http断点续传简单实现（java)

/* YT(1 "{:  
**SiteFileFetch.java 
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*/ 2eR+dT  
package NetFox; ox=7N{+`J  
import java.io.*; h^_taAdS`  
import java.net.*; AIxBZt7{b  
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public class SiteFileFetch extends Thread { Qdr-GODx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1DlcO>#@  
long[] nStartPos; //开始位置 ?^$4)Y>Kf  
long[] nEndPos; //结束位置 CygV_q
  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'GzhZ
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long nFileLength; //文件长度 hYUV9k:  
boolean bFirst = true; //是否第一次取文件 TX [%s@C  
boolean bStop = false; //停止标志 7(g&z%  
File tmpFile; //文件下载的临时信息 2SPFjpG8n  
DataOutputStream output; //输出到文件的输出流 g&F<Uv#mZ  
T!xy^n]}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :
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public SiteFileFetch(SiteInfoBean bean) throws IOException %V1T!<  
{ ^\kHEM|5v  
siteInfoBean = bean; O-lh\9{'R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;$L!`"jn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o4
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if(tmpFile.exists ()) I;Fy k70w;  
{ B{UoNm@  
bFirst = false; ZFuJ2 :  
read_nPos(); Ww tQ>'R"  
} YB3=ij!K  
else .QQI~p0:  
{ RowiSW  
nStartPos = new long[bean.getNSplitter()]; H'\EA(v+  
nEndPos = new long[bean.getNSplitter()]; n9/0W%X>  
} j"sO<Q{6%  
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} \J:T]  
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public void run() yi;t  
{ sK/"  
//获得文件长度 Bg0cC  
//分割文件 6:tr8 X_  
//实例FileSplitterFetch "}+/0$F  
//启动FileSplitterFetch线程 fO(S+}  
//等待子线程返回 @CI6$  
try{ be%*0lr  
if(bFirst) j4r,_lH^r  
{ k[)@I;m  
nFileLength = getFileSize(); .%Q Ea_\  
if(nFileLength == -1) W*`6ero  
{ ld?.o/  
System.err.println("File Length is not known!"); Hll}8d6[  
} K.1yncS^  
else if(nFileLength == -2) emPm^M5/K
 
{ r+pjv_R  
System.err.println("File is not access!"); RAbq_^Q  
} !*UdY(  
else g9Gy3zk=  
{ " z'!il#  
for(int i=0;i<nStartPos.length;i++) xumv I{  
{ #zs\Z]3#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M?zAkHNS$  
} ^(vd8&71  
for(int i=0;i<nEndPos.length-1;i++) S]=Vr%irX  
{ j1+Y=@MA  
nEndPos = nStartPos[i+1]; bI(98V,t  
} Kp8T;&<Iay  
nEndPos[nEndPos.length-1] = nFileLength; fEv36xb2S  
} z5
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} bR,Iq}p  
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//启动子线程 o|q#A3%?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M[_I16s  
for(int i=0;i<nStartPos.length;i++) )6+W6:  
{ uI&M|u:nT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RhmVHhj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #K w\r50  
nStartPos,nEndPos,i); U~t(YT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @ RBwT  
fileSplitterFetch.start(); !;Nh7vG  
} ]!:Y]VYN)\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .9Fm>e+!C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V1A3l{>L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", = g}yA=.  
