http断点续传简单实现（java)

/* m1gJ"k6 `j  
**SiteFileFetch.java Umm_FEU#]  
*/ -vGyEd7  
package NetFox; +AZ=nMgW  
import java.io.*; pCb@4nb  
import java.net.*; 1#^[{XlAx  
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public class SiteFileFetch extends Thread {  s+[_5n~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !Wvzum@5D  
long[] nStartPos; //开始位置 BgA\l+  
long[] nEndPos; //结束位置 }[!;c+ke  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DOkEWqM!  
long nFileLength; //文件长度 }1`Rq?@J  
boolean bFirst = true; //是否第一次取文件 =oluw|TCe7  
boolean bStop = false; //停止标志 )"&-vg<  
File tmpFile; //文件下载的临时信息 ?p. dc~tZ  
DataOutputStream output; //输出到文件的输出流 Q[i;IbY  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GLwL'C'591  
public SiteFileFetch(SiteInfoBean bean) throws IOException BXa1[7Z  
{ UIL5K 
 
siteInfoBean = bean; 6vX+-f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); st{:]yTRk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9K#.0  
if(tmpFile.exists ()) Ki^m&P   
{ v%/8pmZw;  
bFirst = false; kmy?`P10(z  
read_nPos(); yZb@  
} m/0G=%d%k
 
else L FHyiIO  
{ kX'1.<[  
nStartPos = new long[bean.getNSplitter()]; VDPqI+z  
nEndPos = new long[bean.getNSplitter()]; ZZ!d:1'7  
} CLQ\Is^]  
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} ]}ff*W  
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public void run() csRba;Z[  
{ U^VFHIm  
//获得文件长度  *X*D, VY  
//分割文件 >Eik>dQ a  
//实例FileSplitterFetch ?TMo6SU  
//启动FileSplitterFetch线程 k/H<UW?Z]  
//等待子线程返回 :7W5R  
try{ ^[&*B#(  
if(bFirst) ;y=w :r\A  
{ `WWf
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nFileLength = getFileSize(); Bpo~x2p  
if(nFileLength == -1) mrFMdpaHl%  
{ @*is]d+Ya  
System.err.println("File Length is not known!"); Z6K9E=%)c  
} SK;f#quUQ  
else if(nFileLength == -2) x[WT)  
{ |g8 ]WFc  
System.err.println("File is not access!"); tI.(+-q  
} XiKv2vwA  
else {EW}Wd  
{ }mu8fm'  
for(int i=0;i<nStartPos.length;i++) RvDqo d  
{ "9LPq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `dEWP;#cp  
} +(PtOo.  
for(int i=0;i<nEndPos.length-1;i++) at7/KuY!~  
{ BAX])~_  
nEndPos = nStartPos[i+1]; +ZizT.$&  
} 
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nEndPos[nEndPos.length-1] = nFileLength; @{+*ea7M(`  
} u>k;PUH4  
} &_q;X;}  
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//启动子线程 5:iril  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (ter+rTv  
for(int i=0;i<nStartPos.length;i++) Y]Su<tgX?  
{ p7.@ez ;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q>TaaGc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jG)>{D  
nStartPos,nEndPos,i); _'2r=a#`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {[r'+=}l\S  
fileSplitterFetch.start(); [C771~BL>  
} d[TcA2nF
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &+&^Hc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C$ZY=UXz!T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e=8ccj  
nEndPos = " + nFileLength); H#w?$?nIWu  
// fileSplitterFetch[nPos.length-1].start(); KgAc0pz{7H  
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Kh$L~4l  
//等待子线程结束 Q=uwmg86  
//int count = 0; -{7:^K[)  
//是否结束while循环 U> q&+:+  
boolean breakWhile = false; !ae@g q'  
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while(!bStop) yv$MQ~]  
{ @o;m!CYB  
write_nPos(); >x!N@G  
Utility.sleep(500); ffE%{B?  
breakWhile = true; 61jDI^:  
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for(int i=0;i<nStartPos.length;i++) T0tG1/O\  
{ 2cy{d|c  
if(!fileSplitterFetch.bDownOver) v7&$(HJ>]L  
{ BOh&Db*  
breakWhile = false; egr@:5QwZ{  
break; r>z8DX@  
} YJ1P5u:  
} f3v/Y5)  
if(breakWhile) _fMooI)U1  
break; |d{(&s}  
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//count++; Dtr'X@U  
//if(count>4) 5O*+5n  
// siteStop(); veK  
} vP,WV9Q1u  

