http断点续传简单实现（java)

/* {hW +^  
**SiteFileFetch.java L%c]%3A  
*/ 8:3oH!n  
package NetFox; eONeWY9  
import java.io.*; .y/NudD  
import java.net.*; V0SW 5 m  
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8GF[)z&|P:  
public class SiteFileFetch extends Thread { [[Jv)?jm  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Zi[{\7a  
long[] nStartPos; //开始位置 wiK@o$S-  
long[] nEndPos; //结束位置 SK2J`*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F^%{ ;  
long nFileLength; //文件长度 ZNL;8sI?>  
boolean bFirst = true; //是否第一次取文件 *@$($<pY&  
boolean bStop = false; //停止标志 #z-iL!?  
File tmpFile; //文件下载的临时信息 qd#(`%_/  
DataOutputStream output; //输出到文件的输出流 ]yj4~_&O  
#Tgz,e9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (Fbm9(q$d  
public SiteFileFetch(SiteInfoBean bean) throws IOException } K+Q9<~u  
{ 7gZVg@  
siteInfoBean = bean; {kRDegby  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Skr\a\ J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0`g}(}'L  
if(tmpFile.exists ()) T@d_t  
{ |p=.Gg=2  
bFirst = false; $v?
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read_nPos(); n]6}yJJo  
} @4 Os?_gJ\  
else E7Gi6w~\  
{ %>I?'y^  
nStartPos = new long[bean.getNSplitter()]; >[E|p6jgT  
nEndPos = new long[bean.getNSplitter()]; ei|*s+OZu  
} "c!oOaA  
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} (DELxE  
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public void run() '5OVs:)"^  
{ lD;,I^Lt6  
//获得文件长度 \Z6gXO_  
//分割文件 !S >|Qh  
//实例FileSplitterFetch ziB]S@U  
//启动FileSplitterFetch线程 xsY>{/C  
//等待子线程返回 dEAAm=K,<  
try{ 2EqsfU* I  
if(bFirst) +,{Wcb  
{ <
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nFileLength = getFileSize(); Z+`{JE#  
if(nFileLength == -1) 5b{yA~ty  
{ >2/wzs
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System.err.println("File Length is not known!"); WO+?gu  
} #<W
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else if(nFileLength == -2) <De3mZb  
{ cciAMQhA  
System.err.println("File is not access!"); @3expC  
} !mErt2UJl  
else YjIED,eRv  
{ qqz,~EhC  
for(int i=0;i<nStartPos.length;i++) `1[Sv"  
{ ;f ;*Q>!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p.TiTFu/  
} yTq(x4]  
for(int i=0;i<nEndPos.length-1;i++) ;+TF3av0zq  
{ g.`t!6Hc  
nEndPos = nStartPos[i+1]; [-:<z?(n4  
} &\6`[# bT  
nEndPos[nEndPos.length-1] = nFileLength; i Ks,i9j  
} 3>@qQ_8%~  
} Fgc:6<MGM  
_1>(GK5[  
r3BDq  
//启动子线程 ~D`oP/6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VT.{[Kl  
for(int i=0;i<nStartPos.length;i++)  8H%I|fm  
{ zoJkDr=jn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z9 q{r s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4-}A'fTU8  
nStartPos,nEndPos,i); @L>NN>?SGQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >gOI]*!5  
fileSplitterFetch.start(); 0@mX4
.!  
} l~Wk07r3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yZ(Nv $[5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yK>0[6l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i6g[E4nk  
nEndPos = " + nFileLength); 3Ld ;zW  
// fileSplitterFetch[nPos.length-1].start(); Pguyf2/w  
ixJ20A7  
+v[$lh+  
//等待子线程结束 /Y\E68_Fh  
//int count = 0; eI=Y~jy  
//是否结束while循环 c[d'1=Qiy  
boolean breakWhile = false; sWZtbW;)  
nGJIjo_I  
g`5`KU|  
while(!bStop) B,m$ur#$  
{ @IyH(J],h  
write_nPos(); }^Ua  
Utility.sleep(500); 4k&O-70y4^  
breakWhile = true; !Bd* L~D  
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for(int i=0;i<nStartPos.length;i++) B 1ZHV^  
{ 4M<JfD  
if(!fileSplitterFetch.bDownOver) m|cWX"#g  
{ neY=:9  
breakWhile = false; PHiX:0zT  
break; LG@c)H74  
} L};;o+5uJD  
} Hb AMoow!  
