http断点续传简单实现（java)

/* Pf<yLT]  
**SiteFileFetch.java }}ic{931  
*/ !s?SI=B8  
package NetFox; bM5o-U#^ C  
import java.io.*; (xoYYO  
import java.net.*; uubIL+  
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public class SiteFileFetch extends Thread { SWY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pT3icy!A=  
long[] nStartPos; //开始位置 $45.*>,  
long[] nEndPos; //结束位置 V0#Ocq,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (>f`>6 V  
long nFileLength; //文件长度 eG8l^[  
boolean bFirst = true; //是否第一次取文件 U djYRf
k  
boolean bStop = false; //停止标志 ("r:L<xe&  
File tmpFile; //文件下载的临时信息 Ir5|H|b<  
DataOutputStream output; //输出到文件的输出流 Jj\lF*B  
awvP;F?q|  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @6UZC-M0  
public SiteFileFetch(SiteInfoBean bean) throws IOException \v5;t9uBZ  
{ 6>)nkD32g  
siteInfoBean = bean; D6l.x]K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9j
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >KvK'Mus/  
if(tmpFile.exists ()) ^Y+Lf]zz*  
{ GN9kCyPK  
bFirst = false; a@<-L  
read_nPos(); 
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} ?@;)2B|q  
else Z<^!N)  
{ ,W|-?b?   
nStartPos = new long[bean.getNSplitter()]; 02trjp.f  
nEndPos = new long[bean.getNSplitter()]; B>m*!n:l  
} 9xhc:
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} &e;Qabwxva  
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% @+j@i`&  
public void run() QIevps*  
{ 'L-DMNxBr  
//获得文件长度 M@<9/xPS  
//分割文件 f,Dic%$q  
//实例FileSplitterFetch X(X[v]  
//启动FileSplitterFetch线程 ,Kl?-W@  
//等待子线程返回 X-kOp9/.  
try{ qIQRl1Tw;V  
if(bFirst) h~](9es  
{ Rz|@BxB>n  
nFileLength = getFileSize(); gGUKB2)  
if(nFileLength == -1) u:2Ll[ eo  
{ ~6@`;s`[Y  
System.err.println("File Length is not known!"); 3\Q9>>  
} /e?0Iv" 8>  
else if(nFileLength == -2) dt,Z^z+"E  
{ d[J_iD{ &  
System.err.println("File is not access!"); ^r(My}  
} D9A%8o  
else jVQ89vf ~  
{ RR ^7/-  
for(int i=0;i<nStartPos.length;i++) r{9fm,  
{ X!^|Tass  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9J?s:"j  
} -~lq <M  
for(int i=0;i<nEndPos.length-1;i++) xk% 62W  
{ 25-h5$s  
nEndPos = nStartPos[i+1]; megTp  
} AH5;6Q  
nEndPos[nEndPos.length-1] = nFileLength; htR.p7&Tn  
} p/VVb%  
} u;-fG9xs  
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n+hL/aQ+  
//启动子线程 \|HNFxT`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .6a
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for(int i=0;i<nStartPos.length;i++) <?5|(Q"@:  
{ C-;w}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uW[[8+t|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cp"7
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nStartPos,nEndPos,i); ->{-yh]jv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #0[^jJ3J  
fileSplitterFetch.start(); E'DHO2 Y  
} |?2fq&2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7g(Z
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (B
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6`@J=Q?  
nEndPos = " + nFileLength); #o4tG  
// fileSplitterFetch[nPos.length-1].start(); -dB
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3dj|jw5  
//等待子线程结束 v/c]=/  
//int count = 0; 3U+FXK#6  
//是否结束while循环 VDbbA\  
boolean breakWhile = false; v#/Gxk9eX  
@|c])  
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while(!bStop) w"s@q$}]8M  
{ FZj>N(  
write_nPos();  k-=LD  
Utility.sleep(500); aW&)3C2-x  
breakWhile = true; II}M|qHaK  
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for(int i=0;i<nStartPos.length;i++) I"vkfi#=  
{ X]D,kKasG  
if(!fileSplitterFetch.bDownOver) DI
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{ ;s/<wx-C  
breakWhile = false; 4$pV;xV  
break; +)"Rv%.  
} U\tx{CsSz  
} l9&k!kF`  
if(breakWhile) qrlC U4  
break; 9DNp  
tj[E!  
&~Hed_  
//count++; znwKwc8,  
//if(count>4) Nb`qM]&  
// siteStop(); -m%`Di!E  
} `z0q:ME  
/GC&@y0yi  
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System.err.println("文件下载结束！"); 5MAfuHq^  
} ^F+7<$2  
catch(Exception e){e.printStackTrace ();} TjEXR$:<  
} =#S.t:HQ*  
JN|6+.GG  
1d<Uwb>  
//获得文件长度 aY>v  
public long getFileSize() *b. >  
{ nJ2x;';lA  
int nFileLength = -1; PU/<7P*  
try{ 96(Mu% l  
URL url = new URL(siteInfoBean.getSSiteURL()); 6^[4.D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |2u=3#Jp  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?!U[~Gq  
@I`^\oJ  
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int responseCode=httpConnection.getResponseCode(); |j`73@6  
if(responseCode>=400) c Rq2 re  
{ VIP7j(#t_g  
processErrorCode(responseCode); =\WF +r]V  
return -2; //-2 represent access is error r@{TN6U  
} T"_'sSI>tF  
4?'vP'  
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String sHeader; w>&*-}XX
 
