http断点续传简单实现（java)

/* wk@S+Q  
**SiteFileFetch.java p~evPTHnrX  
*/ \46 'j.  
package NetFox; xIb"8,N  
import java.io.*; ->u}b?aF  
import java.net.*; cH7Gb|,M  
v>!tws5e  
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public class SiteFileFetch extends Thread { N!Cy)HnS\w  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rGt/ /6  
long[] nStartPos; //开始位置 JN
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long[] nEndPos; //结束位置 4~DW7(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H[e=^JuD  
long nFileLength; //文件长度 `^G?+p2E  
boolean bFirst = true; //是否第一次取文件 >OotgJnhC  
boolean bStop = false; //停止标志 ej;\a:JL  
File tmpFile; //文件下载的临时信息 [+2iwfD  
DataOutputStream output; //输出到文件的输出流 M/LC:,  
Zk*!,,P!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1(`UzC=R|  
public SiteFileFetch(SiteInfoBean bean) throws IOException Er!s\(h  
{ Rch?@O#J  
siteInfoBean = bean; )1ct%rue  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \-Ipa59U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H\^zp5/  
if(tmpFile.exists ()) ~/R bYvyA  
{ vdFP ^06  
bFirst = false; Q^@z]Sc[  
read_nPos(); VQ(l=k:}2  
} J;#7dRW{  
else [IRWmN-  
{ k@=w? m  
nStartPos = new long[bean.getNSplitter()]; g?1! /+  
nEndPos = new long[bean.getNSplitter()]; }M|,Z'@*  
} k%TjRf{p  
#bZT&YE^  
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} U:+wt}-T"  
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public void run() Pu`;B  
{ ^
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//获得文件长度 '(-SuaH49  
//分割文件 )W0z  
//实例FileSplitterFetch -8%[7Z]  
//启动FileSplitterFetch线程 S @tpd'  
//等待子线程返回 haoQr)S  
try{ iRsK;)<  
if(bFirst) '^ob3N/Y [  
{ xL#UMvZ>;h  
nFileLength = getFileSize(); @";zM&  
if(nFileLength == -1) upefjwm  
{ Bf+7;4-  
System.err.println("File Length is not known!"); qf?X:9Wt  
} Ns#R`WG)  
else if(nFileLength == -2) E%np-is{1  
{ sF!nSr  
System.err.println("File is not access!"); 7]pi.1i  
} 7>$&CWI  
else f~-Ipq;F  
{ ]IeyJ  
for(int i=0;i<nStartPos.length;i++) $PbwC6>8  
{ KOYcT'J@vR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b.lK0 Xo  
} mZ!1Vh  
for(int i=0;i<nEndPos.length-1;i++)  M_ii  
{ ;'7gg]  
nEndPos = nStartPos[i+1]; ? 1 ~C`I;  
} ` Clh;  
nEndPos[nEndPos.length-1] = nFileLength; ])D39  
} 79G& 0 P\  
} 6ntduXeNVh  
3 6-Sw  
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//启动子线程 w^N3Ma  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s;!Tz)  
for(int i=0;i<nStartPos.length;i++) T$vDw|KSVP  
{ -V'h>K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (I0QwB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8TV "9{ n  
nStartPos,nEndPos,i); ]<g`rR
7}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t/Y)%N  
fileSplitterFetch.start(); xa]e9u%  
} ['#3GJz-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )a0%62  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;($"_h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /^^wHW:  
nEndPos = " + nFileLength); F?*ko,  
// fileSplitterFetch[nPos.length-1].start(); JR^#NefJ  
yf@DaIG  
Unc_e  
//等待子线程结束 `p\@b~GM  
//int count = 0; *wNO3tP't  
//是否结束while循环 Di>
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boolean breakWhile = false; /+g)J0
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while(!bStop) SM1[)jZ-  
{  r]lPXj(`  
write_nPos(); 4!)=!sL;  
Utility.sleep(500); SQ0t28N3h  
breakWhile = true; #d
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for(int i=0;i<nStartPos.length;i++) a
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{ l?J|Ip2W  
if(!fileSplitterFetch.bDownOver) bUS"1Tg]*6  
{ wN^$8m5\T^  
breakWhile = false; V+- ]txu|  
break; ,'z=cB`+o  
} eR*y<K(d  
} f'Cx%  
if(breakWhile) b@ S.  
