http断点续传简单实现（java)

/* '
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**SiteFileFetch.java l%O-c}X  
*/ gYZgo  
package NetFox; jdzV&  
import java.io.*; 8~bPoWP  
import java.net.*; Vl%
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public class SiteFileFetch extends Thread { @9L9c  
/\.kH62  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >;Bhl|r~z  
long[] nStartPos; //开始位置 fHiCuF  
long[] nEndPos; //结束位置 H0S7k`.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hH\(>4l  
long nFileLength; //文件长度 2;3q](d   
boolean bFirst = true; //是否第一次取文件 :5(TOF  
boolean bStop = false; //停止标志 `u-}E9{  
File tmpFile; //文件下载的临时信息 8CL05:&  
DataOutputStream output; //输出到文件的输出流 <5.{+!BM  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;4 &~i
 
public SiteFileFetch(SiteInfoBean bean) throws IOException (]JJ?aAF  
{ p81~Lk*Hz@  
siteInfoBean = bean; ;pNfdII(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B3D4fYQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P_;oSN|>  
if(tmpFile.exists ()) &sW/r::,  
{ zAH+{4lC+  
bFirst = false; ;RrfE8mGj  
read_nPos(); c}Qc2D3*  
} |(/"IS]  
else V3-LVgM%  
{ mb#)w`<  
nStartPos = new long[bean.getNSplitter()]; 67e1Y@Xu  
nEndPos = new long[bean.getNSplitter()]; i-Z@6\/a5  
} \6N\6=t!A  
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} H;^6%HV1  
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public void run() Nb$)YMbA  
{ Mfgd;FsX#  
//获得文件长度 U{ Y)\hR-  
//分割文件 GVg0)}  
//实例FileSplitterFetch h_cZ&P|  
//启动FileSplitterFetch线程 t+&WsCN  
//等待子线程返回 KT8Fn+  
try{ }/=VnCfU  
if(bFirst) {U4%aoBd8  
{ ^PDa  
nFileLength = getFileSize(); Z6Mh`:7  
if(nFileLength == -1) eVy,7goh  
{ 8T%z{A1T  
System.err.println("File Length is not known!"); m1
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} L.8-nTg"y  
else if(nFileLength == -2) $GcVC (]  
{ AttDD{Ta  
System.err.println("File is not access!"); WUHijHo5(8  
} G6I>Ry[2?  
else ^rx]Y;  
{
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for(int i=0;i<nStartPos.length;i++) LOp<c<+aW  
{ {AB0 PM;-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SL*B `P~{  
} fFsA[@5tul  
for(int i=0;i<nEndPos.length-1;i++) FzNs >*  
{ )O_Y(^+ $  
nEndPos = nStartPos[i+1]; wp} PQw:  
} +4)Kc9S#  
nEndPos[nEndPos.length-1] = nFileLength; ,l~i|_  
} %POoyH@D}  
} rtOXK4)]I  

