http断点续传简单实现（java)

/* 5)5bt q)[  
**SiteFileFetch.java l_-n&(N2<[  
*/ N>Y50  
package NetFox; Z;'.pU~  
import java.io.*; .l5"X>  
import java.net.*; y]_8. 0zM  
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public class SiteFileFetch extends Thread { J
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SiteInfoBean siteInfoBean = null; //文件信息Bean Z:J.FI@  
long[] nStartPos; //开始位置 ^p zxwt  
long[] nEndPos; //结束位置 0P40K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TK/'
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long nFileLength; //文件长度 W.D3$  
boolean bFirst = true; //是否第一次取文件 `A _8nW)  
boolean bStop = false; //停止标志 { DQE7kI  
File tmpFile; //文件下载的临时信息 `$SEkYdt  
DataOutputStream output; //输出到文件的输出流 arQ%  
#*$@_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tZCe?n]  
public SiteFileFetch(SiteInfoBean bean) throws IOException *F*jA$aY  
{ sVdK^|j  
siteInfoBean = bean; ('6g)@=\U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &qP-x98E?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q;zf|'&*7C  
if(tmpFile.exists ()) tq:tY}:4  
{ %=4ak]As  
bFirst = false; 9r+O!kF(  
read_nPos(); q+n1~AT  
} UdW(\%  
else k)K-mD``U  
{ c_bVF 'Bz  
nStartPos = new long[bean.getNSplitter()]; `s>=Sn&UP  
nEndPos = new long[bean.getNSplitter()]; ZHF(q6T  
} xhkWKB/7  
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#"8[8jyV  
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} B4:l*P'  
*/^2RZg|W  
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public void run() WmjzKCl  
{ m?VRX.>  
//获得文件长度 YATdGLTeq  
//分割文件 9N D+w6"  
//实例FileSplitterFetch 2ZG1n#  
//启动FileSplitterFetch线程 )Ct*G= N  
//等待子线程返回 GP[r^Z  
try{ (5q%0|RzRs  
if(bFirst) RYZE*lWUh  
{ soq".
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nFileLength = getFileSize(); %L13Jsw  
if(nFileLength == -1) l \^nC2  
{ +Sd,l>8\  
System.err.println("File Length is not known!"); G(0y|Eq  
} "c/s/$k//  
else if(nFileLength == -2) Ryq"\Q>+  
{ 4SffP/  
System.err.println("File is not access!"); loUl$X.u  
} fEw=I7{Y  
else y /:T(tk$  
{ $C05iD  
for(int i=0;i<nStartPos.length;i++) d$_q=ywc  
{ ?5yH'9zE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uB<F.!3  
} {y:#
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for(int i=0;i<nEndPos.length-1;i++) p=~h|(M|  
{ H : T N  
nEndPos = nStartPos[i+1]; xeHb89GnoQ  
} q#(/*AoU  
nEndPos[nEndPos.length-1] = nFileLength; (HaKF7Jsi  
} ft/^4QcyAM  
} <P^hYj-swh  
mheU#&|  
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//启动子线程 \5[D7}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D=~B7b:  
for(int i=0;i<nStartPos.length;i++) %7]XW2u  
{ .b#9q6F-/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mUt,Z^ l`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [t.%&#baF  
nStartPos,nEndPos,i); )t,{YGY#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O5^J!(.O\Z  
fileSplitterFetch.start(); T")i+
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} pYfV~Q^3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IypWVr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vj=Xcn#*8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fi&uB9hc  
nEndPos = " + nFileLength); c3V]'~  
// fileSplitterFetch[nPos.length-1].start(); 2>$F0 M  
?]W~ qgA  
Xn/ n|[  
//等待子线程结束 bR'mV-2'  
//int count = 0; w*:GM8=6  
//是否结束while循环 8jjFC9Cbn0  
boolean breakWhile = false; |0L=8~M(j  
e?!L}^f6X  
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while(!bStop) x[vBK8  
{ ~ThVap[*  
write_nPos(); Zlk,])9Q  
Utility.sleep(500); zkh hN"bX  
breakWhile = true; v_z..-7Dq+  
o
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for(int i=0;i<nStartPos.length;i++) 3^\?>C7  
{ hD_5~d  
if(!fileSplitterFetch.bDownOver) pgLtD};S  
{ Har~MO?A  
breakWhile = false; T A\4uy6o  
break; ou'~{-_xd  
} ^q
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} (T|TEt  
if(breakWhile) j2}  
break; j,C,5l=  
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//count++; :xFu_%7  
//if(count>4) hIuMHq7h  
// siteStop(); oTCzYY  
} @~k5+Z  
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*;hY.EuoFz  
System.err.println("文件下载结束！"); V#0 dGP-Z  
} p^1zIC>F  
catch(Exception e){e.printStackTrace ();} PS=e\(6QC  
} JiFA]M`^Q  
S\e&?Y`  
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//获得文件长度 :zdEq")v  
public long getFileSize() Vd+td;9(  
{ u5w&X8x  
int nFileLength = -1; XXW]0{k:y  
try{ wG1y,u'  
URL url = new URL(siteInfoBean.getSSiteURL()); =&A!C"qK4[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :)#hrFp  
httpConnection.setRequestProperty("User-Agent","NetFox"); bauA}3  
VL+N:wb>  
;gDMl57PQ.  