nEndPos = " + nFileLength); ,$-PC=Ti(  
// fileSplitterFetch[nPos.length-1].start(); K_n%`
5  
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//等待子线程结束 oD\+ 5[x  
//int count = 0; _s8_i6 Y  
//是否结束while循环 >.\E'e5^C  
boolean breakWhile = false; #mYxO  
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while(!bStop) e,8-P-h~T  
{ KL4/"$l]  
write_nPos(); CI{x/ e^(  
Utility.sleep(500); T1=M6iJ  
breakWhile = true; uLF55:`<  
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for(int i=0;i<nStartPos.length;i++) rI/KrBM  
{ N{g=Pf?I}  
if(!fileSplitterFetch.bDownOver) :f;|^(]"  
{ JB<
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breakWhile = false; "#jKk6{I0  
break;
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} n}{cs  
} y e'5A   
if(breakWhile) S}
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break; r$5!KO  
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//count++; &&O=v]6,V  
//if(count>4) ) |vFrR  
// siteStop(); ^MUM04l  
} / yCV-L2J  
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System.err.println("文件下载结束！"); :Kiu*&{  
} n:P}K?lg  
catch(Exception e){e.printStackTrace ();} \m&:J>^  
} >nX'RE|F  
$G3P3y: [  
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//获得文件长度 _qV_(TpS+  
public long getFileSize() s/V[tEC*z  
{ kel48B  
int nFileLength = -1; :[doYizk:  
try{ ^d,d<Uc  
URL url = new URL(siteInfoBean.getSSiteURL()); Y2Bu,/9^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +dfSCs  
httpConnection.setRequestProperty("User-Agent","NetFox"); VMp6s%m  
e 6*=Si}V  
h(BN6ZrzKd  
int responseCode=httpConnection.getResponseCode(); D$\ EZ
 
if(responseCode>=400) F~EriO  
{ SPBXI[[-  
processErrorCode(responseCode); #/T)9=m  
return -2; //-2 represent access is error ]P.S5s'  
} 8MIHp[vm%  
7DDot_qb  
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String sHeader; 5gGr|d|(  
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for(int i=1;;i++) Lxl?6wZ  
{ t1kD5^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =$MV3]  
//Utility.log(in.readLine()); "='|c-
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sHeader=httpConnection.getHeaderFieldKey(i); ]Sh&8 #  
if(sHeader!=null) Ex<loVIrP$  
{ <iMLM<J<w  
if(sHeader.equals("Content-Length")) F)C8LH  
{ ips
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6`'^$wKs  
break; K|iNEhuc  
} OnG?@sW+4!  
} _QQO&0Z  
else il:""x7^y  
break; IySlu^a  
} %lujme  
} -Jb I7Le  
catch(IOException e){e.printStackTrace ();} Gb"PMai  
catch(Exception e){e.printStackTrace ();} 7JbN WN  
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Utility.log(nFileLength); B|!Re4`0  
, =#'?>Kq  
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return nFileLength; wEdXaOEB5  
} W)KV"A3C  
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xSw ^v6!2  
//保存下载信息（文件指针位置） DwoO([&I  
private void write_nPos() C@xh$(y  
{ 8kk$:8  
try{ ;:v:pg8qc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )AnX[:y  
output.writeInt(nStartPos.length); J5429Soo  
for(int i=0;i<nStartPos.length;i++) O`*}N1No[  
{ f)>=.sp  
// output.writeLong(nPos); |@Bl?Bs+  
output.writeLong(fileSplitterFetch.nStartPos); k5
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output.writeLong(fileSplitterFetch.nEndPos); QHK$2xtq|  
} 8xLvpgcZ  
output.close(); lV3\5AEW  
} cO' \s  
catch(IOException e){e.printStackTrace ();} M5wj79'l"  
catch(Exception e){e.printStackTrace ();} W@#Y/L:${  
} $P>ci4]t  
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H.*XoktC]  
//读取保存的下载信息（文件指针位置） "Q^Ck7  
private void read_nPos() 8@Pv nOL  
{ Or0=:?4`  
try{ U5odSR$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K^EW*6vB8O  
int nCount = input.readInt(); +[ !K  
nStartPos = new long[nCount]; 4;x{@Ln  
nEndPos = new long[nCount]; (z\@T`6`  
for(int i=0;i<nStartPos.length;i++) 2]hQ56Yv3  
{ 
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nStartPos = input.readLong(); K%O%#Kk  
nEndPos = input.readLong(); u`3J2,.  
} )bXiw3'A  
input.close(); W-2,QVp
%  
} $)mK]57  
catch(IOException e){e.printStackTrace ();} `J#(ffo-  
catch(Exception e){e.printStackTrace ();} voEg[Gg4%I  
} ,!Gw40t  
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private void processErrorCode(int nErrorCode) ycTX\.KV  
{ e<#t]V  
System.err.println("Error Code : " + nErrorCode); L TzD\C'  
} 0"#'Z>"  
&]iiBp#2  
R5(<:]  
//停止文件下载 Kf/1;:^  
public void siteStop() /I(IT=kp  
{ Dyyf%'\M  
bStop = true; PRg^E4  
for(int i=0;i<nStartPos.length;i++) (R5n
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fileSplitterFetch.splitterStop(); 4$ya$Y%s%  
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L)p*D(  
} -{n2^vvF  
} ~PAF2  
//负责部分文件的抓取 L|A}A[P  
**FileSplitterFetch.java 2iO AUo+  
*/ 46OYOa  
package NetFox; Q8OA{EUtq  
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import java.io.*; Y">m g=B  
import java.net.*; 5n{J}0C  
Y>W$n9d&G2  
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public class FileSplitterFetch extends Thread { T%zCAfx m  
5P'o+Vwz  
Va"H.]  