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EKgTRRW  
//启动子线程 8)T.[AP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +}%4]O;  
for(int i=0;i<nStartPos.length;i++) LA1UD+S  
{ ,%Dn}mWu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1{_;`V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kvKbl;<&#  
nStartPos,nEndPos,i); zU]95I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6tj
+  
fileSplitterFetch.start(); WOquG  
} 
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NKh8'=S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /JJU-A(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OTSbhI'v  
nEndPos = " + nFileLength); { "=d7i  
// fileSplitterFetch[nPos.length-1].start(); [$f  
'9*(4/,UJJ  
p"3_u;cN  
//等待子线程结束 jgbE@IA@!'  
//int count = 0; |h4aJv  
//是否结束while循环 !bRoNP  
boolean breakWhile = false; oF8#gn_  
|cUTP!iy  
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while(!bStop) \= =rdW-  
{ 1UT&kD!si  
write_nPos(); v?vm-e  
Utility.sleep(500); { LZ` _1D  
breakWhile = true; 6O>NDTd%  
#Fm,mO$v  
V]&0"HX2r!  
for(int i=0;i<nStartPos.length;i++) }\?UmuolQ  
{ EA) K"C  
if(!fileSplitterFetch.bDownOver) rI23e[  
{ N D`?T &PK  
breakWhile = false; V'alzw7#  
break; uI lm!*0  
} l=4lhFG,Mk  
} qD!qSM  
if(breakWhile) M5\$+Tu  
break; p^J=*jm)x  
:k&R]bc9  
hc#Sy:T>  
//count++; -9)H[}.  
//if(count>4) ;xqN#mqq  
// siteStop(); dA03,s  
} .!
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System.err.println("文件下载结束！"); Z/G`8|A  
} ykMdH:  
catch(Exception e){e.printStackTrace ();} J> Z.2  
} UmEc")3  
:LrB9Cf$n  
{wJ8% ;Z7  
//获得文件长度 "($"T v2  
public long getFileSize() r&rip^40  
{ e)BU6m%  
int nFileLength = -1; +YD_ L  
try{ XiW~? *Z  
URL url = new URL(siteInfoBean.getSSiteURL()); \Dlmrke  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VPi*9(LS  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^jYE4gHM  
o{[w6^D7  
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int responseCode=httpConnection.getResponseCode(); (baBi9<P=  
if(responseCode>=400) [%LIW%t|  
{ X:2)C-l?  
processErrorCode(responseCode); P!xN]or]u  
return -2; //-2 represent access is error ZVIlVuZ}  
} XP%/*a
m  
_ci8!PP  
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String sHeader; \p.eY)>  
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for(int i=1;;i++) @V=HY  
{ R1?LB"aN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q=x1:^rVH  
//Utility.log(in.readLine()); :meq4!g{1  
sHeader=httpConnection.getHeaderFieldKey(i); Vw";< <0HZ  
if(sHeader!=null) ?s]+2Tq  
{ M$Or|HT
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if(sHeader.equals("Content-Length")) @:w[(K[^b/  
{ _z6" C8W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )(V!& w6  
break; v43FU3  
} Y^2]*e%  
} -izZ D  
else ana?;NvC  
break; $:IEpV{  
} tB#-}Gf  
} +`&-xq76  
catch(IOException e){e.printStackTrace ();} :9]"4ktoJ  
catch(Exception e){e.printStackTrace ();} =z4kK_?F,  
<G60R^o  

