http断点续传简单实现（java)

/* 2AK}D%jfc  
**SiteFileFetch.java Qlh?
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*/ J]\^QMX  
package NetFox; ^PQM;"  
import java.io.*; or.\)(m#(  
import java.net.*; B_&^ER5j  
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public class SiteFileFetch extends Thread { qZbHMTnT6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;)|nkI  
long[] nStartPos; //开始位置 dz,+tR~  
long[] nEndPos; //结束位置 jw4TLc7p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 OjATSmZ@@  
long nFileLength; //文件长度 FmI;lVF0j  
boolean bFirst = true; //是否第一次取文件 <kbnu7?a*  
boolean bStop = false; //停止标志 B5`;MQJ  
File tmpFile; //文件下载的临时信息 u){S$</  
DataOutputStream output; //输出到文件的输出流 %zflx~  
O
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?O7iK<5N  
public SiteFileFetch(SiteInfoBean bean) throws IOException @_Sp3nWdu  
{ ^ZVOql&  
siteInfoBean = bean; Yb9cW\lr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Zs73 a
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8A4TAT4,  
if(tmpFile.exists ()) rKIRNc#d  
{ 24X=5Aj  
bFirst = false; XtzOFx/  
read_nPos(); yHOqzq56  
} -TZ
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else "XB4yExy  
{ w%2ziwgh  
nStartPos = new long[bean.getNSplitter()]; UR,?!rJ^B  
nEndPos = new long[bean.getNSplitter()]; ^U{P3%uZ  
} ;@4sd%L8V  
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} 6sy,A~e  
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public void run() vv* |F  
{ l7~Pa0qD  
//获得文件长度 2Pz5f  
//分割文件 D6:DrA:  
//实例FileSplitterFetch kQ[Jo%YT?E  
//启动FileSplitterFetch线程 |Eu*P  
//等待子线程返回 &Ea"hd  
try{ W
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if(bFirst) R#LGFXUj  
{ i'iO H|s  
nFileLength = getFileSize(); #/s7\2  
if(nFileLength == -1) NfqJ=9  
{ Yx 3|G  
System.err.println("File Length is not known!"); /N%zwj/*  
} Hh\ 4MNl  
else if(nFileLength == -2) MYu`c[$jZ  
{ ydyG}XI
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System.err.println("File is not access!"); SctJxY(}!  
} 5Kee2s?*  
else Q[jI=$Q
)  
{ n{$}#NdV  
for(int i=0;i<nStartPos.length;i++) T
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{ =-
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); XD 5n]AL  
} OOfyGvs  
for(int i=0;i<nEndPos.length-1;i++) []=_<]{   
{ T;J7+0  
nEndPos = nStartPos[i+1]; $)f"K  
} i0b.AA  
nEndPos[nEndPos.length-1] = nFileLength; \#2 s4RCji  
} {dBB{.hX  
} ^8Z@^
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//启动子线程 jQ)L pjS1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U Q)!|@&  
for(int i=0;i<nStartPos.length;i++) R~$hWu}}  
{ &M$Bt} <  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F:S"gRKz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^?nP$+gq  
nStartPos,nEndPos,i); !*5_pGe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %6N)G!P  
fileSplitterFetch.start(); S7Znz@  
} blUY.{NN3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l\_x(BH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m^'~&!ba  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o:H'r7N  
nEndPos = " + nFileLength); 5 >'6
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// fileSplitterFetch[nPos.length-1].start(); ]I8]mUiUH  
NtqFnxm
/  
&jt02+Hj'  
//等待子线程结束 x ~wNO/  
//int count = 0; 3`xsK[  
//是否结束while循环 jmSt?M0.xV  
boolean breakWhile = false; #s*k| j}  
)=y.^@UT@  
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while(!bStop) K[*h+Y
O  
{ Shs')Zsbv  
write_nPos(); \zBd<H4S:  
Utility.sleep(500); ftxTX3X  
breakWhile = true; z}iSq$  
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for(int i=0;i<nStartPos.length;i++) 7&h\l6}Yh  
{ xC'mPcU8  
if(!fileSplitterFetch.bDownOver) q)vK`\Y  
{ )sRN
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breakWhile = false; (v]P<3%  
break; U&`6&$]  
} 5[nmP95YK  
} Wux0RF&  
if(breakWhile) lK "'nLL  
break; )4@M`8  
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Y
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//count++; PL9<*.U"=  
//if(count>4) *3!(*F@M,  
// siteStop(); dr.**fGYde  
} (Z5q&#f  
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System.err.println("文件下载结束！"); JIVo=5c}  
} +I*k0"gj6  
catch(Exception e){e.printStackTrace ();} h]<GTWj  
} _cR6ik zW(  
NS h%t+XU]  
3T"2S[gT  
//获得文件长度 w8G7Jy  
public long getFileSize() BQ).`f";d  
{ R_t~UTfI;  
int nFileLength = -1; 2@rp<&s  
try{ rFf:A-#l  
URL url = new URL(siteInfoBean.getSSiteURL()); hJecCOA)'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >9 q]>fJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); G!nl'5|y  
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int responseCode=httpConnection.getResponseCode(); km9Gwg/zT  
if(responseCode>=400) 5BrU'NF  
{ lq~GcM  
processErrorCode(responseCode); B.V?s,U  
return -2; //-2 represent access is error t-'I`I  
} ,NjX&A@  
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Ga]47pQ"F  
String sHeader; d#E(~t(^  
-
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for(int i=1;;i++) bjuYA/w<  
{ r5D jCV"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <9=zP/Q  
//Utility.log(in.readLine()); X'YfjbGo  
sHeader=httpConnection.getHeaderFieldKey(i); qsD?dHi7  
if(sHeader!=null) !>CE(;E>z  
{ V+Y|4Y&  
if(sHeader.equals("Content-Length")) R 4DM_u  
{ XPar_8I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d^ 2u}^kG  
break; s>LA3kT  
} uCY(:;[<  
} F~tm`n8Z  
else @~JB\j9  
break; P]|J?$1K  
} ) ~ l\  
} 1[26w_B3  
catch(IOException e){e.printStackTrace ();} >`<Ued  
catch(Exception e){e.printStackTrace ();} >L#];|  
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Utility.log(nFileLength); &mX5&e  
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return nFileLength; *>EI2HX  
} 8dV.nO  
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//保存下载信息（文件指针位置） f 1sy9nQs  
private void write_nPos() 5oVLv4Z9u  
{ %M|Z}2qv  
try{ 8:Z@lp^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KC&H*  
output.writeInt(nStartPos.length); SNQz8(O  
for(int i=0;i<nStartPos.length;i++) 59&T
/  
{ ST[2]   
// output.writeLong(nPos); *54>iO- c  
output.writeLong(fileSplitterFetch.nStartPos); 'CP/ymf/a  
output.writeLong(fileSplitterFetch.nEndPos); mle_*Gy8  
} L!CX&
 
