http断点续传简单实现（java)

/* Ga"t4[=I  
**SiteFileFetch.java iphe0QE[#}  
*/ x,pzX(  
package NetFox; !h4L_D0  
import java.io.*; mJl|dk_c  
import java.net.*; qlO(z5Ak  
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public class SiteFileFetch extends Thread { l:%4@t`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WOiw 0  
long[] nStartPos; //开始位置 1jpcoJ@s  
long[] nEndPos; //结束位置 lUbQ@7a<'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a~=$9+?w  
long nFileLength; //文件长度 4 @ )|N'  
boolean bFirst = true; //是否第一次取文件 4g
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boolean bStop = false; //停止标志 VU9w2/cM  
File tmpFile; //文件下载的临时信息 =otJf
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DataOutputStream output; //输出到文件的输出流 Nw* >$v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） se2ay_<F+  
public SiteFileFetch(SiteInfoBean bean) throws IOException X2v|O3>/N  
{ @#xh)"}  
siteInfoBean = bean; blEs!/A`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {dTtYL$'"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @|sDb?J  
if(tmpFile.exists ()) [kaj8  
{ r$<[`L+6  
bFirst = false; %i:Sf  
read_nPos(); rjHL06qE  
} eKsc ["  
else PQDWY
 
{ l.Iov?e1S  
nStartPos = new long[bean.getNSplitter()]; |hk?'WGc`0  
nEndPos = new long[bean.getNSplitter()]; gq\ulLyOeZ  
} $n.oY5=\  
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} )OpB\k  
d ]R&mp|'  
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public void run() E]/` JI'%  
{ &==X.2XW  
//获得文件长度 hE@s~~JYd  
//分割文件 $)8b)Tb  
//实例FileSplitterFetch gTa6%GM>  
//启动FileSplitterFetch线程 Y%m^V?k  
//等待子线程返回 F l@%?  
try{ {@ ygq-TZ  
if(bFirst) b\&|030+  
{ D',[M)  
nFileLength = getFileSize(); {]ie|>'=C  
if(nFileLength == -1) h2<Y*j  
{ JL.noV3q$  
System.err.println("File Length is not known!"); =wE1j  
} '[V}]Z>-  
else if(nFileLength == -2) x=s=~cu4,  
{ 5F&xU$$a-  
System.err.println("File is not access!"); 8$4@U;Vh;  
} ?(rJ  
else tn>z%6;&Z  
{ !(QDhnx}9c  
for(int i=0;i<nStartPos.length;i++) av~dH=&=  
{ csABfxi
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); ay4E\=k  
} %\<SSp^n  
for(int i=0;i<nEndPos.length-1;i++) a$-:F$z  
{ ;c};N(2  
nEndPos = nStartPos[i+1]; zI1-l9 o  
} Qv4g#jX{  
nEndPos[nEndPos.length-1] = nFileLength; D_VAtz  
} Twl>Pn>  
} *PEk+e  
0@ccXFE  
" b?1Yc-  
//启动子线程 ` 9iB`<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gK7bP'S8H  
for(int i=0;i<nStartPos.length;i++) St 4YNS.|  
{ O{@m
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >AFX}N#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :56f  
nStartPos,nEndPos,i); Ut|G.%1Vd%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -SO`wL NV  
fileSplitterFetch.start(); ]m&cVy&  
} :70n%3a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bUJ5jkZ)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5^:N]Mp"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fZ8at  
nEndPos = " + nFileLength); z;fi  
// fileSplitterFetch[nPos.length-1].start(); /8](M5X]f  
5BWO7F0v"  
vuP.V#  
//等待子线程结束 \l$gcFXb  
//int count = 0; x.J% c[Q8  
//是否结束while循环 'a1%`rzm  
boolean breakWhile = false; VkKq<`t<  
LNm{}VJ%  
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while(!bStop) q4Z9;^S  
{ e;_ cC7  
write_nPos(); CB&$tDi  
Utility.sleep(500); '(N -jk  
breakWhile = true; ^ hoz<Ns  
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for(int i=0;i<nStartPos.length;i++) ^dc~hD  
{ !w+A3Z>V  
if(!fileSplitterFetch.bDownOver) Pi^5LI6JW  
{ >'\cNM~nf  
breakWhile = false; mI;#Zq_j  
break; X0IXj%\N  
} *p&c}2'  
} WrzyBG_  
if(breakWhile) \:`'!X1*U  
break; 7-*QF>w<a  
YbX3_N&  
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//count++; ]gxt+'iAFS  
//if(count>4) 8V]oR3'  
// siteStop(); ?$:;hGO.<~  
} 7F=Xn@ _  
^&nC)T<w  
: 5=E>!  
System.err.println("文件下载结束！"); X}!r4<;(  
} !sbKJ+V7  
catch(Exception e){e.printStackTrace ();} 4d\"gk  
} >=<qAkk  
'%k<? *  
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//获得文件长度 [;IW'cXNq  
public long getFileSize() <M//zXa  
{ EqY e.dF,  
int nFileLength = -1; +}MV$X
  