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for(int i=1;;i++) hu.o$sV3;  
{ ZP<<cyY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .+/d08]  
//Utility.log(in.readLine()); d}[cX9U/  
sHeader=httpConnection.getHeaderFieldKey(i); v\U
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if(sHeader!=null) +1!iwmch>  
{ Kf[d@L  
if(sHeader.equals("Content-Length")) x?+w8jSR  
{ 'j6O2=1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mLxgvp  
break; "0P`=n  
} 20|`jxp  
} @i1e0;\  
else &Vz$0{d5  
break; 3S:Lce'f  
} eyCZ[SC  
} h^yqrDyJ  
catch(IOException e){e.printStackTrace ();} J, 9NVw$  
catch(Exception e){e.printStackTrace ();} ##7y|AwK  
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Utility.log(nFileLength); rG-T Dm  
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return nFileLength; 0Ds3wNz  
} L=4+rshl!_  
!mmMAsd,  
(90/,@66l  
//保存下载信息（文件指针位置） _fHml  
private void write_nPos() b|d-vnYE  
{ 52e>f5m.  
try{ I+8n;I)]X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Fm
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output.writeInt(nStartPos.length); $v|W2k  
for(int i=0;i<nStartPos.length;i++) o8bdL<  
{ ^}_Ka//k  
// output.writeLong(nPos);
7MKX`S  
output.writeLong(fileSplitterFetch.nStartPos); hzqJ!  
output.writeLong(fileSplitterFetch.nEndPos); 7Q}pKq]P  
} 4I$Y(E}  
output.close(); AI-*5[w#A  
} 2*|T)OA`m,  
catch(IOException e){e.printStackTrace ();} |1U_5w  
catch(Exception e){e.printStackTrace ();} ysW})#7X  
} >NRppPqL  
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^  
//读取保存的下载信息（文件指针位置） FE~D:)Xj'?  
private void read_nPos() Z7;V}[wie  
{ _QPqF{iI  
try{ )>iOj50n3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FZr/trP~  
int nCount = input.readInt(); ZSC*{dD$E  
nStartPos = new long[nCount]; :!%VSem  
nEndPos = new long[nCount]; HZyA\FS  
for(int i=0;i<nStartPos.length;i++) oN7SmP_  
{ > N~8#C  
nStartPos = input.readLong(); 3
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nEndPos = input.readLong(); r )F;8
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} h.jJAVPi  
input.close(); j[G`p^ul  
} }aZuCe_  
catch(IOException e){e.printStackTrace ();} k?+ 7%A]  
catch(Exception e){e.printStackTrace ();} l|P"^;*zq  
} B*(]T|ff<  
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private void processErrorCode(int nErrorCode) [FO4x`  
{ c|&3e84U  
System.err.println("Error Code : " + nErrorCode); 6hxZ5&;(*  
} a+w2cN'  
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//停止文件下载 G;Li!H  
public void siteStop() (Rw<1q`,  
{ KGz Nj%  
bStop = true; L:$4o  
for(int i=0;i<nStartPos.length;i++) Bm$|XS3cD  
fileSplitterFetch.splitterStop(); l4bytI{63  
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} 2c `
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} SH%NYjj  
//负责部分文件的抓取 2}hJe+#v  
**FileSplitterFetch.java A3jxjQ  
*/ Pe`(9&iT.  
package NetFox; D)d]o&  
sg2;"E@  

