http断点续传简单实现（java)

/* F2oY_mA  
**SiteFileFetch.java ,O3"r;  
*/ mN3%;$ND7  
package NetFox; $L:g7?)k  
import java.io.*; :r^i0g|5P  
import java.net.*; u33+ikYv  
EW#.)@-  
9N=Dls  
public class SiteFileFetch extends Thread { #1u4Hi(x5  
,!%[CpM3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =kZPd>&L  
long[] nStartPos; //开始位置 U G^6I5  
long[] nEndPos; //结束位置 a/_sL(F{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wvT!NN K2  
long nFileLength; //文件长度 4w]u: eU  
boolean bFirst = true; //是否第一次取文件 +Z)||MR"  
boolean bStop = false; //停止标志 W1r-uR  
File tmpFile; //文件下载的临时信息 @U5+1Hjc  
DataOutputStream output; //输出到文件的输出流 (M.Sl  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zMtK_ccQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException jh\q2E~,`  
{ X?4
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siteInfoBean = bean; % OiSuw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RG:ct{i  
if(tmpFile.exists ()) !ybEv| =  
{ h5Qxa$Oq  
bFirst = false; HOykmx6$  
read_nPos(); lP9a*>=a  
} :Nc~rOC_  
else ",&}vfD4M  
{ 1/a*8vuGh  
nStartPos = new long[bean.getNSplitter()]; YDjQ&EH  
nEndPos = new long[bean.getNSplitter()]; m>zUwGYEu  
} us`hR!_  
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i  
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} l4R:_Z<  
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public void run() #ye++.7WK  
{ uO
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//获得文件长度 -k$rkKHZ(  
//分割文件 H[]j
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//实例FileSplitterFetch ]C)PZZI='  
//启动FileSplitterFetch线程 ru'Xet  
//等待子线程返回 B Sb!{|]  
try{ O_F<VV*MFQ  
if(bFirst) `Ph4!-6#  
{ aWe H,A%  
nFileLength = getFileSize(); {r'#(\  
if(nFileLength == -1) /Pg66H#RUf  
{ 2{+\\.4Evk  
System.err.println("File Length is not known!"); J&8l1{gd  
} zq{L:.#ha  
else if(nFileLength == -2) p+9vSM #  
{ .O1g'%  
System.err.println("File is not access!"); 8{Zgvqbb  
} Q*mPU=<  
else [R A=M  
{ !i)?j@D  
for(int i=0;i<nStartPos.length;i++) %0:  (''  
{ 4~G9._  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z"e|DP`  
} >-y'N.l^  
for(int i=0;i<nEndPos.length-1;i++) ) I-8.  
{ .]v8W51Y  
nEndPos = nStartPos[i+1]; lpSM p  
} <FGNV+?%e  
nEndPos[nEndPos.length-1] = nFileLength; J]N-^ld\\  
} ^BNg^V.  
} .f(x9|K^  
]MUuz'<
 
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//启动子线程 3ufUB^@4v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5zfaqt`  
for(int i=0;i<nStartPos.length;i++) KS(s<ip|  
{ {CQA@p:Y}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lQ!6n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Rfa1v*(  
nStartPos,nEndPos,i); n~K_|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q4c>gds`  
fileSplitterFetch.start(); YEVH?`G  
} )5&w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l)XzU&Sc~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oWx! 'K6]V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y#?Sqm(  
nEndPos = " + nFileLength); x8zUGvtQ  
// fileSplitterFetch[nPos.length-1].start(); 5<ery~q  
_4.`$n/Z  
GbStqR~^#  
//等待子线程结束 W J^r~*r  
//int count = 0; 4\Q ?4ZX  
//是否结束while循环 i'`Z$3EF)  
boolean breakWhile = false; A5?[j QT0  
nW{7L  
-] J V  
while(!bStop) 3(AgUq  
{ bX5>qqB]  
write_nPos(); 1{nXmtvr  
Utility.sleep(500); Y}nE/bmx&9  
breakWhile = true; eCk}B$ 2  
'y;[ fwo7  
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for(int i=0;i<nStartPos.length;i++) g%RL9-z  
{ e-{k;V7b  
if(!fileSplitterFetch.bDownOver) Xv=n+uo  
{ HRPTP+  
breakWhile = false; +s1mm c  
break; Z$HYXm  
} w(.k6:e  
} 10}\7p8  
if(breakWhile) XQlK}AK  
break; aSKI%<?xN  
#.FtPR  
?L{[84GSO  
//count++; uN6TV*]:  
//if(count>4) Wl::tgU  
// siteStop(); P) GBuW  
} \t^q@}~0Wz  
]hv4EL(zi  
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System.err.println("文件下载结束！"); mv<z%y?Oj  
