http断点续传简单实现（java)

/* IAt;?4  
**SiteFileFetch.java 8?S32Gdu  
*/ ..qAE.%%  
package NetFox; } d /5_X  
import java.io.*; rs01@  
import java.net.*; ,63hO.4M  
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public class SiteFileFetch extends Thread { M.K-)r,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -Iz&/u*}f  
long[] nStartPos; //开始位置 EAQg4N:D7L  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 LOyL:~$  
long nFileLength; //文件长度 xq:.|{HUk  
boolean bFirst = true; //是否第一次取文件 <dx xXzLT  
boolean bStop = false; //停止标志 _//)|.6c3  
File tmpFile; //文件下载的临时信息 bWv4'Y!p  
DataOutputStream output; //输出到文件的输出流 -If-c'"G  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &x{CC@g/  
public SiteFileFetch(SiteInfoBean bean) throws IOException nu,#y"WQ  
{ qO=_i d  
siteInfoBean = bean; #5GIO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -bHQy:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YmM+x=G:  
if(tmpFile.exists ()) 
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{ u7>b}+ak&  
bFirst = false; CIh@H6|  
read_nPos(); D%v4B`4ua'  
} !dB {E  
else :8}QKp  
{ *Dld?Q  
nStartPos = new long[bean.getNSplitter()]; ` bd  
nEndPos = new long[bean.getNSplitter()]; <8MKjf  
} `r+"2.z*  
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} P"0S94o:5J  
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public void run() wZVY h  
{ P0J3ci}^  
//获得文件长度 HlqvXt\  
//分割文件 <va3Ly)c&  
//实例FileSplitterFetch 9I8{2]  
//启动FileSplitterFetch线程 >N>WOLbb7(  
//等待子线程返回 \P]w^  
try{
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if(bFirst) F)/}Q[o8  
{ JqTkNKi/s  
nFileLength = getFileSize(); &P&LjHFK  
if(nFileLength == -1) V6"
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{ #|fa/kb~  
System.err.println("File Length is not known!"); vCT5do"C&  
} y0qrl4S)v  
else if(nFileLength == -2) 9Vz1*4Ln  
{ h)BRSs?v_D  
System.err.println("File is not access!"); Q[^IX  
} zCKZv|j6  
else {J q[N}  
{ T;jp2 #  
for(int i=0;i<nStartPos.length;i++) kM5N#|!  
{ \o9-[V#Gm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hK"hMyH^  
} Ei2Y)_  
for(int i=0;i<nEndPos.length-1;i++) 78>)<$+d  
{ an^"_#8DA@  
nEndPos = nStartPos[i+1]; `m?%{ \  
} U>6MT@\  
nEndPos[nEndPos.length-1] = nFileLength; {4Y@DQ-  
} `O(ec  
} 8;;!2>N  
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L+Yn}"gIs  
//启动子线程 ]kq{9b';  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a'f"Zdh%w  
for(int i=0;i<nStartPos.length;i++) . $uvQpyh  
{ o^;$-O!/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6H67$?jMyJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <jF]SN  
nStartPos,nEndPos,i); cc7*O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^D\1F$AjC  
fileSplitterFetch.start(); xc[@lr  
} YLVV9(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9tsI1]1[m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4k_&Q?1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zQ9"i  
nEndPos = " + nFileLength); $j:$ `  
// fileSplitterFetch[nPos.length-1].start(); $u_0"sUV  
!Uz{dFJf;  
3}=r.\]U  
//等待子线程结束 :S}!i?n  
//int count = 0; 0F-X.Dq  
//是否结束while循环 1C\OL!@L  
boolean breakWhile = false; D_ xPa  
!TY9\8JzV  
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while(!bStop) t m?[0@<s  
{ n"8vlNeW  
write_nPos(); IY6DZP  
Utility.sleep(500); 24PEt%2  
breakWhile = true; ,80qwN,  
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for(int i=0;i<nStartPos.length;i++) D].!u{##  
{ T:q_1W?h]  
if(!fileSplitterFetch.bDownOver) ~4h<nc  
{ 6s\niro2  
breakWhile = false;  S[!K  
break; \$YKw0K  
} :b)IDcW&j:  
} =gS?atbX  
if(breakWhile) J#vIzQ  
break; '_,/N!-V  
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//count++; t!RR5!  
//if(count>4) >c%OnA,3  
// siteStop(); W[BZ/  
} )=l~XV  
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System.err.println("文件下载结束！"); |niYN7 17  
} B*7Y5_N  
catch(Exception e){e.printStackTrace ();} xgHR;USH  