if(breakWhile) MCrO]N($b  
break; 5vh"PlK`s  
ao";5m  
b=QG
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//count++; ";Ig%]  
//if(count>4) FnQ_=b  
// siteStop(); xV 1Z&l  
} )Fr;'JYC1S  
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System.err.println("文件下载结束！"); uA/.4 b  
} *ZSp9g"Z  
catch(Exception e){e.printStackTrace ();} 7%"\DLA  
} uSQ>oi]  
@Jn:!8U0  
w KMk|y>  
//获得文件长度 Y/ac}q  
public long getFileSize() d @kLLDP  
{ LX?r=_\  
int nFileLength = -1; (#l_YI -  
try{ G$kwc F'C  
URL url = new URL(siteInfoBean.getSSiteURL()); DGfQo5#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,ZP3F+XKb  
httpConnection.setRequestProperty("User-Agent","NetFox"); O\8|niW|  
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!%\To(r[  
int responseCode=httpConnection.getResponseCode(); rs<&x(=Hv  
if(responseCode>=400) zf;[nz  
{ ONe!'a0  
processErrorCode(responseCode); 674oL,  
return -2; //-2 represent access is error d|?(c~  
} >8
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*=0r>]  
String sHeader; QKaj4?p$|S  
[QqNsco)  
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for(int i=1;;i++) GxDF7 z%&  
{ oY6|h3T=Q$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NUnc"@  
//Utility.log(in.readLine()); @)'@LF1Z  
sHeader=httpConnection.getHeaderFieldKey(i); <VxpMF  
if(sHeader!=null) MJ/%$  
{ _NqT8C4C  
if(sHeader.equals("Content-Length")) AW;)_|xM  
{ F#bo4'&>@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 68GGS`&  
break; ;pyJ O_R[  
} "oXAIfU#T  
} ST8/ ;S#c  
else `"b7y(M  
break; R6$F<;nw  
} GV@E<dg$R  
} <^'+]?  
catch(IOException e){e.printStackTrace ();} pBnf^Ew1  
catch(Exception e){e.printStackTrace ();} -GWzMBS S  
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Utility.log(nFileLength); *|#JFy?c[  
tc2GI6]
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/Vd#q)b%T  
return nFileLength; 1Da [!^u,D  
} iEgM~  
-+_
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W#\};
P  
//保存下载信息（文件指针位置） Z#:@M[HH{  
private void write_nPos() $H@)hY8wA  
{ 2CgIY89O  
try{ 6')SJ*|yS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jMWwu+w  
output.writeInt(nStartPos.length); +U)|&1oa  
for(int i=0;i<nStartPos.length;i++) ]9< 9F ?  
{ UpseU8Wo  
// output.writeLong(nPos); FRQ("6(  
output.writeLong(fileSplitterFetch.nStartPos); K}/`YDu  
output.writeLong(fileSplitterFetch.nEndPos); '*;eFnmvs:  
} @wg
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output.close(); mL5f_Fb+  
} wR+`("2{r  
catch(IOException e){e.printStackTrace ();} >upUY(3&  
catch(Exception e){e.printStackTrace ();} RkP|_Bf8)  
} $5CY<,f  
DSZhl-uGM  
AbI*/|sY  
//读取保存的下载信息（文件指针位置） 4x?u5L 9o  
private void read_nPos() !3Z|!JY  
{ L\b_,'I  
try{ 8[`<u[Iv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `[:1!I.}-  
int nCount = input.readInt(); YIUmCx0a  
nStartPos = new long[nCount]; d*(Bs$De  
nEndPos = new long[nCount]; i{[H3p8  
for(int i=0;i<nStartPos.length;i++) E/P53CD  
{ r_sl~^* :  
nStartPos = input.readLong(); U105u.#7  
nEndPos = input.readLong(); u,SZ-2K!7~  
} dB)hW'J?  
input.close(); sl @6  
} 5f@YrTO[@  
catch(IOException e){e.printStackTrace ();} '<D}5u72  
catch(Exception e){e.printStackTrace ();} 78~V/L;@S2  
} 'p+QFT>Ca  
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9QZwUQ  
private void processErrorCode(int nErrorCode) J3S+| x h~  
{ -?`l<y(  
System.err.println("Error Code : " + nErrorCode); N_[ Q.HD"  
} $v@$oPmMj  
=V]i?31[  
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//停止文件下载 Sz@?%PnU|  
public void siteStop() 2#M:JgWV  
{ 3Il/3\  
bStop = true; afq +;Sh  
for(int i=0;i<nStartPos.length;i++) Y8'_5?+ 0  
fileSplitterFetch.splitterStop(); QjN3j*@  
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} J,KTc'[  
} -mo ' $1  
//负责部分文件的抓取 %)ov,p|  
**FileSplitterFetch.java yzb&
  
*/ WREGRy  
package NetFox; MJpTr5Vs  
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d6 EJn/  
import java.io.*; bO%ck-om!  
