http断点续传简单实现（java)

/* ];;w/$zke  
**SiteFileFetch.java pG6-.F;  
*/ 5XI*I(.%/  
package NetFox; A.O~'')X  
import java.io.*; ^mpB\D)q  
import java.net.*; .}N^AO=  
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public class SiteFileFetch extends Thread { _vH!0@QFU  
.M2&ad :  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a7\L-T+  
long[] nStartPos; //开始位置 XB-|gPk  
long[] nEndPos; //结束位置 kVnyX@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b]BA,D4  
long nFileLength; //文件长度 AFTed?(  
boolean bFirst = true; //是否第一次取文件 Pfx71*u,  
boolean bStop = false; //停止标志 --`LP[l
l  
File tmpFile; //文件下载的临时信息 #\BI-zt  
DataOutputStream output; //输出到文件的输出流 [Z\1"m  
?w/nZQWi  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .~L4#V{c~  
public SiteFileFetch(SiteInfoBean bean) throws IOException {Ch"zuPX  
{ F |81i$R  
siteInfoBean = bean; "v!HKnDT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v6?\65w,|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m1i+{((  
if(tmpFile.exists ()) TSSt@xQ+  
{ R"gm]SQ/  
bFirst = false; [E (M(w':  
read_nPos(); X-#mv|3  
} JK"uj%  
else HF+fk*_Q  
{ dY@Tt&k8E  
nStartPos = new long[bean.getNSplitter()]; $S8
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nEndPos = new long[bean.getNSplitter()]; >5Oy^u6Ly  
} $Wzv$4
;  
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} zl 0^EltiU  
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public void run() 5qQ(V)ah  
{ \Ntdl:fSw  
//获得文件长度 ]#q7}Sd  
//分割文件 )^S^s>3  
//实例FileSplitterFetch b[o"Uq@8?  
//启动FileSplitterFetch线程 :YXQ9/iRr  
//等待子线程返回 Qfu*F}  
try{ ioa_AG6B
 
if(bFirst) <VR&=YJ  
{ G!LNP&~  
nFileLength = getFileSize(); j_uY8c>3\q  
if(nFileLength == -1) PB<S
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{ N|d.!Q;V.y  
System.err.println("File Length is not known!"); a 8hv.43  
} n;^k
 
else if(nFileLength == -2) 7WfirRM  
{ :$Q]U2$mPS  
System.err.println("File is not access!"); OGi4m |  
} :'rZZeb'  
else bA^:p3  
{ t>GLZzO  
for(int i=0;i<nStartPos.length;i++) 'a/6]%QFd!  
{ 7K]U|K#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D3AtYt  
} p z+}7  
for(int i=0;i<nEndPos.length-1;i++) 4i\aW:_'i  
{ }:l%,DBw  
nEndPos = nStartPos[i+1]; 5YG@[ic  
} $4*E\G8  
nEndPos[nEndPos.length-1] = nFileLength; C+]q  
} pF*~)e  
} OjlB0  

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k&_u\D"^"%  
//启动子线程 hOLy*%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >`?+FDOJ,  
for(int i=0;i<nStartPos.length;i++) y#Za|nt  
{ JS7}K)A2B6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^_S-s\DW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K6yFpVl  
nStartPos,nEndPos,i); UNcJ=   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,iv%^C",)  
fileSplitterFetch.start(); vQTQS[
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} 2\CkX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]G o~]7(5|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l)rvh#D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", awSS..g}L  
nEndPos = " + nFileLength); @uM3iO7&
 
