http断点续传简单实现（java)

/* p@pb[Bx~[  
**SiteFileFetch.java RQ=rB9~:ZN  
*/ U*+-#  
package NetFox; 18X?CoM~  
import java.io.*; h1S)B|~8  
import java.net.*; (?Ko:0+*  
=mLp g4  
&en2t=a  
public class SiteFileFetch extends Thread { |kZ!-?9Z  
8s22VL  
'=nmdqP  
SiteInfoBean siteInfoBean = null; //文件信息Bean zWo  
long[] nStartPos; //开始位置 @7}XBg[pI  
long[] nEndPos; //结束位置 0d2RB^"i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Rir0^XqG  
long nFileLength; //文件长度 l^I?@{W  
boolean bFirst = true; //是否第一次取文件 ~Bl,_?CBr  
boolean bStop = false; //停止标志 d>u^7:  
File tmpFile; //文件下载的临时信息 &&CrF~  
DataOutputStream output; //输出到文件的输出流 _wXT9`|3  
}V]*FCpQ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L4^/O29
 
public SiteFileFetch(SiteInfoBean bean) throws IOException i\lvxbp  
{ ?5't1219  
siteInfoBean = bean; 50 w
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qt.4dTd:_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cEf"m?w  
if(tmpFile.exists ()) ;G`]`=s#Lq  
{ H, 3Bf
 
bFirst = false; X.{xHD&_
 
read_nPos(); 2XL^A[?   
} z:S:[X0  
else `IlhLv  
{ +76'(@(1Y  
nStartPos = new long[bean.getNSplitter()]; { 1~]}K2  
nEndPos = new long[bean.getNSplitter()]; 1D[V{)#  
} 'bRf>=  
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} kKRu]0J~[  
. AA# G  
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public void run() L[PqEN\i  
{ )'jGf;du  
//获得文件长度 BHp>(7,  
//分割文件 ] K&ca  
//实例FileSplitterFetch H.M: cD:  
//启动FileSplitterFetch线程 xY)eU;*  
//等待子线程返回 !.%*Tp#k#  
try{ K"[jrvZ=  
if(bFirst) xj33g6S  
{ q=e;P;u  
nFileLength = getFileSize(); =P,mix|  
if(nFileLength == -1) q2|x$5  
{ t ^>07#z  
System.err.println("File Length is not known!"); u gRyUny  
} Q~"Lyy8  
else if(nFileLength == -2) /Q W^v;^  
{ SeZ+&d  
System.err.println("File is not access!"); Ho}*Bn~i
c  
} Q65M(x+oy  
else 7h(  
{ )+v5H  
for(int i=0;i<nStartPos.length;i++) %@(+`CCA  
{ _!|$i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t{UWb~"  
} 2@T0QJ  
for(int i=0;i<nEndPos.length-1;i++) RF8,qz  
{ ?lqqu#;8  
nEndPos = nStartPos[i+1]; uFmpc7  
} bi-Am/9  
nEndPos[nEndPos.length-1] = nFileLength; k~;~i)Eg  
} 1xtS$^APcd  
} $Vp&7OC]  
| #a{1Z)  
3v$n}.  
//启动子线程 9FC_B+7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,h%n5R$:  
for(int i=0;i<nStartPos.length;i++) [ s/j?/9  
{ & :W6O)uY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  W;yg{y   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =}%:4  
nStartPos,nEndPos,i); lpd~U2&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o4 "HE*  
fileSplitterFetch.start(); 1Z_]Ge<a  
} .rg "(I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O>f*D+A-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rv)Eg
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \{rhHb\|h  
nEndPos = " + nFileLength); r#j3O}(n  
// fileSplitterFetch[nPos.length-1].start(); .0>bnw  
W|;`R{<I%  
oT:wGBW  
//等待子线程结束 SANbg&$  
//int count = 0; MS2/<LD3d  
//是否结束while循环 wBI:}N@.  
boolean breakWhile = false; IN;!s#cl:  
>f9Q&c$R  
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while(!bStop) ,: z]15fX  
{ V
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write_nPos(); 2fayQY xD  
Utility.sleep(500); %26HB w=JF  
breakWhile = true; / E!6]b/  
Z@m5hx&  
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for(int i=0;i<nStartPos.length;i++) ?=?*W7  
{ \2f?)id~  
if(!fileSplitterFetch.bDownOver) dhg($m  
{ B\|^$z
2  
breakWhile = false; ]LCL?zAzH!  
break; $D^27q:H  
} 4y.'O  
} Z5wDf+
 
