http断点续传简单实现（java)

/* [<=RsD_q~  
**SiteFileFetch.java P8c_GEna  
*/ @_`r*Tb)dM  
package NetFox; FJ84'T\~  
import java.io.*; "c[>>t  
import java.net.*; }#1.$a  
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public class SiteFileFetch extends Thread { w}1IP-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .45wwouZkc  
long[] nStartPos; //开始位置 !po,Z&  
long[] nEndPos; //结束位置 DAq H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u8 k^\Do  
long nFileLength; //文件长度 ;d<XcpK}  
boolean bFirst = true; //是否第一次取文件 qtOuA  
boolean bStop = false; //停止标志 %# uw8V  
File tmpFile; //文件下载的临时信息 q5g_5^csM{  
DataOutputStream output; //输出到文件的输出流 <vl(a*4a  
}F1Asn  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Kj?)]Z4  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]yKwH 9sl  
{ L\ysy2E0  
siteInfoBean = bean; pW ~;B*hF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6No.2Oo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) I&|8 qx#  
{ UP-2{zb |?  
bFirst = false; M}jl\{  
read_nPos(); pjO  
} Db2#QQ  
else M(8xwo-W  
{ h`fZ8|yw  
nStartPos = new long[bean.getNSplitter()]; R@WW@ Of  
nEndPos = new long[bean.getNSplitter()]; S?t `/"O  
} Q\X_JZ  
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} 3znhpHO)  
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public void run() ~=wBF  
{ xG~-.  
//获得文件长度 j,,#B4b  
//分割文件 21$^k
5  
//实例FileSplitterFetch JKmd'ZGw  
//启动FileSplitterFetch线程 ~l+~MB  
//等待子线程返回 O'SxTwO  
try{ i_6wD  
if(bFirst) yPbOiA*lHz  
{ T5~Qfl?Y  
nFileLength = getFileSize(); |q o3 E  
if(nFileLength == -1) g'L$m|  
{ 6O5E4=  
System.err.println("File Length is not known!"); Zfu" 8fX  
} UIQ=b;J9  
else if(nFileLength == -2)
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{ }xrrHp  
System.err.println("File is not access!"); [-[|4|CnOm  
}  4z|Yfvq  
else 8HO)",+I  
{ Z?",+|4  
for(int i=0;i<nStartPos.length;i++) *7Sg8\wDn  
{ hYCyc-W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Us9$,(3  
} -JF|770i  
for(int i=0;i<nEndPos.length-1;i++) Hi{!<e2  
{ q33!X!br  
nEndPos = nStartPos[i+1]; E{9{%J  
} cmh/a~vYaY  
nEndPos[nEndPos.length-1] = nFileLength; Y@%6*uTLa  
} (Gxv?\  
} Vo2fr
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}Lwj~{  
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//启动子线程 PZA;10z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -p!KsU  
for(int i=0;i<nStartPos.length;i++) 7 -V_)FK2c  
{ El&pux2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WU,72g=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tbv6-)Hs  
nStartPos,nEndPos,i); 2|w.A!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zk;;~ESOU  
fileSplitterFetch.start(); j'0*|f^z  
} lR^dT4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KF-gcRh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *&2
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #WpO9[b>  
nEndPos = " + nFileLength); E.% F/mM  
// fileSplitterFetch[nPos.length-1].start(); fW}H##b  
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//等待子线程结束 5BCaE)J  
//int count = 0; Q}.y"|^  
//是否结束while循环 gZ!(&u  
boolean breakWhile = false; zB]T5]  
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while(!bStop) YL=k&QG  
{ sBu"$"]  
write_nPos(); $xZk{ rK  
Utility.sleep(500); Y@\5gZ&T  
breakWhile = true; A07P$3>/W  
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for(int i=0;i<nStartPos.length;i++) CC-:dN
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{ f}'gg  
if(!fileSplitterFetch.bDownOver) |8`;55G  
{ I!<v$  
breakWhile = false; /#se>4]  
break; 9G8QzIac  
} \
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} o%QQ7S3P  
if(breakWhile) yl ;'Ru:  
break; J3.Q8f  
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//count++; +?:V\niQI  
//if(count>4) BD0-v`  
// siteStop(); &"h!SkX/  
} !Cy2>6v7  
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System.err.println("文件下载结束！"); '> Q$5R1  
} QMxz@HGa|  
catch(Exception e){e.printStackTrace ();} l.W:6",w  
} X[
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//获得文件长度 `~]ReJ!X%  
public long getFileSize() feW9>f;  
{ Z
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int nFileLength = -1; kZ9pgdI  
try{ 7:<Ed"rdE  
URL url = new URL(siteInfoBean.getSSiteURL()); !~l%6Z5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \
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httpConnection.setRequestProperty("User-Agent","NetFox"); %$xFnGb  
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int responseCode=httpConnection.getResponseCode(); X8x>oV;8  
if(responseCode>=400) ECzNByP  
{ xH[yIfHkG@  
processErrorCode(responseCode); ~`E4E  
return -2; //-2 represent access is error $\!;*SSj  
} WCu%@hh=h  
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String sHeader; [;Ac
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for(int i=1;;i++) hob$eWgr  
{ 9Ol_z\5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Dg+d=I?  
