http断点续传简单实现（java)

/* !n;3jAl&$  
**SiteFileFetch.java d%I7OBBx@
 
*/ `Hw][qy#  
package NetFox; Q&0`(okb  
import java.io.*; nP[Z6h  
import java.net.*; |fyzb=Lg  
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public class SiteFileFetch extends Thread { GPni%P#a@0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3XB`|\:  
long[] nStartPos; //开始位置 aoz+Th3  
long[] nEndPos; //结束位置 Syseiw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]i075bO/  
long nFileLength; //文件长度 |11vm
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boolean bFirst = true; //是否第一次取文件 )a0l:jEOc  
boolean bStop = false; //停止标志 i`52tH y_  
File tmpFile; //文件下载的临时信息 '0~?zP  
DataOutputStream output; //输出到文件的输出流 u`wD6&y*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /":/DwI'  
public SiteFileFetch(SiteInfoBean bean) throws IOException "c} en[  
{ &u^]YE{  
siteInfoBean = bean; Id^q!4Th9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s)E8}-v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wEq&O|Vj  
if(tmpFile.exists ()) q|%+?j(  
{ 8&HBR #  
bFirst = false; ]#DCO8Vk  
read_nPos(); 3]'ab-,Vp  
} U/PNEGuQ  
else uv-O`)  
{ 1P"{TMd?  
nStartPos = new long[bean.getNSplitter()]; 8ZbXGQ  
nEndPos = new long[bean.getNSplitter()]; WJ-.?   
} Q=%W-  
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} bBc<p{
  
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public void run() k4<28  
{ ChUE,)  
//获得文件长度 M`q|GY  
//分割文件 >WZbbd-  
//实例FileSplitterFetch 4x-,l1NMR  
//启动FileSplitterFetch线程 :4 z\Q]  
//等待子线程返回 9XQE5^  
try{ un!v1g9O  
if(bFirst) oLR/\Y(  
{ S?`0,F  
nFileLength = getFileSize(); t\QLj&h}E  
if(nFileLength == -1) {E(2.'d  
{ _3%:m||,XP  
System.err.println("File Length is not known!"); NBasf n  
} ~a3u['B  
else if(nFileLength == -2) RFS}!_t+|  
{ GTfM
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System.err.println("File is not access!"); 2brY\c
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} *)B \M>  
else =$bF[3D  
{ i" u|119  
for(int i=0;i<nStartPos.length;i++) [~|k;\2 +  
{ [S]q'c)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); UMNNAX  
} _~CJitR3  
for(int i=0;i<nEndPos.length-1;i++) }m?Ut|  
{ SfPQ;s'  
nEndPos = nStartPos[i+1]; ;aD~1;q  
} 5QXU"kWH  
nEndPos[nEndPos.length-1] = nFileLength; 7;'UC','  
} l}-k>fug  
} D?S|]]Y!q  
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//启动子线程 [bo"!Qk%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2<n18-|OQ  
for(int i=0;i<nStartPos.length;i++) Si~wig2  
{ "#0P
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?Q=(?yR0]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <bCB-lG*Kb  
nStartPos,nEndPos,i); #WG;p(?:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r^"sZk#  
fileSplitterFetch.start(); AriV4 +  
} G] tT=X[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W2$rC5|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z \ @9*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k)F!gV#  
nEndPos = " + nFileLength); 9dszn^]T  
// fileSplitterFetch[nPos.length-1].start(); Xu_1r8-|=b  
}mZCQJ#`  
n 78!]O  
//等待子线程结束 ;{iTSsb  
//int count = 0; /#_[{lSr?  
//是否结束while循环 $`0^E#Nl  
boolean breakWhile = false; d1^5r 31  
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h;} fdk  
while(!bStop) AoxORPp'  
{ !m_y@~pV#u  
write_nPos(); Z *l&<q>#  
Utility.sleep(500); r_'];  
breakWhile = true; J$jLGy&'  
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for(int i=0;i<nStartPos.length;i++) v,rKuvc'  
{ 0_^3 |n  
if(!fileSplitterFetch.bDownOver) Gh{9nM_\"  
{ 1Nv qtVC  
breakWhile = false; Y3)*MqZlF  
break; @Y9tkJIt  
} \)MzUOZn  
} %3HF_DNOY=  
if(breakWhile) ]nxSVKE4p  
break; ESS1 L$y  
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yzNDXA.  