break; Z`{ZV5  
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//count++; o'auCa,N  
//if(count>4) 4 /Q4sE~<  
// siteStop(); ed:[^#Lj  
} ;fl3'.S[  
2uy<wJE>  
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System.err.println("文件下载结束！"); k<i#agq  
} LktH*ePO  
catch(Exception e){e.printStackTrace ();} ccm(r~lhJ  
} s?pd&_kOv3  
Vb$
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//获得文件长度 R
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public long getFileSize() =&YhA}l\O  
{ .sE5QRVc  
int nFileLength = -1; Q( g&/O  
try{ m\xlSNW'q  
URL url = new URL(siteInfoBean.getSSiteURL()); s6+`cC4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ro`2IE>  
httpConnection.setRequestProperty("User-Agent","NetFox"); -lDAxp6p  
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int responseCode=httpConnection.getResponseCode(); {j!+\neL  
if(responseCode>=400) qrxn%#\XP  
{ oasEG6OI8  
processErrorCode(responseCode); N,F$^ q6  
return -2; //-2 represent access is error e_Un:r@)  
} @?E|]H!S]  
lS!uL9t.  
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String sHeader; 4Ow0g-{  
K|^'`FpPO  
/@qnEP%  
for(int i=1;;i++) 5kbbeO|0G  
{ U,e'vS{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _dk/SWb)  
//Utility.log(in.readLine()); iB0#Z
_  
sHeader=httpConnection.getHeaderFieldKey(i); G>>TB{}  
if(sHeader!=null) &w7Ev21  
{ *Tyr  
if(sHeader.equals("Content-Length")) 2n|]&D3V"'  
{ r>Rm=eKJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v"3($?au0  
break; Li8$Rb~q  
} &K@ RTgb  
} mNDz|Ln  
else b`yb{& ,?  
break; T2/lvvG  
} +2?=W1`  
} PbpnjvVrM  
catch(IOException e){e.printStackTrace ();} v62O+{  
catch(Exception e){e.printStackTrace ();} Z36C7 kw  
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Utility.log(nFileLength); T\3aT  
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return nFileLength; .`@)c/<0  
} yuA+YZ  
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//保存下载信息（文件指针位置） yNc"E  
private void write_nPos() {$H-7-O$  
{ mA2L~=v#  
try{ yDe6f(D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r)xkpa5  
output.writeInt(nStartPos.length); +$y%H  
for(int i=0;i<nStartPos.length;i++) RF$2p4=[  
{ |X6/Y@N  
// output.writeLong(nPos); vv0+F6 @  
output.writeLong(fileSplitterFetch.nStartPos); %!X9>i>  
output.writeLong(fileSplitterFetch.nEndPos); /|MHZ$Y9w?  
} su\iUi  
output.close(); ;%W]b  
} YkuFt>U9,  
catch(IOException e){e.printStackTrace ();} 7G]v(ay  
catch(Exception e){e.printStackTrace ();} vnr{Ek
g  
} 9Q/t+  
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kVeR{i<*(  
//读取保存的下载信息（文件指针位置） jRGslak;  
private void read_nPos() XV %DhR=  
{ |9'
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try{ bpgvLZb>s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X"Ca  
int nCount = input.readInt(); dgp1B\  
nStartPos = new long[nCount]; 3[F9qDAy  
nEndPos = new long[nCount]; o!@}&DE|*L  
for(int i=0;i<nStartPos.length;i++) #ExNiFZ  
{ xP+`scv*m#  
nStartPos = input.readLong(); *l{GD1ZDk  
nEndPos = input.readLong(); }p|S3/G?$!  
} #X t|"Z  
input.close(); I6-.;)McO  
} v1O1-aM  
catch(IOException e){e.printStackTrace ();} :}*  
catch(Exception e){e.printStackTrace ();} sFbN)Cx  
} <N'v-9=2jl  
V]Z!x.x"=y  
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private void processErrorCode(int nErrorCode) kWMz;{I5*w  
{ 7U647G(Sg  
System.err.println("Error Code : " + nErrorCode); OUF
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} 1"yr`,}?8r  
;lP/hG;`  
? dh  
//停止文件下载 ;k|U2ajFJ  
public void siteStop() D8 BmC  
{ {3`cSm6c  
bStop = true; RIdh],-  
for(int i=0;i<nStartPos.length;i++) +=MN_  
fileSplitterFetch.splitterStop(); N> jQe  
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} vN9R.R  
} cMK}BHOC  
//负责部分文件的抓取
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**FileSplitterFetch.java /P%OXn$i/  
*/ 5_7y1  
package NetFox; Aw$+Ew[8 2  
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import java.io.*; w<&R|= 93  
import java.net.*; urhOvC$a  
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public class FileSplitterFetch extends Thread { CuT50N;tk  
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String sURL; //File URL \@B'f  
long nStartPos; //File Snippet Start Position G_]zymXQ  
long nEndPos; //File Snippet End Position o]M1$)>b+  
int nThreadID; //Thread's ID U!i1~)s  
boolean bDownOver = false; //Downing is over ]_(J8v  
boolean bStop = false; //Stop identical uL{CUt  
FileAccessI fileAccessI = null; //File Access interface x/dyb.  