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System.err.println("文件下载结束！"); |/p^e  
} 3%cNePlr  
catch(Exception e){e.printStackTrace ();} Y~Jq!  
} $f)Y !<b
C  
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//获得文件长度 a,
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public long getFileSize() r@ejU'uz  
{ uQ8
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int nFileLength = -1; :+-s7'!4  
try{ JVXBm]  
URL url = new URL(siteInfoBean.getSSiteURL()); jkD5Z`D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); 6fkL@It  
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int responseCode=httpConnection.getResponseCode(); 2t(E+^~  
if(responseCode>=400) ):.]4n{L  
{ DOR
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processErrorCode(responseCode); g$]9xn#_[  
return -2; //-2 represent access is error VF[]E0=u6  
} ;{Ovqo|  
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String sHeader; i<@|+*>M  
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for(int i=1;;i++) -2Ub'*qK  
{ C w$y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K-#Rm%J+Wy  
//Utility.log(in.readLine()); P@*whjPmo  
sHeader=httpConnection.getHeaderFieldKey(i); T1e}WJbFE  
if(sHeader!=null) fY-{,+
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{ &}P62&  
if(sHeader.equals("Content-Length")) 5gEUE{S  
{ !hJKI.XH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sS+9ly{9J  
break; Y<kvJb&1*  
} )IhI~,0Nmj  
} Y
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else g(<@r2p  
break; NB,iC [e  
} +  1v@L  
} =;T971L`  
catch(IOException e){e.printStackTrace ();} Hi|Oeu  
catch(Exception e){e.printStackTrace ();} U` bvv'38#  
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Utility.log(nFileLength); o3uv"# C  
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return nFileLength; ? 8'4~1g`}  
} ~rKo5#D  
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//保存下载信息（文件指针位置） rZzto;NDS  
private void write_nPos() ;=_KLG <  
{ IJ=~hBI  
try{ FC)aR[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VT-&"Jn  
output.writeInt(nStartPos.length); KDCq::P<  
for(int i=0;i<nStartPos.length;i++) M)-+j{<  
{ w#-rl@JQ4  
// output.writeLong(nPos); NShA-G N5  
output.writeLong(fileSplitterFetch.nStartPos); GJH6b7I  
output.writeLong(fileSplitterFetch.nEndPos); #n0P'@d,r  
} r5rK>  
output.close(); kw1PIuz4&  
} \:O5,wf2  
catch(IOException e){e.printStackTrace ();} am@\$Sa4
 
catch(Exception e){e.printStackTrace ();} i1
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} rK"$@tc  
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//读取保存的下载信息（文件指针位置） s>_ne0  
private void read_nPos() FIW*Nr  
{ YSeXCJ:Iy  
try{ #~ /-n&#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )5e}Id  
int nCount = input.readInt(); T!J\Dm-  
nStartPos = new long[nCount]; c\-I+lMBi  
nEndPos = new long[nCount]; N/^r9Nu  
for(int i=0;i<nStartPos.length;i++) )Ax1?Nx$  
{ }`*]&I[P  
nStartPos = input.readLong(); y"P$:l  
nEndPos = input.readLong(); Kb{  
} L2Mcs  
input.close(); Xhi9\wteYw  
} (R Ttz  
catch(IOException e){e.printStackTrace ();} {n|Ra[9_  
catch(Exception e){e.printStackTrace ();} ^oPf>\),C  
} ~|fd=E%  
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private void processErrorCode(int nErrorCode) jh}[7M  
{ 8[xb+_  
System.err.println("Error Code : " + nErrorCode); O/0m|~`iY  
} + PGfQN  
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//停止文件下载 '{Iv?gh"  
public void siteStop() Rl$NiY?2  
{ ud!iy  
bStop = true; ']4sx_)S  
for(int i=0;i<nStartPos.length;i++) {TlS)i`  
fileSplitterFetch.splitterStop(); M~P}80I  
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} }vp\lKP  
} 5C2 *f4|  
//负责部分文件的抓取 J[]YG+r  
**FileSplitterFetch.java .Ml}cE$L  
*/ Wh 8fC(BE  
package NetFox; eWcS>N  
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import java.io.*; [4sbOl5yZ  
import java.net.*; R.+QK6B&  
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public class FileSplitterFetch extends Thread { IO|">a6  
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String sURL; //File URL TzerAX^  
long nStartPos; //File Snippet Start Position uFG]8pj2V1  
long nEndPos; //File Snippet End Position l}Jf;C*j1z  
int nThreadID; //Thread's ID kS3wa3bT  
boolean bDownOver = false; //Downing is over 8?P@<Do%  
boolean bStop = false; //Stop identical .hBE&Y>\  
FileAccessI fileAccessI = null; //File Access interface HWD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d-39G*;1  
{ \jZvP`.2  
this.sURL = sURL; Rq9v+Xq2  
this.nStartPos = nStart; UiF?Nx~  
this.nEndPos = nEnd; nv@$'uQRp  
nThreadID = id; >8oRO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dj #G{X".  
} :+m|KC(Z  
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public void run() zVJwmp^  
{ !<@k\~9^D  
while(nStartPos < nEndPos && !bStop) B%cjRwOT  
{ {i`BDOaL  
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try{ DX
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URL url = new URL(sURL); p\1[cz)B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /dhw~|  
httpConnection.setRequestProperty("User-Agent","NetFox"); $w#C;2k]N  
String sProperty = "bytes="+nStartPos+"-"; bU(t5 [
  
