http断点续传简单实现（java)

/* *boR`[Ond  
**SiteFileFetch.java ay ;S4c/_  
*/ u@UMP@"#  
package NetFox; c /HHy,  
import java.io.*; ?k&Vy  
import java.net.*;
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public class SiteFileFetch extends Thread { R6.hA_ih  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2B[X,rL.pX  
long[] nStartPos; //开始位置 jyUjlYAAv`  
long[] nEndPos; //结束位置 ColV8oVnU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TH&U j1  
long nFileLength; //文件长度 _Xc8Yg }`  
boolean bFirst = true; //是否第一次取文件 +>{2*\cZ5}  
boolean bStop = false; //停止标志 1>_8d"<Gd  
File tmpFile; //文件下载的临时信息 2d #1=+V  
DataOutputStream output; //输出到文件的输出流 KNvZm;Q6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^A$Zw+P  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5|j<`()H :  
{ mbTEp*H  
siteInfoBean = bean; Lv;^My  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %KhI>O<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 36Zf^cFJ  
if(tmpFile.exists ()) iDp)FQ$  
{ D9
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bFirst = false; +T1pJ 89P  
read_nPos(); H9`)BbR  
} %KlrSo  
else x.!V^HQSN  
{ ZF9z~9  
nStartPos = new long[bean.getNSplitter()]; rNWw?_H-H(  
nEndPos = new long[bean.getNSplitter()];  5h=}j  
} %~H-)_d20  
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} EReZkvseC  
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public void run() _LEK%  
{ mZS >O_E  
//获得文件长度 kX7C3qdmt  
//分割文件 }%ojw |  
//实例FileSplitterFetch nLZTK&7}  
//启动FileSplitterFetch线程 \O3m9,a   
//等待子线程返回 A5I)^B<(  
try{ rxvx  
if(bFirst) MDZ640-Y  
{ KK/tu+"  
nFileLength = getFileSize(); _ @NL;w:!  
if(nFileLength == -1) kzQ+j8.,U  
{ X; \+<LE  
System.err.println("File Length is not known!"); pHXm>gTd,J  
} jUYWrYJ  
else if(nFileLength == -2) 45@ I*`  
{ n?!">G  
System.err.println("File is not access!"); oi&VgnSk  
} HSE!x_$  
else +ZaSM~   
{ B dj!ia;H  
for(int i=0;i<nStartPos.length;i++) RNEp4x  
{ T= y}y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,GbR!j@6  
} UJAv`yjG  
for(int i=0;i<nEndPos.length-1;i++) Q0`wt.}V2  
{ / |;RV"  
nEndPos = nStartPos[i+1]; _lJ!R:*  
} mW(W\'~_~  
nEndPos[nEndPos.length-1] = nFileLength; H7&8\FNa  
} FF`T\&u  
} by1<[$8r  
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//启动子线程 urs,34h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .LnGL]/  
for(int i=0;i<nStartPos.length;i++) q.^;!f1  
{ G#q@v(_b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TTX5EDCrC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i4Q@K,$  
nStartPos,nEndPos,i); Y|F9}hj(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I#Y22&G1  
fileSplitterFetch.start(); E1aHKjLQ  
} O_muD\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), njB;&N)I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oQ/E}Zk@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?DS@e@lx  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); (?1y4M  
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//等待子线程结束 Af~$TyX  
//int count = 0; -e"H ^:  
//是否结束while循环 `t>l:<@%  
boolean breakWhile = false; iJ)_RSFK  
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while(!bStop) #K_
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{ +6M}O[LP  
write_nPos(); HT
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Utility.sleep(500); d
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breakWhile = true; FJGlP&v<  
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for(int i=0;i<nStartPos.length;i++) Tt`u:ZwhF  
{ U/66L+1  
if(!fileSplitterFetch.bDownOver) [x=s(:qy  
{ e9Wa<i8  
breakWhile = false; hE'-is@7  
break; eH'av}  
} 3)t.p>VgO  
} Fj8z  
if(breakWhile) P-9)38`5  
break; kr^P6}'  
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//count++; r..iko]T  
//if(count>4) *2>&"B09`  
// siteStop(); ;>U2|>5V  
} '2A)}
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System.err.println("文件下载结束！"); A_"w^E{P  
} ^&9zw\x;z  
catch(Exception e){e.printStackTrace ();} m^!Z_]A![  
} xk9%F?)
