http断点续传简单实现（java)

/* ^& t
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**SiteFileFetch.java
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*/ J6s`'gFns  
package NetFox; dGYn4i2k?  
import java.io.*; Ustv{:7v  
import java.net.*; uD$u2  
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public class SiteFileFetch extends Thread { B:;pvW]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ( iBl  
long[] nStartPos; //开始位置 G C),N\@Q  
long[] nEndPos; //结束位置 .779pT!,M
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?cBwPetp  
long nFileLength; //文件长度 \:# L)  
boolean bFirst = true; //是否第一次取文件 av}k)ZT_  
boolean bStop = false; //停止标志 eueH)Xkf  
File tmpFile; //文件下载的临时信息 0_95|3kc  
DataOutputStream output; //输出到文件的输出流 =)H.cuc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +qtJaYf/0  
public SiteFileFetch(SiteInfoBean bean) throws IOException (lBCO?`fx  
{ (>UZ<2GPL  
siteInfoBean = bean; 2\A$6N;_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ja7R2-0ii#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dh`K`b4I  
if(tmpFile.exists ()) =w_Ype`  
{ xaq-.IQAM$  
bFirst = false; t9kzw*U9  
read_nPos(); ';w#w<yaI  
} ??
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else
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{ 67JA=,EE  
nStartPos = new long[bean.getNSplitter()]; 1b`1{%  
nEndPos = new long[bean.getNSplitter()]; ~drS} V  
}
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} 6"LcJ%o  
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public void run() ?/
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{ )0.kv2o.  
//获得文件长度 }>pknc?  
//分割文件 8O5s`qKMYT  
//实例FileSplitterFetch ]}<}lI9  
//启动FileSplitterFetch线程 fIx+ILs  
//等待子线程返回 4x=v?g&  
try{ %B2'~|g  
if(bFirst) ~RW+GTe  
{ X:f UI4  
nFileLength = getFileSize(); h0*!;Z7  
if(nFileLength == -1) u:6Ic)7'  
{ j78i#}e  
System.err.println("File Length is not known!"); %~O,zs.2p  
} ,8S/t+H  
else if(nFileLength == -2) .KB^3pOpx  
{ tVYF{3BhA  
System.err.println("File is not access!"); :;RMo2Tl  
} YFLZ%(  
else s[RAHU  
{ :T^a&)aL%  
for(int i=0;i<nStartPos.length;i++) |IeTqEu9  
{ rT=rrvV3g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {g'(~ qv  
} <prk8jSWV  
for(int i=0;i<nEndPos.length-1;i++) OZb-:!m*  
{ FZ{h?#2?  
nEndPos = nStartPos[i+1]; [SjqOTon{  
} %+aCJu[k(z  
nEndPos[nEndPos.length-1] = nFileLength; (+w*[qHe  
} h"[AOfTE$  
} MD}w Y><C  
f&NgS+<K$  
=J
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//启动子线程 A9KET$i@v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .Yamc
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for(int i=0;i<nStartPos.length;i++) m<<+  
{ %8RrRW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JU4<|5H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NlA,'`,  
nStartPos,nEndPos,i); oM
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lF<]8m%F  
fileSplitterFetch.start(); N~nziY*C,*  
} +RHS!0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^rB8? kt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6B8VfQ9[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z 4e7PW|  
nEndPos = " + nFileLength); rX U  
// fileSplitterFetch[nPos.length-1].start(); z{%<<pZ  
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I }a`0Y&{  
//等待子线程结束 ")1:F>  
//int count = 0; o@_q]/Mh  
//是否结束while循环 y B81f  
boolean breakWhile = false; ~T"Rw2vb  
H9Gh>u]}  
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while(!bStop) sbfuzpg]*  
{ 77 Q5d"sIi  
write_nPos(); /m!BY}4W  
Utility.sleep(500); `_6C{<O  
breakWhile = true; H-!,yte  
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for(int i=0;i<nStartPos.length;i++) v1#otrf  
{ (fhb0i-  
if(!fileSplitterFetch.bDownOver) h,(26 y/s  
{ CmWeY$Jb  
breakWhile = false; j
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break; [DYQ"A=)d  
} Ex.yU{|c  
}
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if(breakWhile) SjK  
break; ,Y@Gyx!4  
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//count++;  }t!Gey  
//if(count>4) j\ZXG=j  
// siteStop(); b3P+H r  
} Yz9owe8}[  
!@5 9)  
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System.err.println("文件下载结束！"); iR HQ:Y!  
