http断点续传简单实现（java)

/* hC=="4 -  
**SiteFileFetch.java b%,`;hy{  
*/ \(bML#I  
package NetFox; Zx]"2U#  
import java.io.*; wA}+E)x/C  
import java.net.*; ffYiu4$m  
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public class SiteFileFetch extends Thread { ,!4(B1@  
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[(N<E/m%B  
SiteInfoBean siteInfoBean = null; //文件信息Bean SSF4P&  
long[] nStartPos; //开始位置 ]Z\.Vx  
long[] nEndPos; //结束位置 R#Bdfmldq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;=6~,k)  
long nFileLength; //文件长度 3J}bI{3  
boolean bFirst = true; //是否第一次取文件 up7]Yy;o=  
boolean bStop = false; //停止标志 L1k_AC1.M
 
File tmpFile; //文件下载的临时信息 f"5vpU^5*  
DataOutputStream output; //输出到文件的输出流 DP9hvu/85  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wy$9QN  
public SiteFileFetch(SiteInfoBean bean) throws IOException Dl%NVi+n  
{ Pw'3ya8  
siteInfoBean = bean; m.p{+_@M&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8+1tys  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7>J8\=  
if(tmpFile.exists ()) #\$R^u]!  
{ 5!G}*u.  
bFirst = false; u1&pJLK0[  
read_nPos(); Ij}RlYQz  
} ~$i36"  
else 70:a2m  
{ ?c^0%Op  
nStartPos = new long[bean.getNSplitter()]; 2@aVoqrq#  
nEndPos = new long[bean.getNSplitter()]; K/jC>4/c/  
} {@oYMO~  
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} pVt8z|p_;{  
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public void run() ,m:YZ;J(Xd  
{ }CA oB::&  
//获得文件长度 Uok?FEN  
//分割文件 lM5Xw  
//实例FileSplitterFetch =?3D:k7z  
//启动FileSplitterFetch线程 t3b
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//等待子线程返回 N$H0o+9-Y  
try{ AjK'P<:/  
if(bFirst) P-VK=Y1q  
{ 969*mcq'  
nFileLength = getFileSize(); _*+ 7*vAL  
if(nFileLength == -1) %@5f+5{i!z  
{ w7]@QTC  
System.err.println("File Length is not known!");
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} [=-?n6  
else if(nFileLength == -2) ~fE@]~f>  
{ _d&FB~=  
System.err.println("File is not access!"); 5TVDt  
} C-$S]6  
else hof:+aW  
{ ajW[}/)  
for(int i=0;i<nStartPos.length;i++) _.OajE\T  
{ ^'~+w3M@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }}v;V*_V  
} [|\~-6"7N|  
for(int i=0;i<nEndPos.length-1;i++) 8|`4D 'Ln  
{ qd
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nEndPos = nStartPos[i+1]; )G0a72  
} &<-Sxjj  
nEndPos[nEndPos.length-1] = nFileLength; <5A(rDij  
} B8:_yAv o  
} &'UYV>  
aO?(ZL  
|Gb"%5YD  
//启动子线程 x5k6yHn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %^g BDlR^  
for(int i=0;i<nStartPos.length;i++) Y0=qn'`.  
{ /z*?:*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,K8O<Mw8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GH![rK  
nStartPos,nEndPos,i); b:Dr_|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )W~w72j-  
fileSplitterFetch.start(); # &o3[.)9  
} Q uy5H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kgi%Nd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RiF~-;v&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a1Qg&s<  
nEndPos = " + nFileLength); Tz
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// fileSplitterFetch[nPos.length-1].start(); {mMrD 5  
T&I*8 R~  
!j6]k^ra  
//等待子线程结束 67Z|=B!7  
//int count = 0; . Yg)|/  
//是否结束while循环 >z1RCQWju  
boolean breakWhile = false; |<P]yn  
`AeId/A4n  
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while(!bStop)
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{ [L8Bgw1  
write_nPos(); _K>cB<+d  
Utility.sleep(500); K>9]I97g'  
breakWhile = true; 7M<Ae D%  
<XX\4[wb  
Sb+pB58&N  
for(int i=0;i<nStartPos.length;i++) <*~vZT i(  
{ .xuLvNyQr  
if(!fileSplitterFetch.bDownOver) iTi<X
|X  
{ IM}T2\tZ}  
breakWhile = false; p mcy(<  
break; J (Yfup  
} 0ejx;Mum  
} n|Vs27  
if(breakWhile)  a= ;7  
break; &96I4su  
^wCjMi(sj  
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//count++; "d>{hP  
//if(count>4) @;M( oFS9  
// siteStop(); gR"'|c   
} bWo-( qxq  
2c@R!*  
5bR;R{:x  
System.err.println("文件下载结束！"); f@Rn&&-  
} :f?\ mVS+  
catch(Exception e){e.printStackTrace ();} mdR:XuRD"t  
} |S|0'C*  
~T9%%W[  
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//获得文件长度 G0Smss=K  
public long getFileSize() oJb
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{ }9 N, +*  
int nFileLength = -1; \1hbCv$Hf  
try{ u{
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URL url = new URL(siteInfoBean.getSSiteURL()); [ /w{,+U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cHs@1R/-s  
httpConnection.setRequestProperty("User-Agent","NetFox"); $R%xeih1fz  
pHEhB9_A!  
