http断点续传简单实现（java)

/* B2,! 0Re  
**SiteFileFetch.java + S%+Ku  
*/ iT|+<h  
package NetFox; -)$)<k  
import java.io.*; M>vM@j  
import java.net.*; NGxii$F  
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public class SiteFileFetch extends Thread { -6H)GK14b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u_Q3v9  
long[] nStartPos; //开始位置 >2v_fw  
long[] nEndPos; //结束位置 [I^SKvM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I &m~ cBj<  
long nFileLength; //文件长度 ~w$8*2D  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 z5i!GJB  
File tmpFile; //文件下载的临时信息 YobIbpo  
DataOutputStream output; //输出到文件的输出流 5jsnE )  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z]Qm64^I  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y@r#:BH)  
{ hrXN38-  
siteInfoBean = bean; '+}hVfN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eFeeloH?e*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `i.f4]r  
if(tmpFile.exists ()) f|q6<n_nM  
{ }`h}h<B(  
bFirst = false; gB0)ec 0  
read_nPos(); :
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} q,*IR*B:a  
else v =u|D$  
{ C'=C^X%  
nStartPos = new long[bean.getNSplitter()]; ;pULJ}rDb  
nEndPos = new long[bean.getNSplitter()]; O}KT>84M  
} fB:M'A'  
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} I5bi^!i  
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public void run() $OUa3!U_!  
{ <&x_e-;b'  
//获得文件长度 "@f`O  
//分割文件 DL~LSh  
//实例FileSplitterFetch 4$|G$h  
//启动FileSplitterFetch线程 @*_K#3  
//等待子线程返回 g`Rs;  
try{ HML6<U-eS  
if(bFirst) 3^fZUldf  
{ !?+3jzG  
nFileLength = getFileSize(); yx}:Sgv%  
if(nFileLength == -1) `V?{  
{ >Ek`P
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System.err.println("File Length is not known!"); ^%<v| Y(X  
} >*_?^F_  
else if(nFileLength == -2) _>aesp%  
{ )pvZM?  
System.err.println("File is not access!"); $GPA6  
} j&&^PH9ZY  
else ct]5\g?U'  
{ Y]n^(V  
for(int i=0;i<nStartPos.length;i++) 4+W}TKw  
{ PD$'xY|1=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~M\s!!t3  
} Ti'O 2k  
for(int i=0;i<nEndPos.length-1;i++)
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{ PNKmI
 
nEndPos = nStartPos[i+1]; 5q)Eed  
} tb=(L  
nEndPos[nEndPos.length-1] = nFileLength; <<`."RY#0  
} RSnK`N\9jb  
} /stED{j,  
}5]NUxQ_  
*in_Zt3  
//启动子线程 `#(4K4]1.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l,/5$JGnk  
for(int i=0;i<nStartPos.length;i++) $@U`zy
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{ @vv`86bm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UtWoSFZ'o!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !BY=HFT  
nStartPos,nEndPos,i); AX&1-U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2 Sr'B;`p  
fileSplitterFetch.start(); QHQj6]
 
} &/zsIx+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L3W ^ip4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); AI)9E=D%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dE^'URBiA  
nEndPos = " + nFileLength); Yw{](qG7e`  
// fileSplitterFetch[nPos.length-1].start(); w5[POo' 5  
w?/,LV  
Xr~r`bR=  
//等待子线程结束 o2.! G  
//int count = 0; MdyH/.Te  
//是否结束while循环 s9'iHe  
boolean breakWhile = false; /|\`NARI  
=]^*-f}J9  
svQDSif  