// fileSplitterFetch[nPos.length-1].start(); k#:@fH4{PA  
vl{_M*w ;  
;0Ct\[eh  
//等待子线程结束 OG?j6qhpl  
//int count = 0; i&'^9"Z)O  
//是否结束while循环 sa gBmA~  
boolean breakWhile = false; $h]Y<&('G  
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while(!bStop) UFIAgNKl  
{ ~)m t&   
write_nPos(); G5nj,$F+  
Utility.sleep(500); NZ+?Ydr8k  
breakWhile = true; 'oHOFH9:{b  
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for(int i=0;i<nStartPos.length;i++) L[D/#0qp  
{ ;$tv8%_L[  
if(!fileSplitterFetch.bDownOver) q~' K9  
{ Yx}"> ;\  
breakWhile = false; ?(NT!es  
break; L3=YlX`UL  
} <&Y}j&(  
} ^I0GZG  
if(breakWhile) bHQKRV  
break; )<x;ra^  
X?v^>mA  
N4`
9TN7  
//count++; &(uF&-PwO4  
//if(count>4) eYD9#y  
// siteStop(); !Nxn[^[?.  
} Th;gps%b  
Z/6'kE{l  
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System.err.println("文件下载结束！"); 1nlE3Y?AV  
} ?<yq 2`\4O  
catch(Exception e){e.printStackTrace ();} F<ocY0=9p  
} 2) /k`Na  
v1X&p\[d  
r@ T-Hi  
//获得文件长度 ),y!<\oQ  
public long getFileSize() rm)SfT<  
{ !8"$d_=h  
int nFileLength = -1; JX\T {\m#  
try{ 10l1a
4  
URL url = new URL(siteInfoBean.getSSiteURL()); H6PXx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !AD0-fZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); TA@tRGP>  
/VmCN]2AZ  
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int responseCode=httpConnection.getResponseCode(); (4{
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if(responseCode>=400) srCh
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{ ll<9f)  
processErrorCode(responseCode); L%o65  
return -2; //-2 represent access is error Lr24bv
\  
} =N@)C
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9OQ0Yc!3  
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String sHeader; Fyh?4!/.  
2*-ENW2  
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for(int i=1;;i++) 5}d/8tS  
{ SN[L4}{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0,~6TV<K  
//Utility.log(in.readLine()); GOZQ5m -  
sHeader=httpConnection.getHeaderFieldKey(i); q(jkit~`A  
if(sHeader!=null) FQ_%)Ty2  
{ [N+ m5{tT  
if(sHeader.equals("Content-Length")) "3Xv%U9@  
{ <9d-Hz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -e`oW.+  
break; IB#iJ#,  
} bU:}ZO^S  
} VT5cxB<  
else <>T&ab@dE(  
break; *b6I%MZn  
} dIk8TJ  
} Xew1LPI  
catch(IOException e){e.printStackTrace ();} StdS$XW  
catch(Exception e){e.printStackTrace ();} O7'<I|aD  
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_}  
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Utility.log(nFileLength); [B"dH-r7  
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return nFileLength; =YXe1$ $  
} U=&^H!LVY  
4[LLnF--  
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//保存下载信息（文件指针位置） ]M+VSU  
private void write_nPos() ==h|+NFa  
{ :~ZqB\>i  
try{
.0Iun+nUD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QX/X {h6  
output.writeInt(nStartPos.length); S/nj5Lh  
for(int i=0;i<nStartPos.length;i++) ;LQ# *NjL\  
{ l\T!)Ql  
// output.writeLong(nPos); PkPDVv  
output.writeLong(fileSplitterFetch.nStartPos); &*G5J7%w  
output.writeLong(fileSplitterFetch.nEndPos); d%#!nq{vd  
} m?D <{BQ;  
output.close(); tp6csS,  
} (b/A|hl  
catch(IOException e){e.printStackTrace ();} .)"_Q/q  
catch(Exception e){e.printStackTrace ();} gnQo1q{ 4  
} E'e8&3!bx  
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//读取保存的下载信息（文件指针位置） H[BD)  
private void read_nPos() E-yT  
{ PcHSm/d0e  
try{ ~7lTqY\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %1-K);SJ  
int nCount = input.readInt(); e-CNQnO~  
nStartPos = new long[nCount]; kCaO\#ta  
nEndPos = new long[nCount]; ,67"C2Y  
for(int i=0;i<nStartPos.length;i++) "*++55  
{ T3USNc51  
nStartPos = input.readLong(); W_[|X}lWP  
nEndPos = input.readLong(); ]>R`;"(  
} JmU<y  
input.close(); V;h=8C5J  
} e/"yGQu  
catch(IOException e){e.printStackTrace ();} }}^,7npU  
catch(Exception e){e.printStackTrace ();} Q0zW ]a  
} {fGd:2dh  
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private void processErrorCode(int nErrorCode) DA<F{n.Z:  
{ YSR mt/  
System.err.println("Error Code : " + nErrorCode); !_CX2|  
} Awu$g.  
S~@r  
]pW86L%  
//停止文件下载 O1GDugZ  
public void siteStop() ~L-0~  
{ Tub1Sv>J  
bStop = true; NFk}3w
:  
for(int i=0;i<nStartPos.length;i++) [##`Um  
fileSplitterFetch.splitterStop(); 403[oOj  
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} [8>z#*B  
} BdN8 ^W  
//负责部分文件的抓取 LHs-&  
**FileSplitterFetch.java ,Bisu:v6FW  
*/ aWyUu/g<A`  
package NetFox; $4Z+F#mx  
di~]HUZh)  
x(L(l=^"  
import java.io.*; /b{o3, #.M  
import java.net.*; WtEI] WO  
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:.*HQt9N  
public class FileSplitterFetch extends Thread { ojHhT\M`  
!Y (apVQ  
1HMUHZT  
String sURL; //File URL >\V6+$cNp  
long nStartPos; //File Snippet Start Position ]UDd :2yt  
long nEndPos; //File Snippet End Position zVSx$6eiU  
int nThreadID; //Thread's ID f}^I=pS&  
boolean bDownOver = false; //Downing is over y|$R`P  
boolean bStop = false; //Stop identical *)u?~r(F  
FileAccessI fileAccessI = null; //File Access interface 5L8&/EN9-  
$}t=RW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cAD[3b[Gk  
{ N_UQ  
this.sURL = sURL; 9YB2e84j  
this.nStartPos = nStart; (+* ][|T  
this.nEndPos = nEnd; 9A~>`.y
 