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int responseCode=httpConnection.getResponseCode(); Wo2TU!  
if(responseCode>=400) 8i=J(5=  
{ 2ixg ix  
processErrorCode(responseCode); B1oi]hDy  
return -2; //-2 represent access is error :XEP:8  
} t&^9o$  
]tL9y<  
PuqT&|wP l  
String sHeader; ehl){Dd^  
-$J\BkI  
\%z#|oV#<  
for(int i=1;;i++) /Y:&307q  
{ RrRrB"!8nR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N_lQz(nG/2  
//Utility.log(in.readLine());
la>:%SD  
sHeader=httpConnection.getHeaderFieldKey(i); ;BUJ5  
if(sHeader!=null) 
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{ CTQF+Oe8O  
if(sHeader.equals("Content-Length")) [U
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{ hC
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $As;Tvw.  
break; @|v4B[/  
} u~7m
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} xV[X#.3  
else OF&{mJH"g'  
break; RiqYC3Ka  
} 9&fS<Hk  
} A(2_hl-  
catch(IOException e){e.printStackTrace ();} 0]?} kY  
catch(Exception e){e.printStackTrace ();} i,1=5@rw5  
2W:R{dHE  
3 HOJCgit  
Utility.log(nFileLength); Gf(hN|X.  
Q;W[$yv
W  
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return nFileLength; oa$-o/DhB  
} {m~.'DU  
\7rFfN3  
(+q#kKR  
//保存下载信息（文件指针位置） >=BH$4Ce  
private void write_nPos() ggtGecKm  
{ ?TA%P6Lw  
try{ ;= ^kTb`X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _^;+_6&[  
output.writeInt(nStartPos.length); QPB@qx#@  
for(int i=0;i<nStartPos.length;i++) q&OF?z7H  
{ ["Mq  
// output.writeLong(nPos); B,@geJ  
output.writeLong(fileSplitterFetch.nStartPos); Dn~r~aR$g  
output.writeLong(fileSplitterFetch.nEndPos); G66sPw  
} "S)2<tV  
output.close(); <qjNX-|  
} @q:v?AO  
catch(IOException e){e.printStackTrace ();} ?=,4{(/)  
catch(Exception e){e.printStackTrace ();} _
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} /(Mi2$@v1  
&HBqweI  
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//读取保存的下载信息（文件指针位置） ya7PF~:E-  
private void read_nPos() F5la:0fb  
{ !=%0  
try{ )rcFBD{vM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \JmfQrBQ  
int nCount = input.readInt(); A/V"&H[  
nStartPos = new long[nCount]; /{@^
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nEndPos = new long[nCount]; </! `m8\  
for(int i=0;i<nStartPos.length;i++) ^f*}]`S  
{ 1{D_30sG.  
nStartPos = input.readLong(); M &`ZF  
nEndPos = input.readLong(); :j_OO5b!  
} &N4Jpa}w/%  
input.close(); #yz
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} W <.h@Rz+  
catch(IOException e){e.printStackTrace ();} bW03m_<M<1  
catch(Exception e){e.printStackTrace ();} ,{DZvif   
} f}{ lRk  
*FhD%><  
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private void processErrorCode(int nErrorCode) `q =e<$  
{ {6H%4n  
System.err.println("Error Code : " + nErrorCode); ?4>uGaU\  
} #=@H-ZuD7  
+/ s2;G  
qYpuo D  
//停止文件下载 M]9oSi  
public void siteStop() >d#oJ?goX  
{ YDh6XD<Z  
bStop = true; }xhat,9  
for(int i=0;i<nStartPos.length;i++) 5'iJN$7  
fileSplitterFetch.splitterStop(); mBWE^  
oVi_X98R  
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} T.ZPpxY  
} "
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//负责部分文件的抓取 BCnf'0q  
**FileSplitterFetch.java T'YHV}b}vX  
*/ kg@D?VqJP  
package NetFox; x1H?e8  
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:(IPrQ  
import java.io.*; BC!n;IAe  
import java.net.*; MV8Lk/zd?A  
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public class FileSplitterFetch extends Thread { &qR1fbw"  
epz'GN]V  
85;hs  
String sURL; //File URL Q I!c=:u  
long nStartPos; //File Snippet Start Position nT7{`aaQl  
long nEndPos; //File Snippet End Position [HEqMBX=;  
int nThreadID; //Thread's ID n0nf;E  
boolean bDownOver = false; //Downing is over e| AA7  
boolean bStop = false; //Stop identical g~q+a-  
FileAccessI fileAccessI = null; //File Access interface ~vf&JH'!  