while(!bStop) OI-%Ig%C#l  
{ ,wFLOfV@  
write_nPos(); 'shOSB  
Utility.sleep(500); ?Cu$qE!h)[  
breakWhile = true; D,)~j6OG8  
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for(int i=0;i<nStartPos.length;i++) "~Eo=R0O  
{ |[:`izW  
if(!fileSplitterFetch.bDownOver) }8FP5Z'Cf%  
{  %"z W]  
breakWhile = false; J7$=f~$  
break; G%>[I6G  
} }W YY5L8^  
} X%gJ,c(4  
if(breakWhile) _I-0[w  
break; H`".L^  
9XoKOR(  
1'd "O @  
//count++; )GR^V=o7,Y  
//if(count>4) i&l$G55F  
// siteStop(); ZNx{7]=a  
} CHLMY}O0  
Kc(_?`  
c"QI`;D_c  
System.err.println("文件下载结束！"); 16]O^R;r  
} s$]I@;_  
catch(Exception e){e.printStackTrace ();} x:@e ID  
} xqG` _S l  
(V+(\<M  
w S;(u[W  
//获得文件长度 |{_%YM($  
public long getFileSize() qD9B[s8  
{ PC3wzJ\\S  
int nFileLength = -1; crmnh4-  
try{ S^n:O  
URL url = new URL(siteInfoBean.getSSiteURL()); wF&\@H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z1"UF4x*  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8CYJR/  
4o|~KX8Qz  
L@+j8[3BX  
int responseCode=httpConnection.getResponseCode(); ^L[Z+7|  
if(responseCode>=400) jQ[Z*^"}  
{ fZGKVxo"  
processErrorCode(responseCode); ZHB'^#b  
return -2; //-2 represent access is error * T~sR'K+|  
} ilNm\fQ.  
~PV>3c3l=  
}%:?s6Ler  
String sHeader; !Q?4sAB  
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:<jf}[w!  
for(int i=1;;i++) mq "p"iI  
{ A#p@`|H#B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Llzowlfe  
//Utility.log(in.readLine()); 69L s"e  
sHeader=httpConnection.getHeaderFieldKey(i); ^yb_aCw  
if(sHeader!=null) yn=1b:kid  
{ ,CvU#ab8$  
if(sHeader.equals("Content-Length")) 5Q^~Z},  
{ Q647a}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ck^Z,AKL+  
break; 6Z'zB&hM}  
} p;'vOb  
} )WzCUYE1/  
else qVY\5`f@  
break; w68qyG|wM  
} wbpxJtJB  
} tC&y3!k2jR  
catch(IOException e){e.printStackTrace ();} wU
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catch(Exception e){e.printStackTrace ();} o3`Z@-.G  
q!7\`>.2:{  
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Utility.log(nFileLength); (+>n/I6  
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]>:>":<:  
return nFileLength; LZ@^ A]U  
} jrW7AT)\  
x,V_P/?%  
tF;aB*  
//保存下载信息（文件指针位置） im?nR+t+X  
private void write_nPos() g)"6|Z?D"  
{  ,cB`j7p(  
try{ D2hvf^g'*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M,[ClQ 9  
output.writeInt(nStartPos.length); R0+m7mx#E  
for(int i=0;i<nStartPos.length;i++) !7w-?1?D  
{ 1DBzD%@Oz  
// output.writeLong(nPos); !K@yB)9  
output.writeLong(fileSplitterFetch.nStartPos); ^8\pJg_0  
output.writeLong(fileSplitterFetch.nEndPos); G(4k#jB  
} `W/6xm(X5;  
output.close(); wgufk{:  
} y_nh~&  
catch(IOException e){e.printStackTrace ();} R@EFG%|`_  
catch(Exception e){e.printStackTrace ();} Vt&I[osC  
} O8lOr(|l  
SrKF\h%/+  
6z(_^CY  
//读取保存的下载信息（文件指针位置） \jfW$TtZm  
private void read_nPos() jXdn4m/O  
{ iUO5hdOM  
try{ l%)XPb2$J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kxO$Uk&TX  
int nCount = input.readInt(); :Rq D0>1  
nStartPos = new long[nCount]; *R:nB)(6<  
nEndPos = new long[nCount]; m]%cNxS  
for(int i=0;i<nStartPos.length;i++) :1s1wY3Y  
{ =];FojC6I  
nStartPos = input.readLong(); 1HZexV  
