http断点续传简单实现（java)

/* -"u9s[L{  
**SiteFileFetch.java 0~qnwe[g}  
*/ .Rq|F  
package NetFox; Jf<+VJ>t  
import java.io.*; (A.%q1h  
import java.net.*; <"|BuK  
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public class SiteFileFetch extends Thread { :Oz! M&Ov  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [[{y?-U  
long[] nStartPos; //开始位置 tx=~bm"*?  
long[] nEndPos; //结束位置 JFw<Po,MEa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k_)H$*  
long nFileLength; //文件长度 ^rd]qii"  
boolean bFirst = true; //是否第一次取文件 &%QtUPvr9  
boolean bStop = false; //停止标志 BdHLow  
File tmpFile; //文件下载的临时信息 &5fM8Opkd  
DataOutputStream output; //输出到文件的输出流 vi+k#KE  
92}UP=RW!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a0y7a/@c  
public SiteFileFetch(SiteInfoBean bean) throws IOException V,=V   
{ F<wwuCbF  
siteInfoBean = bean; &lg+uK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !C&
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A;~u"g'z&  
if(tmpFile.exists ()) /aa'ryl_%  
{ tlo"tl_]  
bFirst = false; =;(wBj  
read_nPos(); k(>hboR5n  
} !b<c*J?f  
else !o.l:Mr  
{ Xj:?V;  
nStartPos = new long[bean.getNSplitter()]; ^+CTv  
nEndPos = new long[bean.getNSplitter()]; Yrb[:;Y  
} ]-O/{FIv  
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[ Fid  
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} 9o7E/wP  
2J;h}/!H  
" $5J7  
public void run() D4?qw$"  
{ nKn,i$sO/.  
//获得文件长度 %;0Llxf"  
//分割文件 _aOisN{  
//实例FileSplitterFetch q=8I0E&q  
//启动FileSplitterFetch线程 zItf>j7|Z  
//等待子线程返回 ^Xjh?+WM  
try{ Y$8 >fv  
if(bFirst) 7o?6Pv%HJC  
{ Jt6~L5[_s  
nFileLength = getFileSize(); |s
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if(nFileLength == -1)  :~JgB  
{ 3^kZydZCN  
System.err.println("File Length is not known!"); )ymd#?wq
 
} xmz83Ll9  
else if(nFileLength == -2) j>s>i  
{ Lc;4 Hg  
System.err.println("File is not access!"); Qn>0s  
} OZdiM&Zss  
else nU$;W  
{ HpI[Af}l  
for(int i=0;i<nStartPos.length;i++) (7w`BR9B  
{ Ct[{>asun  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OF^v;4u  
} F)4Y;;#  
for(int i=0;i<nEndPos.length-1;i++) F0 WM&{v  
{ wPT
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nEndPos = nStartPos[i+1]; =\7
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} Kx.I'_Qk  
nEndPos[nEndPos.length-1] = nFileLength; l;$HG
oJ  
} R.Xh&@f`  
} !%n3_tZC  
}9[E+8L1
 
;RNU`Ip  
//启动子线程 b`N0lH.V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]v7f9MC'\  
for(int i=0;i<nStartPos.length;i++) w[Ee#Yaj.-  
{ MKSiOM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8"R;axeD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \O 9j+L"  
nStartPos,nEndPos,i); ,a&N1G.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ej
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fileSplitterFetch.start(); cOa.]Kk  
} zJNiAc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _y{z%-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JgXP2|Y!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B:dk>$>uQ  
nEndPos = " + nFileLength); 1ipfv-hb6  
// fileSplitterFetch[nPos.length-1].start(); ehQ"<.sQ  
a]^hcKo4  
rnWU[U8
%  
//等待子线程结束 Z_{`$nW  
//int count = 0; T4n.C~  
//是否结束while循环 7r,'a{Rcn  
boolean breakWhile = false; &!uw;|%  
"X~ayn'@w,  
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while(!bStop) ?r"][<  
{ &RQQVki3  
write_nPos(); -:IG{3fnu  
Utility.sleep(500); p?S:J`q  
breakWhile = true; 9B&QY 2v  
`C 'WSr  
2*:lFvwP  
for(int i=0;i<nStartPos.length;i++) d5$2*h{^v  
{ tpw0j CVu  
if(!fileSplitterFetch.bDownOver) MkJ}dncg*  
{ [v$_BS#u^3  
breakWhile = false; F4+mkB:w*7  
break; g _fvbVX  
} 6kH47Yc?  