} b;L\EB  
catch(Exception e){e.printStackTrace ();} ~kV/!=  
} H[T?\Lq  
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//获得文件长度 0RzEY!9g+  
public long getFileSize() PgAf\.48a  
{ pP1|&`}ux  
int nFileLength = -1; TbMW|0 #w  
try{ MnmVl"(/  
URL url = new URL(siteInfoBean.getSSiteURL()); hy9\57_#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1l9G[o *  
httpConnection.setRequestProperty("User-Agent","NetFox"); U
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int responseCode=httpConnection.getResponseCode(); t <~h'U  
if(responseCode>=400) >:SHV W  
{ g%o(+d  
processErrorCode(responseCode); ]iVcog"T  
return -2; //-2 represent access is error 2y75  
} xexaQuK  
)',R[|<  
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String sHeader; $Ph|e)p  
53_Hl]#qZ  
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for(int i=1;;i++) SV4E0c>  
{ $+Z[K.2J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WpDSg*fk=Y  
//Utility.log(in.readLine()); aNsBcov3O  
sHeader=httpConnection.getHeaderFieldKey(i); 7lTC{7C57  
if(sHeader!=null) gE-tjoJ  
{ eNh39er  
if(sHeader.equals("Content-Length")) EZgwF=lO  
{ \eTwXe]Pv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KA5v+~  
break; m5n#v  
} qyb?49I  
} '(6z. toQ  
else %64)(z  
break; `K"L /I9  
} v4<nI;Ux  
} 5{TsiZh4  
catch(IOException e){e.printStackTrace ();} 3l]lwV  
catch(Exception e){e.printStackTrace ();} 'B$
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Utility.log(nFileLength); B
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return nFileLength; ';k5?^T  
} W<{h,j8  
!"AvY
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//保存下载信息（文件指针位置）
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private void write_nPos() _{ue8kGt  
{ ,O5NLg-  
try{ ~i= _J3'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I@\lN&HC  
output.writeInt(nStartPos.length); t3WiomNCc  
for(int i=0;i<nStartPos.length;i++) .N;=\C
*  
{ :]K4KFM  
// output.writeLong(nPos); cdH>n)  
output.writeLong(fileSplitterFetch.nStartPos); E,Z$pKL?  
output.writeLong(fileSplitterFetch.nEndPos); Xfc-UP|}  
} q_lKKzA  
output.close(); Q>qUk@  
} ux-/>enc  
catch(IOException e){e.printStackTrace ();} evJ4C#Pr  
catch(Exception e){e.printStackTrace ();} W ~<^L\Lu  
} y8y5*e~A-)  
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//读取保存的下载信息（文件指针位置） !<|4C6X:4  
private void read_nPos() sfH_5 #w  
{ 5&g@3j]  
try{ Oamg]ST  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]OhiYU4  
int nCount = input.readInt(); &<g|gsG`  
nStartPos = new long[nCount]; f^ZRT@`O  
nEndPos = new long[nCount]; Rr$-tYy6  
for(int i=0;i<nStartPos.length;i++) 1UgEI"#a6g  
{ `cn#B BV  
nStartPos = input.readLong(); 2ACCh4(/P  
nEndPos = input.readLong(); H H)!_(SA  
} of~4Q{f$6  
input.close(); &3>)qul  
} m,28u3@r  
catch(IOException e){e.printStackTrace ();} ;]puq  
catch(Exception e){e.printStackTrace ();} _RYxD"my  
}  'c&Ed  
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private void processErrorCode(int nErrorCode) "9uKtQS0o  
{ 3yme1Mb  
System.err.println("Error Code : " + nErrorCode); yF:1( 4  
} 0JS?;fk  
bRDYGuC  
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//停止文件下载 OKZV{Gja  
public void siteStop() 234p9A@  
{ GMx&y2. Z  
bStop = true; ;>hO+Wo  
for(int i=0;i<nStartPos.length;i++) `RT>}_
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fileSplitterFetch.splitterStop(); iXkF1r]i  
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} ]EbM9Fo-U  
} ^0)g/`H^>  
//负责部分文件的抓取 G't$Qx,IC  
**FileSplitterFetch.java GKqm&/M*=  
*/ ;O5zUl-`  
package NetFox; Ty\R=y}}  
;C#F>SG\S  
+480 l}  
import java.io.*; ,pfG  
import java.net.*; M^Yh|%M  
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public class FileSplitterFetch extends Thread { uc{Ihw  
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String sURL; //File URL XW H5d-  
