http断点续传简单实现（java)

/* /GD4GWv :  
**SiteFileFetch.java ^$}9 Enj+Y  
*/ ~Pq1@N>n  
package NetFox; FctqE/>}I  
import java.io.*; J\^ZRu_K  
import java.net.*; 33z)F  
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public class SiteFileFetch extends Thread { r({!ejT{U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _~ZNX+4  
long[] nStartPos; //开始位置 /7/d u[P6  
long[] nEndPos; //结束位置 OXd617  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B2w\  
long nFileLength; //文件长度 .'k]]2%ILp  
boolean bFirst = true; //是否第一次取文件 `xMmo8u4  
boolean bStop = false; //停止标志 ) jv]Oz  
File tmpFile; //文件下载的临时信息 =ZR9zL=h  
DataOutputStream output; //输出到文件的输出流 =Yg36J4[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） z-$bce9*  
public SiteFileFetch(SiteInfoBean bean) throws IOException XkLl(uyh  
{ kscZ zXv  
siteInfoBean = bean; ?-1r$z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KHV5V3q4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KCu@5`p  
if(tmpFile.exists ()) =NMT H[  
{ y!)  
bFirst = false; Y&!M#7/'J3  
read_nPos(); ,7&`V=C  
} ZG:#r\a  
else ACm9H9:Vd  
{ |\;oFuCv##  
nStartPos = new long[bean.getNSplitter()]; +[Cdd{2  
nEndPos = new long[bean.getNSplitter()]; v]SHude{  
} K<TVp;N  
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} q<Gn@xc'  
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public void run() bL soKe  
{ onL&lE  
//获得文件长度 . J[2\"W  
//分割文件 t[*;v  
//实例FileSplitterFetch qKNX^n;  
//启动FileSplitterFetch线程 Y7
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//等待子线程返回 ChO?Lm$y  
try{ mO<sw  
if(bFirst) wTb7 xBI  
{ Whp;wAz  
nFileLength = getFileSize(); 41Bp^R}^/  
if(nFileLength == -1) s3@sX_2  
{ t>.1,'zb  
System.err.println("File Length is not known!"); H<T9$7Yr%r  
} {C3AxK0  
else if(nFileLength == -2) q/w<>u  
{
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System.err.println("File is not access!"); db#QA#^S  
} ]k~Vh[[  
else ['~j1!/;6  
{ '?7th>pC  
for(int i=0;i<nStartPos.length;i++) m}/LMY  
{ 8fA9yQ8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7fRL'I#[@  
} tgoOzk^  
for(int i=0;i<nEndPos.length-1;i++) AE0d0Y~9  
{ 'NCxVbyYD  
nEndPos = nStartPos[i+1]; yZkHBG4  
} ^T*^L=L_(  
nEndPos[nEndPos.length-1] = nFileLength; ."b=dkx  
} $Lg%CY  
} =Lx*TbsFYt  
]+A>*0
#"  
.I\)1kjX  
//启动子线程 :a$ZYyD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f[v~U<\R  
for(int i=0;i<nStartPos.length;i++) cfI5KLG~#  
{ [GKSQt{)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )#ze  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3S='/^l  
nStartPos,nEndPos,i); w}n:_e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]yu,YZ@7  
fileSplitterFetch.start(); L$zI_ z  
} #;cDPBv*wS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KQ'fp:5|/@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jCdKau&9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3&i8C,u]/O  
nEndPos = " + nFileLength); kcT?<r  
// fileSplitterFetch[nPos.length-1].start(); \%\b*OO  
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r"#h6lYK&  
//等待子线程结束 5<M
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//int count = 0; K|*Cka{  
//是否结束while循环 9`{[J['V  
boolean breakWhile = false; 2}`Q9?  
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while(!bStop) . 2_t/2  
{ [XFZ2'OO  
write_nPos(); 1o)Vzv  
Utility.sleep(500); SR>Sq2cW0  
breakWhile = true; 47I5Y5  
mtDRF'>P:  
!R,9Pg*Ey  
for(int i=0;i<nStartPos.length;i++) ?3 J  
{ A6w/X`([O  
if(!fileSplitterFetch.bDownOver) ^aVoH/q*C  
{ 'G z>X :  
breakWhile = false; 9HMW!DSK`  
break; <}'hkEh{d=  
} pKK&+umg  
} d5<@WI:wz  
if(breakWhile) *UVjN_na5  
break; YbZ<=ZzO4  
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8>q:Q<BB2  
//count++; ]PdpC"  
//if(count>4) BcV;EEi  
// siteStop(); Yh/-6wg  
} p'{ `Uvr  
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System.err.println("文件下载结束！"); /bA\O   
} kf~7
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catch(Exception e){e.printStackTrace ();} js )G  
} 2,|*KN*e`W  
=y>P>&sI  
1xK'T_[  
//获得文件长度 0@a6r=`el  
public long getFileSize() U|odm58s  
{ m'1NZV%#  
int nFileLength = -1; #|^7{TN   
try{ 2D-ogSIo  
URL url = new URL(siteInfoBean.getSSiteURL()); qg#WDx /  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @'[w7HsJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); QI>yi&t  
QC>I<j&`!  