try{ auzrM4<tz  
URL url = new URL(siteInfoBean.getSSiteURL()); }PdHR00^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _'g'M=E  
httpConnection.setRequestProperty("User-Agent","NetFox"); =e<;B_~.  
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JjH#,@'.  
int responseCode=httpConnection.getResponseCode(); {u/G!{N$  
if(responseCode>=400) Z @:5vo  
{ u!iBAr5  
processErrorCode(responseCode); ,}9G|$  
return -2; //-2 represent access is error *)PCPYB^  
} (6Ssk4  
*Ey5F/N}$H  
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String sHeader; <4
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for(int i=1;;i++) |sa{!tKJ  
{ NS^(5g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); caK<;bmu-  
//Utility.log(in.readLine()); @O~
  
sHeader=httpConnection.getHeaderFieldKey(i); o_!=-AWV  
if(sHeader!=null) m-{t%[Y  
{ s`:>"1\|  
if(sHeader.equals("Content-Length")) j\,HquTR  
{ 37#|
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KK}?x6wV0,  
break; 7N@4c   
} P|r
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} A
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else i&|fGX?-I  
break; gH{X?  
} +3@d]JfMh  
} yQ^k%hHa  
catch(IOException e){e.printStackTrace ();} 6mFH>T*jzH  
catch(Exception e){e.printStackTrace ();} D)yCuw{M:  
@y{i.G  
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Utility.log(nFileLength); :'\4%D=w  
w&A&BE^O/  
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return nFileLength; 1x\Vz\  
}
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!11x&Db  
//保存下载信息（文件指针位置） y:FxX8S$'e  
private void write_nPos() ^H0`UKE  
{ fB\+.eN  
try{ AnB]f~Yjl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qv3g 4iJ  
output.writeInt(nStartPos.length); R.(cGZS  
for(int i=0;i<nStartPos.length;i++) 8 *Fr=+KN  
{ @,b:s+]rp  
// output.writeLong(nPos); bzz{ p1e  
output.writeLong(fileSplitterFetch.nStartPos); ^8_`
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output.writeLong(fileSplitterFetch.nEndPos); ) h*)
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} (6jr}kP  
output.close(); =1rq?M eX  
} a$Lry?pb  
catch(IOException e){e.printStackTrace ();} @<GVY))R8  
catch(Exception e){e.printStackTrace ();} ?q}XDc  
} 9u3~s<  
.JR"|;M}  
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//读取保存的下载信息（文件指针位置） >JNK06T  
private void read_nPos() qr5ME/)z  
{ hq5=>p  
try{ pq \M;&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /0w?"2-  
int nCount = input.readInt(); fz)i9D@  
nStartPos = new long[nCount]; Bld%d:i  
nEndPos = new long[nCount]; b4_"dg~gK  
for(int i=0;i<nStartPos.length;i++) =:fFu,+{  
{  T?!&a0  
nStartPos = input.readLong(); O2W EA  
nEndPos = input.readLong(); ?[[K6v}q{  
} 4JF8S
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input.close(); {gSR49!Q  
} IIN"'7Z^R  
catch(IOException e){e.printStackTrace ();} M6ol/.G[  
catch(Exception e){e.printStackTrace ();} *`}4]OGv.  
} {{FA"NW  
-
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private void processErrorCode(int nErrorCode) ^':Az6Z  
{ \M]w I  
System.err.println("Error Code : " + nErrorCode); 7l-`k  
} PI"&-lXI-m  
?0Xt|  
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//停止文件下载 "@xF(fyg  
public void siteStop() l:!4^>SC  
{ .Yxx   
bStop = true; ObDcNq/b!  
for(int i=0;i<nStartPos.length;i++) jGB2`^&d  
fileSplitterFetch.splitterStop(); 9]Q\Pr\Ub$  
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B3 mD0  
} IN? A`A  
} 97H2hYw9l  
//负责部分文件的抓取 -j%!p^2j9  
**FileSplitterFetch.java ]jWe']T  
*/ !}sYPz]7!  
package NetFox; OL{U^uOh
Y  
m6qmZ2<  
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import java.io.*; 8T5s6EmIOW  
import java.net.*; {FR#je  
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public class FileSplitterFetch extends Thread { 
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8G?{S.%.  
u~X]W3  
String sURL; //File URL {u BpM9KT  
long nStartPos; //File Snippet Start Position 7)S;VG k  
long nEndPos; //File Snippet End Position :#!m(s`  
int nThreadID; //Thread's ID Ga\E`J$c  
boolean bDownOver = false; //Downing is over /jI>=:z  
boolean bStop = false; //Stop identical %eoO3"//  
FileAccessI fileAccessI = null; //File Access interface 4m%RD&ZN
 