} "MHm9D?5  
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&v|Uy}h&%1  
//获得文件长度 =!T@'P?  
public long getFileSize() !E!i`yF  
{ DhY.5  
int nFileLength = -1; .?R~!K{`  
try{ iSu7K&X9q  
URL url = new URL(siteInfoBean.getSSiteURL()); w>Iw&US  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W1'F)5(?7  
httpConnection.setRequestProperty("User-Agent","NetFox"); uKc x$  
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int responseCode=httpConnection.getResponseCode(); ,Oa-AF/p  
if(responseCode>=400) stuj,8  
{ >QO^h<.>  
processErrorCode(responseCode); )3#gpM  
return -2; //-2 represent access is error +\g/KbV7  
} X{4jyi-<  
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String sHeader; '
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for(int i=1;;i++) MuXp*s3[  
{ O O?e8OU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FsQeyh>  
//Utility.log(in.readLine()); {y)O?9q  
sHeader=httpConnection.getHeaderFieldKey(i); MCOiB<L6  
if(sHeader!=null) Z`x|\jI  
{ Cbu/7z   
if(sHeader.equals("Content-Length")) !>QS746S@  
{ fB^h2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xIu#  
break; Py*( %  
} M)S(:Il6Xx  
} /(IV+  
else X[/>{rK  
break; ]v^/c~"${  
} fy+fJ )4sj  
} mdjPKrF<  
catch(IOException e){e.printStackTrace ();} &*2\1;1tB  
catch(Exception e){e.printStackTrace ();} biAI*t  
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Utility.log(nFileLength); _8t5rF  
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return nFileLength; |vW(;j6  
} rEz-\jLD~  
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//保存下载信息（文件指针位置） c%1k'Q  
private void write_nPos() @}[>*Xy%  
{ Mx9#YJ?t~  
try{ DV+M;rs  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9R_2>BDn  
output.writeInt(nStartPos.length); 9/A$3#wF  
for(int i=0;i<nStartPos.length;i++) 5=/&[=  
{ /`(Kbwh  
// output.writeLong(nPos); 0XouHU  
output.writeLong(fileSplitterFetch.nStartPos); UNLmnj;-Q  
output.writeLong(fileSplitterFetch.nEndPos); X3[gi`  
} W\]bh'(  
output.close(); ;R[  xo!  
} 1 
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catch(IOException e){e.printStackTrace ();} vByt_X  
catch(Exception e){e.printStackTrace ();} =&+]>g{T  
} 337
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//读取保存的下载信息（文件指针位置） B ~u9"SR.  
private void read_nPos() $t*>A+J  
{ |-Rg].  
try{ =$bJ`GpJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fP 1V1ao  
int nCount = input.readInt(); vTnrSNdSE  
nStartPos = new long[nCount]; Pdgn9  
nEndPos = new long[nCount]; 3a9%djGq  
for(int i=0;i<nStartPos.length;i++) 5)712b(&  
{ rP4v_?Zg
+  
nStartPos = input.readLong(); vW6 a=j8  
nEndPos = input.readLong(); 5cc;8i  
} lMkDLobos  
input.close(); .CJQ]ECl7p  
} Xae0xs  
catch(IOException e){e.printStackTrace ();} d)@Hx8  
catch(Exception e){e.printStackTrace ();} 'ec G:B`S  
} (!b_o A8V  
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private void processErrorCode(int nErrorCode) S
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{ 5L ]TV\\  
System.err.println("Error Code : " + nErrorCode); 8CXZ7p  
} >?Y)evW  
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//停止文件下载 1XfH,6\8i  
public void siteStop() {u!Q=D$3  
{ Yz<,`w5/6~  
bStop = true; V+\L@mz;  
for(int i=0;i<nStartPos.length;i++) F; upb5  
fileSplitterFetch.splitterStop(); zzlqj){F  
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} E lf'1  
} +IS+!K0?)  
//负责部分文件的抓取 TtZZjeg+V  
**FileSplitterFetch.java TcB^Sctf  
*/ P9d%80(b4  
package NetFox; mM`zA%=  
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}
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import java.io.*; |E{tS,{OhJ  
import java.net.*; ]JGh[B1gh  
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public class FileSplitterFetch extends Thread { kXjrc  
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String sURL; //File URL 01N]|F:  
long nStartPos; //File Snippet Start Position $? 'JePC
 