 
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//获得文件长度 j1Y~_  
public long getFileSize() L Tm2G4+]  
{ !,_u)4  
int nFileLength = -1; hIYNhZv  
try{ y1jCg%'H  
URL url = new URL(siteInfoBean.getSSiteURL()); )
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '|6]_  
httpConnection.setRequestProperty("User-Agent","NetFox"); @(EAq<5{  
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int responseCode=httpConnection.getResponseCode(); t4."/.=+  
if(responseCode>=400) 9R!atPz9  
{ 
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processErrorCode(responseCode); F$y$'Rzu_B  
return -2; //-2 represent access is error NR$3%0 nC6  
} W 8<&gh+  
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String sHeader; ]#iigPZ7  
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for(int i=1;;i++) `P@<3]  
{ Y,qI@n<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hk;5w{t}}  
//Utility.log(in.readLine()); v4a8}G  
sHeader=httpConnection.getHeaderFieldKey(i); +qN>.y!Y  
if(sHeader!=null) ;}I:\P  
{ '0;l]/i.  
if(sHeader.equals("Content-Length")) ^ox=HNV  
{ c8 )DuJ#U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +)AG*  
break; aL\PGdgO  
}  h},IF  
} B9_X;c  
else X;+sUj8  
break; ~Py`P'+  
} a K[&V't~  
} wA ,6bj  
catch(IOException e){e.printStackTrace ();} *xAqnk   
catch(Exception e){e.printStackTrace ();} ~f2z]JLr:  
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Utility.log(nFileLength); Ot0ap$&  
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return nFileLength; u=*FI  
} c1(RuP:S  
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//保存下载信息（文件指针位置） PudS2k_Qv  
private void write_nPos() R`5.[?Dt  
{ 4d4ZT?V[  
try{ *gb*LhgO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V;VHv=9`o  
output.writeInt(nStartPos.length); 3Y4?CM&0v  
for(int i=0;i<nStartPos.length;i++) 5+0gR &|j  
{ LtF,kAIt7v  
// output.writeLong(nPos); #FLb*%Nr  
output.writeLong(fileSplitterFetch.nStartPos); l+K'beP  
output.writeLong(fileSplitterFetch.nEndPos); wQl ,  
} tPWLg),  
output.close(); &GO}|W  
} jxJ8(sr$  
catch(IOException e){e.printStackTrace ();} >{n,L6_t  
catch(Exception e){e.printStackTrace ();} VOsRAn/N  
} IxN9&xa
  
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//读取保存的下载信息（文件指针位置） hg]]Ok~cAs  
private void read_nPos() 3PWL@>zi  
{ W&W5lArr  
try{ #<"~~2?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JPI3[.o  
int nCount = input.readInt(); BQHVQs   
nStartPos = new long[nCount]; mkk6`,ov  
nEndPos = new long[nCount]; sRR(`0Zp  
for(int i=0;i<nStartPos.length;i++) G^|:N[>B  
{ .[KrlfI  
nStartPos = input.readLong(); 6dr%;Wp  
nEndPos = input.readLong(); PcMD])Z{G  
} y3Qsv  
input.close(); ha<[bue  
} 1Faf$J~7|  
catch(IOException e){e.printStackTrace ();} @Ns Qd_e  
catch(Exception e){e.printStackTrace ();} w$iX.2|9%u  
} @Sn(lnlB  
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private void processErrorCode(int nErrorCode) ./Zk`-OBT  
{ Lnl(2xD  
System.err.println("Error Code : " + nErrorCode); KhR81\  
} nsC3  
,.8KN<A2]'  
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//停止文件下载 epe)a  
public void siteStop() CI0C1/:@  
{ |kg7LP3(8,  
bStop = true; |$Sedzj'  
for(int i=0;i<nStartPos.length;i++) N7zft  
fileSplitterFetch.splitterStop(); ?pmHFlx  
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} e2TiBTbQaF  
} ^98~U\ar  
//负责部分文件的抓取 UYJZYP%r  
**FileSplitterFetch.java 13=AW  
*/ kd(8
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package NetFox; O"9\
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import java.io.*; lIS-4QX1  
import java.net.*; e{K 215  
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public class FileSplitterFetch extends Thread { nPl?K
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String sURL; //File URL n0 {i&[I~+  
long nStartPos; //File Snippet Start Position 9wwqcx)3(  
long nEndPos; //File Snippet End Position OX!tsARC@  
int nThreadID; //Thread's ID ~rKrpb]ow  
boolean bDownOver = false; //Downing is over I;|B.j  
boolean bStop = false; //Stop identical sY Q
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FileAccessI fileAccessI = null; //File Access interface %/.b~|,-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8qTys8  
{ dn
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this.sURL = sURL; _7L-<  
this.nStartPos = nStart; ASySiHz  
this.nEndPos = nEnd; *Kgks4  
nThreadID = id; "?xHlYj@+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D=Gtq6jd  
} zu{P#~21  
,!y$qVg'\f  
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public void run() b=NxUd O  
{ xsbE TP?  