output.close(); hB|H9+  
} (%``EIc<8  
catch(IOException e){e.printStackTrace ();} !7ei1  
catch(Exception e){e.printStackTrace ();} ( rA\_FOJ  
} Mfnlue](  
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UN cYu9[  
//读取保存的下载信息（文件指针位置） xI=}z
 
private void read_nPos() $sU5=,
  
{ _fczE~O/  
try{ 1{SrHdD=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B'WCN&N  
int nCount = input.readInt(); @5{.K/s  
nStartPos = new long[nCount]; 1Z^`l6|2  
nEndPos = new long[nCount]; 4M;sD;3  
for(int i=0;i<nStartPos.length;i++) tQNk=}VR7r  
{ ovhC42i  
nStartPos = input.readLong(); Z7tU0  
nEndPos = input.readLong(); .`oJcJ  
} b&\3ps  
input.close(); jF%)Bhn(  
} r Iya\z1W  
catch(IOException e){e.printStackTrace ();} /e-ka{WS  
catch(Exception e){e.printStackTrace ();} zjluX\  
} Z!C`f/h9  
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private void processErrorCode(int nErrorCode) .Q=2WCv0  
{ (z8]FT  
System.err.println("Error Code : " + nErrorCode); @-)<|orU4  
} \iFMU#  
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9@KUqoX  
//停止文件下载 #rn4$  
public void siteStop() (lyt"Ty  
{  ltCwns  
bStop = true; ;n(#b8r9  
for(int i=0;i<nStartPos.length;i++) ]`#xR*a  
fileSplitterFetch.splitterStop(); e5*5.AB6&  
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} )LXoey!aZ  
} blKDQ~T2  
//负责部分文件的抓取 N0y;PVAGu  
**FileSplitterFetch.java J6@(X8w{j  
*/ ^4xlZouCb  
package NetFox; e3yorQ][  
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import java.io.*; @Og\SZhn  
import java.net.*; @{J!6YGh  
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public class FileSplitterFetch extends Thread { 9TYw@o5V  
&A ;3; R  
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String sURL; //File URL `^XRrVX<  
long nStartPos; //File Snippet Start Position x
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long nEndPos; //File Snippet End Position [?|l X$<  
int nThreadID; //Thread's ID dXA{+<!!  
boolean bDownOver = false; //Downing is over Q%,o8E2~  
boolean bStop = false; //Stop identical nZ2mEt  
FileAccessI fileAccessI = null; //File Access interface fWtb mUq  
A&NC0K}G!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ifJv~asp   
{ w%i+>\tO  
this.sURL = sURL; X_-Hrp!h  
this.nStartPos = nStart; rE1np^z7  
this.nEndPos = nEnd; cM> G>Yzo  
nThreadID = id; ! /|0:QQi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 
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} ugIm:bg&  
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public void run() 9[t]]  
{ ({d,oU$>y  
while(nStartPos < nEndPos && !bStop) dvg;  
{ x*loACee.  
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try{ vxbH^b  
URL url = new URL(sURL); ZXssvjWQV}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4*N@=v  
httpConnection.setRequestProperty("User-Agent","NetFox"); [3{:H"t  
String sProperty = "bytes="+nStartPos+"-"; sx)$=~o  
httpConnection.setRequestProperty("RANGE",sProperty); sUyCAKebRr  
Utility.log(sProperty); 2-"Lxe65f  
3oppV_^JdT  
/ctaAQDUh\  
InputStream input = httpConnection.getInputStream(); A:8FJ3'  
//logResponseHead(httpConnection); d+YVyw.z  
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byte[] b = new byte[1024]; vc>^.#7
 