int responseCode=httpConnection.getResponseCode(); EntF@ln!  
if(responseCode>=400) Y?yo\(Cdx  
{ D~#Ei?aH  
processErrorCode(responseCode); E *F*nd]K  
return -2; //-2 represent access is error 9>by~4An?  
} &{%MjKJ._  
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String sHeader; q!6|lZB3  
&]P"48NT  
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for(int i=1;;i++) :{LAVMG&^  
{ 2fl4h<V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &E bI Op  
//Utility.log(in.readLine()); ;%' b;+  
sHeader=httpConnection.getHeaderFieldKey(i); AZwl fdLB  
if(sHeader!=null) @}<"N  
{ XZS5B~E '  
if(sHeader.equals("Content-Length")) 8|O=/m^]  
{ QR<`pmB~y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); } h[>U  
break; d%0+i/p  
} <i{K7}':  
} .xO _E1Ku;  
else !;%y$$gxh  
break; /XcDYMKgh  
} wGvhB%8K  
} zJ9v%.e  
catch(IOException e){e.printStackTrace ();} bpCNho$  
catch(Exception e){e.printStackTrace ();} 6*IpA
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Utility.log(nFileLength); OL3UgepF  
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return nFileLength; nH@(Y&S  
} 8L%M<JRg~  
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//保存下载信息（文件指针位置） [C1 LT2a  
private void write_nPos() bAf,aV/C&|  
{ g\U/&.}DN  
try{ wtXY:O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %Rp8{.t7  
output.writeInt(nStartPos.length); AoYaVlKG8  
for(int i=0;i<nStartPos.length;i++) XS?gn.o\
 
{ .WvlaPK  
// output.writeLong(nPos); -ynBi;nH
 
output.writeLong(fileSplitterFetch.nStartPos); n@!wp/J,  
output.writeLong(fileSplitterFetch.nEndPos); >3 l=*|9  
} $r\"6e  
output.close(); rK1-Mu  
} uWjN2#&,  
catch(IOException e){e.printStackTrace ();} fW?
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catch(Exception e){e.printStackTrace ();} ["y6b*;x  
} ju|]Qlek  
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//读取保存的下载信息（文件指针位置） DP9LO_{  
private void read_nPos() vE%s,E,  
{ 2*[QZ9U[@  
try{ ACg;CTBb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); AF}gSNX  
int nCount = input.readInt(); zI^]esX!2_  
nStartPos = new long[nCount]; +dk fcG  
nEndPos = new long[nCount]; xzsdG?P  
for(int i=0;i<nStartPos.length;i++) {tw+#}T a  
{ ,zhJY ?sk  
nStartPos = input.readLong(); %{!R l@  
nEndPos = input.readLong(); ZF6c{~D  
} LY 0]l$  
input.close(); &<3&'*ueW  
} irbw'^;y  
catch(IOException e){e.printStackTrace ();} 1vnYogL  
catch(Exception e){e.printStackTrace ();} .@#A|fgv  
} aJhxc<"e  
}rq9I"/L  
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private void processErrorCode(int nErrorCode) e(?]SU|  
{ m&*JMA;^  
System.err.println("Error Code : " + nErrorCode); I9?Ec6a_  
} \]uV!)V5B  
}!p`1]gem  
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//停止文件下载 ;=4Xz\2  
public void siteStop() *bd[S0l  
{ !4(zp;WY^  
bStop = true; o]ePP,  
for(int i=0;i<nStartPos.length;i++) ]
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fileSplitterFetch.splitterStop(); :YP#  
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} L\%orLEmK  
} 0hY{<^"Y  
//负责部分文件的抓取 W$0^(FH[  
**FileSplitterFetch.java ~q+hV+fa>  
*/ +s++7<C  
package NetFox;
S >yLqPp  
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import java.io.*; 0[Ht_qxb  
import java.net.*; *.#oxcll  
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public class FileSplitterFetch extends Thread { s{0aBeq  
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String sURL; //File URL ?e[lr>-  
long nStartPos; //File Snippet Start Position 1)m@?CaI`  
long nEndPos; //File Snippet End Position 8[vc?+>&  
int nThreadID; //Thread's ID "]K>j'^Zs<  
boolean bDownOver = false; //Downing is over 1y#D?R=E  
boolean bStop = false; //Stop identical ",6M)3{|c  
FileAccessI fileAccessI = null; //File Access interface +M' H0-[  
a.N{-2ptH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fGhn+8VfX  
{ ApBWuXp|u  
this.sURL = sURL; a=cvCf  
this.nStartPos = nStart; >zAUW[]C:I  
this.nEndPos = nEnd; Wbr+KX8)  
nThreadID = id; 7frTTSZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HK`I\,K  
} 7d LuX   
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public void run() .X# `k  
{ y@0E[/O  
while(nStartPos < nEndPos && !bStop) cufH?Xg<  
{ okbQ<{9  
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try{ S$QG.K:<!  