//count++; FB~IO#E8W  
//if(count>4) R\6dvd  
// siteStop(); 7.yCs[Z  
} ;Q5o38(  
1yc$b+TH  
3?&P^{  
System.err.println("文件下载结束！"); X4bZ4U*  
} b^P
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catch(Exception e){e.printStackTrace ();} qs (L2'7/  
} yyVE%e5nl  
\
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G$lE0_j2{  
//获得文件长度 [&p/7  
public long getFileSize() S)^eHuXPI  
{ wFL7JwK:G  
int nFileLength = -1; 3HndE~_C&  
try{ 6ZC~q=my  
URL url = new URL(siteInfoBean.getSSiteURL()); 17ynFHMd,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T'14OU2N{Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q6PMRG}/o  
//
}KWz  
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int responseCode=httpConnection.getResponseCode(); AT"!Ys|  
if(responseCode>=400) l]5!$N*  
{ TzV~I\a|  
processErrorCode(responseCode); +Jq~39  
return -2; //-2 represent access is error JZ"XrS0?  
} @p9YHLxLjQ  
+tv"j;z  
u< 5{H='6  
String sHeader; ]7%+SH,RdD  
212  
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for(int i=1;;i++) V_H0z  
{ g;</|Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D{iPsH6};5  
//Utility.log(in.readLine()); q>dERN&  
sHeader=httpConnection.getHeaderFieldKey(i); $7&t`E)qY  
if(sHeader!=null) A@ 4Oq  
{ h8?E+0  
if(sHeader.equals("Content-Length")) _!E/em  
{ 2@$`xPg   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o<i\1<eI  
break; JcI~8;Z@Z~  
} [!>DQE  
} 9{n?Jy  
else Te&5IB-  
break; } !RBH(m%  
} fdzaM&  
} HT=-mwa_]  
catch(IOException e){e.printStackTrace ();} |C.[eHe&D  
catch(Exception e){e.printStackTrace ();} !1ZrS  
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Utility.log(nFileLength); Nd61ns(N  
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return nFileLength; b
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} K._* ~-A  
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//保存下载信息（文件指针位置） k5]`:k6  
private void write_nPos() 8d*W7>rq  
{ KPMId`kf  
try{ ])uhm)U@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cr<ty"3\  
output.writeInt(nStartPos.length); )0p7d:%mV  
for(int i=0;i<nStartPos.length;i++) qB44;!(  
{ f%5 s8)  
// output.writeLong(nPos); Ob>M]udn  
output.writeLong(fileSplitterFetch.nStartPos); oV Hh  
output.writeLong(fileSplitterFetch.nEndPos); $mq@g  
} }KCb5_MDF  
output.close(); 3pk`&'  
} w.6Gp;O  
catch(IOException e){e.printStackTrace ();} i*-L_!cc:  
catch(Exception e){e.printStackTrace ();} GtSvb6UNn  
} >,s.!
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//读取保存的下载信息（文件指针位置） tWN hFQ'  
private void read_nPos() 1pT-PO3=  
{ 3ZEV*=+T5  
try{ ;&v~tD7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p!]$!qHO(  
int nCount = input.readInt(); &mJ +#vT  
nStartPos = new long[nCount]; Zn]njf1x  
nEndPos = new long[nCount]; xesZ7{ o  
for(int i=0;i<nStartPos.length;i++) }E%#g#  
{ mzkv/  
nStartPos = input.readLong(); //_aIp  
nEndPos = input.readLong(); vOKWi:-U  
} /degBL+  
input.close(); =A< Fcl\Rz  
} &>]c"?C*  
catch(IOException e){e.printStackTrace ();} '**dD2 n  
catch(Exception e){e.printStackTrace ();} +>uiI
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} _R 6+bB$  
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private void processErrorCode(int nErrorCode) v3`k?jAaI  
{ g*& |Eq/  
System.err.println("Error Code : " + nErrorCode); >m-VBo  
} ZWH9E.uj  
:4V8Iz 71  
qij<XNZU"&  
//停止文件下载 5UgxuuP4  
public void siteStop() 1K`7  
{ |pA  
bStop = true; N#Y|MfLc  
for(int i=0;i<nStartPos.length;i++) g]V_)}
 
fileSplitterFetch.splitterStop(); 5
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} @3Lh/&  
} fUg<+|v*  
//负责部分文件的抓取 RiPxz=kr  
**FileSplitterFetch.java hN5?u:  
*/ [K=M;$iQ  
package NetFox; oE
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a At<36{?  