nEndPos = input.readLong(); j@:LMR>  
} ,rN7X<s54  
input.close(); >s>5k O  
} dp?uq'  
catch(IOException e){e.printStackTrace ();} ZqhINM*Rm  
catch(Exception e){e.printStackTrace ();} k82'gJ;MC=  
} ="4jk=on  
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private void processErrorCode(int nErrorCode) _6|b0*jv'&  
{ Zw3|HV(so  
System.err.println("Error Code : " + nErrorCode); {k)MC)%  
} cEN^H  
Z]6D0b  
yWs/~5[F  
//停止文件下载 }`eeItI+  
public void siteStop() 1|`9Hp6  
{ &Y,Rm78  
bStop = true; Z# :Ww  
for(int i=0;i<nStartPos.length;i++) 1-,l|K  
fileSplitterFetch.splitterStop(); )Y:CV,`  
z6Hl+nq B  
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} <k)rfv7  
} "
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//负责部分文件的抓取 t9=rr>8)  
**FileSplitterFetch.java |?0C9  
*/ ;m\(fW*ii  
package NetFox; %URyGS]*  
<;Xj4 J  
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import java.io.*; )PwDP  
import java.net.*; rN*4Y  
f{vnZ|WD  
4f>Vg$4  
public class FileSplitterFetch extends Thread { qzH97<M}T  
> vahj,CZZ  
r"4:aKF>  
String sURL; //File URL $V+ze*ra  
long nStartPos; //File Snippet Start Position r9QNE>UG  
long nEndPos; //File Snippet End Position nqV7Db~  
int nThreadID; //Thread's ID [`:\(( 8  
boolean bDownOver = false; //Downing is over <vAg\Tv:S  
boolean bStop = false; //Stop identical p'R}z|d)  
FileAccessI fileAccessI = null; //File Access interface 6Y=$7%z  
y
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'tdjPdw  
{ >Qi2;t~G  
this.sURL = sURL; N_T;&wibO  
this.nStartPos = nStart; )S5Q5"j&=f  
this.nEndPos = nEnd; U2h?l `nP  
nThreadID = id; LsmC/+7r$1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YS/DIH{9e  
} [k.<x'#  
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public void run() #-{4 Jx  
{ UrtN3icph  
while(nStartPos < nEndPos && !bStop) t
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{ )UxF lp;\  
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9
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try{ .qHgQ_%  
URL url = new URL(sURL); !]"T`^5,Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cLXMq"?C  
httpConnection.setRequestProperty("User-Agent","NetFox"); uYs+xX
_  
String sProperty = "bytes="+nStartPos+"-"; *f,EDSN1@d  
httpConnection.setRequestProperty("RANGE",sProperty); +DU}f;O8v  
Utility.log(sProperty); =T+<>/[  
jbG #__#_  

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InputStream input = httpConnection.getInputStream(); /6f$%:q  
//logResponseHead(httpConnection); {!<zk+h$  
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}(  
byte[] b = new byte[1024]; h-6kf:XP%  
int nRead; -f'z_&KI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H_jMl$f)j  
{ 9iGJYMWf  
nStartPos += fileAccessI.write(b,0,nRead); H*!E*_  
//if(nThreadID == 1) 3vMfms  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `?La  
} pV1~REk$&  
9_&.G4%V  
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Utility.log("Thread " + nThreadID + " is over!"); x=9drKIw>  
bDownOver = true; Q.!D2RZc  
//nPos = fileAccessI.write (b,0,nRead); f>Ij:b`Z2  
} X)'uTf0  
catch(Exception e){e.printStackTrace ();} C7nLa@  
} r% qgLP{v  
} []'BrG)!  
