http断点续传简单实现（java)

/* R>dd#`r"  
**SiteFileFetch.java jxTYW)E   
*/ {q|Om?@  
package NetFox; J:oAzBFpA  
import java.io.*; EN{o3@ O'  
import java.net.*; lq}g*ih  
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public class SiteFileFetch extends Thread { q-TDg0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w[Q)b()  
long[] nStartPos; //开始位置 )T!3du:M  
long[] nEndPos; //结束位置 ^{l$>e]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &~sirxR p  
long nFileLength; //文件长度 5;q{9wvqO  
boolean bFirst = true; //是否第一次取文件 0. mS^g,M-  
boolean bStop = false; //停止标志 v5dLjy5
 
File tmpFile; //文件下载的临时信息 .l +yK-BZ  
DataOutputStream output; //输出到文件的输出流 > ,;<Bz|X  
^~K[bFbW  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j-9Zzgr  
public SiteFileFetch(SiteInfoBean bean) throws IOException a/dq+  
{ pT'jX^BU  
siteInfoBean = bean; O
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^s_7-p])(  
if(tmpFile.exists ()) `$i/f(t6`  
{ XWv;l)  
bFirst = false; yNOoAnGT W  
read_nPos(); +S ],){  
} Ucd~-D  
else Qkb=KS%z  
{ 0UOjk.~b  
nStartPos = new long[bean.getNSplitter()]; oJe`]_XZ  
nEndPos = new long[bean.getNSplitter()]; eH^~r{{R  
} aDZ]{;  
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} (qdvvu#E  
LGT?/gup  
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public void run() OmLe+,7'  
{ 'e:(61_  
//获得文件长度 LZ<^b6Dxk  
//分割文件 ]oxi~TwY^  
//实例FileSplitterFetch 0Ait7`  
//启动FileSplitterFetch线程 M*2 Nq=3  
//等待子线程返回 (
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try{ MZ"|Jn  
if(bFirst) s"B+),Jod  
{ )%vnl~i!  
nFileLength = getFileSize(); jj6yf.r6c  
if(nFileLength == -1) ch]{=61  
{ njckPpyb@  
System.err.println("File Length is not known!"); M$U
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} X}B]0z>  
else if(nFileLength == -2) ;bRyk#  
{ {B[ }}wX$  
System.err.println("File is not access!"); Nx=rw h  
} 2(H-q(  
else d
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{ 52t6_!y+V  
for(int i=0;i<nStartPos.length;i++) *cAI gO7  
{ RZP7h>y6@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Kjt\A]R%  
} +0g L!r  
for(int i=0;i<nEndPos.length-1;i++) tR(nD UHV5  
{ -mw`f)?Ev  
nEndPos = nStartPos[i+1]; p((a(Q/
  
} -_ <z_IL\%  
nEndPos[nEndPos.length-1] = nFileLength; qylI/
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} ip!-~HNwJ  
} +F+M[ef<ws  
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//启动子线程 KZ@'NnQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n}/4em?  
for(int i=0;i<nStartPos.length;i++) M< /
 
{ tn}MKo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .zv BV_I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8p_6RvG  
nStartPos,nEndPos,i); 9J$-E4G.M
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zD;k|"e  
fileSplitterFetch.start(); uR6 `@F  
} lRR A2Kql  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "{[\VsX|c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gUY~ l= c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u6SQq-)d  
nEndPos = " + nFileLength); 8]Q#P  
// fileSplitterFetch[nPos.length-1].start(); *USG p<iH  
fwNj@fl_,e  
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//等待子线程结束 !<?
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//int count = 0; <.&84c]/&  
//是否结束while循环 ?!y<%&U  
boolean breakWhile = false; ;OZl' . %`  
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while(!bStop) Lg{M<Q)4  
{ }:57Ym)7w  
write_nPos(); 7 j6<  
Utility.sleep(500); B>g(i=E  
breakWhile = true; H*Tzw,f~ v  
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for(int i=0;i<nStartPos.length;i++) 
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{ H$.K   
if(!fileSplitterFetch.bDownOver) LVT:oIQ  
{ Kc,i$FH  
breakWhile = false; 8Qhj_  
break; Xw3j(`w$,  
} ,B'fOJ.2  
} .y<u+)  
if(breakWhile) |}b~YHTs  
break; ,Oe:SZJ>  
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//count++; :IucH%6V  
//if(count>4) OY8P  
// siteStop(); N'i)s{'  
} [iZH[7&j  
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System.err.println("文件下载结束！"); <w`EU[y_  
} ;cB3D3fR.  
catch(Exception e){e.printStackTrace ();} SP/'4m  
} -Aojk8tc  
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//获得文件长度 nW}jTBu_K+  
public long getFileSize() i%[+C  
{ LosRjvQ:  
int nFileLength = -1; v3]5`&3~  
try{ XJ5@/BW  
URL url = new URL(siteInfoBean.getSSiteURL()); '6; {DX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @JGFG+J}  
httpConnection.setRequestProperty("User-Agent","NetFox"); \*[DR R0  
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int responseCode=httpConnection.getResponseCode(); YmOj.Q&  
if(responseCode>=400) ea]qX6)UZ  
{ $JUkwsc  
processErrorCode(responseCode);
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return -2; //-2 represent access is error Wf^sl  
} x-]:g&5T  
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String sHeader; (cyvE}g  
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for(int i=1;;i++) zXD/hM  
{ U8J9 #+:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lrj&60R`w  
//Utility.log(in.readLine()); bv VkN