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import java.io.*; d54iZ`  
import java.net.*; @(t3<g  
=+zDE0Qs  
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public class FileSplitterFetch extends Thread { VmS_(bM  
|7qt/z  
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String sURL; //File URL Q_5l.M/9]  
long nStartPos; //File Snippet Start Position 82r8K|L.<y  
long nEndPos; //File Snippet End Position -$Oh.B`i  
int nThreadID; //Thread's ID 3_(_yEKx  
boolean bDownOver = false; //Downing is over <DF3!r  
boolean bStop = false; //Stop identical qE[S>/R"  
FileAccessI fileAccessI = null; //File Access interface 3JnpI,By  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y t(D  
{ 9]4
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this.sURL = sURL; sPH2KwEv  
this.nStartPos = nStart; lSxb:$g  
this.nEndPos = nEnd; Br1R++]  
nThreadID = id; {)[o*+9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pSs*Z6c)@  
} pgU[di  
ij"~]I  
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public void run() A;oHji#*  
{ ci0A!wWD  
while(nStartPos < nEndPos && !bStop) ['d9sEv.  
{ |Y9>kXMl  
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try{ Pfd1[~,  
URL url = new URL(sURL); FuhmLm'p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); broLC5hbQU  
httpConnection.setRequestProperty("User-Agent","NetFox"); rB>ge]$.  
String sProperty = "bytes="+nStartPos+"-"; cD
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httpConnection.setRequestProperty("RANGE",sProperty); &>sbsx\y  
Utility.log(sProperty); As:O|!F  
@DN/]P  
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InputStream input = httpConnection.getInputStream(); 0SQ!lr  
//logResponseHead(httpConnection); ~ao:9ynY  
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byte[] b = new byte[1024]; djd/QA
fSC  
int nRead; )U/jD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VYk:c`E  
{ J9^NHU  
nStartPos += fileAccessI.write(b,0,nRead); #Hw|P  
//if(nThreadID == 1) Cf% qa
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YT\`R  
} U3(+8}Q  
=[B\50]  
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Utility.log("Thread " + nThreadID + " is over!"); 7^L  
bDownOver = true; ).~ "  
//nPos = fileAccessI.write (b,0,nRead); Kk3+ ]W<  
} 2+1ybOwb  
catch(Exception e){e.printStackTrace ();} V9c.(QY|f  
} <c+.%ka  
} DT-VxF6h  
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s9- qR_  
//打印回应的头信息 ejN/U{)jK'  
public void logResponseHead(HttpURLConnection con) u`bD`kfT>  
{ 'eM0i[E+`  
for(int i=1;;i++) J
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{ A5<t>6Y  
String header=con.getHeaderFieldKey(i); 57\ 0MQO  
if(header!=null) c=!>m  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9&+]YYCS-  
Utility.log(header+" : "+con.getHeaderField(header)); K<S3gb?0  
else n`Q@<op  
break; K;F1'5+=D  
} .. `I<2  
} #M-!/E  
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public void splitterStop() \"lz,bT  
{ I G1];vX  
bStop = true; ,\4]uZ<  
} N' hT
  
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} %:3XYO.w-  
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/* zt
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**FileAccess.java e@D_0OZ  
*//文件访问(定位，写) '|8dt "C  
package NetFox; <jh4P!\&j  
import java.io.*; MN?aPpr>  
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public class FileAccessI implements Serializable{ Tzq@ic#!B  
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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 QiK>]xJ'  
RandomAccessFile oSavedFile; qTsy'y;Z  
long nPos; zdN[Uc+1Bd  
b:==:d:0s  
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public FileAccessI() throws IOException o'2eSm0H  
{ PK|-2R"M
  