while(nStartPos < nEndPos && !bStop) WPMSm<[  
{ )9`qG:b'  
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try{ +gtbcF@rx  
URL url = new URL(sURL); OKR "4n:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,/F~Y&1I  
httpConnection.setRequestProperty("User-Agent","NetFox"); .j0$J\:i  
String sProperty = "bytes="+nStartPos+"-"; ChPmX+.i_  
httpConnection.setRequestProperty("RANGE",sProperty); vMH  
Utility.log(sProperty); :q%M_  
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InputStream input = httpConnection.getInputStream(); k"iOB-@B+  
//logResponseHead(httpConnection); ?mxMk6w  
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byte[] b = new byte[1024]; xj;H&swo  
int nRead; c9 _rmz8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) agDM~=#F  
{ *H2r@)Y[~  
nStartPos += fileAccessI.write(b,0,nRead); k9
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//if(nThreadID == 1) k)=s>&hl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3ym',q  
} F_{Yo?_  
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:bq8N@P/  
Utility.log("Thread " + nThreadID + " is over!"); s8t;.^1}  
bDownOver = true; F/kWHVHU[  
//nPos = fileAccessI.write (b,0,nRead); #gs`#6 ,'  
} 29
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catch(Exception e){e.printStackTrace ();} 08\,<9  
} oY3;.;'bk  
} fxHH;hRfv  
0 ZKx<]!  
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//打印回应的头信息 Vv=. -&'  
public void logResponseHead(HttpURLConnection con) |3"KK  
{ PB*&aYLU  
for(int i=1;;i++) p%=u#QNi  
{ )}Kf
=  
String header=con.getHeaderFieldKey(i); #r\4sVg  
if(header!=null) .|fHy  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); `mJ6K&t$<  
else >@_^fw)  
break; J<h$ wM  
} `l[c_%Bm  
} .?sx&2R2  
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public void splitterStop() ;$wVu|&  
{ !?h;wR  
bStop = true; >SHhAEF  
} iz PDd{[  
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} n 0L^e  
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/* E*K;H8}s  
**FileAccess.java )F]]m#`  
*//文件访问(定位，写) zHRplm+i  
package NetFox; xfe+n$~ c  
import java.io.*; jm/`iXnMf  
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public class FileAccessI implements Serializable{ \Uq(Zga4)  
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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 I,vJbvvl!  
RandomAccessFile oSavedFile; ]GkfEh7/J  
long nPos; "@0]G<H  
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public FileAccessI() throws IOException t-bB>q#3>  
{ Lk}J8 V^2  
this("",0); 7~.9=I'A  
} V {ddr:]
4  
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public FileAccessI(String sName,long nPos) throws IOException #.)0xfGW)n  
{ RMu~l@  
oSavedFile = new RandomAccessFile(sName,"rw"); <R=Zs[9M1  
this.nPos = nPos; lzVq1@B  
oSavedFile.seek(nPos);
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} >U27];}y  
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public synchronized int write(byte[] b,int nStart,int nLen) HY:o+ciH'  
{ }00BllJ  
int n = -1; n9ej7
oj  
try{ Z,Dl` w  
oSavedFile.write(b,nStart,nLen); M!D3}JRm  
n = nLen; wjB:5~n50k  
} .|i.Cq8  
catch(IOException e) f(y:G^V  
{ S3Xl  
e.printStackTrace (); 'e'cb>GnA  
} @<EO`L)Z  
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return n; K`fuf=  
} M&9+6e'-F  
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} PIS2Ed]  
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/* '3^'B03  
**SiteInfoBean.java *_\_'@1|J)  
*/ oV78Hq6  
package NetFox; >e5qv(y]  
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public class SiteInfoBean { vy:Z/1q  
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private String sSiteURL; //Site's URL A;?|&`f  
private String sFilePath; //Saved File's Path RPL:-  
private String sFileName; //Saved File's Name P.9>z7l{  
private int nSplitter; //Count of Splited Downloading File lA8`l>I  
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ml }{|Yz  
public SiteInfoBean() -r]W  
{//nSplitter的缺省值为5 _L=h0H l  
//default value of nSplitter is 5 oE]QF.n#  
this("","","",5); AFE~ v\Gz  
} d<P\&!R(  
hv>\gBe i  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8&b,qQ~  
{ O)r4?<Q  
sSiteURL= sURL; WOL:IZX%  
sFilePath = sPath; L$M9w  
sFileName = sName; =]0&i]z[.  