int nRead; ??$i*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BRo R"#'  
{ eLDL  "L  
nStartPos += fileAccessI.write(b,0,nRead); a>)_ `m  
//if(nThreadID == 1) N8DiEB3~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {Gk}3u/  
} uNPD~TYN  
$+!}Vtb  
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Utility.log("Thread " + nThreadID + " is over!"); |k7ts&2  
bDownOver = true; xVHQ[I%  
//nPos = fileAccessI.write (b,0,nRead); fJF8/IQ4  
} V\k5h  
catch(Exception e){e.printStackTrace ();} O
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} {jx#^n&5R  
} ;H m-,W  
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5H'b4Cyi`  
//打印回应的头信息 @ 2%.>0s.  
public void logResponseHead(HttpURLConnection con) 6S! lD=  
{ m5'__<  
for(int i=1;;i++) , IMT '*  
{ :uT fhr  
String header=con.getHeaderFieldKey(i); T_(e(5  
if(header!=null) .=b +O~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #RLch  
Utility.log(header+" : "+con.getHeaderField(header)); hZss  
else %WJ{IXlz  
break; bY"eC i{K  
} Ol/2%UJXL  
} HAI1%F236  
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public void splitterStop() b]so9aCz  
{ +X%fcoc  
bStop = true; %b>y  
} X."h Tha5  
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} GH; F3s  
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/* qs8K jG@  
**FileAccess.java 3*2&Fw!B  
*//文件访问(定位，写) {Gb)Et]<  
package NetFox; gk_Xu  
import java.io.*; zM8/s96h  
?^G$;X7B  
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public class FileAccessI implements Serializable{ R<0!?`b  
,39$iHk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zhR_qW+  
RandomAccessFile oSavedFile; 6Ymo%OT  
long nPos; V)?x*R*T)  
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public FileAccessI() throws IOException M*T# 5  
{ P`IMvOs&  
this("",0); ++p& x{  
} j9L+.UVI,  
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9^Vx*KVrU  
public FileAccessI(String sName,long nPos) throws IOException d@>k\6%j  
{ n4r( Vg1GS  
oSavedFile = new RandomAccessFile(sName,"rw"); <8z[,X}bM  
this.nPos = nPos; um0}`Xq^  
oSavedFile.seek(nPos); 1o6J9kCq^3  
} Med"dHo7  
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uy*x~v*I]  
public synchronized int write(byte[] b,int nStart,int nLen) 82@;.%  
{ 1Sc~Vb|>  
int n = -1; {;z L[AgCg  
try{ h>5~ (n8  
oSavedFile.write(b,nStart,nLen); B|q3;P  
n = nLen; xz+`]Q  
} &_%+r5  
catch(IOException e) _I70qz8  
{ nO.+&kA  
e.printStackTrace (); ;~1/eF  
} @Ozf}}#  
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q  
return n; ~3-YxCn%  
} oj4)7{  
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} szsZFyW)+  
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/*  ?Ge*~d  
**SiteInfoBean.java 0R^(rE"2#  
*/ VV}fW"_ND  
package NetFox; iN9!?Ov_  
_~#C $-T  
X9`C2fyVd  
public class SiteInfoBean { :;#}9g9  
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FLnAN;  
private String sSiteURL; //Site's URL wM&x8 <  
private String sFilePath; //Saved File's Path fvBC9^3  
private String sFileName; //Saved File's Name zl8\jP  
private int nSplitter; //Count of Splited Downloading File I(kIHjV|  
>dC(~j{  
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public SiteInfoBean() R\Ynn^w  
{//nSplitter的缺省值为5 ?yM/j7Xn  
//default value of nSplitter is 5 2'^OtM,  
this("","","",5); N4]6LA6x6  
} [N$_@[  
jvKaxB;e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hr,lA(  
{ 0v)mgrl=,  
sSiteURL= sURL; ?bYQZJ>&  
sFilePath = sPath; Qs[EA_  
sFileName = sName; om39;nk!}  
this.nSplitter = nSpiltter; 4y}a,  
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27  
} /g-X=|?F  
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3\l9Sf=M|
 