 
sHeader=httpConnection.getHeaderFieldKey(i);
< Sgc6>)  
if(sHeader!=null) &>]U c%JK  
{ 6~Dyr82"B  
if(sHeader.equals("Content-Length")) *V7mM?  
{ Yxbg _RQm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ="v`W'Pd  
break; eh> |m>JY  
} r}es_9*~Z  
} ?|98Y"w  
else (~o"*1fk>  
break; M[~{!0Uz g  
} P;o{t  
} JsNj!aeU%  
catch(IOException e){e.printStackTrace ();} *5.wwV  
catch(Exception e){e.printStackTrace ();} 1y\bJ  
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Utility.log(nFileLength); :P/VBX
h  
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return nFileLength; ]
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} (qvH=VTwP  
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//保存下载信息（文件指针位置） ;mT}Q;F#  
private void write_nPos() : NA(nA 3  
{ 3UaW+@  
try{ ^ghYi|kQq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qxDMDMN  
output.writeInt(nStartPos.length); "T{WOGU+  
for(int i=0;i<nStartPos.length;i++) Km $o@  
{ }Nd1'BVf  
// output.writeLong(nPos); >}\s-/  
output.writeLong(fileSplitterFetch.nStartPos); f;Oh"Yt  
output.writeLong(fileSplitterFetch.nEndPos); "[!b5f3!I  
} v/9DD%An  
output.close(); !Ve0:$  
} EQ ee5}  
catch(IOException e){e.printStackTrace ();} 1Acs0`3  
catch(Exception e){e.printStackTrace ();} ?'Hd0)yZ  
} ^3BPOK[*gB  
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l)*(UZ"  
//读取保存的下载信息（文件指针位置） |Q%P4S"B?  
private void read_nPos() l cHf\~  
{ ZnRT$ l O  
try{ *Z^`H!&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  5{oc  
int nCount = input.readInt(); }oA>0Nw$K  
nStartPos = new long[nCount]; JRw,${W  
nEndPos = new long[nCount]; KILX?Pt[7  
for(int i=0;i<nStartPos.length;i++) U 7.kYu  
{ eG1V:%3  
nStartPos = input.readLong(); `WN80d\)&  
nEndPos = input.readLong(); >5#}/G&  
} NLY=o@<  
input.close(); Lc5zu7ncg  
} (_"Zbw%cJy  
catch(IOException e){e.printStackTrace ();} VC/-5'_6  
catch(Exception e){e.printStackTrace ();} h?p_jI  
} E& i (T2c  
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private void processErrorCode(int nErrorCode) oe]*Q  
{ :`zO%h  
System.err.println("Error Code : " + nErrorCode); KD,3U/3  
}
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//停止文件下载 !#_2 ![  
public void siteStop() ~qj(&[U{c\  
{ ,c
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bStop = true; O*GF/ R8B  
for(int i=0;i<nStartPos.length;i++) !IdV
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fileSplitterFetch.splitterStop(); uR :EH.K  
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} Ba8=nGa4KY  
}  Q&xH  
//负责部分文件的抓取 WM?-BIlT=  
**FileSplitterFetch.java W/bW=.d Jd  
*/ 9Z!n!o7D  
package NetFox; F0p=|W  
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import java.io.*; H" `'d  
import java.net.*; 'k[qx}  
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public class FileSplitterFetch extends Thread { A6]X aF  
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String sURL; //File URL Z8ea)_{#  
long nStartPos; //File Snippet Start Position G|f9l?p  
long nEndPos; //File Snippet End Position P0}{xq'k9v  
int nThreadID; //Thread's ID =yZq]g6Q  
boolean bDownOver = false; //Downing is over 3\@2!:>  
boolean bStop = false; //Stop identical &Y?t  
FileAccessI fileAccessI = null; //File Access interface 88v8lt;R  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HvG %
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{ u_$4xNmQ  
this.sURL = sURL; dEtjcId  
this.nStartPos = nStart; ;6P>
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this.nEndPos = nEnd; hg" i;I  