long nEndPos; //File Snippet End Position v %?y5w  
int nThreadID; //Thread's ID ,/m@<NyK  
boolean bDownOver = false; //Downing is over "h@|XI  
boolean bStop = false; //Stop identical g>k"R4  
FileAccessI fileAccessI = null; //File Access interface `2WtA_  
VV_Zrje  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U,G!u=+  
{ Drn{ucIs  
this.sURL = sURL; Kmk}Yz  
this.nStartPos = nStart; kzky{0yKk=  
this.nEndPos = nEnd; Fe:M'.  
nThreadID = id; 2
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 2/*F}w/  
} |6qxRWT"  
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public void run() sObH#/l`  
{ 7z.(pg=  
while(nStartPos < nEndPos && !bStop) KOQiX?'  
{ Z.Otci>J  
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try{ ^A&i$RRO  
URL url = new URL(sURL); jwP}{mi*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;q=0NtCS=4  
httpConnection.setRequestProperty("User-Agent","NetFox"); q+j.
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String sProperty = "bytes="+nStartPos+"-"; g]fdsZv  
httpConnection.setRequestProperty("RANGE",sProperty); "ITC P<+  
Utility.log(sProperty); AD$$S.zoD<  
`5HFRgL`.
 
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InputStream input = httpConnection.getInputStream(); ^Vbx9UN/  
//logResponseHead(httpConnection); !b !C+ \v  
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byte[] b = new byte[1024]; i146@<\G{P  
int nRead; PpxLMe]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qVHXZdGL  
{ )+Nm@+B  
nStartPos += fileAccessI.write(b,0,nRead); }Q }&3m~g  
//if(nThreadID == 1) 0XkLWl|k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S]Y3nI  
} asT/hsSNS  
{2A| F{7>  
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Utility.log("Thread " + nThreadID + " is over!"); \(4"kY_=  
bDownOver = true; Dw%V.J/&o  
//nPos = fileAccessI.write (b,0,nRead); ]"ZL<?3g
 
} .o27uB.  
catch(Exception e){e.printStackTrace ();} '}nH\?(  
} |"K<  
} *Ce8( "v,  
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//打印回应的头信息 `[OJ)tHE  
public void logResponseHead(HttpURLConnection con) ZWtlOP#]  
{ /w!!jj^  
for(int i=1;;i++) 8fG$><@
 
{ bqo+b{i\  
String header=con.getHeaderFieldKey(i); %=ZN2)7{  
if(header!=null) b]-~{' +  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F!>92H~3G  
Utility.log(header+" : "+con.getHeaderField(header)); gI~4A,  
else AQUl:0!  
break; \n&l  
} wgN)*dpuI
 
} P#8+GN+bF  
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public void splitterStop() 3?}\Hw  
{ ;^[VqFpeS  
bStop = true; UQ7E7yY#  
} FnZMW, P  
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} +vDEDOS1  
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/* QbN7sg~~  
**FileAccess.java slQxz;t  
*//文件访问(定位，写) cC4 2b2+  
package NetFox; GlVb|O"  
import java.io.*; \!*3bR  
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public class FileAccessI implements Serializable{
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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 I[x+7Y0k9  
RandomAccessFile oSavedFile; %2S+G?$M?  
long nPos; }L!%^siG_  
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public FileAccessI() throws IOException %(P\"hE'  
{ +zl2|'  
this("",0); MrW*6jY
@  
} <FkoWN  
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public FileAccessI(String sName,long nPos) throws IOException <P%<EgOE  
{ FX->_}kL=  
oSavedFile = new RandomAccessFile(sName,"rw"); 2!w5eWl,  
this.nPos = nPos; i"B q*b@  
oSavedFile.seek(nPos); 9s.x%m,  
} Mnv2tnU]  
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|}?o=bO  
public synchronized int write(byte[] b,int nStart,int nLen) CnXl 7"
 