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import java.io.*; s IE2a0+  
import java.net.*; ,DZoE~  
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public class FileSplitterFetch extends Thread { <Pm!#)-g9  
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1
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String sURL; //File URL 0'QX*xfa>  
long nStartPos; //File Snippet Start Position C+m%_6<  
long nEndPos; //File Snippet End Position V4
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int nThreadID; //Thread's ID /FthT  
boolean bDownOver = false; //Downing is over GGQ%/i]:  
boolean bStop = false; //Stop identical 6/5Xy69:h  
FileAccessI fileAccessI = null; //File Access interface z]%c6ty  
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_ g8CvH)?!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V'q?+p] a  
{ ixY[ HDPq  
this.sURL = sURL; iCtDV5  
this.nStartPos = nStart; (6crWw{3  
this.nEndPos = nEnd; ?]AF? 0/  
nThreadID = id; j6:jN-z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [2P6XoI#  
} }`~n$OVx  
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public void run() YZk.{#^c  
{ Ab In\,x  
while(nStartPos < nEndPos && !bStop) rQD^O4j R  
{ N`HiNb [  
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try{ bgYUsc*uR  
URL url = new URL(sURL); 3oOr*N3R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CUN1.i<pk8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z0[d;m*  
String sProperty = "bytes="+nStartPos+"-"; }0IeKpu5  
httpConnection.setRequestProperty("RANGE",sProperty); E1`TQA  
Utility.log(sProperty); EeR}34  
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!(HPx@_  
InputStream input = httpConnection.getInputStream(); O.DO,]Uh  
//logResponseHead(httpConnection); w>o/)TTJL  
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byte[] b = new byte[1024]; :8`~dj.  
int nRead; fC".K Yjp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -wT!g;v;%  
{ [MuZ^'dR  
nStartPos += fileAccessI.write(b,0,nRead); jV[;e15+  
//if(nThreadID == 1) }xry
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .8->n aj|  
} }K5okxio  
:(\JY?+w  
L~%7=]m  
Utility.log("Thread " + nThreadID + " is over!");  wX5q=I  
bDownOver = true; \wDL oR  
//nPos = fileAccessI.write (b,0,nRead); CBv0fQtL  
} T%;V_iW-  
catch(Exception e){e.printStackTrace ();} {-lpYD^k3  
} mITNx^p4f  
} ^|SiqE  
:}yT?LIyP  
9;'#,b*(  
//打印回应的头信息 hbg$u$1`,  
public void logResponseHead(HttpURLConnection con) aL_/2/@X8  
{ L
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for(int i=1;;i++) [}M!ez  
{ F}7sb#G  
String header=con.getHeaderFieldKey(i); cS'{h  
if(header!=null) \+#EO%sN1%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Aj|->Y  
Utility.log(header+" : "+con.getHeaderField(header)); vJaWHC$q  
else A.Wf6o  
break; <gFa@at  
} FuBt`H  
} p0WUF\"  
+]nIr'V  
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public void splitterStop() :09NZ !!  
{ *V%"q|L8  
bStop = true; '.1P\>x!]  
} &hO-6(^I  
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} =`QYy-b X  
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/* `VKFA<T  
**FileAccess.java -dixiJ
=  
*//文件访问(定位，写) UuWIT3W>%  
package NetFox; 1oej<67PdJ  
import java.io.*; y\Aa;pL)RQ  
?!P0UTe~  
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public class FileAccessI implements Serializable{ Q?i_Nl/|  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5[jcw`  
RandomAccessFile oSavedFile; bRx
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long nPos; UHZ&7jfl  
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public FileAccessI() throws IOException s#s">hMrI  
{ bgi_QB#k\  
this("",0); &))d],t
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} (N9-YP?qm  
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public FileAccessI(String sName,long nPos) throws IOException ed,A'S=d  
{ 8OZj24*'DS  
oSavedFile = new RandomAccessFile(sName,"rw"); HDHG~<s  
this.nPos = nPos; &u2;S?7m  
oSavedFile.seek(nPos);
7#R)+  
} $xWwI(SaB  
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public synchronized int write(byte[] b,int nStart,int nLen) e_=K0fFz  
{ X<L=*r^C,=  
int n = -1; e'K~WNT  
try{
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oSavedFile.write(b,nStart,nLen); ..}P$
 
n = nLen; xsH1)  
} .^wpfS  
catch(IOException e) |{N{VK  
{ :0r,.)  