if(breakWhile) @d5t%V\  
break; BVv-1$ U^  
b!QRD'31'j  
7 mA3&<&q  
//count++; ~s?y[yy6i  
//if(count>4) DjZTr}%q  
// siteStop(); blG?("0!  
} KKg\n^  
:[PA.Upi  
 hOqNZ66{  
System.err.println("文件下载结束！"); rCGKE`H
 
} Q[!?SSX%  
catch(Exception e){e.printStackTrace ();} v!S(T];)  
} F_}y[Yn^  
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I_
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//获得文件长度 q|lP?-j  
public long getFileSize() dn%'bt
 
{ RXWdqaENx  
int nFileLength = -1;
KI\ 9)  
try{ A|mE3q=  
URL url = new URL(siteInfoBean.getSSiteURL()); q`|E9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); su60j^e*  
httpConnection.setRequestProperty("User-Agent","NetFox"); EcR[b@YI  
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vl`St$$|  
int responseCode=httpConnection.getResponseCode(); \WUCm.w6\%  
if(responseCode>=400) Nhjz~S<o  
{ "|WKK}  
processErrorCode(responseCode); d.>O`.Mu)}  
return -2; //-2 represent access is error !*wd d8
 
} :K \IS`  
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#)
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String sHeader; I$TD[W  
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for(int i=1;;i++) -|czhO)R  
{ F9IPA%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xnZ  
//Utility.log(in.readLine()); EL *l5!Iu  
sHeader=httpConnection.getHeaderFieldKey(i); MA 6uJT  
if(sHeader!=null) *z'Rl'j9[  
{ hz2f7g  
if(sHeader.equals("Content-Length")) #\}xyPS  
{ dKPx3Y'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :'!_PN  
break; p|r>tBv?x  
} `Z`o[]%  
} )qWO}]F  
else p:!FB8  
break; CS xB)-  
} MA mjoH  
} 1ww~!R  
catch(IOException e){e.printStackTrace ();} &9n=!S'Md  
catch(Exception e){e.printStackTrace ();} ;[,#VtD  
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Utility.log(nFileLength); /5XdZu6k`h  
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return nFileLength; lb)i0`AN+  
} ',Oc+jLR  
pAtxEaXh  
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//保存下载信息（文件指针位置） i?F~]8  
private void write_nPos() mndNkK5o  
{ ,ce$y4%(  
try{ 7ws[Rp8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B/EGaYH  
output.writeInt(nStartPos.length); {RH)&k&%  
for(int i=0;i<nStartPos.length;i++) ;sSRv9Xb  
{ \D! I"mr  
// output.writeLong(nPos); g+k yvI7o  
output.writeLong(fileSplitterFetch.nStartPos); `]2y=f<{X  
output.writeLong(fileSplitterFetch.nEndPos); N1]P3  
} Wc/B_F?2  
output.close(); LC/%AbM  
} C:}"?tri  
catch(IOException e){e.printStackTrace ();} =co6.Il  
catch(Exception e){e.printStackTrace ();} 38RyUHL=  
} Or()AzwE@  
0^MRPE|f5  
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//读取保存的下载信息（文件指针位置） &Mh]s\  
private void read_nPos() 2CPh'7|l  
{ _4t  
try{ k'd=|U;(FV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T!H }^v  
int nCount = input.readInt(); v$|cF'yyF=  
nStartPos = new long[nCount]; F)tcQO"G  
nEndPos = new long[nCount]; O/f+B}W  
for(int i=0;i<nStartPos.length;i++) Ar$Am  
{ y-:d`>b>\  
nStartPos = input.readLong(); >uz3 O?z P  
nEndPos = input.readLong(); X gA( D  
} l9$"zEC  
input.close(); [Kanj/  
} KQrG|<J  
catch(IOException e){e.printStackTrace ();} /.@"wAw:  
catch(Exception e){e.printStackTrace ();} Jpo(O>\P  
} NFb<fD[C  
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private void processErrorCode(int nErrorCode) Dn.%+im-u  
{ qmGLc~M0  
System.err.println("Error Code : " + nErrorCode); EYKV}`  
} RMxFo\TK;  
K!SFS   
y$HV;%G{26  
//停止文件下载 ,fD#)_\g2  
public void siteStop() RZ:=';  
{ &B ^LaRg  
bStop = true; IaR D"oCH  
for(int i=0;i<nStartPos.length;i++) xAAwH@ +  
fileSplitterFetch.splitterStop(); USyOHHPW@  
.|3&lb6  
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} ^9?IS<N0]  
} p#AQXIF0  
//负责部分文件的抓取 N/N~>7f  
**FileSplitterFetch.java Z[zRZ2'i5  
*/ >iI-Cs7TD  
package NetFox; $2pkh%  
@7,k0H9Moa  
=E-V-?N\  
import java.io.*; ]9NA3U7F  
import java.net.*; 6n$g73u<=3  
Z {*<Gx  
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public class FileSplitterFetch extends Thread { V82N8-l  
h2m@Q={  
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String sURL; //File URL IpI|G!Y,  
long nStartPos; //File Snippet Start Position qv$m5CJvK
 