eXQLE]L]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BIh^b?:zU  
{ Mz6PH)e;  
this.sURL = sURL; `Kbf]"4q  
this.nStartPos = nStart; ")YD~ZA%)  
this.nEndPos = nEnd; bRD-[)  
nThreadID = id; H
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 C2{*m{ D  
} T5Iz{Ha  
_9C,N2a{C  
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public void run() 0bG#'.-  
{ 8b!xMFF"  
while(nStartPos < nEndPos && !bStop) 5.$/]2VK  
{ *,|x p  
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try{ f?$yxMw:@  
URL url = new URL(sURL); 9ZNzC i!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hof>:Rk  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~)pso7^:  
String sProperty = "bytes="+nStartPos+"-"; N[A9J7}_R  
httpConnection.setRequestProperty("RANGE",sProperty); ,bzC|AK  
Utility.log(sProperty); IIN,Da;hD  
,T*\9'Q  
)#8}xAjV  
InputStream input = httpConnection.getInputStream(); }9kn;rb$g  
//logResponseHead(httpConnection); iG#92e4  
,FwpHs $A  
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byte[] b = new byte[1024]; Eh^gR`I  
int nRead; Rl&nR$#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zZ,"HY=jN  
{ ++n_$Qug  
nStartPos += fileAccessI.write(b,0,nRead); xR8y"CpE  
//if(nThreadID == 1) W_6gV  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =ld!=II  
} $_3)m  
6"?#E[ #[  
!jf!\Uu[U  
Utility.log("Thread " + nThreadID + " is over!"); ep4?;Qmho  
bDownOver = true; +IMt$}7[  
//nPos = fileAccessI.write (b,0,nRead); >;lrH&  
} -24ccN;  
catch(Exception e){e.printStackTrace ();} PjofW%7F  
} I@5$<SN  
} =KAN|5yn  
?D|kCw69SE  
* =*\w\ te  
//打印回应的头信息 L1WvX6  
public void logResponseHead(HttpURLConnection con) *pDS%,$xe  
{ p()LQT!  
for(int i=1;;i++) !L( )3=  
{ k{O bm g  
String header=con.getHeaderFieldKey(i); kZhd^H.  
if(header!=null) IwBO#HR
~)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D<:zw/IRE  
Utility.log(header+" : "+con.getHeaderField(header)); X,c`,B03  
else r9*6=*J|  
break; U_hzSf  
} J\>/J%  
} F("|SOhc  
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public void splitterStop() aK_k'4YTm  
{ }u1h6rd `  
bStop = true; _Fn`G.r<  
} ZvLI~ul(zT  
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} 6Eus_aP  
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/* C4GkFD   
**FileAccess.java r i)`
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*//文件访问(定位，写) Ms5R7<O.7  
package NetFox; _2)QL  
import java.io.*; R\Ckk;<$  
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*K& $9fah  
public class FileAccessI implements Serializable{ F(ZczwvR  
%eh.@8GL`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]826kpq_  
RandomAccessFile oSavedFile; j<6+p r  
long nPos; 
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public FileAccessI() throws IOException .;S1HOHz4  
{ d^v.tYM$N  
this("",0); k2.k}?w!JO  
} L4ct2|w}ul  
7F_N{avr  
kZ]pV=\Y*  
public FileAccessI(String sName,long nPos) throws IOException ;@:-T/=  
{ vR>GE?s6  
oSavedFile = new RandomAccessFile(sName,"rw"); lauq(aD_C  
this.nPos = nPos; u#`51Hr
$  
oSavedFile.seek(nPos); <>Ha<4A =E  
} =(Y0wZP|  
jW4>WDN:  
5y] %Cu1.u  
public synchronized int write(byte[] b,int nStart,int nLen) $pt~?ZZ3-  
{ mB6%. "  
int n = -1; GctV  
try{ OEX\]!3_Fm  
oSavedFile.write(b,nStart,nLen); LPZ\T}<l  
n = nLen; ks %arm&  
} -3y
  
catch(IOException e) V#+F*w?&D  
{ VS!v7-_N5  
e.printStackTrace (); I~Qi):&x  
} _3NH"o d  
1~},}S]id  
OF)*kiJ  
return n; [Q\(kd*4  
} 3xmPY.  