String sURL; //File URL lOB*M!8   
long nStartPos; //File Snippet Start Position Av6=q=D  
long nEndPos; //File Snippet End Position DO6Tz-%o  
int nThreadID; //Thread's ID Z1Y/2MVSb  
boolean bDownOver = false; //Downing is over j=c=Pe"?u  
boolean bStop = false; //Stop identical '9d<vWg  
FileAccessI fileAccessI = null; //File Access interface  =ie8{j2:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IY_u|7d  
{ o\<m99Ub  
this.sURL = sURL; GY%^!r  
this.nStartPos = nStart; ^jY/w>UdH  
this.nEndPos = nEnd; 4PdJ  
nThreadID = id; $FR1^|P/G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3%HF"$Gg  
} }MU}-6  
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public void run() B"; >
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{ [k<"@[8)  
while(nStartPos < nEndPos && !bStop) cl\Gh  
{ Jr2x`^aNO  
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try{ `3wzOMgJ  
URL url = new URL(sURL); HV0!G-h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }253Q!f  
httpConnection.setRequestProperty("User-Agent","NetFox"); x{'3eJ^8  
String sProperty = "bytes="+nStartPos+"-"; *;N6S~_'Y  
httpConnection.setRequestProperty("RANGE",sProperty); @$:T]N3m  
Utility.log(sProperty); ,q_'l?Pn  
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InputStream input = httpConnection.getInputStream(); H]I^?+)9  
//logResponseHead(httpConnection);
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.
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byte[] b = new byte[1024]; xbTvv>'U  
int nRead; _0GM!Cny  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W~W`fm  
{ l^~E+F~  
nStartPos += fileAccessI.write(b,0,nRead); 0aWy!d
  
//if(nThreadID == 1) %jBI*WzR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BdMmeM2h  
} Gd%X> ~  
?^X e^1(  
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Utility.log("Thread " + nThreadID + " is over!"); wO-](3A-8P  
bDownOver = true; M"W~%   
//nPos = fileAccessI.write (b,0,nRead); xPcH]Gs^b  
} U@'F9UB`  
catch(Exception e){e.printStackTrace ();} Hyn*O)q!  
} !dcGBj  
} s.uw,x  

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ZH s' #  
//打印回应的头信息 q@@C|oqEX  
public void logResponseHead(HttpURLConnection con) N!=$6`d  
{ /c4@QbB  
for(int i=1;;i++) cUDo}Yu  
{ n !oxwA!  
String header=con.getHeaderFieldKey(i); WVMkLMg8d  
if(header!=null) =QG0:z)K<v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cD5^mxd%  
Utility.log(header+" : "+con.getHeaderField(header)); v:xfGA nP  
else <\6<-x(H5  
break; #q-7#pp  
} uG:xd0X+W  
} ;zpSyyp@  
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public void splitterStop() RIg `F#,3  
{ 2y;J 11\  
bStop = true; [@4.<4Y  
} J|gRG0O9Ya  
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} o)U4RY*  
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/* &}."sGK  
**FileAccess.java MEled:i  
*//文件访问(定位，写) i^I U)\  
package NetFox; K:_5#!*^98  
import java.io.*; (;(P3h  
WKDa]({k%  
mAZfo53  
public class FileAccessI implements Serializable{ !7fL'  
ji] H|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ))xyaYIZkk  
RandomAccessFile oSavedFile; `(Eiu$h6V-  
long nPos; =TcT
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public FileAccessI() throws IOException Jp#Onl+d6  
{ 'ai3f  
this("",0); w15QqhlK  
} Q}qw`L1  
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public FileAccessI(String sName,long nPos) throws IOException L';b908r2  
{ J}M_Ka  
oSavedFile = new RandomAccessFile(sName,"rw"); c1>:|D7w  
this.nPos = nPos; a*GiLq  
oSavedFile.seek(nPos); Kx<T;iJ}  
} mQiVTIP3[O  
>x0)  
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public synchronized int write(byte[] b,int nStart,int nLen) 6U!zc]>  
{ ^U@-Dp,k+  
int n = -1; Mb
+  
try{ q8-*3
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oSavedFile.write(b,nStart,nLen); tY>_+)oi  
n = nLen; g6V>_|  
} x } X1 O)  
catch(IOException e) VQe@H8>3  
{ M"l<::z  
e.printStackTrace (); wLW[Vur[  
} 6:$+"@ps  
PS
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return n; sQ05
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} A!bH0=<I  
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} L32[IL|  
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[:Y`^i
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/* </@3}rfUPg  
**SiteInfoBean.java x+;"(]#  
*/ vOnhJN  
package NetFox; *v6 j7<H  
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public class SiteInfoBean { WN`|5"?$  
2J0N]`|)  
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private String sSiteURL; //Site's URL iM'rl0  
private String sFilePath; //Saved File's Path `k.Nphx~%  
private String sFileName; //Saved File's Name Vh o3I[C  
private int nSplitter; //Count of Splited Downloading File 3`3`iN!8\@  
ckCb)r_  
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public SiteInfoBean() ){S/h<4m  
{//nSplitter的缺省值为5 .Km6 (U  
//default value of nSplitter is 5 >?yxig:_  
this("","","",5); 9 U!-Zn!  