long nStartPos; //File Snippet Start Position I|!OY`ko  
long nEndPos; //File Snippet End Position hag$GX'2k
 
int nThreadID; //Thread's ID c]-<vkpV  
boolean bDownOver = false; //Downing is over w"F 9l  
boolean bStop = false; //Stop identical \7eUw,~Q>  
FileAccessI fileAccessI = null; //File Access interface ,t744k')  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Es`Px_k  
{ s)t@ol  
this.sURL = sURL; ~Cttzn]pR  
this.nStartPos = nStart; (x|T+c"bAX  
this.nEndPos = nEnd; G>=*yqo  
nThreadID = id; octL"t8w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2s8a $3  
} l30EKoul)  
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@{e}4s?7od  
public void run() *Q
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{ =BeygT^  
while(nStartPos < nEndPos && !bStop) Jr4Ky<G_i  
{ }tuC}  
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try{ dQX6(Jj  
URL url = new URL(sURL); QL/(72K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4@gG<QJW  
httpConnection.setRequestProperty("User-Agent","NetFox"); U>SShpmZA  
String sProperty = "bytes="+nStartPos+"-"; Vt~{
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httpConnection.setRequestProperty("RANGE",sProperty); Pm?KI<TH~  
Utility.log(sProperty); M0"_^?  
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InputStream input = httpConnection.getInputStream(); Zl!kJ:0  
//logResponseHead(httpConnection); RBd7YWo\|j  
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byte[] b = new byte[1024]; 1.hyCTnI  
int nRead; Ee#q9Cx^J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hfB%`x#akQ  
{  }v{LRRi  
nStartPos += fileAccessI.write(b,0,nRead); 3\,4 ]l|  
//if(nThreadID == 1) 7EEl+;wK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LOYk9m  
} G!##X: 6'  
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Utility.log("Thread " + nThreadID + " is over!"); e%M;?0j  
bDownOver = true; =XQ%t @z0  
//nPos = fileAccessI.write (b,0,nRead); {S\{Ii6  
} ?z+eWL  
catch(Exception e){e.printStackTrace ();} {YC@T(  
} ]/6z; ~3U  
} IPpN@  
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//打印回应的头信息 G_JA-@i%  
public void logResponseHead(HttpURLConnection con) 372rbY  
{ TX/Xt7#R:  
for(int i=1;;i++) ,p
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{ 'Is kWgc  
String header=con.getHeaderFieldKey(i); t?gic9 q  
if(header!=null) T!{w~'=F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .{^5X)  
Utility.log(header+" : "+con.getHeaderField(header)); kZ:ZtE  
else f~[7t:WD*  
break; 
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} wlvgg  
} @HCVmg:  
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public void splitterStop() @mBQ?;qlK  
{ >U>(`r*  
bStop = true; UkC!1Jy  
} -2[a2^a'  
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} }.(B}/$u  
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/* #{6/ (X  
**FileAccess.java xo&_bMO  
*//文件访问(定位，写) mJnIwdW*  
package NetFox; b%`1cV  
import java.io.*; ;'K5J9k  
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public class FileAccessI implements Serializable{ aXYY:;  
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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 Vb_4f"  
RandomAccessFile oSavedFile; ,4$>,@WW~  
long nPos; P@B]

 
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public FileAccessI() throws IOException n\DV3rXI9  
{ {tZ.v@  
this("",0); m s\}  
} f}e`X
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public FileAccessI(String sName,long nPos) throws IOException 7$=InK  
{ KpGhQdR#  
oSavedFile = new RandomAccessFile(sName,"rw"); "+s++@ z  
this.nPos = nPos; GefTdO.&  
oSavedFile.seek(nPos); >GRxHK@G  
} RrB&\9=  
b$joY*< 6  
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public synchronized int write(byte[] b,int nStart,int nLen) VONDc1%ga  
{ eauF~md,  
int n = -1; t{96p77)=  
try{ +<C!U'  
oSavedFile.write(b,nStart,nLen); 6_Y,eL]"  
n = nLen; ~?BXti<!  
