !7a^8   
{ sq6%=(q(?  
try{ m+8b2H:V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -O>mY)  
int nCount = input.readInt(); E["t Ccg  
nStartPos = new long[nCount]; j{w,<Wt>  
nEndPos = new long[nCount]; @p` CAB  
for(int i=0;i<nStartPos.length;i++) V1b_z  
{ /zP)2q^  
nStartPos = input.readLong(); iYQy#kO  
nEndPos = input.readLong(); gwB>oi*OE  
} HF=C8ZtlL  
input.close(); WQmiG=Dw^  
} r-Xe<|w  
catch(IOException e){e.printStackTrace ();} {Ljl4Sp&  
catch(Exception e){e.printStackTrace ();} ht)*Ync  
} Fh4w0u*Q  
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private void processErrorCode(int nErrorCode) 0B:{4Lsn&  
{ W me1w\0  
System.err.println("Error Code : " + nErrorCode); |b@A:8ss  
} oYm{I ~"  
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//停止文件下载 Tvw2py q  
public void siteStop() e`2R
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{ xr3PO?:  
bStop = true; #2'&=?J1r  
for(int i=0;i<nStartPos.length;i++) =ZIFS  
fileSplitterFetch.splitterStop(); >s?;2T2"yx  
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} xdU pp~}+.  
} w8#>xV^~  
//负责部分文件的抓取 z>g& ?vo2  
**FileSplitterFetch.java 0Lz56e'j  
*/ 2Xs< 1rF  
package NetFox; ef;="N  
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5)NfZN#&  
import java.io.*; A-!qO|E[-  
import java.net.*; ^X'7>{7Io  
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public class FileSplitterFetch extends Thread { 1L qJ@v0  
J` --O(8Ml  
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String sURL; //File URL F9J9pgVP  
long nStartPos; //File Snippet Start Position .Tqvy)'  
long nEndPos; //File Snippet End Position #@"rp]1xv  
int nThreadID; //Thread's ID *!s?hHv  
boolean bDownOver = false; //Downing is over +NMSvu_?  
boolean bStop = false; //Stop identical TmAb! Y|F  
FileAccessI fileAccessI = null; //File Access interface 4\WkXwoqQO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1vudT&  
{ iL' ]du<wk  
this.sURL = sURL; kakWXGeR  
this.nStartPos = nStart; 4c@F.I  
this.nEndPos = nEnd; w~?eX/;  
nThreadID = id;
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,.F+x}  
} ,IATJs$E  
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public void run() gq &85([  
{ _Hj,;Z  
while(nStartPos < nEndPos && !bStop) V7i`vo3Cc  
{ 3iL&;D  
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try{ >9|+F[Fc  
URL url = new URL(sURL); 9DKB+K.1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kO"aE~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7^X_tQf  
String sProperty = "bytes="+nStartPos+"-"; ZA@"uqa6b  
httpConnection.setRequestProperty("RANGE",sProperty); K#m o+n5-;  
Utility.log(sProperty); dBn.DU*B  
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InputStream input = httpConnection.getInputStream(); "ET"dMxU  
//logResponseHead(httpConnection); M/;g|J jM  
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byte[] b = new byte[1024]; H>9$L~  
int nRead; xbA2R4|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \C|06Bs$  
{ XE\bZc  
nStartPos += fileAccessI.write(b,0,nRead); ,/9|j*9H  
//if(nThreadID == 1) 7X>3WF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Px_vtqP  
} H;E{Fnarv  
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Utility.log("Thread " + nThreadID + " is over!"); 1]~}0;,  
bDownOver = true; $<PVzW,$o  
//nPos = fileAccessI.write (b,0,nRead); k/O&,T77}J  
} $i Tgv?.Q  
catch(Exception e){e.printStackTrace ();} R\?!r4  
} ZS]e}]Zwp  
} R)z|("%ec  
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//打印回应的头信息 IK);BN2<L  
public void logResponseHead(HttpURLConnection con)
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{ In2D32"F  
for(int i=1;;i++) mHy]$Z  
{ xm5D$m3#  
String header=con.getHeaderFieldKey(i); i`;
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if(header!=null) %e(,PL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6G],t)<A'-  
Utility.log(header+" : "+con.getHeaderField(header)); G <q@K-  
else \ZB;K~BV&  
break; 8:bNFgJD  
} zO,sq%vQn'  
} Khl7Ez  
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public void splitterStop() Jo ^o`9  
{ (ym)q#^  
bStop = true; zoU.\]#C  
} M}>q>  
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} Gmb57z&:  
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L_  
{)M4h?.2  
/* %j,Ny}a  
**FileAccess.java shB(kb{{  
*//文件访问(定位，写) 6yU~^))bx  
package NetFox; F-6* BUqJ  
import java.io.*; zV]0S o  
+J} 41  
*QVE>{  
public class FileAccessI implements Serializable{ jL# akV  
]8#{rQ(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4}CRM# W2  
RandomAccessFile oSavedFile; )I#kG{z|P;  
long nPos; tv0xfAV  
[qz6_WOo  
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public FileAccessI() throws IOException I'gnw~  
{ i0P+,U  
this("",0); ^V:YNUqp#  
} Z#Fw 1  
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public FileAccessI(String sName,long nPos) throws IOException ps]6,@uyB  
{ !"kvXxp^  
oSavedFile = new RandomAccessFile(sName,"rw"); ;?rW`e2  
this.nPos = nPos; )D^P~2  
oSavedFile.seek(nPos); 5q<kt{06\  
} ~ 0[K%]]  
?:ZH%R_`a  
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public synchronized int write(byte[] b,int nStart,int nLen) fkYQ3d,`  
{ IH0Uq_  
int n = -1; ovl@[>OB  
try{ S$#Awen"@  
oSavedFile.write(b,nStart,nLen); )-9/5Z0v  
n = nLen; iPIA&)x}  
} ]mc,FlhU@  
catch(IOException e) &qr7yyY  
{ 8177x7UG2[  
e.printStackTrace (); L]VK9qB  
} RHxd6Gs"  
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return n; }
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} /; _"A)0  
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/* )KNFS,5  
**SiteInfoBean.java 6e*JCf>  
*/ $OJ*K
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package NetFox; 3drgB;:g`  
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8'YL!moG|  
public class SiteInfoBean { B
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private String sSiteURL; //Site's URL 2|T@  
private String sFilePath; //Saved File's Path u/MIB`@,  
private String sFileName; //Saved File's Name _E~uuFMn*R  
private int nSplitter; //Count of Splited Downloading File BYGLYT;Z  
^cY5!W.q8  
8FMP)N4+  
public SiteInfoBean() Y8P  
{//nSplitter的缺省值为5 V +hV&|=  
//default value of nSplitter is 5 []Z6<rC|  
this("","","",5); .