{ ,/bSa/x`  
int n = -1; bG|aQ2HW  
try{ odPdWV,&*  
oSavedFile.write(b,nStart,nLen); &'mq).I2  
n = nLen; eG@0:  
} Ala~4_" WL  
catch(IOException e) +,g"8&>  
{ K1_]ne)  
e.printStackTrace (); mDCz=pk)  
} YKWiZ  
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return n; Li?_P5+a  
} &*
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} TwaK>t96[  
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/* }|Ao@UvH  
**SiteInfoBean.java 4t]YHLBS  
*/ _Yms]QEZ  
package NetFox; }+m")=1{  
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O:I"<w9_1  
public class SiteInfoBean { 3jh: K  
;1^([>|  
+HpPVuV  
private String sSiteURL; //Site's URL S>6f0\F/Y%  
private String sFilePath; //Saved File's Path rsGQ :c  
private String sFileName; //Saved File's Name c1wP/?|.>  
private int nSplitter; //Count of Splited Downloading File FG6bKvEQm^  
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public SiteInfoBean() y$Y*%D^w  
{//nSplitter的缺省值为5 ov9+6'zya  
//default value of nSplitter is 5 VJf|r#2  
this("","","",5); 'f "KV|  
} !EuqJjh  
8NUVHcB6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f~rq)2V:  
{  W>HGB  
sSiteURL= sURL; 2C&G'@>  
sFilePath = sPath; AWG;G+  
sFileName = sName; O'i!}$=g  
this.nSplitter = nSpiltter; O^L#(8bC  
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} "J
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public String getSSiteURL() \I[f@D-J  
{ Osk'zFiL<  
return sSiteURL; WxrGoo^  
} `Vf k
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gx55.}  
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public void setSSiteURL(String value) !VzbNJ&'  
{ +{5y,0R  
sSiteURL = value; Pc:5*H  
} 26D,(Y$*  
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)[]*Y]vSx  
public String getSFilePath() -"9&YkN  
{ :MFF*1  
return sFilePath; vTk\6o q  
} 2x<A7l)6  
937 z*mh  
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public void setSFilePath(String value) 7%0V?+]P  
{ |l#<vw wE  
sFilePath = value; \$B%TY  
} yd>b2 M  
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public String getSFileName() x&4gy%b  
{ O'L9 s>B  
return sFileName; $[*QsU%%  
} hUo}n>Aa  
>69-[#P!  
6 *GR_sMm  
public void setSFileName(String value) Ks>l=5~v|  
{ }NgevsV>;  
sFileName = value; kHhxR;ymA7  
} {)5tov1  
n]Z() "D  
|vUjoa'.7E  
public int getNSplitter() v&]k8Hc-  
{ ~5@bWJ  
return nSplitter; wa f)S=  
} ":meys6t#  
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public void setNSplitter(int nCount) oz[
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{ H-g CY|W  
nSplitter = nCount; +WTO_J7  
}  qH9bo-6  
} M. o}?  
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t"Tv(W?_  
/* t8:QK9|1  
**Utility.java m~;}8ObQE  
*/ '&+5L.  
package NetFox; "WfVZBWG$  
5%#V>|@e#  
nPRv.h  
public class Utility { 
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public Utility() wnr<# =,I'  
{ DN0`vl{*  
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} CEXD0+\q  
[zsUboCkc  
//线程睡眠 =g3o@WD/G  
public static void sleep(int nSecond) Z.$)#vM5  
{ BufXnMh.  
try{ kwAL]kI  
Thread.sleep(nSecond); QMQ\y8E  
} r Y#^C  
catch(Exception e) 0n)99Osq(u  
{ vjz 'y[D  
e.printStackTrace (); - xE%`X  
} 7mBH#Q)  
} g=)OcTd#  
ZT d)4f  
//日志 b uOpHQn  
public static void log(String sMsg) bZ-_Q  
{ gCjW !t  
System.err.println(sMsg); /<e<-C*d&<  
} (Z |Nz*<  
: pkOZ+t  
z?M_Cz;:J  
public static void log(int sMsg) sogdM{tz\  
{ *P; cSx?2  
System.err.println(sMsg); Vm]xV_FOd  
} R|g50Q  
} |EZ\+!8N:{  
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/* &peUC n  
**TestMethod.java !3;KC"o  
*/ jM5w<T-2/  
package NetFox; < pWk   
+zL|j/q?  
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public class TestMethod { s%/x3anz=  
L}Rsg'U  
H-C$Jy)f"  
public TestMethod() x"83[0ib  
{ ///xx/weblogic60b2_win.exe HE{JiAf  
try{ A3s-C+@X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h#~\-j9>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Qk[YF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5i1E 5@
~  
fileFetch.start(); Hpj7EaMZ_  
} A?+cdbxJw  
catch(Exception e){e.printStackTrace ();} w^Atd|~gi  
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bB+ 4  
} TJ_pMU  
FnWN]9  
wi-F@})f#  
public static void main(String[] args) E5QQI9ea  
{ ZGsI\3S  
new TestMethod(); y"T(Unvc  
} KJYcP72P  
} HaA2y  
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