'qLk"   
int responseCode=httpConnection.getResponseCode(); E&0A W{  
if(responseCode>=400) :4$Ex2  
{ oQ!}@CaN|  
processErrorCode(responseCode); J)(H-xvV  
return -2; //-2 represent access is error 2^Gl;3  
} +T[3wL~  
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String sHeader; X?$Eb  
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for(int i=1;;i++) bj`cYL%  
{ ]!H*oP8a*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); , 6\i  
//Utility.log(in.readLine()); >VP\@xt(R[  
sHeader=httpConnection.getHeaderFieldKey(i); #V-qS/ q"  
if(sHeader!=null) l ,)l"6OV  
{ g92M\5 x9  
if(sHeader.equals("Content-Length")) S4
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{ | (P%<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); HCQv"i}-  
break; Rf2/[  
} <Xw 6m$fr:  
} ;}K1c+m!5V  
else aq"E@fb  
break; U0u@[9!  
} D+rDgrv  
} [a;lYsOsJ  
catch(IOException e){e.printStackTrace ();} )Y~q6D K  
catch(Exception e){e.printStackTrace ();} 3hR7 ./  
dv4)fG]W;_  
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Utility.log(nFileLength); {d(PH7R  
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return nFileLength; *Q=-7am  
} aGp <%d  
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0]8+rWp|Nz  
//保存下载信息（文件指针位置） FVG|5'V^  
private void write_nPos() &{&lCBN  
{ H*|Bukgt/M  
try{ &.kg8|s{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ni@D7:h  
output.writeInt(nStartPos.length); v)N6ZOj*C  
for(int i=0;i<nStartPos.length;i++) #Vn=(U4}!_  
{ m'k`p5[=h  
// output.writeLong(nPos); y=9a2[3Dz  
output.writeLong(fileSplitterFetch.nStartPos); -j3 -H&  
output.writeLong(fileSplitterFetch.nEndPos); L3q)j\ls  
} bXq,iX  
output.close(); 2 T{PIJg3  
} ~'fa,XZ<  
catch(IOException e){e.printStackTrace ();} BO[Q"g$Kon  
catch(Exception e){e.printStackTrace ();} X_s;j5ur  
} H#
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//读取保存的下载信息（文件指针位置） ABhza|  
private void read_nPos() DJ}xD&G  
{ xx;'WL,g  
try{ 6z%3l7#7Yi  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;~~Oc  
int nCount = input.readInt(); a,cDj  
nStartPos = new long[nCount]; 7u5B/M!  
nEndPos = new long[nCount]; 9][Mw[k>  
for(int i=0;i<nStartPos.length;i++) c}Z,xop<P{  
{ rA*,)I_v@  
nStartPos = input.readLong(); s>~&:GUwR  
nEndPos = input.readLong(); 9[T#uh!DC  
} JPQ
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input.close(); 4)Pt
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} 8SAz,m!W)  
catch(IOException e){e.printStackTrace ();} q*{"6"4(  
catch(Exception e){e.printStackTrace ();} ]CC~Eo-%-  
} w?M*n<) O  
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private void processErrorCode(int nErrorCode) vW$]:).  
{
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System.err.println("Error Code : " + nErrorCode); ie.cTTOI  
} gK)B3dH*&  
7C2/^x P  
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//停止文件下载 A9l^S|r  
public void siteStop() $<s@S;Ri  
{ 5jNBt>.0  
bStop = true; t1C{  
for(int i=0;i<nStartPos.length;i++) [&3"kb  
fileSplitterFetch.splitterStop(); NlcWnSv  
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} K&|zWpb  
} {zF  
//负责部分文件的抓取 eA4*Be;9e  
**FileSplitterFetch.java dJ24J+9}]j  
*/ ixKQh};5/  
package NetFox; 4zf#zJw  
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) ]~HjA;  
import java.io.*; %< j=&  
import java.net.*; kI[EG<N1k  
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public class FileSplitterFetch extends Thread { eazP'(rc  
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String sURL; //File URL ae!_u \$  
long nStartPos; //File Snippet Start Position }f-rWe{gs>  
long nEndPos; //File Snippet End Position IL
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int nThreadID; //Thread's ID r1?LKoJOn  
boolean bDownOver = false; //Downing is over A{+ZXu}  
boolean bStop = false; //Stop identical m9e$ZZG$  
FileAccessI fileAccessI = null; //File Access interface #='#`5_5  
pu>LC6m3a  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J7cqnj  
{ D3^v[>E2  
this.sURL = sURL; }+=@Ci  
this.nStartPos = nStart; xq~=T:>/A  
this.nEndPos = nEnd; &H+<uYV  
nThreadID = id; O0$ijJa|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y4?>5{`W  
} R,^FJ  
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public void run() 0?`#ko7~d  
{ z.H`a+cl  
while(nStartPos < nEndPos && !bStop) w^p2XlQ<  
{ }Ql;%7  
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try{ jgMWjM6.  