nThreadID = id; QV7,G9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cv}aS_`f  
} ^YGTh0$W  
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public void run() !O|ql6^;  
{ 3gAR4  
while(nStartPos < nEndPos && !bStop) xq}-m!nX  
{ \[yr=X  
pz{'1\_+9  
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try{ i3#'*7f%j  
URL url = new URL(sURL); 8".2)W4*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yL6^\x  
httpConnection.setRequestProperty("User-Agent","NetFox"); C,/O   
String sProperty = "bytes="+nStartPos+"-"; H@GE)I>^@  
httpConnection.setRequestProperty("RANGE",sProperty); o\Uu?.-<  
Utility.log(sProperty); )l&D]3$6K  
#%:c0=  
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InputStream input = httpConnection.getInputStream(); F|>05>8  
//logResponseHead(httpConnection); (Yv{{mIy  
B MM--y@  
.}q]`<]ze  
byte[] b = new byte[1024]; ;f:gX`"\  
int nRead; ^i+[m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }Z\wH*s`  
{ K UKACUL  
nStartPos += fileAccessI.write(b,0,nRead); >!L&>OOx  
//if(nThreadID == 1) HTV ~?E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H3, ut  
} 8-m 3e  
`\bT'~P  
~2@Lx3t$  
Utility.log("Thread " + nThreadID + " is over!"); (9 sIA*,}  
bDownOver = true; jNA1O68N  
//nPos = fileAccessI.write (b,0,nRead); 4:7mK/Z  
} {^#2=`:)O
 
catch(Exception e){e.printStackTrace ();} ?c]n^GvG  
} Q$~n/  
} [:iv4>ZZ  
aBhV3Fd[B  
!SO8O  
//打印回应的头信息 b O=yi)  
public void logResponseHead(HttpURLConnection con) +L0w;wT  
{ ]ab#q=  
for(int i=1;;i++) XM/vDdR  
{ Tkw;pb  
String header=con.getHeaderFieldKey(i); LH2PTW\b!6  
if(header!=null)
|Y},V_@d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sYqgXE.  
Utility.log(header+" : "+con.getHeaderField(header)); y500Xs[c  
else i0:>Nk  
break; :]PM_V|  
} P`S@n/}  
} +f>cxA  
]5' d&f  
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public void splitterStop() _OMpIdY,R*  
{ `S3>3  
bStop = true; z[C3  
} a^t?vv  
H6K`\8/SeN  
)}MHx`KT2  
} s =Umj'1k  
?<U
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/* kkS~4?-*  
**FileAccess.java @%hCAm  
*//文件访问(定位，写) .&1C:>  
package NetFox; c)}2K0  
import java.io.*; 
#aar9  
&
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l>6@:nq|R  
public class FileAccessI implements Serializable{ x[(?#  
,+`HQdq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rY0u|8.5Q  
RandomAccessFile oSavedFile; + H_WlYg-  
long nPos; %0,-.(h  
+oc >S  
jjzA .8?(7  
public FileAccessI() throws IOException ]]0,|My7  
{ 6GAaV[])'  
this("",0); ~Rpm-^  
} egk7O4zwP  
-c%dvck^,  
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public FileAccessI(String sName,long nPos) throws IOException t<j^q`;@v  
{ amWD-0V  
oSavedFile = new RandomAccessFile(sName,"rw"); zR;X*q"T$4  
this.nPos = nPos; ?4 S+edX  
oSavedFile.seek(nPos); wQ+8\ s=  
} LD>\#q8a*  
*Dmx&F=3,5  
yxt[= C  
public synchronized int write(byte[] b,int nStart,int nLen) yX!HZu;j  
{ C&~1M}I  
int n = -1; <7_KeOLJ  
try{ ::5E8919  
oSavedFile.write(b,nStart,nLen); !#2=\LUC  
n = nLen; ?GA&f2]a  
} ORN6vX(1  
catch(IOException e) "LhvzM-<8  
{ "O[j!fG8,  
e.printStackTrace (); N587(wZ  
} o>Er_r  
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j*v40mXl`2  
return n; V9wI\0  
} m#vL*]c}  
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} A{eLl  
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5kypMHJm  
/* nmU_N:Y  
**SiteInfoBean.java Lw1EWN6}_&  
*/ .|qK+Hnc  
package NetFox; A3N]8?D  
P>ceeoYQuA  
H*^
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public class SiteInfoBean { H( jXI  
4mjgt<`  
Y-mK+12  
private String sSiteURL; //Site's URL {c?JuV4q?  
private String sFilePath; //Saved File's Path lbdTQ6R  
private String sFileName; //Saved File's Name H9)m^*  
private int nSplitter; //Count of Splited Downloading File "syh=BC v  
 p?D2)(  
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public SiteInfoBean() $2^
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{//nSplitter的缺省值为5 + @9.$6N  
//default value of nSplitter is 5 A>`945|  
this("","","",5); Kv'n:z7Md  
} l%ayI  
$rF=_D6  
eN?Y7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TL$EV>Nr  
{ D4Al3fe  
sSiteURL= sURL; `;
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sFilePath = sPath; :<Y}l-x  
sFileName = sName; [D-Q'"'A  
this.nSplitter = nSpiltter; 9^"b*&>P  
g"s$}5{8:  
,#FLM`  
} B vo5-P6XY  
>(w2GD?  
`afIYXP  
public String getSSiteURL() `p b5*h6r!  
{ RO;Bl:x4  
return sSiteURL; p(;U@3G  
} do*}syQ`
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=gfI!w  
?"#%SKm  
public void setSSiteURL(String value) QxuhGA  
{ p.I.iAk%G^  
sSiteURL = value; 9SlNq05G
7  
} eI.2`)>  
$Nrm!/)*'}  
<~TP#uAz  
public String getSFilePath() pLa[}=  
{ f4-a?bp  
return sFilePath; XC 7?VE  
} TD[EQ  
%*aJLn+]_R  
^,l_{  
public void setSFilePath(String value) ?Xdak|?i  
{ 9Zry]$0~R
 