} gt'0
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catch(Exception e){e.printStackTrace ();} i(L;1 `  
} obaJT"1  
H$;K(,'  
kF6X?mqgD  
//获得文件长度 X`^9a5<"  
public long getFileSize() XP6R$0yN  
{ ]}KmT"vA  
int nFileLength = -1; l_+s$c  
try{ [y=k}W}z  
URL url = new URL(siteInfoBean.getSSiteURL()); .w[]Q;K_[)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4wBMBCJ;P  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Q6R6xW  
 3xV  
9s5CqB  
int responseCode=httpConnection.getResponseCode(); 5XA6IL|/l  
if(responseCode>=400) )}n`MRDB  
{ J%3S3C2*m  
processErrorCode(responseCode); tC-(GDGy5  
return -2; //-2 represent access is error u -CY-  
} . (Q;EF`_U  
J<u,Y= -~  
el7P  
String sHeader; m{gt(n  
:
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for(int i=1;;i++) ]W-:-.prh  
{ Zpl?zI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); & UL(r  
//Utility.log(in.readLine()); [ o3}K  
sHeader=httpConnection.getHeaderFieldKey(i); ZZzf+F)T  
if(sHeader!=null) }c%QF  
{ :6N{~[:4  
if(sHeader.equals("Content-Length")) H:y.7  
{ ?<xGO@b .  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L;E9"7
Jo  
break; QZt/Rm>W0  
} 2/qfK+a  
} ]}~*uT}>  
else i nF&Pv  
break; ak0KrVF  
} ,R ]]]7)+  
} URX>(Y}g9^  
catch(IOException e){e.printStackTrace ();} MDl  
catch(Exception e){e.printStackTrace ();} rkG*0#k  
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8WfF: R;  
Utility.log(nFileLength); 5pE[}@-c9  
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return nFileLength; 2syKYHV  
} Ny p5=  
;:8_H0X'K  
'h
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//保存下载信息（文件指针位置） 76mQ$ze  
private void write_nPos() c i_XcG  
{ jO<K0cc  
try{ pkjL2U:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mS&[<[x  
output.writeInt(nStartPos.length); "xdXHuX  
for(int i=0;i<nStartPos.length;i++) #CHsH{d  
{ [[oX$0Fp\!  
// output.writeLong(nPos); WTSY:kvcCY  
output.writeLong(fileSplitterFetch.nStartPos); =TwV_Dro~  
output.writeLong(fileSplitterFetch.nEndPos); M2%<4(UwI  
} ]^/:Xsk$  
output.close(); E/Eny5  
} IAhyGD{b  
catch(IOException e){e.printStackTrace ();} YJ.'Yc  
catch(Exception e){e.printStackTrace ();} #B;`T[  
} -"<H$  
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`c(,_oa{  
//读取保存的下载信息（文件指针位置） .e"De-u  
private void read_nPos() b4S7Q"g  
{ ) m%ghpX  
try{ J$j&j`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #O\4XZ,Lv  
int nCount = input.readInt(); 2JUX29rER  
nStartPos = new long[nCount]; D0us<9q  
nEndPos = new long[nCount]; D0~WK stl  
for(int i=0;i<nStartPos.length;i++) ?b^VEp.;}  
{ t`Mm  
nStartPos = input.readLong(); TB*g$*  
nEndPos = input.readLong(); 1CFrV=d  
} toX4kmC  
input.close(); l/DV ?27  
} =_D82`
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catch(IOException e){e.printStackTrace ();} B`T|M$Ug  
catch(Exception e){e.printStackTrace ();} t A\N$  
} k2j:s}RHY  
q !EJs:AS  
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private void processErrorCode(int nErrorCode) )wCA8  
{ 4(bV#   
System.err.println("Error Code : " + nErrorCode); F,%q
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} zTAt% w5  
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OzX\s=  
//停止文件下载 F2AM/m^!q  
public void siteStop() J=Ak+J  
{ HC?yodp^  
bStop = true; >O9j},X  
for(int i=0;i<nStartPos.length;i++) wU2y<?$\8  
fileSplitterFetch.splitterStop(); 7iLm_#M  
7h&$^  
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} (|bMtT?"x  
} }rn}r4_a  
//负责部分文件的抓取 Kbg`
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**FileSplitterFetch.java y@nWa\iG  
*/ |pqLwnOu  
package NetFox; VahR nD  
V/"XC3/n*  
xX{uDMYa;  
import java.io.*; ]6pxd \Q  
import java.net.*; =yz#L@\!  
!jU<(eY  
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public class FileSplitterFetch extends Thread { <{[AG3/Zj4  
h<Yn0(.  