} /~nPPC  
%*Aq%,.={  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }p$@.+  
{ |o0?u:  
sSiteURL= sURL; KH_~DZU*5  
sFilePath = sPath; #lo1GoL\  
sFileName = sName; \&#pJBBG  
this.nSplitter = nSpiltter; 3<vw#]yL  
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JrhDqyk*  
} klON6<w  
b
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V3] Z~@  
public String getSSiteURL() R3\oLT4  
{ :^92B?q  
return sSiteURL; G zw $M  
} T#:n7$M|?A  
2S#|[wq(  
$u-yw1FT  
public void setSSiteURL(String value) J3P)oM[  
{ rM5{R}+;  
sSiteURL = value; /_g-w93   
} pipO,n  
+D&aE$<  
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public String getSFilePath() `:y
{  
{ DuV@^qSbG.  
return sFilePath; AQR/nWwx  
} "oc&uj  
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public void setSFilePath(String value) OqNtTk+  
{
:i8B'|DN5  
sFilePath = value; y/d/#}\:  
} }k7t#O  
+;*dFL  
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public String getSFileName() 2zQ62t}  
{ V\4zK$]  
return sFileName; ` 0}z ;&:  
} ;kv/(veQ1<  
[n!5!/g>j  
,Q>RtV  
public void setSFileName(String value) E Qn4+  
{ Jg:%|g  
sFileName = value; \n}@}E L  
} N~] 4,~  
\u@*FTS  
-YD+xPD  
public int getNSplitter() ugT;NB  
{ $ &III  
return nSplitter; {P[>B}'rW  
} hI Q 2s  
|2'u@<(Z/  
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public void setNSplitter(int nCount) YB&b_On,f  
{ 5l]G1+  
nSplitter = nCount; 08 $y1;  
} I(2qXOG  
} Y(D&JKx  
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/* A\IQM^i  
**Utility.java EJ&aT etQ  
*/ nz%{hMNYH  
package NetFox; zUNWcv!& "  
l]wjH5mz=i  
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public class Utility { QhqXd  
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public Utility() oI2YJ2?Je8  
{ 5OS|Vp||
b  
xQ{n|)i>  
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} 45+w)Vf!  
@s[Vtw%f  
//线程睡眠 ja1WI  
public static void sleep(int nSecond) HC[)):S*  
{ U.mVz,k3  
try{ Za4X ;  
Thread.sleep(nSecond); iT;~0XU7F  
} [@RJ2q$  
catch(Exception e) N~/D| ?P~2  
{ NrTK+6 z  
e.printStackTrace (); e_iXR#bZc  
} HXY,e$c#y  
} [->uDbtzL  
%n7mN])  
//日志 )08mG_&atL  
public static void log(String sMsg) bU+ z(Eg6  
{ 1_Ag:>#X  
System.err.println(sMsg); 9f+S-!  
} 0w24lVR
.  
n@ rphJb  
oI/jGyY;  
public static void log(int sMsg) LEJ8 .z6$  
{ 9"%ot=)  
System.err.println(sMsg); |}YeQl  
} 2wKW17wj,  
} =Y;w O8  
6L\?+=X  
/ZcqKC  
/* :% o32  
**TestMethod.java p=-:Z?EW1  
*/ QL{{GQ_dn  
package NetFox; v\;hI5WY  
h4\j=Np  
`VB]4i}u  
public class TestMethod { EoOB0zo}Y+  
`fA|])3T  
&-s/F`  
public TestMethod() X?Yp=%%
 
{ ///xx/weblogic60b2_win.exe 1`;,_>8  
try{ 5*
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q,1TD2)h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K/OE;;<IA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P{{pp<tX*&  
fileFetch.start(); spVE'"^  
} &q?A)R  
catch(Exception e){e.printStackTrace ();} liuF;*  
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'&<T;V%  
} !4ZszQg  
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v]tNJ=aI  
public static void main(String[] args) 9sR?aW^$,/  
{ mV58&SZT  
new TestMethod(); 9)Jc'd|  
} HS% P  
} k8~/lE.Wy  
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