sFilePath = value; !Fo*e  
} M.-"U+#aD  

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public String getSFileName() WW+l'6.  
{ k#8Ti"0  
return sFileName; {oc igR0  
} E$9Y
s  
HEL!GC>#  
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public void setSFileName(String value) 5D M"0  
{ -9RDr\&`(  
sFileName = value; g%F"l2M  
} g(VNy@  
0;S,tJg  
/@AEJ][$  
public int getNSplitter() -jgysBw+Xb  
{ +3s%E{  
return nSplitter; 43?^7_l-  
} _&K  
08X_}97#WF  
j!
7`]  
public void setNSplitter(int nCount) y4h=Lki@
 
{ EbeI{-'aF  
nSplitter = nCount; [
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} &g2 Eptx#  
} G}5#l  
1/p*tZP8i  
hcVJBK  
/* syU9O&<  
**Utility.java f.24:Dw,  
*/ ~GE$myUT\p  
package NetFox; =@TQ>Qw%b  
o=FE5"t  
eC5$#,HiC  
public class Utility { #%J5\+ua  
$+.l*]  
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public Utility() $/6;9d^  
{ BCe_@  
G'YH6x,  
ARcv;H 5  
} w9 w%&{j  
JS}{%(B  
//线程睡眠 XLMb=T~S  
public static void sleep(int nSecond) *'ZB*>  
{ >~`C-K#  
try{ ^(viM?*  
Thread.sleep(nSecond); M#|dIbns H  
} GGhM;%H_99  
catch(Exception e) .]aF 1}AI  
{ %OgS^_tu  
e.printStackTrace (); 
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} Y>jiXl?&  
} AeAp0cbet  
;3_l@dP"  
//日志 (KvROV);  
public static void log(String sMsg) &uC@|dbC5  
{ [AV4m   
System.err.println(sMsg); eNiaM6(J  
} `jST  
?\8?%Qk  
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public static void log(int sMsg) hHqh{:q{v  
{ Kx_h1{  
System.err.println(sMsg); ]Qm]I1P  
} wP,JjPUt  
} fDx9iHGv  
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eT2*W$  
/* qRbf2;  
**TestMethod.java h*u`X>!!  
*/ iAa;6mH  
package NetFox; "`6n6r42  
AkOO)0  
\.
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public class TestMethod { <AJ97MLcc  
tGB@$UmfU  
U-n;xX0=  
public TestMethod() AyMd:5;  
{ ///xx/weblogic60b2_win.exe k
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try{ []s^   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); l }XU59  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z$J#|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dL|+d:v  
fileFetch.start(); jY_T/233d  
} !%dN
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catch(Exception e){e.printStackTrace ();} o:V|:*1Q  
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h
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} RmZ]" `  
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public static void main(String[] args) xeGb?DPu  
{ \c^45<G2qA  
new TestMethod(); V]90  
} v9T_
&  
} v@#b}N0n  
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