} ?tbrbkx  
catch(IOException e) ZE}}W_  
{ :I#V.  
e.printStackTrace (); &QgR*,5eo  
} Rm( "=(  
}7Q%6&IR  
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return n; 8ib:FF(= u  
} i_%_x*  
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} 1+s;FJ2}  
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/* *2l7f`K  
**SiteInfoBean.java !Vk^TFt`  
*/ ;=z
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package NetFox; @ 6vIap|  
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public class SiteInfoBean {
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private String sSiteURL; //Site's URL |6-nbj  
private String sFilePath; //Saved File's Path 2>%=U~5  
private String sFileName; //Saved File's Name HRA|q  
private int nSplitter; //Count of Splited Downloading File zb3tIRH  
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public SiteInfoBean() l/5 hp.  
{//nSplitter的缺省值为5 [/r(__.  
//default value of nSplitter is 5 ob]w;"  
this("","","",5); W>r+h-kR  
} J&_n9$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Di{de`  
{ PKz':_|  
sSiteURL= sURL; (
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sFilePath = sPath; h?U O&(  
sFileName = sName; i%?*@uj  
this.nSplitter = nSpiltter; *;FdD{+  
}GM'.yutX  
(ZlU^Gw#UB  
} ~xTt204S  
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public String getSSiteURL() omx=  
{ Mtx4'WZ  
return sSiteURL; ~W/z96' 5  
} V7/Rby Q  
[}m[)L\  
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public void setSSiteURL(String value) DlJo^|5  
{ *T1_;4i  
sSiteURL = value; {!`6zBsP  
} HzJz+ x:  
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public String getSFilePath() Fr-SvsNFB  
{ 7tp36TE  
return sFilePath; 3so%gvY.'  
} l]SX@zTb  
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public void setSFilePath(String value) rJB}qYD  
{ Z_NCD`i;  
sFilePath = value; =_^X3z0  
} * y,v}-  
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public String getSFileName() LP=)~K
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{ RnN!2K  
return sFileName; 
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} ;.C\Ss<>*  
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public void setSFileName(String value) ,!9zrYi}  
{ O6Y0XL  
sFileName = value; 2g<Xtt7+o  
} eS!/(#T  
ssL
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public int getNSplitter() 5zJq9\)d+  
{ :6dxtl/{b:  
return nSplitter; FI.\%x  
} GvAb`c=  
H?w6C):]  
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public void setNSplitter(int nCount) fqd^9wl>P6  
{ D_MmW  
nSplitter = nCount; 'ga/  
} VU#7%ufu&  
} jiGTA:v
 
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/* d zMb5puH  
**Utility.java c@Is2 9t*  
*/ l-3~K-k<@  
package NetFox; 18Emi<&A  
?]5qr?W%  
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public class Utility { Rb;'O89Hj@  
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public Utility() iow"n$/  
{ Ul#
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} x1<|hTPk  
A}^mdw9  
//线程睡眠 VN.Je:Ju  
public static void sleep(int nSecond) kGJC\{N5N  
{ }B^tL$k  
try{ >GuM]qn  
Thread.sleep(nSecond); dWW.Y*339  
} $Kd>:f=A  
catch(Exception e) 7$#u  
{ UZ";a453r  
e.printStackTrace (); xx $cnG  
} +ai< q>+  
} bK7J}8hH  
&3&HY:yF  
//日志 g{LP7D;6  
public static void log(String sMsg) H*6W q  
{ R-14=|7a-  
System.err.println(sMsg); _dU\JD  
} Xc.`-J~Il  
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public static void log(int sMsg) s[N@0  
{ _Ey5n!0:  
System.err.println(sMsg); ,z6~?6m  
} 0`H# '/  
} ZC8wA;
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)}vl\7=  
/* P {'b:C  
**TestMethod.java 2zpr~cB=  
*/ DwF hK*  
package NetFox; @|!z9Y*  
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public class TestMethod { QL*IiFR  
vSh`&w^*  
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public TestMethod() 5-M-X#(  
{ ///xx/weblogic60b2_win.exe AwN!;t_0+N  
try{ s^SJY{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]^
]wP]R_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kVL.PY\K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }WV:erg`  
fileFetch.start(); #"an9<  
} ;}t(Wnu.  
catch(Exception e){e.printStackTrace ();} K^[?O{x^B  
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$^{  
} I:.s_8mH}  
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public static void main(String[] args) zreU')a  
{ 0IpmRH/  
new TestMethod(); /tLVX} &  
} ;rS{:  
} KlqY@Xt  
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