this("",0); 35\ |#2qw6  
} =p5D

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h}Otz "  
public FileAccessI(String sName,long nPos) throws IOException `/O`%6,f1!  
{ R%UTYRLUn  
oSavedFile = new RandomAccessFile(sName,"rw"); 0jTReY-W  
this.nPos = nPos; z8\YMr6o  
oSavedFile.seek(nPos); q/O2E<=w*c  
} M2Q,&>M   
:_e[xB=Yy  
;aQ``B  
public synchronized int write(byte[] b,int nStart,int nLen) _ *f>UW*,  
{ omE- c  
int n = -1; =AIts[!qd  
try{ v[dUUR f  
oSavedFile.write(b,nStart,nLen); dq93P%X24  
n = nLen; ]?^V xB7L  
} adLL7  
catch(IOException e) z33UER"  
{ CG1MT(V7?  
e.printStackTrace (); }gbLWx'iG  
} hGtz[u#p  
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return n; Q-7?'\h  
} }c/p;<  
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} 3FBLCD3  
!se1W5ke#  
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/* ;cMQ0e  
**SiteInfoBean.java Oeh A3$|#  
*/ VLXA6+  
package NetFox; ddQ+EY@!  
wJC[[_"3 I  
L FWp}#%  
public class SiteInfoBean { lV\iYX2#  
1K Vit{  
JduO^Fit  
private String sSiteURL; //Site's URL J"aw 1  
private String sFilePath; //Saved File's Path 
L}h_\1  
private String sFileName; //Saved File's Name LG[N\%<!H  
private int nSplitter; //Count of Splited Downloading File .S//T/3O]Q  
}0'LKwIR  
|]7c&`  
public SiteInfoBean() -1Q24jrO-  
{//nSplitter的缺省值为5 Xm#W}Y'  
//default value of nSplitter is 5 Xg dBLb  
this("","","",5); /4x\}qvU  
} Q yqOtRk  
+ktv:d  
#W~jQ5NS\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sOhn@*X  
{ Qs1CK;+zU  
sSiteURL= sURL; p:08q B|uQ  
sFilePath = sPath; ?%,LZw^[  
sFileName = sName; T5:Q_o]  
this.nSplitter = nSpiltter; lHM+<Z  
p/Pus;*s  
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} p9"dm{  
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public String getSSiteURL() m.D8@[y  
{ aE~T!h  
return sSiteURL; 4R'CLN |t  
} Ul8HWk[6Iw  
1KZigeHXI  
?UsCSJ1V  
public void setSSiteURL(String value) z~t0l  
{ VeQGdyhY  
sSiteURL = value; :E9pdx+  
} /EjXyrn2  
coXg]bUKo  
?t'V5$k\  
public String getSFilePath() Im6gWDdq@6  
{ v0C+DKi  
return sFilePath; |]G%b[
 
} 
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public void setSFilePath(String value) 2;gvo*k  
{ 'KH+e#?Ar  
sFilePath = value; 4X^$"lM  
} C3'xU`=7  
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d*8*9CpO:  
public String getSFileName() iq' PeVo  
{ ?^U?ua6  
return sFileName; Jl_W6gY"Z  
} L6h<B :l  
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public void setSFileName(String value) [H*JFKpx  
{ &g;!n&d zP  
sFileName = value; .jJD$FC  
} .57p4{  
e]VW\6J&  
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public int getNSplitter() Bz
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{ 7(}'
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return nSplitter; Y
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} PhyIea  
35l%iaj]G5  
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public void setNSplitter(int nCount) Jg$<2CR&  
{ LDQ
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nSplitter = nCount; V/#Ra  
} '8]p]#l  
} a,w|r#x]  
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/* M P8Sd1_=  
**Utility.java Hs)Cf)8u  
*/ ?z>J7 }w*=  
package NetFox; DKf(igw  
j""ZFh04  
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public class Utility { @_kF&~  
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public Utility() .e7tq\k  
{ Qs\a&Q=0H  
q=pRe-{  
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} N# }A9t  
eA7 Iv{M  
//线程睡眠 !dT+cZsf  
public static void sleep(int nSecond) P4@`C{F5m  
{ (tYZq86`  
try{ Z3JUYEAS  
Thread.sleep(nSecond); JuSS(dJw  
} J
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catch(Exception e) m\qeYI6,Z  
{ Gko"iO#  
e.printStackTrace (); MsXw 8D  
} nYSe0w  
} :.5l  
) (YNNu  
//日志 1(@$bsgu2  
public static void log(String sMsg) c:m=9>3  
{ f- (i%  
System.err.println(sMsg); %rrA]\C'  
}
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}i  
JaUzu3*=  
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public static void log(int sMsg) R%KF/1;/  
{ b*Y Wd3  
System.err.println(sMsg); t8-P'3,Q$  
} $w*L' <  
} 4|K\pCw  
UF7h{V})  
f|,Kh1{e  
/* RiQ]AsTtl  
**TestMethod.java (6$P/k8  
*/ 6C2~0b   
package NetFox; ]JkEf?;.  
u{DEOhtI4  
estiS  
public class TestMethod { ~5+RK16  
%rb$tKk  
9nN1f@Y  
public TestMethod() 36{GZDGQ  
{ ///xx/weblogic60b2_win.exe >[Vc$[62  
try{ ;p+'?%Y}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~1+6gG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zx%WV@O9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r>(,)rs(l  
fileFetch.start(); -Fd&rq:GB(  
} 0{b} 1D  
catch(Exception e){e.printStackTrace ();} T[$-])iK  
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<-k!
  
} 9" q-Bb  
hY.i`sp*/  
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public static void main(String[] args) d
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{ e4` L8  
new TestMethod(); 3A`Gx#  
} ZxNTuGOB:  
} 5;}W=x^$a  
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