URL url = new URL(sURL); lOtDqb&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UQ{L{H   
httpConnection.setRequestProperty("User-Agent","NetFox"); /p8dZ
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String sProperty = "bytes="+nStartPos+"-"; x)(|[  
httpConnection.setRequestProperty("RANGE",sProperty); 15o9 .   
Utility.log(sProperty); feQ **wI  
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InputStream input = httpConnection.getInputStream(); |yx6X{$k  
//logResponseHead(httpConnection); 8F._9U-EN  
&Z`#cMR{H  
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byte[] b = new byte[1024]; #B4%|v;`E?  
int nRead; +HBd %1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8F'x=lIO  
{ s&RVJX>Rt  
nStartPos += fileAccessI.write(b,0,nRead);
6Vz9?puD  
//if(nThreadID == 1) HDF|{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O#F4WWF  
} @3zg=?3  
!QvZ<5(  
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Utility.log("Thread " + nThreadID + " is over!"); gHo?[pS%y  
bDownOver = true; c@893<_  
//nPos = fileAccessI.write (b,0,nRead); MdvcnaCG  
} 9jw\s P@  
catch(Exception e){e.printStackTrace ();} V,cBk  
} p,eTY[k?  
} Ft&]7dT{W  
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//打印回应的头信息 ;C2K~8,  
public void logResponseHead(HttpURLConnection con) #w' k
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{ [Al&  
for(int i=1;;i++)  iKT[=c  
{ T\D}kQM  
String header=con.getHeaderFieldKey(i); iv4H#rJ  
if(header!=null) `hQ5VJo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Fvbh\m ~  
Utility.log(header+" : "+con.getHeaderField(header)); 4rLL[??  
else !6*"(  
break; S[J}UpV  
} _no*k?o*  
} ?vbvBu{a  
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public void splitterStop() R}!:'^  
{ vkri+:S3  
bStop = true; $w`=z<2yo1  
} L6|oyf  
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} 2QyV%wz  
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/* 9,:l8  
**FileAccess.java <+?7H\b  
*//文件访问(定位，写) W*),y:  
package NetFox; JehrDC2N  
import java.io.*; 1cpiHZa  
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public class FileAccessI implements Serializable{ {#?N  
vunHNHltW0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ix)M`F%P3  
RandomAccessFile oSavedFile; 42$VhdG  
long nPos; \o*5  
/<|%yE&KhJ  
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public FileAccessI() throws IOException P-yjN  
{ eg;~zv  
this("",0); vqDu(6!2  
} N"Zt47(  
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public FileAccessI(String sName,long nPos) throws IOException ^ *k?pJ5  
{ W$hx,VEy`  
oSavedFile = new RandomAccessFile(sName,"rw"); Jh,]r?Bd  
this.nPos = nPos; Z>:NPZODf  
oSavedFile.seek(nPos); I9_RlAd  
} ~=M7 3U#  
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public synchronized int write(byte[] b,int nStart,int nLen) 6-N?mSQU  
{ !Xf5e*1IS  
int n = -1; 4&<oFW\r  
try{ ;=)k<6  
oSavedFile.write(b,nStart,nLen); naG=Pq<  
n = nLen; 2=,lcWr  
} *+Ek0M  
catch(IOException e) p& y<I6a,  
{ j4gF;-m<  
e.printStackTrace (); JVvs-bK5
 
} 3%#3iZ=_  
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return n; k:t]s_`<  
} SYAyk  
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} (y=C_wvqZ  
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X9v.1s,  
/* :;t:H] f  
**SiteInfoBean.java hgYZOwQ  
*/ `uv2H$  
package NetFox; U6glp@s  
l+xX/A)  
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public class SiteInfoBean { v|XTr,#  
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private String sSiteURL; //Site's URL 8g@<d^8@  
private String sFilePath; //Saved File's Path |s7s6k)mm  
private String sFileName; //Saved File's Name \pa"%c)  
private int nSplitter; //Count of Splited Downloading File ?ZV/U!y  
w$3,A$8  
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public SiteInfoBean() dN$0OS`s[  
{//nSplitter的缺省值为5 J{.{f  
//default value of nSplitter is 5 >!eAM )  
this("","","",5); $SlIr<'*"  
} Z^bQ^zk-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qzYwt]GNS  
{ ]FJjgu<  
sSiteURL= sURL; q$0*b]=E  
sFilePath = sPath; Mo|;'+  
sFileName = sName; [T8WThs  
this.nSplitter = nSpiltter; }~YA5^VQ$  
rMdt:`  
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} >~''&vdsk\  
AHD=<7Rs  
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public String getSSiteURL() ,82S=N5V!  