e.printStackTrace (); [./FzlAs  
} 2`4m"DtA  
]{1{XIF  
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return n; pa
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} D~C'1C&W  
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} q^aDZzx,z  
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/* A8m06  
**SiteInfoBean.java ok\-IU?  
*/ Xq135/d  
package NetFox; .ck?JXg  
E.K^v/dNdq  
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public class SiteInfoBean { XKWq{,Ks  
P{o)Ir8Tt  
tpJA~!mG3  
private String sSiteURL; //Site's URL ]E/0iM5  
private String sFilePath; //Saved File's Path _*o<<C\E  
private String sFileName; //Saved File's Name :H]d1  
private int nSplitter; //Count of Splited Downloading File Lwl1ta-  
]hS:0QE  
,6>3aD1w~q  
public SiteInfoBean() k6bct@7  
{//nSplitter的缺省值为5 h&'|^;FM  
//default value of nSplitter is 5 Z}S[
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this("","","",5); _LaG%* R6  
} Tx.N#,T|  
e8vy29\S  
 vD#U+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V?Jy
 
{ v5M4Rs&t  
sSiteURL= sURL; T~E;@weR  
sFilePath = sPath; <wSJK  
sFileName = sName; &Gt{9#  
this.nSplitter = nSpiltter; bWo  
:+"4_f0  
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} W:i Q&[f  
>kQp@r\nQ  
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public String getSSiteURL() o ]*yI[\  
{ PLz{EQ[cV  
return sSiteURL; }+!"mJx@  
} FDl/7P`b(  
4;YP\{u  
|Y!^E %*  
public void setSSiteURL(String value) q9
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{ A;d@NOI#,K  
sSiteURL = value;  :tZsSK  
} g4^-B  
s&E,$|80  
|m-N5
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public String getSFilePath() Iy_5k8]  
{ )|=1;L  
return sFilePath; WXxnOLJr  
} @{@b^tk  
VrW]|jIu*  
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public void setSFilePath(String value) 9y7hJib  
{ HB )+.e  
sFilePath = value; qXtC7uNj$  
} Kz;Ar&^`N  
%i?  
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public String getSFileName() +j: &_  
{ _EMXx4J  
return sFileName; yM 7{v$X0  
} <7y/)b@  
{U-
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46vC/  
public void setSFileName(String value) #eYYu2ND  
{ D<v< :  
sFileName = value; &7'=t6  
} 1R_@C.I  
| K|AUI  
2+u+9rW  
public int getNSplitter() -)%\$z  
{ r Hq1%)B  
return nSplitter; G739
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}
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public void setNSplitter(int nCount) #_\**%,<  
{ 2L^/\!V#  
nSplitter = nCount; zecM|S_  
} ]pNM~,  
} Z3o HOy  
qh bagw~  
7/&taw%i  
/* v$`3}<3-  
**Utility.java xe OfofC(l  
*/ HziQ%QR  
package NetFox; y<gRl/e  
 l  
1$))@K-I  
public class Utility { e]1)_;b*  
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public Utility() &%3}'&EBv  
{ uYFy4E3  
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} O&CY9 2)Lk  
E08!
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//线程睡眠 FBi&MZ`  
public static void sleep(int nSecond) *` -  
{ O?#<kmd/)  
try{ {JQV~rfh`  
Thread.sleep(nSecond); SP=8v0  
} J{;\TNkJ  
catch(Exception e) d<]eJ{  
{ nKwOSGPQt  
e.printStackTrace (); 2zsDb'r  
} )CH\]>-FO  
} t:'^pYN:g  
!{r@ H+Kf  
//日志 0 4ceDe  
public static void log(String sMsg) T~lHm  
{ >U:.5Tch'V  
System.err.println(sMsg); Q:b>1  
} gfXit$s  
6 #jpA.;  
[r1\FF@v,  
public static void log(int sMsg) A
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{ St3/mDtH  
System.err.println(sMsg); 78'3&,+si  
} |dqAT.  
} .P!pC  
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/a-OBU  
/* ;3O=
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**TestMethod.java om0g'Qa  
*/ O=}jg0k  
package NetFox; /pgn?e'lk  
mm`yu$9gbP  
3AC/;WB9  
public class TestMethod { tb'O:/  
&Y8S! W@4  
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public TestMethod() K1|xatx1V  
{ ///xx/weblogic60b2_win.exe `yua?n  
try{ AI*1kxR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Cq%1j[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }Lb[`H,}A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /-C6I:  
fileFetch.start(); )tR@\G>%  
} A:Kit_A  
catch(Exception e){e.printStackTrace ();} CW;=q[+
w  
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} -x0u}I  
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public static void main(String[] args) L[.RV*sL  
{ S,2{^X  
new TestMethod(); x`gsD3C  
} 2:Q2w3Xe  
} T!Eyq,]  
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