} 1.WdxMpW9  
if(breakWhile) Z'c{4b`N  
break; n|`L>@aw,  
@@$=MSN  
4?YhqJ  
//count++; BEM_y:#  
//if(count>4) X51pRP $R  
// siteStop(); ='f<_FD  
} J5Rr7=:*S  
Rz% Px:M  
oL0Q%_9hW  
System.err.println("文件下载结束！"); ?Pz:H/$  
} ]|g{{PWH  
catch(Exception e){e.printStackTrace ();}  `=b)fE  
} PZ2$ [s0W  
-Si'[5@  
xi=Z<G  
//获得文件长度 cQEK>aAd  
public long getFileSize() |aef$f5  
{ 3c] oU1GfF  
int nFileLength = -1; 5_";EED  
try{ <%klrQya  
URL url = new URL(siteInfoBean.getSSiteURL()); %Y8#I3jVJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g+8{{o=  
httpConnection.setRequestProperty("User-Agent","NetFox"); X~XpX7d!  
`btw*{.[  
J1DX}h]  
int responseCode=httpConnection.getResponseCode(); F-Mf~+=Dn  
if(responseCode>=400) wic"a Y<m  
{ C!xqp   
processErrorCode(responseCode); vwQY_J8  
return -2; //-2 represent access is error un|
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} }{;m:Iia_  
?_36uJo}  
A,-UW+:  
String sHeader; *njdqr2c~  
w J FEua  
cy|]}n85  
for(int i=1;;i++) HU]Yv+3   
{ b0PqP<{t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !7ct=L  
//Utility.log(in.readLine()); 8 PI>Q  
sHeader=httpConnection.getHeaderFieldKey(i); nWpqAb  
if(sHeader!=null) 0eq="|n^|  
{ qk~ni8  
if(sHeader.equals("Content-Length")) B4AV ubMbe  
{ 8_0j^oh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vk\a>};  
break; Aat_5p  
} pk2OZ,14Mj  
} ^n#6CW*n  
else )70-q yA  
break; ZrJAfd\5c  
} dr3
#?%  
} to~Ap=E  
catch(IOException e){e.printStackTrace ();} '&@'V5}C{  
catch(Exception e){e.printStackTrace ();} ~oO>6  
v^2q\A-?  
\{  
Utility.log(nFileLength); ;&4}hPq  
&~oBJar  
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return nFileLength; wi/Fx=w  
} ; V)pXLE  
]pi"M3f_  
\C;cs
&\Q  
//保存下载信息（文件指针位置） igFz~  
private void write_nPos() !-1UJqO  
{ +[C(hhk("  
try{ &rs+x<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s0,c4y  
output.writeInt(nStartPos.length); t|q@~B :  
for(int i=0;i<nStartPos.length;i++) dH"wYMNL  
{ ?&?gQ#\N_J  
// output.writeLong(nPos); 0Q>f,}W%>  
output.writeLong(fileSplitterFetch.nStartPos); P)x&9OHV  
output.writeLong(fileSplitterFetch.nEndPos); qP? V{N  
} @{16j#'R  
output.close(); RWM9cV5  
} b*w izd  
catch(IOException e){e.printStackTrace ();} ${\iHg[vZ  
catch(Exception e){e.printStackTrace ();} kBZnR$Cl  
} ZN75ONL  
0LX;Vvo  
^hPREbD+f  
//读取保存的下载信息（文件指针位置） jA@jsv  
private void read_nPos() C}grY5:  
{ ST'M<G%4E  
try{ /KDKA)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $<R\|_6J  
int nCount = input.readInt(); r|2Y|6@  
nStartPos = new long[nCount]; l1*qDzb  
nEndPos = new long[nCount]; 297X).  