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Utility.log(nFileLength); lG R6S  
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return nFileLength; _ipY;  
} O Ce;8^  
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q~6((pWi|  
//保存下载信息（文件指针位置） eUEO~M2&U{  
private void write_nPos() &XZS}n  
{ vj4n=F,Z  
try{ 6R';[um?q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IHStN,QD  
output.writeInt(nStartPos.length); |z]--h  
for(int i=0;i<nStartPos.length;i++) 6rg?0\A<  
{ Av"^uevfs  
// output.writeLong(nPos); .vk|aIG  
output.writeLong(fileSplitterFetch.nStartPos); * vW#XDx  
output.writeLong(fileSplitterFetch.nEndPos);  "?(N  
} -Gn0TA2/C  
output.close(); RqE|h6/  
} 4pC.mRu 0  
catch(IOException e){e.printStackTrace ();} Nlk'  
catch(Exception e){e.printStackTrace ();} e{fm7Cc)D  
} tZqy \_G  
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//读取保存的下载信息（文件指针位置） 3PgiV%]  
private void read_nPos() s6.#uT7h  
{ 8}<4f|?  
try{ 3|9 U`@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z
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int nCount = input.readInt(); k.("<)  
nStartPos = new long[nCount]; _5JwJcQ  
nEndPos = new long[nCount]; 0VBbSn}Z<  
for(int i=0;i<nStartPos.length;i++) g}Esj"7  
{ ^*A8 NdaB  
nStartPos = input.readLong(); 'v:%} qMv  
nEndPos = input.readLong(); WC *e#QP  
} :qL1jnR^  
input.close(); i_kKE+Q  
} b$k|D)_|  
catch(IOException e){e.printStackTrace ();} ^oT!%"\  
catch(Exception e){e.printStackTrace ();} Qkq9
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} j@4AY}[tX  
@EV*QC2l;Y  
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private void processErrorCode(int nErrorCode) i |IG  
{ <C6*-j1oz  
System.err.println("Error Code : " + nErrorCode); *D6X&Hg&5  
} l\%LT{$e  
8fX<,*#I  
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//停止文件下载 ic]b"ItD  
public void siteStop() kjVJ!R\  
{ @Wb_Sz4`  
bStop = true; eg$y,Tx  
for(int i=0;i<nStartPos.length;i++) jDwLzvMO  
fileSplitterFetch.splitterStop(); <JNiW8 PG  
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} z6+D=<  
} rjLPX  
//负责部分文件的抓取 1{pU:/_W  
**FileSplitterFetch.java j|/4V  
*/ H$o=kQN  
package NetFox; KqNbIw*sR  
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4>I >y@^  
import java.io.*; K,'v{wSr  
import java.net.*; dW`!/OaQD  
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public class FileSplitterFetch extends Thread { eKw!%97>  
d$}z,~sN  
  iE8  
String sURL; //File URL THl={,Rw`  
long nStartPos; //File Snippet Start Position ?0%3~E`l:  
long nEndPos; //File Snippet End Position ~aZy52H_#.  
int nThreadID; //Thread's ID 8M,AFZ>F  
boolean bDownOver = false; //Downing is over X
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boolean bStop = false; //Stop identical eGF+@)K1"  
FileAccessI fileAccessI = null; //File Access interface X{YY)}^  
:
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iXsX@ S^F  
{ xB<^ar  
this.sURL = sURL; W7PL]5y&  
this.nStartPos = nStart; f}%paE"  
this.nEndPos = nEnd; EpsjaOmAF  
nThreadID = id; G9 g -EP\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b$W~w*O  
} XGCjB{IV  
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;ifPqLkO  
public void run() wdo(K.m  
{ \fD)|  
while(nStartPos < nEndPos && !bStop) :H(wW   
{ FOS5?%J  
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try{ mNk@WY_F  
URL url = new URL(sURL); 1&.q#,EMn(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f'WRszrF  
httpConnection.setRequestProperty("User-Agent","NetFox"); V<&^zIJUR  
String sProperty = "bytes="+nStartPos+"-"; =73aME}  
httpConnection.setRequestProperty("RANGE",sProperty); E3"j7y[S  
Utility.log(sProperty); kIwq%c;  
w =2; QJ<  
\WPy9kRU  
InputStream input = httpConnection.getInputStream(); #i'wDvhol  
//logResponseHead(httpConnection); <To$Hb,NP  
%)#yMMhR  
F"| ;  
byte[] b = new byte[1024]; /)*si  
int nRead; \f-@L;8#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wvcj*{7[  
{ U)6Ew4uRxV  
nStartPos += fileAccessI.write(b,0,nRead); [O@U@bD9  
//if(nThreadID == 1) EL^j}P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U9Gg#M4tY  
} 's\rQ-TV  
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Utility.log("Thread " + nThreadID + " is over!"); oEJxey]B7  
bDownOver = true; o\
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//nPos = fileAccessI.write (b,0,nRead); [5;_XMj%  
} 2= )V"lR\  
catch(Exception e){e.printStackTrace ();} R+5yyk\  
} ?W\KIp\Kn  
} -?L3"rxAP  
#Fckev4  
*]>~lO1  
//打印回应的头信息 4&<zkAMR  
public void logResponseHead(HttpURLConnection con)
#SR )tU  
{ 1B`JvNtd  
for(int i=1;;i++) tpQ
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{ c?}{>ig/)  
String header=con.getHeaderFieldKey(i); H8A=]Gq  
if(header!=null) "Z#MR`;&29  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M
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Utility.log(header+" : "+con.getHeaderField(header)); F#Bi*YY  
else B*^8kc:)L  
break; *qKf!&  
} 'e*:eBoyb  
} "u3 N9  
^:2>I$
 
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public void splitterStop() @#::C@V]  
{ A&C?|M?M  
bStop = true; q]DE\*@  
} =`t%p1   
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} 7,ffY/  
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_))--+cL  
/* bkL5srH  
**FileAccess.java fYzZW  
*//文件访问(定位，写) aq$adPtu  
package NetFox; .]BJM?9  
import java.io.*; }O8#4-E_Ji  
YA@OA$`E  
cp5  
public class FileAccessI implements Serializable{ gg QI  
h9j/mUwV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "kkZK=}Nv  
RandomAccessFile oSavedFile; Q*caX   
long nPos; vDVE#Nm_  
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5#$5ct  
public FileAccessI() throws IOException qb$f,E[  
{ k?ksv+e\
 
this("",0); (C!33s1  
} -,}ppTG  
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public FileAccessI(String sName,long nPos) throws IOException e"6!0Py#*  
{ jl~?I*Gr  
oSavedFile = new RandomAccessFile(sName,"rw"); /]"2;e-s+  
this.nPos = nPos; kV3Zt@+  
oSavedFile.seek(nPos); %SD=3UK6  
} $_NP4V8|z/  
[";<YR7iRN  
1U< g  
public synchronized int write(byte[] b,int nStart,int nLen) FT.;}!"l  
{ ^PI8Bvs>j  
int n = -1; :s`\j
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try{ d}RR!i`<N  
oSavedFile.write(b,nStart,nLen); ({#M*=&"  
n = nLen; 6zJfsKf$  
} "1Oe bo2  
catch(IOException e) x"Q
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{ q+Cq&|4 ?2  
e.printStackTrace (); o$-!E(p  
} #Jqa_$\.  
6_h'0~3?`  