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String sURL; //File URL Hm-+1Wx  
long nStartPos; //File Snippet Start Position })M$#%(  
long nEndPos; //File Snippet End Position |n}W^}S5  
int nThreadID; //Thread's ID --Dw  
boolean bDownOver = false; //Downing is over PC.$&x4w1  
boolean bStop = false; //Stop identical awHfd5nRS  
FileAccessI fileAccessI = null; //File Access interface fB3O zff  
0u,=OvU  
69dFd!G\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [{}9"zB$x0  
{ h|!B;D  
this.sURL = sURL; oeDsJ6;  
this.nStartPos = nStart; r{YyKSL1*K  
this.nEndPos = nEnd; L`R,4mI.W  
nThreadID = id; CbQ@l@d]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bv\V>s  
} >QE^KtZ  
95T%n{rz  
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public void run() U`W^w%  
{ >-s}1*^=oD  
while(nStartPos < nEndPos && !bStop) dsR{ P,!  
{ H'q&1^w)  
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try{ ?uU0NKZA  
URL url = new URL(sURL); \S=!la_T@m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9(ZzwkD'>  
httpConnection.setRequestProperty("User-Agent","NetFox"); htX'
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String sProperty = "bytes="+nStartPos+"-"; CBnD)1b\  
httpConnection.setRequestProperty("RANGE",sProperty); 6KnD(im  
Utility.log(sProperty); Ook3B  
9`4h"9dO  
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InputStream input = httpConnection.getInputStream(); cuq7eMG6z  
//logResponseHead(httpConnection); Y@9L8XNP>  
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byte[] b = new byte[1024]; x^+ C[%  
int nRead; L]K*Do  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iJ?8)}  
{ Q,#M 0  
nStartPos += fileAccessI.write(b,0,nRead); 'x+0 yd  
//if(nThreadID == 1) 2}$Vi$ R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c`doR(oZ  
} UM|GX  
>B8)Wb:  
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Utility.log("Thread " + nThreadID + " is over!"); AN^
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bDownOver = true; ])m",8d&T  
//nPos = fileAccessI.write (b,0,nRead); Ef%
8+_  
} iN`/pW/JE  
catch(Exception e){e.printStackTrace ();} EOtrrfT&  
} Pk8L-[&v  
} f910drg7  
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^>%=/RX  
//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) 5\R8>G~H  
{ ?aOR ^ K  
for(int i=1;;i++) + {a  
{ 45kMIh~~X  
String header=con.getHeaderFieldKey(i); R3?~+y&  
if(header!=null) :&?#~NFH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D1
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Utility.log(header+" : "+con.getHeaderField(header)); ?z:xQ*#X  
else k\ I$ve"*  
break; "MoV*U2s,  
} "5{Yn!-:  
} M#<x2ojW  
Z"Et]xSU%$  
Sw5H+!  
public void splitterStop() lz{>c.Ll[  
{ 1 _5[5K^  
bStop = true; C>T6{$xkC  
} <>j,Q  
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} {H])Fob  
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/* A: 0] n  
**FileAccess.java +%U@  
*//文件访问(定位，写) u52;)"&=)  
package NetFox; De>pIN;B>  
import java.io.*; RK rBHqh@  
cLR8U1k'  
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public class FileAccessI implements Serializable{ B2845~\.  
|I OTW=>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Rx`0VQ  
RandomAccessFile oSavedFile; QO#ZQ~  
long nPos; l\$C)q6O  
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public FileAccessI() throws IOException q8kt_&Ij  
{ "hy#L 0\t  
this("",0); "H G:by  
} e}K
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public FileAccessI(String sName,long nPos) throws IOException !%Z1"FDm/  
{ /f#rN_4  
oSavedFile = new RandomAccessFile(sName,"rw"); U]R7=  
this.nPos = nPos; *Gu=O|Mm  
oSavedFile.seek(nPos); ][?GJ"O+U  
} Z<&: W8n  
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public synchronized int write(byte[] b,int nStart,int nLen) xPb`CY7  
{ C{2UPG4x  
int n = -1; |9_e2OwH  
try{ )9<)mV*EB(  
oSavedFile.write(b,nStart,nLen); "UAW  
n = nLen; X0!48fL*  
} %H}+
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catch(IOException e) Qz$.t>@V=  
{ ?C $_?Qi  
e.printStackTrace (); Mm/GIa  
} O$&p<~  
K} ;uH,  
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return n; l
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} 0j_!)B  
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} mS%D" e  
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/* el[6E0!@  
**SiteInfoBean.java w\@Anwj#L  
*/ ;c;;cJc!  