//Utility.log(in.readLine()); 8|NJ(D-$  
sHeader=httpConnection.getHeaderFieldKey(i); ~(/HgFLLu  
if(sHeader!=null) Q$L(fHkw  
{ Y`?X Fy:  
if(sHeader.equals("Content-Length")) 9%14k  
{ QJM!W
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SYPMoE!U
:  
break; H;|:r[d!  
} Z<<gz[$+p  
} f;H#TSJ  
else qjzW9yV+  
break; c|( ?  
} ld}$Tsy0  
} p30&JJ!~"  
catch(IOException e){e.printStackTrace ();} ]GPJ(+5  
catch(Exception e){e.printStackTrace ();} hyfnIb@~}  
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Utility.log(nFileLength); bXwoJ2  
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return nFileLength; '#PqI)P  
}  &Z!K]OSY  
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//保存下载信息（文件指针位置） #x@lZ!Y  
private void write_nPos() yL x .#kx6  
{ IKzRM|/  
try{ k5;Vl0Ho  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D *I;|.=u  
output.writeInt(nStartPos.length); aC~n:0v  
for(int i=0;i<nStartPos.length;i++) <-B"|u
 
{ kefv=n*]l  
// output.writeLong(nPos); !FO^:V<|5  
output.writeLong(fileSplitterFetch.nStartPos); !M&un*  
output.writeLong(fileSplitterFetch.nEndPos); =l2Dm  
} 9_WPWFO  
output.close(); oA;Ty7s  
} k;_KKvQ  
catch(IOException e){e.printStackTrace ();} R 4$Q3vcH  
catch(Exception e){e.printStackTrace ();} t_>bTcsU  
} m_!vIUOz  
k)
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//读取保存的下载信息（文件指针位置） h>Uid &:?  
private void read_nPos() =6Sj}/  
{ ^Z>B/aJq  
try{ s'aV qB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  Ep\  
int nCount = input.readInt(); s|gD  
nStartPos = new long[nCount]; iQ|,&K0d]  
nEndPos = new long[nCount]; me:|!lI7YU  
for(int i=0;i<nStartPos.length;i++) CI!Eq&D,  
{ ,> (bt%b  
nStartPos = input.readLong(); Bq~hV;9nf  
nEndPos = input.readLong(); 8S1P&+iKs  
} qH h'l;.  
input.close(); }xf='lE  
} S@}B:}2  
catch(IOException e){e.printStackTrace ();} UGmuX:@y76  
catch(Exception e){e.printStackTrace ();} 6/mkJj+"  
} `?]rr0.}hp  
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private void processErrorCode(int nErrorCode) C^/ -lc  
{ ;;YcuzQI3  
System.err.println("Error Code : " + nErrorCode); NDRW  
} )pjjW"C+  
~[zFQ)([  
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//停止文件下载 1c)\  
public void siteStop() Z#4JA/c!  