this.nSplitter = nSpiltter; Se =`N  
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} /aZ`[m2  
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public String getSSiteURL() 'E""amIJ  
{ toC^LZgZ_6  
return sSiteURL; 4 "'~NvO  
} 9InVQCf2J  
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public void setSSiteURL(String value) q^<?]8  
{ II{&{S'HU  
sSiteURL = value; Qd3 j%(  
} Wg]Qlw`\|  
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public String getSFilePath() ~2-1 j  
{ ln dx"prW  
return sFilePath; 9~[Y-cpoi  
} kMN~Y  
k\?Ii<m  
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public void setSFilePath(String value) k@W1-D?  
{ U&p${IcEm  
sFilePath = value; YT(AUS5n  
} BLD gt~h#  
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public String getSFileName() *(DV\.l`  
{ vUM4S26"NT  
return sFileName; P+/e2Y  
} zIAD9mQex  
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public void setSFileName(String value) s!$7(Q86R  
{ XZd,&YiaG  
sFileName = value; 3)ywX&4"L  
} ^k9I(f^c-_  
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public int getNSplitter() =B@2#W#  
{ {R6ZKB  
return nSplitter; $6SW;d+>n  
} 1]b.fD  
v` 1lxX'*  
~b8]H|<'Y  
public void setNSplitter(int nCount) P/_['7  
{ j&qub_j"xX  
nSplitter = nCount; -(H0>Ap  
} %1+4_g9  
} (SAs-  
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y  
)+9Uoe~6  
/* $~T4hv :  
**Utility.java <wD-qTW  
*/ [/8%3  
package NetFox; S30%)<W  
|&i<bqLw:  
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public class Utility { `<d }V2rdz  
h<<v^+m  
?4T-@~~*`=  
public Utility() ysY*k`5  
{ /N.U/
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} d8P^lv*rQW  
|P?*5xPB  
//线程睡眠 `r 3  
public static void sleep(int nSecond) jAlv`uB|G"  
{ ; BHtCuY  
try{ -aCKRN8
5  
Thread.sleep(nSecond); O?#7N[7  
} 4{|"7/PE1  
catch(Exception e) ^} >w<'0  
{ Ml-6OvQ7g  
e.printStackTrace (); Ab.(7GFK  
} $/Uq0U  
}  a0)QH  
!R`
{ TbN  
//日志 ~*];pV]A[  
public static void log(String sMsg) $6R-5oQ  
{ 5]:U9ts#  
System.err.println(sMsg); }i&/G+_  
} JNnDts*w  
dioGAai'  
(KZ{^X?a  
public static void log(int sMsg) gw<q.XL  
{ $VOFOc  
System.err.println(sMsg); kb!%-k  
} 5wU]!bxr  
} SQ+Gvq%Q]  
) ;Y;Q  
j8:\%|  
/* Dk51z@  
**TestMethod.java 'i|YlMFIg  
*/ ="l/klYV  
package NetFox; ,f?*{Q2  
)Hr`MB  
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public class TestMethod { XfIJ4ZM5  
Ar#(psU  
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public TestMethod() b4Ekqas  
{ ///xx/weblogic60b2_win.exe 6[AL|d DK  
try{ S~G]~gt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q{x8_E!L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jT;;/Fd3/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n|yO9:Uw<  
fileFetch.start(); QIFgQ0{  
} R`-S/C  
catch(Exception e){e.printStackTrace ();} MVUJD{X#  
<b*DQ:N  
A?OQE9'  
} &_8947  
T6$+hUM$1  
<(#ej4ar,  
public static void main(String[] args) ~v6D#@%A  
{ |CbikE}kL  
new TestMethod(); @BMx!r5kn  
} lq7E4r  
} b" [|:F>P  
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