nThreadID = id; Pgr2S I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (T#$0
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} 7/IL" D  
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public void run() {WrEe7dLy  
{ 0fXMY-$I  
while(nStartPos < nEndPos && !bStop) K 77iv  
{ G-
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try{ |qn2b=  
URL url = new URL(sURL); W
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]5"k%v|  
httpConnection.setRequestProperty("User-Agent","NetFox"); t<Yi!6  
String sProperty = "bytes="+nStartPos+"-"; "jum*<QZz  
httpConnection.setRequestProperty("RANGE",sProperty); PiKP.  
Utility.log(sProperty); x^[,0?y2  
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InputStream input = httpConnection.getInputStream(); uKP4ur@1  
//logResponseHead(httpConnection); " _2k3  
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byte[] b = new byte[1024]; ce\d35x!  
int nRead; !6'N-b1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Dhn7N8(LF!  
{ UmWXv#q\l  
nStartPos += fileAccessI.write(b,0,nRead); /%& d:  
//if(nThreadID == 1) ^1.*NG8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m}wn+R  
} T06(Q[)  
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Utility.log("Thread " + nThreadID + " is over!"); W]oD(eZ  
bDownOver = true; ae sk.  
//nPos = fileAccessI.write (b,0,nRead); a ~v$ bNu  
} xc#t8`  
catch(Exception e){e.printStackTrace ();} N x&/p$d  
} ~|}]  
} B[@q.n  
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//打印回应的头信息 .Z[4:TS  
public void logResponseHead(HttpURLConnection con) R|C`  
{ +<1 |apS1  
for(int i=1;;i++) qS+;u`s  
{ Qjfgxy]  
String header=con.getHeaderFieldKey(i); rQimQ|+  
if(header!=null) K|Sq_/#+U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *,$5EN  
Utility.log(header+" : "+con.getHeaderField(header)); >8(i;)(3  
else 4]U=Y>\Sr  
break; _cs(f<>oCO  
} /9R0}4i7  
} M(I%y0  
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public void splitterStop() juOStTq<  
{ !Ap5Uwd  
bStop = true; xx`YBn~"  
} *lSu=dk+  
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} fmz"Zg9=  
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/* :'DyZy2Fd  
**FileAccess.java {}YA7M:L  
*//文件访问(定位，写) Da(k>vR@4  
package NetFox; TRm#H$  
import java.io.*; ZW [&7[4  
h:8P9WhWF  
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public class FileAccessI implements Serializable{ srv4kodj  
44ty,M3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _X4Y1zh  
RandomAccessFile oSavedFile; S $p>sItO  
long nPos; eyMn! a  
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public FileAccessI() throws IOException $ZI]  
{ o`S``?`^)^  
this("",0); E#KZZ lbx  
} r W`7<3  
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public FileAccessI(String sName,long nPos) throws IOException j
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{ ?kO
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oSavedFile = new RandomAccessFile(sName,"rw"); g5nJ0=9  
this.nPos = nPos; +LRKS  
oSavedFile.seek(nPos); be8T<F  
} 0/su`  
dC({B3#e{  
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public synchronized int write(byte[] b,int nStart,int nLen) sGu.G  
{ xT+_JT65  
int n = -1; iM<$ n2t  
try{ B5z'Tq1  
oSavedFile.write(b,nStart,nLen); ?sk>Mzr  
n = nLen; f`hZb  
} "A}sD7xy9  
catch(IOException e) 6'^E
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{ ;TJpD0  
e.printStackTrace (); n*7^lAa2  
} +c~&o83[  
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return n; 9w=7A>.U  
} XjN4EDi+E  
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} PMytk`<`zw  
 cHvm
 