httpConnection.setRequestProperty("RANGE",sProperty); W1Ur~x`  
Utility.log(sProperty); Kh'/Ne?  
5;C+K~Y  
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InputStream input = httpConnection.getInputStream(); }4 5|  
//logResponseHead(httpConnection); lLyMm8E%pZ  
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byte[] b = new byte[1024]; O=u.PRNT8  
int nRead; 69TQHJ[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y)g<> }F  
{ kbBX\*{yh  
nStartPos += fileAccessI.write(b,0,nRead); 7bCTR2e\@w  
//if(nThreadID == 1) M[@).4h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (X QgOR#  
} ld$LG6[PA  
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Utility.log("Thread " + nThreadID + " is over!"); fG2\p&z  
bDownOver = true; N1zB;-0t  
//nPos = fileAccessI.write (b,0,nRead); srO{Ci0  
} HG5|h[4Gt  
catch(Exception e){e.printStackTrace ();} wT3QSJ  
} P%g[!9 '  
} <0k(d:H-  
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//打印回应的头信息 WDWb7  
public void logResponseHead(HttpURLConnection con) ?&pjP,a  
{ _{TGO jZr  
for(int i=1;;i++) G6]M~:<i  
{ N9Y,%lQ|B8  
String header=con.getHeaderFieldKey(i); W9t%:wF  
if(header!=null) Dwe_ytjpc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ng0V&oDI  
Utility.log(header+" : "+con.getHeaderField(header)); o[!]xmj  
else +_3>T''_  
break; ePP-&V"`"  
} #Kn=Q  
} 4\Mh2z5  
?SkYFa`u*  
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public void splitterStop() 71mdU6Kq  
{ blk~r0.2  
bStop = true; :L&-
  
} LoPWho[8  
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:S{[^-"  
} yE. ZvvQA  
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l  
9<W0'6%{/  
/* d_-{-@  
**FileAccess.java .^X IZ  
*//文件访问(定位，写) {UT^pIP\  
package NetFox;  M#IGq  
import java.io.*; #Kyb9Qg  
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public class FileAccessI implements Serializable{ ICTl{|i ]  
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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 XuVbi=pN.2  
RandomAccessFile oSavedFile; %($sj|_l  
long nPos; W+Z] Y  
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public FileAccessI() throws IOException bu1O<*  
{ MR:Co4(  
this("",0); {()8 Wr  
} lGwX.cA!'  
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public FileAccessI(String sName,long nPos) throws IOException RM|<(kq  
{ >t.2!Z_RQ  
oSavedFile = new RandomAccessFile(sName,"rw"); 5lu620o  
this.nPos = nPos; ygW,4Vz7J  
oSavedFile.seek(nPos); Mmq{]q~At
 