{ A!od9W6  
return sSiteURL; 52@C9Q,  
} /K+r? ]kf  
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public void setSSiteURL(String value) { }:#G  
{ 1h^:[[!c  
sSiteURL = value; m]'#t)B_m  
} "IZa!eUW  
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public String getSFilePath() 8o3E0k1  
{ xsIY7Ss U  
return sFilePath; J4k=A7^N  
} VpE*(i$  
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u}#(.)a:  
public void setSFilePath(String value) 1vS#K=sb  
{ Ow+GS{-q  
sFilePath = value; ] ]u s %  
} 1auIR/=-  
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public String getSFileName() k9<;woOBO  
{ 35h8
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return sFileName; 'F/~o1\.  
} fW{(lPx  
{0L1X6eg  
^%d\qd`   
public void setSFileName(String value) YX!{P=Ua  
{ n7zm>&  
sFileName = value; ~Q Oe##  
} F|IAiE  
lS"T4 5  
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public int getNSplitter() '*Z1tDFS  
{ 5Y.)("1f}f  
return nSplitter; DF&(8NoX~  
} &u]8IEv}u  
f&=AA@jLv  
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public void setNSplitter(int nCount) B~'vCuE  
{ P9/q|>F  
nSplitter = nCount; Wvq27YK'  
} #oS<E1  
} sZ3KT&  
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/* R6 y#S&]x  
**Utility.java v3*_9e  
*/ 6`&a&%,O  
package NetFox; EH-sZAv  
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/{EP*,/*  
public class Utility { !`M,XSp(  
I:E`PZ  
df*#!D7oz  
public Utility() ,[N%Q#  
{ >>QY'1Eu  
k)i3   
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} ?3/qz(bM  
H/"-Z;0{  
//线程睡眠 S:u:z=:r  
public static void sleep(int nSecond) _Ym]Mj' ln  
{ q?Cnav`DY  
try{ 0^v`T%|fTX  
Thread.sleep(nSecond); Lt2u,9  
} x/%aM1"X^  
catch(Exception e) 1]d!~  
{ ,D5
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e.printStackTrace (); d}Xr}  
} fIM,lt  
} )n1_(;  
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//日志 FX;QG94!  
public static void log(String sMsg) O5!7'RZ  
{ _;W.q7b]  
System.err.println(sMsg); i9rN9Mq?O  
} @g|v
;B|{  
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2_)\a(.Qu  
public static void log(int sMsg) {WJm  
{ G5{T5#  
System.err.println(sMsg); xv46r=>  
} O8f?; ]  
} *HU &4E\a  
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/* r^2p*nr}  
**TestMethod.java "N;`1ce  
*/ ?K1/ <PE+  
package NetFox; "H2EL}3/]  
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mR!1DQ.\<  
public class TestMethod { M|VyV(f  
2Zm0qJ  
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public TestMethod() +|*IZ:w)  
{ ///xx/weblogic60b2_win.exe <:_wbVn-  
try{ 1kz\IQ{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )z>|4@,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m.hkbet/R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K:J3Z5"  
fileFetch.start(); c7?_46J  
} ,yC-+VL  
catch(Exception e){e.printStackTrace ();} 6o^,@~:R  
p}&#jE  
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} !H#bJTXB  
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W=lyIb{?^0  
public static void main(String[] args) 88Ey12$  
{ \Bz_p'[G  
new TestMethod(); }I2wjO  
} v/@^Q1G/:  
} N%kt3vmQ_  
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