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} gt ?&!S^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hIdGQKr>V  
{ $Fo ,$  
sSiteURL= sURL; O`2%
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sFilePath = sPath; Ah"RxA  
sFileName = sName; K<t(HK#[  
this.nSplitter = nSpiltter; 9/'j<v6M  
]s<Q-/X  
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} SsaF><{5R  
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5Ph"*Rz%  
public String getSSiteURL() L'c4i[~s  
{ f[z#
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return sSiteURL; _x:K%1_[  
} \'p)kDf  
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public void setSSiteURL(String value) 0wc+<CUW  
{ Q8P;AN_JS  
sSiteURL = value; *z(.D\{%  
} ld3,)ZY  
c,+oH<bZZs  
Fa;CWyt  
public String getSFilePath() \zKVgywR  
{ MF& +4$q  
return sFilePath; \^_F>M  
} $[z*MQ  
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public void setSFilePath(String value) Kr9 @  
{ O ~"^\]\  
sFilePath = value; l lQ<x  
} ,,i;6q_f  
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public String getSFileName() )2R:P`U
 
{ r*kk/$,2  
return sFileName; HC$_p,9OV  
} D L$P  
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)[/+j"F   
public void setSFileName(String value) =!p6}5Z  
{ xOS4J+'s@  
sFileName = value; z/;NoQ-  
} 4u"O/rt  
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public int getNSplitter() Vls*fY:W  
{ PI }A')Nq.  
return nSplitter; Z EG  
} YRB,jwne  
}J:~}?^%n  
}bHdU]$}  
public void setNSplitter(int nCount) }mX;0qO  
{ >YLwWU<X  
nSplitter = nCount; +]B^*99  
} )82x)c<e  
} {Rbc  
* \f(E#wa  
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/* j_Dx4*vg  
**Utility.java [<bfwTFsl  
*/ U+nwLxe'  
package NetFox; _ 57m] ;&  
 x@Q}sW92  
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public class Utility { 1 aIJ0#nE  
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, Lhgv1  
public Utility() ~,dj)x 3M  
{ RaG-9gujI  
nz+DPk["  
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} spgY &OI;  
c7S<ex,  
//线程睡眠 oE)tK1>;H  
public static void sleep(int nSecond) 7@MV
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{ 4RJ8 2yq-  
try{ tOS%.0W5J  
Thread.sleep(nSecond); 91`biVZfA  
} hyFq>XFo  
catch(Exception e) q4Qm:|-  
{ Rm"lRkY4I[  
e.printStackTrace (); "wA3l%d[Y  
}
8qo{%  
} NhXTt!S6C  
8gr&{-5  
//日志 USJ4qv+-  
public static void log(String sMsg) ]MRE^Je\h  
{ ,)u}8ty3j  
System.err.println(sMsg); @UE0.R<  
} (\>_{"*=  
H+\rCefba  
74xI#`E  
public static void log(int sMsg) hPP+lqY[  
{ AZxOq !B  
System.err.println(sMsg); "pQM$3n(  
} !JJCG  
} !G Z2|~f9  
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}mk9-7  
/* {HlUV33O  
**TestMethod.java L*Xn!d%  
*/ F;}?O==H;  
package NetFox; e#)}.   
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public class TestMethod { s=u0M;A0Q  
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public TestMethod() <~<I K=n  
{ ///xx/weblogic60b2_win.exe WQ|d;[E  
try{ &7XB$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); KSMe#Qnw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u'<Y#bsR#/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `9kjYSd#E  
fileFetch.start(); 0[x?Q[~S_0  
} 'h([Y8p{  
catch(Exception e){e.printStackTrace ();} w(<; $9  
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)Tpc8Hr  
} vFV->/u  
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public static void main(String[] args) U"<Z^)  
{ 1W"9u   
new TestMethod(); gPd:>$  
} WIQt5=-  
} AuX&  
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