} Ie`kzssM  
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public synchronized int write(byte[] b,int nStart,int nLen) vq B)PL5)  
{ L0/0<d(K  
int n = -1; .ZJt  
try{ nsqc^ K^  
oSavedFile.write(b,nStart,nLen); aF1pq  
n = nLen; \/p\QT@mm  
} Ji\8(7 {8  
catch(IOException e) \h~;n)FI  
{ D"oyl`q  
e.printStackTrace (); Y?=+A4v  
} 8sOM%y9M  
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return n; `r &IA  
} />S=Y"a/7  
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} o}mD1q0yE  
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/* 4nzUDeI3MG  
**SiteInfoBean.java s(q\!\FS  
*/ V/j+Z1ZW  
package NetFox; 7z9gsi  
R;,+0r^i  
}rz}>((ZHF  
public class SiteInfoBean { yHT8I  
@]":3  
US 9cuah1/  
private String sSiteURL; //Site's URL &EYO[~D06  
private String sFilePath; //Saved File's Path ?*zRM?*  
private String sFileName; //Saved File's Name |d?0ZA:z  
private int nSplitter; //Count of Splited Downloading File rLGh>bw#`3  
r4D*$H-rR  
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public SiteInfoBean() HA&][%^  
{//nSplitter的缺省值为5 'oBT*aL  
//default value of nSplitter is 5 ~rN~Ql%S  
this("","","",5); GxL5yeN@(  
} #uVH~P5TM  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .-T^S"`d|  
{ !run3ip`Z  
sSiteURL= sURL; 0&E{[~Pv  
sFilePath = sPath; Jb Hn/$  
sFileName = sName; NdZv*  
this.nSplitter = nSpiltter; T52A}vf4  
@
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} J)D/w[w  
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public String getSSiteURL() :jKDM  
{ by,"Orpwq;  
return sSiteURL; 23BzD^2a  
} f8'D{OP"G  
r%A-  
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public void setSSiteURL(String value) )"s <hR,  
{ eL[BH8l  
sSiteURL = value; ,d'x]&a  
} 7Rqjf6kX`O  
s|.V:%9e  
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public String getSFilePath() H]K(`)y}4  
{ Q"n|<!DN  
return sFilePath; (E )@@p7,:  
} `j{5$X  
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public void setSFilePath(String value) ig3HPlC  
{ fx2r\ usX[  
sFilePath = value; : &>PN,q>  
} zBV7b| j  
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public String getSFileName() yPL1(i;  
{ DS0c0lsx  
return sFileName; JJ[.K*dO  
} Z;`ts/?SY]  
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public void setSFileName(String value) &[ejxK"  
{ 2'UWPZgE  
sFileName = value; Rqu_[M  
} g0NtM%  
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public int getNSplitter() 60(j[d-$p  
{ LK5,GWF;  
return nSplitter; h BD .IB  
} 2&7:JM~#  
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public void setNSplitter(int nCount) ]JF>a_2wG  
{ #e:cB'f  
nSplitter = nCount; b:VCr^vp  
} KfD=3h=  
} 9bd$mp  
'r3yFoP}  
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/* hF|N81T  
**Utility.java l0N~mes  
*/ tjYqdbA)  
package NetFox; g.$a]pZz  
706-
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public class Utility { U7i WYdt$  
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public Utility() r/o1a't;  
{ (Ubz@s^  
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} ehehTP  
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//线程睡眠 wj$l 093  
public static void sleep(int nSecond) 9n\:grW  
{ OI:G~Wg  
try{ g:&YSjO>G  
Thread.sleep(nSecond); Yl}'hRp  
} SStaS<q'  
catch(Exception e) IqEE.XhaK  
{ xv|?;Zf6w  
e.printStackTrace (); R]L$Ld< ij  
} YQ/  
} 5,Rxc=  
C]/]ot0%t  
//日志 ^\o3V<  
public static void log(String sMsg) ]=Im0s  
{ APye  
System.err.println(sMsg); FO[x
c;  
} [{R^!Az&b<  
r:rM~``  
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public static void log(int sMsg) 3(?V!y{@  
{ )T2V<3l  
System.err.println(sMsg); PD,s,A  
} e'"2yA8dh"  
} 7I\qEr57  
s0EF{2
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/* )67pBj  
**TestMethod.java 5t('H`,2  
*/ 4th*=ku  
package NetFox; YCMXF#1  
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public class TestMethod { b({K6#?'[  
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8/i];/,v*M  
public TestMethod() &oJ1v<`  
{ ///xx/weblogic60b2_win.exe 5f#N$mh  
try{ ]{.iv_I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @la/sd4`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '.{tE*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dUvgFOy|P  
fileFetch.start(); v,}
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}
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catch(Exception e){e.printStackTrace ();} \t=ls  
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} 0R21"]L_M  
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public static void main(String[] args) K$1(HbL  
{ Q
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new TestMethod(); .5_zh; `  
} z*oeho  
} Xh5&J9pw   
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