long nEndPos; //File Snippet End Position Ya-kMUW  
int nThreadID; //Thread's ID I=9sTR)  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical jB%aHUF;  
FileAccessI fileAccessI = null; //File Access interface -1tiy.^$F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W(,3j{d2i  
{ _T.k/a  
this.sURL = sURL; 5}"9)LT@@w  
this.nStartPos = nStart; z[0B"f  
this.nEndPos = nEnd; }w/6"MJ[n  
nThreadID = id; 4,qhWe`/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QlK]2r9  
} ~-o[v-\  
&`Ek-b!7  
=^`?O* /;  
public void run() ^ah9:}Ll  
{ ) i=.x+Q  
while(nStartPos < nEndPos && !bStop) ,FDRU  
{  MON]rj7  
)TzQ8YpO}  
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try{ n]fMl:77  
URL url = new URL(sURL);
wj<fi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6k*,Yei  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ni-@El99  
String sProperty = "bytes="+nStartPos+"-"; g.T:72"  
httpConnection.setRequestProperty("RANGE",sProperty); 4
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Utility.log(sProperty); #8qhl  
.FpeVjR''  
?I332,,q  
InputStream input = httpConnection.getInputStream(); "TP^:Ln  
//logResponseHead(httpConnection); GEUC<bL+  
S<UWv@`U"  
0;2"X
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byte[] b = new byte[1024]; @PAT|6  
int nRead; 2*ByVK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;HoBLxb P  
{ .l$:0a  
nStartPos += fileAccessI.write(b,0,nRead); h0)Dj(C  
//if(nThreadID == 1) R-J^%4U`7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6>&h9@  
} #l#8-m8g)  
K:(E"d;  
?n(OH~@$i  
Utility.log("Thread " + nThreadID + " is over!"); +Un(VTD  
bDownOver = true; yU'<b.]  
//nPos = fileAccessI.write (b,0,nRead); <S68UN(Ke  
} 0Tq=nYZA  
catch(Exception e){e.printStackTrace ();} r6gfxW5  
} &ws^Dm]R  
} 6,a:s:$>}R  
dh S7}n  
xY>@GSO1  
//打印回应的头信息 m< Y I}  
public void logResponseHead(HttpURLConnection con) Z]qbLxJV  
{ 5)iOG#8qJ  
for(int i=1;;i++) $*hqF1Q  
{ z1S p'h$  
String header=con.getHeaderFieldKey(i); pq$-s7#  
if(header!=null) hU6oWm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iR]K!j2  
Utility.log(header+" : "+con.getHeaderField(header)); dpSNh1  
else =bJ7!&  
break; k{ ~0BK  
} TP{2q51yM  
} B"?ivxM:U  
#.j}:  
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public void splitterStop() bYAtUEv  
{ Lv UQ&NmY  
bStop = true; IRyZ0$r:e\  
} H5>
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AX;!-|bW  
I>JBGR`j  
} F<TIZ^gFP  
#ADm^UT^  
vb`R+y@  
/* Ake@krh>$  
**FileAccess.java SNtk1pG>  
*//文件访问(定位，写) <NWq03:&  
package NetFox; ZXl_cq2r  
import java.io.*; Hg5:>?Lw@  
+h08uo5c  
a'Yi^;2+\  
public class FileAccessI implements Serializable{ %z~=Jz^  
55Y
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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 ?kdan  
RandomAccessFile oSavedFile; <.".,Na(J0  
long nPos; i
936+[  
V:h7}T95  
O',
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public FileAccessI() throws IOException %'OY  
{ _Wqy,L;J  
this("",0); ,49Z/P  
} bEm9hFvd  
\{ve6`7Rn  
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public FileAccessI(String sName,long nPos) throws IOException =M=v; ,I-  
{ 8W Etm}  
oSavedFile = new RandomAccessFile(sName,"rw"); 10_#Z~aU  
this.nPos = nPos; 7-gT:  
oSavedFile.seek(nPos); s  }Ql9  
} YD;G+"n?T  
ly:2XvV3~  
|'-%d^Z  
public synchronized int write(byte[] b,int nStart,int nLen) R$X~d8o>%  
{ O,JS*jXl  
int n = -1; GZ^Qt*5 {  
try{ }OY/0p-Z  
oSavedFile.write(b,nStart,nLen); X,{ 3_  
n = nLen; ALj~e#{;z  
} BP}@E$  
catch(IOException e) h4#'@%   
{ 1mD)G55Ep  
e.printStackTrace (); dci<Rz`h  
} m?kyAW'|  
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t)1`^W}  
return n; 1yVhO2`7]  
} w2db=9  
j#0JD!Vr  
||?@pn\  
} !Au#j^5K-o  
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/* d6W\ \6V  
**SiteInfoBean.java P ^ 4 @  
*/ C;j&Vbf  
package NetFox; stUUez>  