URL url = new URL(sURL); EhVnt#`Si  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r}5GJ|p0  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1Gqtd^*;  
String sProperty = "bytes="+nStartPos+"-"; U)l>#gf8  
httpConnection.setRequestProperty("RANGE",sProperty); /KV@Ce\  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); 0y ;gi3W  
//logResponseHead(httpConnection); LnyA5T  
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byte[] b = new byte[1024]; 9,>M/_8>  
int nRead; }}xR?+4A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -OW$  
{ ~,guw7F  
nStartPos += fileAccessI.write(b,0,nRead); :m~lgb<  
//if(nThreadID == 1) ~g,QwaA[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _j2`#|oG  
} @v'<~9vG  
%FRkvqV*  
dW5z0VuB$/  
Utility.log("Thread " + nThreadID + " is over!"); 23fAc"@ B  
bDownOver = true; D2mB4  
//nPos = fileAccessI.write (b,0,nRead); e,4G:V'NX  
} w##Fpv<m  
catch(Exception e){e.printStackTrace ();} [&4y@  
} {38aaf|'/  
} .5z|g@ 6  
Zuh
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//打印回应的头信息 }hf*Jw  
public void logResponseHead(HttpURLConnection con) =0-qBodbl  
{ Z:OO|x  
for(int i=1;;i++) KWYG\#S0]  
{ ^49moC-  
String header=con.getHeaderFieldKey(i); 8]L.E  
if(header!=null) R.QcXz?d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Eg:p_F*lr  
Utility.log(header+" : "+con.getHeaderField(header)); 3HiW1*5W  
else lt]U?VZ   
break; QRjt.Ry|  
} t2gjhn^p  
} zJy{Ry
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public void splitterStop() 0k>&MkM\^  
{ 6]3ZUH;  
bStop = true; W | }Hl{}  
} 7wnzef?)  
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} {+EPE2X=C  
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i@6 /#  
/* .G]# _U  
**FileAccess.java gdT_kb5HL8  
*//文件访问(定位，写) vP2QAGk<  
package NetFox; !L_ SHlU  
import java.io.*; 5a&wM  
IO'Q}bU4vs  
^`7t@G$ D  
public class FileAccessI implements Serializable{ t<7WM'2<y  
7AiCQWf9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [ bW=>M  
RandomAccessFile oSavedFile; 3{z|301<m  
long nPos; r?TK@^z  
K6U>Qums  
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public FileAccessI() throws IOException i<?4iwX%i*  
{ 6.jZy~  
this("",0); Hn~1x'$  
} 6b|`[t  
E~P0}'  
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public FileAccessI(String sName,long nPos) throws IOException QhUraZ  
{ B@=<'/S\7  
oSavedFile = new RandomAccessFile(sName,"rw"); (?!0__NN;  
this.nPos = nPos; E-D5iiF  
oSavedFile.seek(nPos); ss<'g@R  
} abnd U,s  
#77UKYj2L-  
U VKN#"_{  
public synchronized int write(byte[] b,int nStart,int nLen) ^4[[+r  
{ %np#Bv-L  
int n = -1; "Zk6B"o)  
try{ u2<h<}Y  
oSavedFile.write(b,nStart,nLen); a:}"\>Aj  
n = nLen; )'~FDw\6  
} Anv8)J!9u  
catch(IOException e) uH[0kh  
{ OpLSjr  
e.printStackTrace (); mW-W7-JhO7  
} E'8Bw7Tz  
5m42Bqy"  
02[II_< 1  
return n; R!,)?j;  
} gxM8IQ  
"~<~b2Y"5  
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} gpWS_Dw9  
A.O~'')X  
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/* @UX@puK`/  
**SiteInfoBean.java =fG8YZ(  
*/ @W8}N|jek  
package NetFox; DZRxp,  
a`*WpP\+  
:$aW@?zAY  
public class SiteInfoBean { [r8 d+  
MF}Lv1/[-J  
>EtP^Lu~f_  
private String sSiteURL; //Site's URL HW726K*
 
private String sFilePath; //Saved File's Path dA/o4co  
private String sFileName; //Saved File's Name |vz;bJG  
private int nSplitter; //Count of Splited Downloading File zDyeAxh4  
"ru1;I  
(N|xDl&;  
public SiteInfoBean() &o@5%Rz2/  
{//nSplitter的缺省值为5 k+$4?/A  
//default value of nSplitter is 5 PAV2w_X~  
this("","","",5); 3gy;$}Lq T  
} NRSse"  
QV$dKjMS  
B5HdC%8/}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IGT_ 5te  
{ :QV6z*#zD  
sSiteURL= sURL; ukf\*  
sFilePath = sPath; ]a#]3(o]}  
sFileName = sName; tq[",&K  
this.nSplitter = nSpiltter; ~@b}=+n  
\C#b@xLnX  
5,BkwAr+6[  
} Y&f[2+?2NK  
3b@1Zahz  
jA4v?(AO}#  
public String getSSiteURL() OIty ]c  
{ L"7` \4  
return sSiteURL; a=.db&;vY  
} 8M+F!1-#  
xKST-:c+  
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public void setSSiteURL(String value) 14 'x-w^~k  
{ up3<=u{>  
sSiteURL = value; ysJhP .  