z9> yg_Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \Xy]z  
{ CR*9-Y93  
this.sURL = sURL; Cjvgf.>$  
this.nStartPos = nStart; $lJu2omi1  
this.nEndPos = nEnd; agQ5%t#  
nThreadID = id; 1-z*'Ghys  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9a.r(W[9  
} {sn:Lj0  
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public void run() 1\v$8pP+  
{ Y>OL2g  
while(nStartPos < nEndPos && !bStop) k:?+75?$  
{ eFO+@  
$`nKq4Y   
T9 @^@l$  
try{ i?7%z`  
URL url = new URL(sURL); {HgW9N(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,!`94{Ggv  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]U :1NC"  
String sProperty = "bytes="+nStartPos+"-"; p(2j7W-/  
httpConnection.setRequestProperty("RANGE",sProperty); ,H{ /@|RW  
Utility.log(sProperty); K?l1Gj  
|=OO$z;q|  
R=D\VIu,Z  
InputStream input = httpConnection.getInputStream(); 'WqSHb7  
//logResponseHead(httpConnection); to0tH^pD  
%9_wDfw~  
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byte[] b = new byte[1024]; 4SG22$7W  
int nRead; id^U%4J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )B d`N^k+  
{ FV[6">;
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nStartPos += fileAccessI.write(b,0,nRead);
Dl862$_Q  
//if(nThreadID == 1) nMU#g])y)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3t(8uG<rL  
} 47Y|1  
Q37VhScs  
K#"@nVWJ.m  
Utility.log("Thread " + nThreadID + " is over!"); eO,  
bDownOver = true; /)80@  
//nPos = fileAccessI.write (b,0,nRead); ] =Js5  
} //--r5Q  
catch(Exception e){e.printStackTrace ();} {$iJYS\  
} (xU+Y1*g"%  
} {Y5h*BD>  
my#qmI  
 FNZB M  
//打印回应的头信息 _/[n/"gn  
public void logResponseHead(HttpURLConnection con) {GF>HHQb  
{ ^qpa[6D6x  
for(int i=1;;i++) vOYcS$,^X%  
{ .js4
)$W^  
String header=con.getHeaderFieldKey(i); -;$+`<%  
if(header!=null) UQ|zSalv,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F"a^`E&  
Utility.log(header+" : "+con.getHeaderField(header)); =q|fe%#  
else uTJi }4cw  
break; D#%J||  
} QN(f8t(  
} &%pB; dk  
#( nheL  
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public void splitterStop() {nQ}t }B  
{ 1A23G$D  
bStop = true; VmQ7M4j*  
} #
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} |Sg *j-.  
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/* [BhpfZNKRA  
**FileAccess.java S&-sl
  
*//文件访问(定位，写) sF;1)7]Pq  
package NetFox; +N[dYm  
import java.io.*; bcpH|}[F)  
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k?Jzy  
public class FileAccessI implements Serializable{ (2@b ,w^  
4qda!%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4x'^?0H@  
RandomAccessFile oSavedFile; 1elx~5v1.=  
long nPos; y_"GMw  
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public FileAccessI() throws IOException [[D}
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{ P's<M  
this("",0); )ymF:]QC  
} *DkA$Eu3u  
,WOF)
  
9[N'HpQ3  
public FileAccessI(String sName,long nPos) throws IOException nVG\*#*]|  
{ NQfIY`lt'  
oSavedFile = new RandomAccessFile(sName,"rw"); Vm8;{Sq  
this.nPos = nPos; $#4z>~0  
oSavedFile.seek(nPos); [v-?MS  
} 6@2p@eYo  
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!W$3p'8Tu  
public synchronized int write(byte[] b,int nStart,int nLen) K=sQ_j.&Z  
{ 9r1pdG_C@  
int n = -1; E08AZOY&g  
try{ B4R,[WE"  
oSavedFile.write(b,nStart,nLen); `@.YyPxX\  
n = nLen; svpWABO  
} Op3 IL/  
catch(IOException e) |ry;'[*  
{ U7crbj;c)d  
e.printStackTrace (); any\}   
} B_cn[?M  
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return n; Q,\lS  
} KvilGh10  
8gC(N3/E"  
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} (%0X\zvu/  
`ss]\46>  
1rPeh{SZ  