&d0sv5&s  
4jt(tZS  
public class SiteInfoBean { mRa\ wEg%  
0<O()NMv  
)2_[Ww|.  
private String sSiteURL; //Site's URL -n8d#Qm)  
private String sFilePath; //Saved File's Path 9:P]{}  
private String sFileName; //Saved File's Name wZs 2aa  
private int nSplitter; //Count of Splited Downloading File qV6WT&)T  
hJsP;y:@Lm  
w@<II-9L)<  
public SiteInfoBean() $1g1Bn  
{//nSplitter的缺省值为5 C!|LGzs0  
//default value of nSplitter is 5 z;!"i~fFK  
this("","","",5); ^GyZycch  
} }Ba_epM  
N<1+aL\  
-]+pwZ4g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "F%JZO51  
{ [q Uv|l1  
sSiteURL= sURL; vxHFNGI  
sFilePath = sPath; r! HXhl  
sFileName = sName; X =%8*_  
this.nSplitter = nSpiltter; 7f4O~4.[i  
:eSsqt9]9  
&7oL2Wf  
}
7[w<v(Rc  
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ZP5 !O[Ut  
public String getSSiteURL() 4M|uT 9-  
{ QW$p{ zo  
return sSiteURL; l<BV{Gl  
} !1fZ7a  
),-gy~  