package NetFox; ]]7s9PCN  
CX1'B0=\r  
'E7|L@X"r  
public class SiteInfoBean { |2
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private String sSiteURL; //Site's URL V'6%G:?0a  
private String sFilePath; //Saved File's Path G7),!Qol  
private String sFileName; //Saved File's Name 5k\61(*s  
private int nSplitter; //Count of Splited Downloading File #v~5f;[AAs  
9JUlu  
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public SiteInfoBean() XDI@mQmzB  
{//nSplitter的缺省值为5 ?EpY4k8,  
//default value of nSplitter is 5 3ea6g5kX  
this("","","",5); sxuYwQ  
} Z#Zk)  
|H |ewVUY  
sXfx[)T<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k*n5+[U^tP  
{
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sSiteURL= sURL; =nY*,Xu<  
sFilePath = sPath; @0)bY*njj  
sFileName = sName; 2smLv1w@  
this.nSplitter = nSpiltter; : 0%V:B  
( E0be.  
k@wxN!w;  
} zb9$
 
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public String getSSiteURL() @,s[l1P  
{ |9
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return sSiteURL; 4W1"=VL[g  
} |\b*p:el  
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/[us;=CM  
public void setSSiteURL(String value) *.i`hfRc  
{ my*/MC^O  
sSiteURL = value; k'S/n
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} &PGU%"rN  
g.,IQ4o  
,7/N=mz  
public String getSFilePath() M/#<=XhA  
{ [1Vh3~>J6  
return sFilePath; un..UU4  
} X#pE!mT  
OP>'<FK  
fwOvlD&e  
public void setSFilePath(String value) ]^.#d   
{ u/``*=Y@  
sFilePath = value; ,c7 8O8|  
} rt."P20T  
Z!ub`coV[  
SFh6'v'1N@  
public String getSFileName() Z,Q)\W<'-  
{ R[Pyrs!H  
return sFileName; q,+d\-+  
} _STN^   
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j4Lf6aUOX  
public void setSFileName(String value) s K s D  
{ /<M08ze  
sFileName = value; >0u4>=#  
} \5O4}sm$*  
zQD$+q5h  
 4INO .  
public int getNSplitter() F7L+bv   
{ 4egq Y0A  
return nSplitter; & XcY|y=W  
} 8wwD\1pLS  
/(XtNtO*  
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public void setNSplitter(int nCount) iGm[fxQ|  
{ +]Ydf^rF  
nSplitter = nCount; 9r8*'.K`Z  
} Oi=kL{DG:s  
} &|55:Y87  
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@@_f''f$  
/* XG*Luc-v  
**Utility.java M2mte#h  
*/ mVW:]|!s  
package NetFox; tE- s/  
=3l%ZL/  
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public class Utility { b6
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public Utility() hbzU?_}  
{ #(T  
dz&8$(f,  
(wnkdI{  
} U c$RYPq  

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//线程睡眠 .[NB"\<q  
public static void sleep(int nSecond) `/8Dmg  
{ %fo+Y+t  
try{ E"nIC,VZ  
Thread.sleep(nSecond); `(.K|l}  
} PiP\T.XANa  
catch(Exception e) y2yW91B,  
{ OT&J OTk\  
e.printStackTrace (); hK&jo(V  
} 9v8{JaI3  
} TE3A(N'  
-y)i
j``VY  
//日志 }RDGk+x7|  
public static void log(String sMsg) oxha8CF]D  
{ >7p?^*&7;  
System.err.println(sMsg); u-$(TyDEl|  
} 7q^osOj"  
y08.R. l  
|Xlpgdiu  
public static void log(int sMsg) 4(f[Z9 iZ]  
{ db'Jl^  
System.err.println(sMsg); Zchs/C 9{  
} 2X!O
'  
} {'NdN+_C  
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D ]:sR  
/* R6r'[-B2  
**TestMethod.java Cq(dj^/~m  
*/ Xk8+m>   
package NetFox; esIEi!d  
! av B&Z  
2Xys;Dwx  
public class TestMethod { rzsb(  
[kM)K'-  
1>r7s*  
public TestMethod() :GBWQXb G  
{ ///xx/weblogic60b2_win.exe */;[ -9  
try{ MkEr|w'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7F!_gj p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;K
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SiteFileFetch fileFetch = new SiteFileFetch(bean); oi^2Pvauh  
fileFetch.start(); 33z)F  
} ^1sX22k  
catch(Exception e){e.printStackTrace ();} lTBPq?4{  
r({!ejT{U  
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} $!)Sgb  
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public static void main(String[] args) hy3j8?66  
{ ms@*JCL!t  
new TestMethod(); ^V#9{)B  
} FAkjFgUJp  
} Ue^2H[zs-  
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