for(int i=0;i<nStartPos.length;i++) Ax &Z=  
{ H4DM
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nStartPos = input.readLong(); e7X#C)  
nEndPos = input.readLong(); |HhqWja  
}  A.nU8  
input.close(); >*/\Pg6^  
} q~_DR4xZ  
catch(IOException e){e.printStackTrace ();} It$'6HV~Sb  
catch(Exception e){e.printStackTrace ();} # +OEO  
} Q/'jwyj_  
qRk&bF/  
;tK%Q~To  
private void processErrorCode(int nErrorCode) tQz=_;jy  
{ R5PXX&Q  
System.err.println("Error Code : " + nErrorCode); t[$C r;  
} $80TRB#  
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//停止文件下载 GZY8%.1{"a  
public void siteStop() La&?0PA  
{ :&*Y Io  
bStop = true; *d%"/l^0  
for(int i=0;i<nStartPos.length;i++) @'UbTB!  
fileSplitterFetch.splitterStop(); YC(7k7  
-E, d)O`;$  
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} f.Wip)g  
} (bpO>4(S  
//负责部分文件的抓取 G i1Jl"  
**FileSplitterFetch.java |C;8GSw>|F  
*/ (C{l4  
package NetFox; .!#0eAT  
1+wmR4o  
S0-f_,(  
import java.io.*; }4'5R  
import java.net.*; P`ZzrN  
}J=>nL'B  
k:1p:&*m  
public class FileSplitterFetch extends Thread { aMaICM  
\<k5c-8Hb  
gumT"x .^  
String sURL; //File URL er<yB#/;-  
long nStartPos; //File Snippet Start Position +fh@m h0[  
long nEndPos; //File Snippet End Position ']Q4SB"q  
int nThreadID; //Thread's ID !4"(>Rnw  
boolean bDownOver = false; //Downing is over uY6]rt_#a  
boolean bStop = false; //Stop identical 25e*W>SLw  
FileAccessI fileAccessI = null; //File Access interface OH.lAF4E(  
1!N|a< #  
!e>+O^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O9%`G  
{ r7dwj  
this.sURL = sURL; zVEG) Hr  
this.nStartPos = nStart; T'VZ=l[  
this.nEndPos = nEnd; (2 nSZRB  
nThreadID = id; EI+RF{IKh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m |Isi  
} An0DqjR  
+Cf"rN  
j@g`Pm%u`  
public void run() ^,-2";2Xh  
{ gX29
c  
while(nStartPos < nEndPos && !bStop) EKQ\MC1  
{ r{+P2MPW  
hJ~Na\?w  
&m{SWV+  
try{ (!cG*FrN  
URL url = new URL(sURL); R1sWhB99  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); > nHaMj  
httpConnection.setRequestProperty("User-Agent","NetFox"); !TNp|U!  
String sProperty = "bytes="+nStartPos+"-"; ??Lda='  
httpConnection.setRequestProperty("RANGE",sProperty); E;`@S  
Utility.log(sProperty); exW|c~|m{A  
>:C0ZQUW  
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InputStream input = httpConnection.getInputStream(); Ms4~P6;%  
//logResponseHead(httpConnection); r6WSX;K  
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/RG
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byte[] b = new byte[1024]; k
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int nRead; y$Nqw9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +8xC%eE  
{ !=uaB.  