import java.net.*; UI|@5:J  
zR_l^NK  
:Zo2@8@7  
public class FileSplitterFetch extends Thread { 5MU@g*gj,C  
@$}\S  
r9*H-V$  
String sURL; //File URL p&doQh
  
long nStartPos; //File Snippet Start Position `z`;eR2oX  
long nEndPos; //File Snippet End Position k r^#B^  
int nThreadID; //Thread's ID NVZNQ{  
boolean bDownOver = false; //Downing is over 1U9N8{xg9  
boolean bStop = false; //Stop identical 1+c(G?Ava  
FileAccessI fileAccessI = null; //File Access interface *]?YvY  
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5{aQ4H>~tx  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4GA-dtyV&  
{ c}s3c >`d  
this.sURL = sURL; |sM#g1D@  
this.nStartPos = nStart; [N+ruc?)  
this.nEndPos = nEnd; :S6 <v0`Z  
nThreadID = id; vJ}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vz5RS  
} Cms"OkN  
8^i,M^f^{  
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public void run() 5j5t?G;d,  
{ )3"
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while(nStartPos < nEndPos && !bStop) oYx f((x  
{ Ap18qp  
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|]b/5s;>  
try{ W\Y 4%y}  
URL url = new URL(sURL); q`zR6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S^=/}PT'  
httpConnection.setRequestProperty("User-Agent","NetFox"); 30`H Xv@  
String sProperty = "bytes="+nStartPos+"-"; n:kxG  
httpConnection.setRequestProperty("RANGE",sProperty); m]pvJJ@  
Utility.log(sProperty); <QLj6#d7Y  
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InputStream input = httpConnection.getInputStream(); 4HmRsOl  
//logResponseHead(httpConnection); W7>_nK+g?  
 :Xr3 3  
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byte[] b = new byte[1024]; D)6||z}  
int nRead; (XWs4R.mkb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (I g *iJ%2  
{ 1&nrZG9  
nStartPos += fileAccessI.write(b,0,nRead); T5G+^XDA  
//if(nThreadID == 1) [/]3:|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !XceiQu  
} f2f$aZ  
jZyh   
)A;<'{t #L  
Utility.log("Thread " + nThreadID + " is over!"); f89<o#bm7h  
bDownOver = true; 36UWoo  
//nPos = fileAccessI.write (b,0,nRead); Yy1Pipv  
} ||NCVGJG  
catch(Exception e){e.printStackTrace ();} C.p*mO&N  
} '11hIu=:  
} Hb4rpAeP  
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//打印回应的头信息 -ZJ:<  
public void logResponseHead(HttpURLConnection con) gRSG[GMV  
{ 4}j}8y2)H  
for(int i=1;;i++) 5@5="lNjS  
{ N`fY%"5U>  
String header=con.getHeaderFieldKey(i); Fd'L:A~  
if(header!=null) X/"H+l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W0hLh<Go  
Utility.log(header+" : "+con.getHeaderField(header)); cH ?]uu(  
else )~kb7rfl  
break; qIp`'.#m  
} $nWmoe)  
} Yb*}2  
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public void splitterStop() =B2=UF  
{ vS
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bStop = true; 2YQ$hL~  
} $E6uA}s  
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} -n-X/M  
E ..[F<5  
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/* E"!
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**FileAccess.java $!lxVZ>  
*//文件访问(定位，写) &*~ WK  
package NetFox; `dhK$jYD  
import java.io.*; h#9)M  
{D8IA3w  
#^Y-*vf2  
public class FileAccessI implements Serializable{ O;"%z*g.  