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return n; PK<+tIm\  
} qg#|1J6e  
{ |[n>k   
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} =vZF/r  
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/* t\
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**SiteInfoBean.java y}t1r |p  
*/ uWE :3  
package NetFox; vMB`TpZ  
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public class SiteInfoBean { z<c%Xl\$%  
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}hy, }2(8  
private String sSiteURL; //Site's URL _rU%DL?  
private String sFilePath; //Saved File's Path ')mR87  
private String sFileName; //Saved File's Name yhpeP  
private int nSplitter; //Count of Splited Downloading File K-CF5i:  
2)zAX"#
/  
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public SiteInfoBean() J*} warf&  
{//nSplitter的缺省值为5 @ysc?4% q  
//default value of nSplitter is 5 jJK`+J,i}X  
this("","","",5); 2/W5E-tn  
} gx',~  
R@8pKCL.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aF41?.s  
{ (:P-ef$]C  
sSiteURL= sURL; V|n}v?f_q  
sFilePath = sPath; k:qS'  
sFileName = sName; 4Lb!Au|Y  
this.nSplitter = nSpiltter; DQy<!Wb+  
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x<fF1];  
} ^.|P&f~  
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public String getSSiteURL() ODO'!T-  
{ D,l&^diz  
return sSiteURL; h7"c_=w+  
} nign"r  
r&/M')}?Lw  
.;$Ub[
  
public void setSSiteURL(String value) NtfzAz/  
{ f
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sSiteURL = value; E;tEmGf6F  
} Z)^1~
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+ ;LO|!  
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public String getSFilePath()
y9)w(y!  
{ m0Geq.  
return sFilePath; 6|G&d>G$_  
} VchI0KL?  
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!y\r.fm!A  
public void setSFilePath(String value) _@5|r|P>  
{ e=^^TX`I  
sFilePath = value; 1]A$  
} Fc6o6GyL|o  
@u @~gEt  
2rV]n  
public String getSFileName() 3%[;nhbA7  
{ +6`+Q2qi  
return sFileName; KcvstC`  
} xfa-  
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%b[>eIJU#  
public void setSFileName(String value) z?^oy.  
{ m{;j r<  
sFileName = value; yT~rql  
} l+a1`O  
RY
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public int getNSplitter() \$4 [qG=  
{ R4y]<8}  
return nSplitter; n_4 r'w  
} @ry/zG#  
>qz#&  
*4ido?  
public void setNSplitter(int nCount) H76iBJ66  
{ lrAhdi  
nSplitter = nCount; '451H3LC0  
}  k^Q.lb {  
} \xlG3nz  
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/* [j}JCmWY   
**Utility.java z2>LjM) #  
*/ 57~y
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package NetFox; 1<Sg@  
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public class Utility { |{&M#qXe  
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public Utility() M+0PEf.  
{ {vGJ}q?Sd"  
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} NNF"si\FE  
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//线程睡眠 #]x3
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public static void sleep(int nSecond) d)emTXB(  
{ |DV?5>>  
try{ .G8>UXX  
Thread.sleep(nSecond); +]s,VSL5`  
} p_h/hTi  
catch(Exception e) {$,\Qg  
{ ~%8P0AP  
e.printStackTrace (); |82q|@e  
} d?8OY  
} gLB(A\yG  
R7/S SuG6\  
//日志 Wk<fNHg  
public static void log(String sMsg) V6X )L>!xx  
{ VD$5 Djq  
System.err.println(sMsg); l[Z o,4*  
} BYB4-,  
V9
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_6nAxm&x`%  
public static void log(int sMsg) T@tsM|pI  
{ SvT0%2  
System.err.println(sMsg); 7a1o#O  
} lN#j%0MaUo  
} v-tI`Qpb  
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ryVYY>*(K  
/* :QGkYJ  
**TestMethod.java !?nO0Ao-$  
*/ 2%sZaM  
package NetFox; `qc"JB  
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public class TestMethod { rx2)uUbR  
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public TestMethod() gz~oQ l)zJ  
{ ///xx/weblogic60b2_win.exe J'}+0mln  
try{ ~HB#7+b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L5bq\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wa8jr5/k"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '#7k9\  
fileFetch.start();

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} qWhW4$7x  
catch(Exception e){e.printStackTrace ();} E7L>5z  
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}
::>|[ND  
/o9it;  
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public static void main(String[] args) `lY-/Ty  
{ ()|e xWW  
new TestMethod(); <W!T+sMQj  
}
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} l3u[  
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