nStartPos += fileAccessI.write(b,0,nRead); \v\f'eQ  
//if(nThreadID == 1) Jy^.L$bt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .ei5+?V<i  
} <cof   
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QUQw/  
Utility.log("Thread " + nThreadID + " is over!"); Am'%tw ~  
bDownOver = true; M6nQ17\{  
//nPos = fileAccessI.write (b,0,nRead); `[)!4Jb  
} Jn:h;|9w  
catch(Exception e){e.printStackTrace ();} S4ys)!V1V  
} T]_]{%z  
} "26=@Q^Y  
\&8 61A;  
yg@8&;bP`  
//打印回应的头信息 o=zr]vv  
public void logResponseHead(HttpURLConnection con) }srmG|@:  
{ j^1Yz}6nR  
for(int i=1;;i++) 4*U5o!w1{  
{ 
ur$=%3vM  
String header=con.getHeaderFieldKey(i); (IXUT6|  
if(header!=null) VY#
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?zk#}Ex1  
Utility.log(header+" : "+con.getHeaderField(header)); A<szY92&5  
else k_?Z6RE>  
break; 1 ORA6  
} h_>DcVNIx  
} .ZtW y) U  
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m7#v2:OD+  
public void splitterStop() dZWO6k9[H  
{ Q8H+=L:  
bStop = true; /R(]hmW  
} xYd]|y  
btR~LJb  
"@^^niSFl  
} >vPv4e7&3  
31GqWN`>$  
M!Ua/g=u  
/* # 4&t09  
**FileAccess.java 14pyHMOR  
*//文件访问(定位，写) vojXo|c  
package NetFox; e"(SlR  
import java.io.*; c5em*qCw$  
|Vo{ {
)  
Y*QoD9<T?;  
public class FileAccessI implements Serializable{ :Tcvj5  
BUs={"Pa  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 po!bRk[4  
RandomAccessFile oSavedFile; Zmc"  
long nPos; 3\ {?L  
O=5q<7PM.  
;#?G2AAv  
public FileAccessI() throws IOException .<zN/
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{ z -c1,GOD  
this("",0); C=Tq/L w  
} {ePtZyo0  
vR7S!  
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public FileAccessI(String sName,long nPos) throws IOException Ya `$.D  
{ m:D0O]2  
oSavedFile = new RandomAccessFile(sName,"rw"); 6r.#/' "  
this.nPos = nPos; #LR.1zZ  
oSavedFile.seek(nPos); k`((6  
} Q~f mVWq  
Ge`PVwn  
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public synchronized int write(byte[] b,int nStart,int nLen) =D&XE*qkZ  
{ R>t?6HOcp  
int n = -1; _Ie?{5$ng`  
try{ qi*Dd[OG  
oSavedFile.write(b,nStart,nLen); &n'@L9v81  
n = nLen; IhHKRb[  
} RT. %\)))  
catch(IOException e) Alk+MwjR  
{ `t"7[Zk  
e.printStackTrace (); f>iDqC4  
} cE^Ljk  
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l* z"wA-  
return n; nR=!S5>S  
} USg,=YM  
&. MUSqo9  
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} .lAPlJOO  
;efF]")  
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/* m al?3*x/  
**SiteInfoBean.java H]}mg='kI  
*/ 9vP#/-g  
package NetFox; '=`af>Nc  
-(},%!-_  
}9V0Cu1  
public class SiteInfoBean { Px3I+VP  
*P/DDRq(2  
Ss3~X90!*B  
private String sSiteURL; //Site's URL 3Rhoul[S  
private String sFilePath; //Saved File's Path +NJIi@  
private String sFileName; //Saved File's Name >0UY,2d  
private int nSplitter; //Count of Splited Downloading File 9PUobV_^Wo  
mT/^F{c  
)3WUyD*UZN  
public SiteInfoBean() }9 ]7V<  
{//nSplitter的缺省值为5 KF6N P  
//default value of nSplitter is 5 ]9-iEQ  
this("","","",5); PXG@]$~3  
} zE Ly1v\"  
EbeSl+iMx_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xf[;^?]X  
{ r PTfwhs  
sSiteURL= sURL; $Xh5