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public void setSSiteURL(String value) ddyX+.LMk  
{ HC/z3b;  
sSiteURL = value; !3Pbu=(cte  
} !Av9?Q:  
fum.G{}  
P.qzP/Ny  
public String getSFilePath() I{jvUYrKH  
{ )9:5?,SO  
return sFilePath; EG;E !0  
}  RQb}t,  
@1Q-.54a  
`/ayg:WSU  
public void setSFilePath(String value) P/girce0  
{ hd u2?v@  
sFilePath = value;
8M@'A5]  
} kJp~'\b  
tw>2<zmSi%  
zD79M  
public String getSFileName() Cf3!Ud  
{ qS2Nk.e]o  
return sFileName; Z sTtSM\Ac  
} dw3Hk$"h  
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BUJ\[/  
public void setSFileName(String value) `}$o<CJ  
{ %KXiB6<4  
sFileName = value; |7tD&9<  
} =I'3C']Z W  
o[T+/Ej&  
!6T"J!F#  
public int getNSplitter() ~?AEtl#&"  
{ PmRvjSIG  
return nSplitter; J+J,W5t^  
} #uw&u6*\q  
*L$2M?xkY  
Zn'tNt/  
public void setNSplitter(int nCount) E5d$n*A  
{ Z0jgUq`r  
nSplitter = nCount; /}(d'@8p  
} :Ko6.|  
} r8Mx+r  
fq]PKLW'  
RhH1nf2UR  
/* {K]5[bMT  
**Utility.java {O^u^a\m  
*/ !qj[$x-ns  
package NetFox; <4"-tYa  
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public class Utility { 6:]N%  
l9I
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public Utility() Dj&~x  
{ kg[%Q]]  
/Hyz]46  
^Tm`motzh  
} .p&@;fZ  
*h!fqT%9  
//线程睡眠 '7-Yo Q  
public static void sleep(int nSecond) QEhn  
{ ?)xIn)#ls  
try{ h_vT
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Thread.sleep(nSecond); w +t@G`d  
} hm`=wceK  
catch(Exception e) `}
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{ :"\,iH  
e.printStackTrace (); RZm%4_p4s  
} [@vz0!@s5  
} NQk aW)  
-{cHp  
//日志 6Dlm.~G  
public static void log(String sMsg) qd*}d)!  
{ &riGzU]  
System.err.println(sMsg); IOcQI:4.`  
} /o9T [^\  
,^UqE{  
;*<tU n^t  
public static void log(int sMsg) fFjpQ~0  
{ %lF*g  
System.err.println(sMsg); oJz2-PmX  
} n|w+08c"  
} 1F^Q*t{  

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q%  
}}AIpYp,P  
/* }TmOoi(X@  
**TestMethod.java ~~tTr$  
*/ %ou,|Dww  
package NetFox; py*22Ua^  
Dcl$?  
6#?T?!vZ  
public class TestMethod { \<4N'|:  
>cu%Cs=m  
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public TestMethod() { mi}3/  
{ ///xx/weblogic60b2_win.exe SB_Tzp  
try{ {PHH1dC{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J D\tt-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tE7jTe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z2%HQL2  
fileFetch.start(); L"bOc'GfQ  
} liKlc]oM  
catch(Exception e){e.printStackTrace ();} eUyF<j  
Jl Do_}  
> ;,S||  
} -/yqiC-yx  
%tCv-aX4  
RgJ@J/p"  
public static void main(String[] args) Ys"wG B>  
{ /{i~CGc;"  
new TestMethod(); _4ag-'5  
} aF{_"X2  
} -aoYoJ '  
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