public String getSSiteURL() ]~ 8N  
{ <.B> LU  
return sSiteURL; mt]YY<l  
} wU3ica&[   
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public void setSSiteURL(String value) 9oN'.H^  
{ )PNH| h  
sSiteURL = value; 8uD%]k=#!  
} <^
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public String getSFilePath() ej53O/hP  
{ Tu#k+f*s  
return sFilePath; 9@>hm>g.  
} LK}eU,m=  

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public void setSFilePath(String value)
#"YWz)8  
{ -ddatc|  
sFilePath = value; _~&vs<  
} en6AAr:U}  
{
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public String getSFileName() %.gjBI=  
{ Fm~}A4  
return sFileName; mNB ]e5;N  
} %z_b/yG  
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6 FxndR;  
public void setSFileName(String value) ;8Q?`=a  
{ SL5DWZ  
sFileName = value; `l40awGCz  
} !b8|{#qh.  
c)~|#v  
*jSc&{s~  
public int getNSplitter() s/|'1E\F  
{ dOgM9P  
return nSplitter; ptL}F~  
} 'QS~<^-j"  
`.Q3s?1F  
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public void setNSplitter(int nCount) j~> #{"C  
{ qiJ;v1  
nSplitter = nCount; j0NPd^  
} <[??\YOc  
} j?ubh{Izm  
5]ob;tAm  
e
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/* aV#;o9H{
  
**Utility.java 9cPucKuj  
*/ "Z?":|%7  
package NetFox; pl/$@K?L  
g+F_M  
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public class Utility { ;]o^u.PC  
j`hbQp\`  
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public Utility() <xz-7EqbwX  
{ P?ol]MwaB  
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vxZUtyJfe  
} m5
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oK[,xqyA  
//线程睡眠 e+aQ$1^t  
public static void sleep(int nSecond) FJ. :*K[  
{ jH/%Z5iu  
try{ r{;4(3E2  
Thread.sleep(nSecond); f}d@G/L  
} Ki\jiflc7  
catch(Exception e) (~o+pp!  
{ 'm((G4  
e.printStackTrace (); *Y?]="8c#;  
} f 8U;T$)  
} >u[ln@ l  
</Lqk3S-!  
//日志 hZG{"O!2s  
public static void log(String sMsg) P3>2=qK"E(  
{ 8\_,Y ji  
System.err.println(sMsg); AG=1TZI"  
} >qZRIDE5$  
mJqP#Unik  
=~*u(0sJa  
public static void log(int sMsg) -p~B -,  
{ 0nn#U  
System.err.println(sMsg); P1jkoJ  
} c3mlO[(  
} SjU6+|l  
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1 crjRbi  
/* F.hC%Ncu  
**TestMethod.java OQyOv%g5C  
*/ GQ8P}McA  
package NetFox; pc>R|~J{2  
;^]F~x}  
SS

-  
public class TestMethod { }DwXs`M7  
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4 .qjTR  
public TestMethod() VW/1[?HG5  
{ ///xx/weblogic60b2_win.exe
h@8  
try{ W`kgYGnFG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .!! yj,bQz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )A"7l7?.n)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :W55JD'  
fileFetch.start(); BJTljg({o  
} XoOe=V?I )  
catch(Exception e){e.printStackTrace ();} A&#Bf#!G  
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} U[u6UG  
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public static void main(String[] args) [ j_jee  
{ YN3uhd[2  
new TestMethod(); v4zARE9#  
} wVB8PO8  
} i
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