/* mA^>Y_:  
**SiteInfoBean.java 6\o.wq  
*/ 5!nZvv  
package NetFox; r.ajw&J2  
z5'VsK:  
'&<-,1^L  
public class SiteInfoBean { 5 (H; x74  
 jMp{  
BC
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private String sSiteURL; //Site's URL I:6xDDpZG`  
private String sFilePath; //Saved File's Path %oor7 -l  
private String sFileName; //Saved File's Name M2xUs  
private int nSplitter; //Count of Splited Downloading File T[Gz  
}4 $EN  
jilO%  "  
public SiteInfoBean() D[-Ct  
{//nSplitter的缺省值为5 D[tGbk  
//default value of nSplitter is 5 }p- %~Y  
this("","","",5); B!tte)  
} vY;Lc  
[\.>BK  
-x_iqrB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >8AtT=}w  
{ 8dZH&G@;  
sSiteURL= sURL; .`h+fqa  
sFilePath = sPath; O3BU.X1'%  
sFileName = sName; to?"{  
this.nSplitter = nSpiltter; z:fhq:R(  
pP/o2  
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} lmc-ofEv  
8v6rS-iHP  
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public String getSSiteURL() v'@LuF'e8  
{ ^#t<ILUa  
return sSiteURL; SQ1&n;M}f  
} eqf~5/Z  
/gdo~  
$OhL 95}7  
public void setSSiteURL(String value) <%Rr-,  
{ Fh/C{cX9g  
sSiteURL = value; =H?Nb:s  
} G?_,(  
5g5pzww  
'#Fh J%x  
public String getSFilePath() #62ww-E~  
{ .z4FuG,R  
return sFilePath; *oWzH_  
} =N0cz%  
=~S   
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public void setSFilePath(String value) uJ y@  
{ $Yxy(7d7w  
sFilePath = value; d!X?R}  
} ]s SoIT  
2M1mdkP3  
ky%%H;  
public String getSFileName() .R"L$V$RU.  
{ X5yhS  
return sFileName; N|)V/no6  
} 1lQ10J  
b>(lF%M  
Dm^kuTIG  
public void setSFileName(String value) f:0n-me  
{ n%0vQ;Z1  
sFileName = value; u'b_zlW@  
} )K6{_~Kc\  
'
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xr2:bu  
public int getNSplitter() }<S2W\,G  
{ LYFvzw>M  
return nSplitter; -XyuA:pxx  
} H}~^,B2;  
srkOad  
<KA@A}  
public void setNSplitter(int nCount) /W>"G1)  
{ 7L6M#B[)e5  
nSplitter = nCount; ?n+\T'f!  
} q<8HG_  
} Z}C%%2Iz  
aKy|$ {RC  
E;Hjw0M'k  
/* {cI<4><  
**Utility.java J)-> 7h=  
*/ A~>=l=  
package NetFox; y_&XF>k91  
X9j+$X\j  
=R"tnjR  
public class Utility { N-|Jj?c  
bW|y -GM  
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public Utility() yB1>83!q  
{ gk#rA/x  
f+Go8Lg=M  
3"n8B6
 
} "lZ<bG  
jFv<]D%A[  
//线程睡眠 Uy:.m  
public static void sleep(int nSecond) ?0a 0 R  
{ hdL2`5RFF  
try{ MO/N*4U2  
Thread.sleep(nSecond); n}?G!y
Sg  
} 7A6sSfPUy  
catch(Exception e) }b(e  
{ J5T#}!f  
e.printStackTrace (); BxU1Q&  
} K=)R!e8  
} DeSTo9A}!  
xW4+)F5P(  
//日志 Fm':sd)'X  
public static void log(String sMsg) dFFqs&cQ  
{ QR'g*Bro  
System.err.println(sMsg); kDh(~nfj  
} +GS=zNw#  
;gnr\C*G  
W!X]t)Ow  
public static void log(int sMsg) c,wU?8Nc|$  
{ /f<(K-o]  
System.err.println(sMsg); 1n"X?K5;A  
} &L]*]Xz;  
} !y?hn$w0  
sQs5z~#51*  
zOdKB2_J7  
/* sD+G+  
**TestMethod.java E=NY{|>  
*/ {SJ7Yfs  
package NetFox; ?<QFW#:)  
!?/bK[ P,  
Uzn|)OfWP  
public class TestMethod { QO/7p]$_  
\[EWxu  
I "2FTGA  
public TestMethod() 5.#9}]  
{ ///xx/weblogic60b2_win.exe >}*jsqaVU  
try{ z:5ROlk0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G{~p.?f:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E5{)d~q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z]AS@}wWqg  
fileFetch.start(); @\8gzvkt  
} A#: c  
catch(Exception e){e.printStackTrace ();} mU$7_7V~  
8v 1%H8  
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} yZ$;O0f&&  
?/MXcI(  
~[q:y|3b  
public static void main(String[] args) `&zobbwq  
{ 1I_q3{  
new TestMethod(); s[4!R&b  
} 63Yu05'  
} qXGLv4c`Q  
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