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} *cCj*Zr]  
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]=]MJ3_7  
/* ykH@kv Qt  
**SiteInfoBean.java 9'e<{mlM  
*/  =zDvZ(5  
package NetFox; ):nC%0V  
(_+ux1h6^  
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public class SiteInfoBean { :zvAlt'q=  
^<uQ9p^B  
V]"pM]>3X  
private String sSiteURL; //Site's URL Z}Q/u^Z  
private String sFilePath; //Saved File's Path HD1/1?y!@q  
private String sFileName; //Saved File's Name WTjmU=<\  
private int nSplitter; //Count of Splited Downloading File vS[\j  
;Bw3@c  
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public SiteInfoBean() 9'(m"c_  
{//nSplitter的缺省值为5 "DH>4Q] d  
//default value of nSplitter is 5 U!K#g_}  
this("","","",5); +x/vZXtOK  
} >6@,L+-6r  
&3xda1H  

?^^TR/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `*`ZgTV  
{ #l.s>B4  
sSiteURL= sURL; OECVExb@eH  
sFilePath = sPath; yu>;m.e_  
sFileName = sName; 4x?I,cAN  
this.nSplitter = nSpiltter; ~2yhZ  
Fu\#:+5\  
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} Tj\hAcD  
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public String getSSiteURL() 'A\0^EvVv  
{ O*B9Bah  
return sSiteURL; Snp(&TD<<  
} Dkh=(+> <  
x9 n(3Oa  
- DYH>!  
public void setSSiteURL(String value) vQy<%[QO  
{ }w2Et  
sSiteURL = value; +_gA"I  
} gS`Z>+V5!c  
G `B=:s]  
cWo__EE  
public String getSFilePath() $2blF)uYE  
{ u6IM~kk>5  
return sFilePath; a40>_;}:x  
} ae
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Z:V<P,N  
:S!!J*0  
public void setSFilePath(String value) BQeg-M  
{ T!pZj_ h=  
sFilePath = value; 'aEN(Mdz1e  
} \_i22/Et  
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e 0Z2B2  
public String getSFileName() D~`RLPMk  
{ D$rn?@&g  
return sFileName; "gD
k?w
 
} JE*?O*&|Q  
:<0lCj  
wyAh%'V  
public void setSFileName(String value) p6)6Gcx  
{ npbf>n^R  
sFileName = value; ~DB:/VSmu  
} wAzaxeV=  
jIHY[yDT  
jZvIqR/  
public int getNSplitter() se}$/Y}t  
{ g2 mq?q(g  
return nSplitter; zzh7 "M3Qn  
} r?^L/HGc  
9(_n8br1  
9#~jlq(  
public void setNSplitter(int nCount) Y`6<:8[?  
{ Gc5mR9pV   
nSplitter = nCount; g?Rq .py]!  
} YhooD,[.  
}  p1&=D%/  
/Bk`3~]E>  
EQM[!g^a  
/* 98uMD  
**Utility.java fZJM'+J@A  
*/ 77 Z:!J|  
package NetFox; #T`1Z"h<  
_G/uDP%  
+@7c:CAy(  
public class Utility { u09D`QPP]  
+>c%I&h}`  
+#A
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public Utility() Q7UQwAN'  
{ beV+3HqB8  
DiZv sc  
#!_ViG )2^  
} ="Azg8W  
d`j<Bbf-  
//线程睡眠 r?pFc3~N  
public static void sleep(int nSecond) Z-" NLwt[  
{ iuM ,aF  
try{ f3h]t0M  
Thread.sleep(nSecond); 2n#H%&^?a  
} }/IP\1bG  
catch(Exception e) (hRg0Z=  
{ y`/:E<fVk  
e.printStackTrace (); :x^e T  
} d?cCSf  
} ST4[
d'|j  
t~qAA\p}o  
//日志 IEI&PRD  
public static void log(String sMsg) C*t0`3g d  
{ ~4] J'E >  
System.err.println(sMsg); <Skf n`).  
} xf|C{XV@H  
ld5+/"$
 
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public static void log(int sMsg) qzSm]l?z  
{ bhfKhXh8  
System.err.println(sMsg); \`-xxhb?e  
} ;rnhv:Iw  
} b'ir$RL] c  
3u s^\w#  
`dl^)
4J  
/* qK%#$Jgq
A  
**TestMethod.java X2P8Zq=%a  
*/ Wi~?2-!   
package NetFox; }b{7+ + Ah  
+]~}kvk:  
hxw6^EA  
public class TestMethod { %xp 69  
?]+!gz1  
>J:
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public TestMethod() 8zjJshE/  
{ ///xx/weblogic60b2_win.exe _5OxESE  
try{ *hpS/g/3\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Sg\+al7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SxkY ;^-U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &7{yk$]*  
fileFetch.start(); zIr-Rx'dL^  
} 5)->.*G*  
catch(Exception e){e.printStackTrace ();} X8~?uroq  
3 [O+wVv  
f/m0,EERk  
} uw@-.N^  
fEGnI
\  
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public static void main(String[] args) ^^YP kh6sS  
{ ~ET XXu${I  
new TestMethod(); &F*eo`o}6  
} {rygIl{V  
} '+*'sQvH[  
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