_ ?f~UvK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _7SOl.5ZE  
{ M) 9Ss  
this.sURL = sURL; 8-cB0F=j_  
this.nStartPos = nStart; a#X[V5|6Q  
this.nEndPos = nEnd; s[:e '#^  
nThreadID = id; ArBgg[i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \h6_m)*H4  
} e_6@oh2s-  
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public void run() cdL$T6y  
{ EP#3+BsH  
while(nStartPos < nEndPos && !bStop) mw<LNnT{8  
{ 5S'89 r3m  
XUUl*5^  
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try{
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URL url = new URL(sURL); P,Fs7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Aa*UV6(v  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3@e#E4+ff  
String sProperty = "bytes="+nStartPos+"-"; !+T9NqDv[  
httpConnection.setRequestProperty("RANGE",sProperty); WU-.lg'c'  
Utility.log(sProperty); kV7c\|N9  
<C\snB  
/H+j6*}r  
InputStream input = httpConnection.getInputStream(); a;AvY O  
//logResponseHead(httpConnection);  MD~03  
gIS<"smOo  
}q-_|(b;  
byte[] b = new byte[1024];  WpX)[au  
int nRead; tP2hU[7Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >Pv#)qtm  
{ #RoGyrLo  
nStartPos += fileAccessI.write(b,0,nRead); rlYAy5&  
//if(nThreadID == 1) V7u;"vD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T78`~-D4<  
} l]whL1N3  
TD+V.}  
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Utility.log("Thread " + nThreadID + " is over!"); )*N]Q  
bDownOver = true; oB8u[!  
//nPos = fileAccessI.write (b,0,nRead); iXtar;%  
} B8z3W9  
catch(Exception e){e.printStackTrace ();} ,u|vpN  
} U/E M(y  
} S?nXpYr  
uzL)qH$b  
#_{3W-35*  
//打印回应的头信息 HK>!%t0S  
public void logResponseHead(HttpURLConnection con) w">XI)*z  
{ <5MnF  
for(int i=1;;i++) `,ZsKxI  
{ M xUj7ae  
String header=con.getHeaderFieldKey(i); %-?HC
jT  
if(header!=null) ppIMaP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I9Af\ k|^  
Utility.log(header+" : "+con.getHeaderField(header)); 7g3vh%G.  
else msS5"Qr  
break; @giipF2$  
} aG QC  
} uArs[e|f  
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[gFpFz|b<  
public void splitterStop() W0eb9g`s  
{ -Cv:lJj  
bStop = true; g*Nc+W](P>  
} t{tcy$bw  
9mkt.>$  
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} HjKj.f
V  
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/* {ScilT  
**FileAccess.java 1HxE0>  
*//文件访问(定位，写) j}Lt"r2F  
package NetFox; |xyN#wi  
import java.io.*; JnH>L|G{;%  
B*E:?4(<P  
s%"3F<\  
public class FileAccessI implements Serializable{ #\1;d8h  
oqOv"yLJ:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |lAu6d !  
RandomAccessFile oSavedFile; r>4.{\C  
long nPos; A1x?_S"a  
<*0^X%Vf\  
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public FileAccessI() throws IOException fk,[`n+  
{  .BJ;
}  
this("",0); ac6Lv}w_  
} =ZjF5,@  
x3O$eKy\|5  
8r(S=dA  
public FileAccessI(String sName,long nPos) throws IOException DSad[>Uj],  
{ K.G}*uy  
oSavedFile = new RandomAccessFile(sName,"rw"); F`-|@k  
this.nPos = nPos; w;}pebL:  
oSavedFile.seek(nPos); Q~<$'j  
} eZR{M\Q  

w
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 UN[rW0*  
public synchronized int write(byte[] b,int nStart,int nLen) "jly[M}C  
{ 5$0@f`sj  
int n = -1; |=2E?&%?  
try{ MHmaut#  
oSavedFile.write(b,nStart,nLen); vs;T}'O  
n = nLen; |H 0+.f;  
} Bh?K_{
e  
catch(IOException e) i6M_Gk}  
{ Au,xIe!t
 
e.printStackTrace (); j@$p(P$  
} cx M=#Go  
dQLR%i#P8  
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return n; |k3ZdM  
} ;=>4 '$8  
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} !Vl>?U?AN  
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5CH9m[S
 