{ i5 L:L  
bStop = true; ){+[$@9  
for(int i=0;i<nStartPos.length;i++) a1g6}ym\  
fileSplitterFetch.splitterStop(); m%oGzx+  
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} QGH h;  
} (!ZQ  
//负责部分文件的抓取 ` URSv,(  
**FileSplitterFetch.java |jahpji6  
*/ K,eqD<  
package NetFox; 1 [Sv  
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import java.io.*; ,4H;P/xsb  
import java.net.*; zBk_-'z  
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public class FileSplitterFetch extends Thread { `*e4m  
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String sURL; //File URL @J-plJ4e  
long nStartPos; //File Snippet Start Position 8yE!7$Mj  
long nEndPos; //File Snippet End Position 5%<TF.;-J  
int nThreadID; //Thread's ID  d?:`n9`  
boolean bDownOver = false; //Downing is over EHpu*P~W  
boolean bStop = false; //Stop identical  9t{|_G  
FileAccessI fileAccessI = null; //File Access interface 2?GXkPF2;A  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DpA\r_D  
{ `FUFK/7 w\  
this.sURL = sURL; >9-Dd)<  
this.nStartPos = nStart;
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this.nEndPos = nEnd; 9c#lLKrzG  
nThreadID = id; `$J'UXtGc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {b
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} Ns'FH(:  
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public void run() hzaU8kb  
{ RNGO~:k?r  
while(nStartPos < nEndPos && !bStop) 43
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{ r+o_t2_b*  
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try{ 4 GUA&qs  
URL url = new URL(sURL); g{e/X~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'r~8  
httpConnection.setRequestProperty("User-Agent","NetFox"); P"b8!k?  
String sProperty = "bytes="+nStartPos+"-"; WPIZi[hBs  
httpConnection.setRequestProperty("RANGE",sProperty); !6lOIgn  
Utility.log(sProperty); 5`"iq "5Cf  
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InputStream input = httpConnection.getInputStream(); k=e`*LB\  
//logResponseHead(httpConnection); +vf:z?I
8  
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byte[] b = new byte[1024]; 2SYKe$e  
int nRead; VrVDm*AGQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xWDR726  
{ xpAok]  
nStartPos += fileAccessI.write(b,0,nRead); #*^e,FF<  
//if(nThreadID == 1) }B`Ku5 M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0*/kGvw`i  
} >Co)2d]  
/ $_M@>  
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Utility.log("Thread " + nThreadID + " is over!"); h(nj,X+  
bDownOver = true; nWk e#{[  
//nPos = fileAccessI.write (b,0,nRead); ;=a_B1"9u  
} Ls1B\Aw_  
catch(Exception e){e.printStackTrace ();} zZ:xEc  
} #ra*f~G  
} 9mDnKW  
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grspt}  
//打印回应的头信息 tF^g<)S;t  
public void logResponseHead(HttpURLConnection con) h48YDWwy  
{ Yk'm?p#~  
for(int i=1;;i++) wN(&5rfS  
{ Z5$fE7ba+  
String header=con.getHeaderFieldKey(i); _%B/!)v  
if(header!=null) s9i|mVtm8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); U7h(-dV   
Utility.log(header+" : "+con.getHeaderField(header)); RU|X*3";T  
else 6WeM rWx  
break; 'C
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} {~_Y _-  
} >?I/;R.-  
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public void splitterStop() [1SMg$@<  
{ FY4T(4#  
bStop = true; h&`y$Jj  
} '1-maM\r  
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} D"^'.DL@wG  
Gq1)1  
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/* A[)C:q,  
**FileAccess.java "%@v++4y  
*//文件访问(定位，写) R/~,i;d>  
package NetFox; "VTF}#Uo  
import java.io.*; |>+uw|LtZ  
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public class FileAccessI implements Serializable{ ^2C>L}  
}`_(<H  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x+7*ADKb  
RandomAccessFile oSavedFile; (s&&>M]r_  
long nPos; nB] Ia?  