} OCO,-
(  
' 5 
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({kGK0
 
public String getSFilePath() S aet";pf`  
{ h$ iyclX  
return sFilePath; jQeE07g  
} zMzf=~  
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public void setSFilePath(String value) zRo
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{ vKf;&`^qE  
sFilePath = value; GnrW{o  
} zw0 r i6  
W#7-%oT  
=tRe3o0(  
public String getSFileName() -sH.yAvC6  
{ k,iV$,[TF  
return sFileName; +Y9D!=_lj  
} -_*XhD  
B m@oB2x)  
?Wz(f{Hm  
public void setSFileName(String value) rn[}{1I33Q  
{ 4i\aW:_'i  
sFileName = value; ^=Tu>{uD  
} 5YG@[ic  
K<  
_B7?C:8Q-  
public int getNSplitter()
YS
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{ ?CW^*So  
return nSplitter; P}WhE  
} _E<O+leWf  
X1V}%@3:  
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public void setNSplitter(int nCount) b, **$  
{ CE7pg&dJ)i  
nSplitter = nCount; 5A]
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} `MYKXBM  
} `Y({#U  
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ah"MzU)  
/* KY
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**Utility.java M|E2&ht  
*/ 19w,'}CGk  
package NetFox; &B7+>Ix,  
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t
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public class Utility { ny_ kr`$42  
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public Utility() i&'^9"Z)O  
{ vb.Y8[  
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} uZ`d&CEh  
p5# P r  
//线程睡眠 ]^6y NtLK  
public static void sleep(int nSecond) ~)m t&   
{ G5nj,$F+  
try{ NZ+?Ydr8k  
Thread.sleep(nSecond); 'oHOFH9:{b  
} voej ~z+  
catch(Exception e) CWe>jlUQ  
{ L[D/#0qp  
e.printStackTrace (); Rr;LV<q+  
} vD)A)  
} T.
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$L&9x3+?Kg  
//日志 $7gB&T.x  
public static void log(String sMsg) vLK\X$4  
{ ;]oXEq`  
System.err.println(sMsg);
EO9kE.g  
} HSr"M.k5  
o!l3.5m2d  
Xm^h5jAr  
public static void log(int sMsg) _Dcc<-.  
{ sg6w7fp>  
System.err.println(sMsg); oA3W {  
} E_![`9i  
} %L\{kUam  
lgjo
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/* b6WC@j`*T  
**TestMethod.java 6|9g4@Hy  
*/ ?<yq 2`\4O  
package NetFox; &DbGyV8d"|  
0q>NE
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$kD`$L@U  
public class TestMethod { 4z0R\tjT  
leb^,1/D6  
zmL~]!~&  
public TestMethod() \BbOljM=  
{ ///xx/weblogic60b2_win.exe bUAR<R'E  
try{ ?;r8SowZ7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X.T\=dm%v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =
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SiteFileFetch fileFetch = new SiteFileFetch(bean); =S[FJaIu7  
fileFetch.start(); 6Er0o{iI  
} ghJ,s|lH  
catch(Exception e){e.printStackTrace ();} 9?l?G GmQ  
(4{
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srCh
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} ll<9f)  
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public static void main(String[] args) =N@)C
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{ L`HH);Ozw  
new TestMethod(); BudWbZ5>Ep  
} we H@S  
} A}#]g>L  
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