qB`P7!VN^]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i"@?eq#h  
RandomAccessFile oSavedFile; V;=T~K|)>  
long nPos; 5E8PbV-l  
;?9~^,l  
g!UM8I-$  
public FileAccessI() throws IOException J4; ".Y=  
{ dl4.jLY  
this("",0); L2%P  
} DTY=k  
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public FileAccessI(String sName,long nPos) throws IOException 3 -FNd~%  
{ `)fGw7J {  
oSavedFile = new RandomAccessFile(sName,"rw"); |v&&%>A2  
this.nPos = nPos; )Ec;krb+  
oSavedFile.seek(nPos); R_}(p2  
} @ ri.r1  
Fk:(%ci  
/uVB[Tk^  
public synchronized int write(byte[] b,int nStart,int nLen) &0`L;1R  
{ f#jAjzmYL  
int n = -1; xM,3F jF  
try{ 9S^-qQH3}  
oSavedFile.write(b,nStart,nLen); WUWQcJj  
n = nLen; FtXEudk  
} tKs0]8tc  
catch(IOException e) HT'dft #  
{ H#D=vx'  
e.printStackTrace (); 0=iJT4IEJ  
}
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return n; sAxn ; `  
} LO229`ARr|  
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} |(fWT}tg  
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/* u/AN| y  
**SiteInfoBean.java 2iu
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*/ <fxYTd<#D[  
package NetFox; ^]kDYhe*Y  
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public class SiteInfoBean { Kh>^;`h  
x;I*Ho  
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private String sSiteURL; //Site's URL T-MLW=Vu  
private String sFilePath; //Saved File's Path bm^ou#]|  
private String sFileName; //Saved File's Name C>HUG  
private int nSplitter; //Count of Splited Downloading File 4%pvw;r  
*\>7@r[%5  
*KMCU m  
public SiteInfoBean() P*}Oi7Z  
{//nSplitter的缺省值为5 sbVeB%k  
//default value of nSplitter is 5 +MEWAW[}^  
this("","","",5); SE\`JGA[  
} p`It=16trT  
`CV a`%  
,[x'S>N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {974m` 5  
{ ~ rRIWfhb  
sSiteURL= sURL; q+z,{K  
sFilePath = sPath; Sb<=ROCg@  
sFileName = sName; ,^3D"Tky
 
this.nSplitter = nSpiltter; 6^p6v  
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r8qee$^M  
} 607#d):Y  
J&5|'yVX  
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public String getSSiteURL() 7HzKjR=B  
{ iU &V}p  
return sSiteURL; :%Bo)0a9  
} xKxWtZ0  
I++!F,pB  
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public void setSSiteURL(String value) 7>.^GD  
{ +}^
  
sSiteURL = value; TGg*(6'z  
} =U:iR  
#xO`k1W.  
1{A4_/R
 
public String getSFilePath() X:DHz0S  
{ HLS^Ga,(  
return sFilePath; I(2ID +  
} j*P@]&e7d  
)/BKN`,  
1vobfZ-w9  
public void setSFilePath(String value) Y}0-&  
{ /%.K`BMN  
sFilePath = value; {MIs%w.G  
} N@k:kI  
U-k6ZV3&8  
o;"!#Z 1SJ  
public String getSFileName() (\]_/ W  
{ REHfk6YE  
return sFileName; -wY6da*.W  
} %o5GD  
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public void setSFileName(String value) R (6Jvub"I  
{ /GEqU^ B  
sFileName = value; Blu^\:?#z-  
} JAgec`T%  
|u03~L9G  
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public int getNSplitter() -
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{ &We'omq  
return nSplitter; J?%Z7&/M>  
} B-o"Y'iXs  
b+{,c@1rd  
;]p#PNQ0  
public void setNSplitter(int nCount) _I2AJn`#  
{ uu(.,11`  
nSplitter = nCount; "3Ec0U \s  
} 0evG  
} m(9E{;  
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%e3lb<sv6  
/* K~[/n<ks  
**Utility.java Qg3 -%i/@  
*/ olh|.9Kdj}  
package NetFox; xe}"0'g  
I5  
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public class Utility { @T1-0!TM')  
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public Utility() Ff|?<\x0}A  
{ iHTxD1D+H  
eqXW|,zUm  
a "8/y4Y  
} o6'`W2P  
GAQVeL1  
//线程睡眠 ~bgFU  
public static void sleep(int nSecond) t:W`=^  
{ cD7q;|+  
try{ $lUZm\R|k  
Thread.sleep(nSecond); lxV> rmD  
} qxk1Rzm?x  
catch(Exception e) 89~)nV)  
{ ?9/%K45  
e.printStackTrace (); 0^zu T  
} bD=_44
I  
} QRx'BY$5  
1Hzj-u&N/  
//日志 <` HLG2  
public static void log(String sMsg) 'j>Q7M7q{  
{ )0!hw|0|  
System.err.println(sMsg); %$S.4#G2  
} i |cSO2O+  
XYf;72*  
9].!mpR  
public static void log(int sMsg) I8e{%PK  
{ 3xbA]u;gp  
System.err.println(sMsg); n&k1'KL&  
} |7%M:7Q  
} jR*1%.Ng  
R$wo{{KX  
s!uewS.  
/* Au@U;a4UU  
**TestMethod.java !%sj-RMvG  
*/ pvkru-i]  
package NetFox; 0!\pS{$zB  
*S`& XPj  
cy%^P^M  
public class TestMethod { SkVW8n*s  
?;!l-Dy  
<{:$]3  
public TestMethod() & Z*&&  
{ ///xx/weblogic60b2_win.exe , En D3 |  
try{ {-tCLkE 3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |G!-FmIK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L~CwL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |Kh#\d  
fileFetch.start(); e*=N\$  
} 7hY~  
catch(Exception e){e.printStackTrace ();} sYgpK92  
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/mF%uI>:  
} <LH(>  
!/sXG\  
P
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public static void main(String[] args) 02SFFqm  
{ $D<LND=o=  
new TestMethod(); _L<IxOZh+  
} mQ:lj$Gf  
} _.yBX\tf[  
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