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public FileAccessI() throws IOException |`0n"x7  
{ gKi{Y1
 
this("",0); 6Hf,6>  
} >2lwWXA  
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public FileAccessI(String sName,long nPos) throws IOException KY.ZT2k  
{ Md&WJ };L  
oSavedFile = new RandomAccessFile(sName,"rw"); G5Ykbw#  
this.nPos = nPos; /XbW<dfl  
oSavedFile.seek(nPos); {/ 2E*|W~I  
} r*XLV{+4  
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*y]+dK&-  
public synchronized int write(byte[] b,int nStart,int nLen) orfp>B) 0  
{ -LWK*q[J;*  
int n = -1; {_>em*Vb  
try{ %!|O.xxRR  
oSavedFile.write(b,nStart,nLen); |"Z{I3Umg  
n = nLen; ,={t8lN  
} RE"^ )-  
catch(IOException e) .%}+R|g  
{ =.Tv)/ea  
e.printStackTrace (); Yj3I5RG  
} a`c:`v2o  
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return n; 3yO=S0`  
} 8dO?K*J,H'  
.*5Z"Q['G  
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} JAjku6  
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*hY2.t; X  
/* j*R,m1e8  
**SiteInfoBean.java Z-X?JA\&  
*/ Ng=ONh  
package NetFox; Xm!-~n@-m7  
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public class SiteInfoBean { <L0#O(L  
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private String sSiteURL; //Site's URL ccJM>9  
private String sFilePath; //Saved File's Path zsQoU&D
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private String sFileName; //Saved File's Name E6MA?Ax&=  
private int nSplitter; //Count of Splited Downloading File N{Qxq>6 G  
S::>N.y  
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public SiteInfoBean() 3Ofc\  
{//nSplitter的缺省值为5 gP}+wbk  
//default value of nSplitter is 5 BlC<`2S  
this("","","",5); L^`}J7r  
} sM2MLh'D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  iThSt72  
{ {MBTP;{*~  
sSiteURL= sURL;
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sFilePath = sPath; uaPx"  
sFileName = sName; Y3U9:VB  
this.nSplitter = nSpiltter; z8_XX$Mnt  
} p:%[  
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} nms8@[4-  
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public String getSSiteURL() ]+Ixi o  
{ KLWDo%%u  
return sSiteURL; Tl("IhkC  
} /F/;G*n  
2-+f1,  
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public void setSSiteURL(String value) b{7E;KyY,  
{ )7cb6jCU  
sSiteURL = value; X@A1#z+s0]  
} -7qIToO.  
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public String getSFilePath() N_C;&hJN$w  
{ (8a#
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return sFilePath; $4=
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} F\JUx L@8  
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public void setSFilePath(String value) 30j|D3-  
{ :Ixx<9c.  
sFilePath = value; "y?\Dx   
} ~p1EF;4#  
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public String getSFileName() a}yXC<}$  
{ IZ,oM!Y  
return sFileName; YPDf Y<?v  
} l,|%7-  
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public void setSFileName(String value) L:nXWz  
{ {}~:&.D  
sFileName = value; :a[Ihqfg  
} bzpFbfb  
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public int getNSplitter() [IZM.r`Z  
{ X@N$Z{  
return nSplitter; DbI!l`Vn4  
} ;U=q-tb  
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public void setNSplitter(int nCount) koG{ |elgB  
{ NcS.49  
nSplitter = nCount; :;;E<74e i  
} %V!iQzL1  
} 'fV%Z  
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/*
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**Utility.java M5L{*>4|6  
*/ <E|s\u  
package NetFox; pE]?x$5U  
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public class Utility { .\Fss(Zn  
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public Utility()  }alj[)  
{ >>Ar$  
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} GV|9H]_,I  
b8KsR=]4I  
//线程睡眠 n^(A=G  
public static void sleep(int nSecond) n`Z"rwKmNw  
{ &[R8Q|1j  
try{ VL+C&k v]  
Thread.sleep(nSecond); mdih-u(T|  
} 4R%*Z~  
catch(Exception e) F!!N9VIC  
{ /TQ}} YVw  
e.printStackTrace (); V\~WvV  
} fIC9WbiH-  
} yoe}
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L6P1L)
 
//日志 b4 #R!  
public static void log(String sMsg) ^4Am %yyT  
{ N^0uit  
System.err.println(sMsg); E:E4ulak  
} {i~8 :  
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public static void log(int sMsg) ?kw&=T!  
{ Oc?+M 5  
System.err.println(sMsg); eLD?jTi'  
} hIv@i\`  
} Kr`]_m  
\kamcA  
@JkK99\(>9  
/* iX{G]< n  
**TestMethod.java &xZyM@  
*/ g&/p*c_  
package NetFox; ;!@EixN-YH  
/(C~~XP)  
nQK|n^AU/  
public class TestMethod { H&}ipaDO  
8G%yB}pa  
,38Eq`5&W  
public TestMethod() n";02?@F  
{ ///xx/weblogic60b2_win.exe &sVvWNO#2  
try{ 6~meM@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ft JjY@#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }f>H\iJe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uZKP"Oy  
fileFetch.start(); ]LPQYL  
} vm23U^VJ  
catch(Exception e){e.printStackTrace ();} rd|uz4d  
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g\oSG)  
} 2Nc>6  
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=;~I_)Pg1  
public static void main(String[] args) 0IM8  
{ lVH<lp_ZtK  
new TestMethod(); *y[PNqyd  
} Q'B6^%:<~  
} l?E a#  
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