,H{9`a#+:  
/* c7XBZ%D  
**SiteInfoBean.java &+#5gii1i  
*/ R&Lqaek&W  
package NetFox; mWv$eR  
KkCGL*]K  
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public class SiteInfoBean { C
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private String sSiteURL; //Site's URL fd )v{OC  
private String sFilePath; //Saved File's Path f'=u`*(b7  
private String sFileName; //Saved File's Name 8%,#TMOg  
private int nSplitter; //Count of Splited Downloading File R/oi6EKv  
d1cp=RbC  
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public SiteInfoBean() E2dM0r<]  
{//nSplitter的缺省值为5 Z^|N]Ej  
//default value of nSplitter is 5 ~X3g_<b_8  
this("","","",5); F}}!e.>c  
} $2a
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tDRR3=9pX  
]6e(-v!U  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Jc#D4e1#  
{ i.t%a{gL  
sSiteURL= sURL; G!6b )4L-  
sFilePath = sPath; &[[r|  
sFileName = sName; Nm"P8/-09  
this.nSplitter = nSpiltter; NBPP?\1  
!i
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} c& ;@i$X(  
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public String getSSiteURL() Rn?JMM]  
{ FaeKDbLJr  
return sSiteURL; iN&oSpQ  
} vaB ql(?'2  
4 . 7X*1  
/ dJz?0  
public void setSSiteURL(String value) hVF^"$  
{ :IZAdlz[@  
sSiteURL = value; yh E%X  
} |,$&jSe  
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public String getSFilePath() )
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{ ~z:]rgX  
return sFilePath; q\@Zf}  
} ]VjvG};  
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public void setSFilePath(String value) &G"s!:  
{ /0/ouA>+  
sFilePath = value; 3Q$4`p;  
} ;5ki$)v"  
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public String getSFileName() gML8lu0)  
{ g
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return sFileName; $E@n;0P  
} E
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public void setSFileName(String value) M 2hZ'  
{ un 5r9  
sFileName = value; ~LS</_N  
} iE''>Z  
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public int getNSplitter() +;~N; BT  
{ "s0,9; }  
return nSplitter; 6Hnez@d  
} Dz0D ^(;V  
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5!?5S$>  
public void setNSplitter(int nCount) e6taQz@}  
{ "B{3q`(  
nSplitter = nCount; Onq^|r's&  
} `PbY(6CF  
} DO
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/* 0''p29  
**Utility.java O]tR~a  
*/ )jOa!E
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package NetFox; 66&uK|  
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uP* kvi:e  
public class Utility { RxqNgun@  
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public Utility() :xr^E]  
{ 7GO9z<m)  
n
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} :XhF:c[.:  
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//线程睡眠 (?Mn_FNE|  
public static void sleep(int nSecond) 1L*[!QT4  
{ b WNa6x  
try{ Sh(ys*y>  
Thread.sleep(nSecond); }>6e-]MHfR  
} 'd~(=
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catch(Exception e) VZt%cq  
{ Wo "s;Z  
e.printStackTrace (); S' $;  
} CK[8y&  
} 1gV?}'jq  
3*<@PXpK&  
//日志 \1Y|$:T/  
public static void log(String sMsg) kf'(u..G  
{ D>y5&`  
System.err.println(sMsg); @/^<9  
} 8r(awp  
\oWpyT _  
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public static void log(int sMsg) u:APGR^  
{ X:UlL"G  
System.err.println(sMsg); ]owgsR  
} |yk/iO(  
} )pl5nu#<  
j;`pAN('  
b,+Sa
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/* av!;k2"
 
**TestMethod.java C4(xtSJSd!  
*/ q\<l"b z  
package NetFox; %nkP" Z#  
pL,XHR@Iv  
u9 &$`N_G  
public class TestMethod { QQW}.>N  
:6(\:  
f,yl'2{  
public TestMethod() dE"_gwtX  
{ ///xx/weblogic60b2_win.exe uaO.7QSwN  
try{
w8X5kk   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y-26\eY^P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l+6c|([  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8e-nzc,]  
fileFetch.start(); A8.noV  
} +UDt2  
catch(Exception e){e.printStackTrace ();} {`D]%e
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} wKpBH}  
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N~flao^  
public static void main(String[] args) Nqj@p<y/q  
{ ^<!R%"o-  
new TestMethod(); ULt5Zi  
} zH~P-MqC  
} MJiVFfYW  
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