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sFilePath = sPath; 0 ;].q*|#  
sFileName = sName; <MKXFV  
this.nSplitter = nSpiltter; !>N+a3  
kCALJRf~d  
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} V|TD+7.`QB  
jNI9 .45y  
w9StW94p  
public String getSSiteURL() +k h Tl:  
{ P:WxhO/  
return sSiteURL; 9^8_^F  
} C[';B)a  
v cUGBGX_&  
= c1>ja  
public void setSSiteURL(String value) +,g!xv4Q  
{ o@hj.)u  
sSiteURL = value; l<qEX O  
} njaKU?6%d2  
*+k yuY J  
l_4^TYF  
public String getSFilePath() Cd]g+R}j  
{ :*/g~y(fE  
return sFilePath; B6j/"x6N15  
} ]4r&Q4d>O  
c_>AbF{  
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public void setSFilePath(String value) |S~$IFN4  
{ K"[\)&WBG  
sFilePath = value; K,6{c^qf  
} ;Ea8>  
dq
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})`z6d]3  
public String getSFileName() )w5!'W4Z8  
{ P#MUS_x  
return sFileName; F vTswM>  
} WFzM s  
q{%~(A5*H  
5i}g$yjZ<  
public void setSFileName(String value) upaQoX/C  
{ ;<GK{8  
sFileName = value; VT-%o7%N  
} N`{6<Z0  
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D+jE{v'  
public int getNSplitter() |#{ i7>2U  
{ YNl".c  
return nSplitter; 4cqf=  
} $=ESY>MO  
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w ~"%&SNN  
public void setNSplitter(int nCount) *2}f $8  
{ >$yA ,N  
nSplitter = nCount; }I MV@z B  
} @4Zkkj
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} Pd& Npp3  
jse!EtB:  
(`_fP.Ogb  
/* u.G aMl4 (  
**Utility.java FhPCFmmUT  
*/ wv\V&U$  
package NetFox; $iMLT8U  
Qg]A^{.1  
!G6h~`[  
public class Utility { l@1=./L?  
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public Utility() ,t;US.s([.  
{ @Kn@j D;  
#d<|_  
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} :>o0zG[;f  
Fa\jVFIQ  
//线程睡眠 mhOgv\?  
public static void sleep(int nSecond) eMdf[eS  
{ hSXJDT2  
try{ K3UN#G
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Thread.sleep(nSecond); *W^a<Zm8>  
} gHkHAOe/  
catch(Exception e) ?Bl/bY$*h  
{ ms!|a_H7r  
e.printStackTrace (); 9:GP~oI j  
} '\+"3!$  
} +A^|aQ  
{IvA 5^  
//日志 |Ldvfd  
public static void log(String sMsg) qX; F+~  
{ l(-"rE  
System.err.println(sMsg); `@WJ_-$#  
} Y"r728T`K  
.Pte}pM"v  
6w(r}yO]
 
public static void log(int sMsg) En#Q p3  
{ Cz$q"U  
System.err.println(sMsg); Lfdg5D5.P  
} ij~-  
} S0gxVd(  
+Mhk<A[s  
F u^j- Io  
/* f[.'V1  
**TestMethod.java rlawH}1b  
*/ ~Hv>^u Mh  
package NetFox; J .TK<!  
$~/cxLcT  
r\FZ-gk}Q  
public class TestMethod { = &?&}pVF  
rly%+B `/  
/H
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public TestMethod() ~tV7yY|zr  
{ ///xx/weblogic60b2_win.exe o)n)Z~  
try{ D/ sYH0.V$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O"df5x9@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rnQ_0d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X9SOcg3a  
fileFetch.start(); DpQWh+WRy  
} O^ui+44wp  
catch(Exception e){e.printStackTrace ();} Xdl dUK[  
6>;OVX  
0!KYi_3  
}
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*)`PY4zF  
q#Q%p+  
public static void main(String[] args) K/*"U*9Kv  
{ GvgTbCxnN  
new TestMethod(); r}^1dO  
} afna7TlS  
} N{&Lo}6F  
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