/* #jn6DL@[{  
**SiteInfoBean.java Lw<?e;  
*/ ]}H;`H  
package NetFox; 4
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<<!XWV*m  
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public class SiteInfoBean { z(L
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[3h~y7  
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private String sSiteURL; //Site's URL +"rZ<i  
private String sFilePath; //Saved File's Path LM}0QL m?  
private String sFileName; //Saved File's Name *&{M,  
private int nSplitter; //Count of Splited Downloading File eU?SLIof[{  
H~JPsS;  
91|=D \8aE  
public SiteInfoBean() _!6~o>  
{//nSplitter的缺省值为5 OnFx8r:q@%  
//default value of nSplitter is 5 AHX_I  
this("","","",5); 4HEp}Y"}V  
} VE1 B"s</  
RGh`=D/yE  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F }l_=  
{ Kg^L 4Q  
sSiteURL= sURL; m~ :W$x1+  
sFilePath = sPath; tep_g4CQR_  
sFileName = sName; X+"8yZz3?  
this.nSplitter = nSpiltter; v+dt1;  
(%]&Pe]  
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} i~:FlW]  
.n1]Yk;,1  
!~PLW]Z4  
public String getSSiteURL() 1^rODfY0  
{ .PBma/w W  
return sSiteURL; BtDi$d%'  
} sr,8zKM)  
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}T{!P+6  
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public void setSSiteURL(String value) h3Kv0^{  
{ r!+-"hS!  
sSiteURL = value; `r;e\Cp  
} U WYLT-^x  
u|h>z|4lJj  
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public String getSFilePath() ];bB7+  
{ cU7 c}?J<  
return sFilePath; mwLp~z%OX  
} Kt3/C'zu  
*L>gZ`Q  
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public void setSFilePath(String value) NMb`d0;(  
{ A;Rr#q<  
sFilePath = value; oW3{&vfz  
} E`%Ewt$Z  
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public String getSFileName()
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{ d54(6N%  
return sFileName; >Z ZX]#=I  
} 0kP,Z
j<  
{#YGor|  
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public void setSFileName(String value) VKRj 1LXz  
{ kK+<n8R2  
sFileName = value; oyV@BHJO@  
} xgP/BK2"  
44axOk!G[/  
TIlBT{A<  
public int getNSplitter() 6( TG/J  
{ <*u[<  
return nSplitter; &scHyt  
} Qk?;nF  
(5S(CYls  
p\5DW'  
public void setNSplitter(int nCount) O@St^o*A}  
{ 4RYK9=NH  
nSplitter = nCount; ~9#[\/;"  
} 9Cbf[\J!bq  
} aLapb5VV  
l%]S7|PKx  
;7CE{/Bq.p  
/* D/C,Q|Ya6  
**Utility.java y1P KoN|K  
*/ `iuo([E d  
package NetFox; }ybveZxv5A  
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m'H%O-h\  
public class Utility { v7"' ^sZ?  
qXO@FW]  
@WVpDhG  
public Utility() sLh9=Kh`  
{ BhC.#u/   
++ !BSQ e  
)HWf`;VQ  
} @mM'V5
_#  
xv;'27mUt  
//线程睡眠 7kapa
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public static void sleep(int nSecond) <wV?B9j  
{ ]F kLtq  
try{ Ym IVtQ  
Thread.sleep(nSecond); J{c-'Of2yi  
} `[x`#irD  
catch(Exception e) iDej{95  
{ xKIzEN &  
e.printStackTrace (); "F%w{bf  
} _hlLM,p  
} @#[<5ld  
tpp.
9  
//日志 =9@{U2 =l  
public static void log(String sMsg) 3n-~+2l  
{ 9fR`un)f}  
System.err.println(sMsg); 3}{od$3G  
} V"=(I'X
 
3>%oGbo  
4kZX$ct}  
public static void log(int sMsg) f,{O%*PUA  
{ h ,;f6  
System.err.println(sMsg); ?h)Z ;,}  
} v:0.  
} ~_^#/BnAl  
k fS44NV  
`0a=A#]1o  
/* /Zs;dam  
**TestMethod.java 1s5FjD?M  
*/ lJHV c"*/  
package NetFox; WO{V,<;  
hd*bPj;  
Cisv**9  
public class TestMethod { $oKT-G  
<RzGxhT  
b z3&  
public TestMethod() `BA wef  
{ ///xx/weblogic60b2_win.exe K cI'P(
 
try{ E
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T0Lh"_X3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JD1IL` ta;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9AQMB1D*v4  
fileFetch.start(); LlAMtw"  
} 'lwLe3.c  
catch(Exception e){e.printStackTrace ();} ];X[xs  
F!m/n!YR  
0c*y~hUVZ  
} RzG7Xr=t  
Z9rmlVU6!  
\%Wu`SlDp9  
public static void main(String[] args) 5&V0(LT]C  
{ R7YLI1ov  
new TestMethod(); /.!ytHw8  
} o'nju.'  
} _ZUtQ49  
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