Xo'_|-N+  
o8Tt|Lxb$8  
//打印回应的头信息 tNq~M  
public void logResponseHead(HttpURLConnection con) ]r|X[9  
{ 3p")  
for(int i=1;;i++) 0dXWy`Mn  
{ XC~
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String header=con.getHeaderFieldKey(i); A?Uyj  
if(header!=null) 0*+i~g,Kl@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g_-Y-.M  
Utility.log(header+" : "+con.getHeaderField(header)); sv =6?uYW  
else [ibnI2I]`  
break; dMYDB  
} -cOLgrmp  
} A5z5e# ,u  
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rZ *}jD[  
public void splitterStop() !hEtUF  
{ )$Mgp*?  
bStop = true; 
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} 1_f(;WOg  
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} LKTIwb>  
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/* *ewE{$UpK  
**FileAccess.java yX/ 9jk  
*//文件访问(定位，写) 6>X7JMRY  
package NetFox; K
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import java.io.*; 7]62=p2R  
]w"r4HlCx  
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public class FileAccessI implements Serializable{ h#B%'9r  
,A4v|]kq]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '0lX;z1  
RandomAccessFile oSavedFile; j0>Q:hn  
long nPos; r_F\]68  
COZ<^*=A#p  
;&oS=6$  
public FileAccessI() throws IOException P|l62!m<  
{ I^emH+!MW  
this("",0); I& DEF*  
} "sdzm%  
Ho2#'lSKM  
&Y4S[-   
public FileAccessI(String sName,long nPos) throws IOException %`?IY<  
{ ~ep-XO  
oSavedFile = new RandomAccessFile(sName,"rw"); krFuEaO  
this.nPos = nPos; 6* (6>F5  
oSavedFile.seek(nPos); a~>+I~^K5q  
} 9'Le}`Gf  
XShi[7  
-c{O!z6sX  
public synchronized int write(byte[] b,int nStart,int nLen) 'S;INs2|->  
{  At@H  
int n = -1; J>y}kzCz  
try{ 8KiG(6*Q  
oSavedFile.write(b,nStart,nLen);  LhKaqR{  
n = nLen; Nawph  
} bbCH(fYbu  
catch(IOException e) 6j/g/!9c!  
{ xf% _HMKc  
e.printStackTrace (); uB_8P+h7  
} H`d595<=i;  
@y]ek/  
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return n; _)XQb1]  
} Tr*3:J }  
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} '"qTmo!  
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/* ]{^'{z$i  
**SiteInfoBean.java +Nn $  
*/ lJb1{\|.,  
package NetFox; ;UUpkOQO(  
3Xcjr2]~  
:{BD/6  
public class SiteInfoBean { u
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Gj!9#on$7R  
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private String sSiteURL; //Site's URL rZ'&'#Q  
private String sFilePath; //Saved File's Path 4}.PQ{  
private String sFileName; //Saved File's Name /Z^"[Ke  
private int nSplitter; //Count of Splited Downloading File [J{\Ke0<e1  
Bie#GKc  
=>3wI'I  
public SiteInfoBean() #0kVhx7%  
{//nSplitter的缺省值为5 EdcbWf7  
//default value of nSplitter is 5 .Q!_.LX  
this("","","",5); ~?#>QN\\c  
} F\0>/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w.X MyHj  
{ (w[#h9j  
sSiteURL= sURL; 7M8oI.?C|  
sFilePath = sPath; yzyBr1s  
sFileName = sName; RD6n1Wb(@  
this.nSplitter = nSpiltter; Cf
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vG'6?%38  
 3-~*  
} _nwsIjsW  
$/p0DY  
kx{LY`pY  
public String getSSiteURL() 9[2qgw\D  
{ (;!92ct[?  
return sSiteURL; {'#1do}{  
}  B_Ul&V  
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public void setSSiteURL(String value) Ah2*7@U  
{ epN
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sSiteURL = value; |VX )S!  
} &u+l`F^Z  
VdL*"i  
~ECIL7,  
public String getSFilePath() =e)t,YVm  
{ pq"Z,9,F%  
return sFilePath; zEVQ[y6BcM  
} OI^??joQ  
^ YOCHXg  
PfR|\{(  
public void setSFilePath(String value) 2t7P| b~V1  
{ g?.y7!m  
sFilePath = value; ]SC|%B_*  
} R?t_tmKXC!  

/9pN.E  
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public String getSFileName() Z)&!ZlM  
{ ='vD4}"j  
return sFileName; `.z"Q%uz  
}  \OJam<hZ  
.} O@<t  
8$F"!dc _  
public void setSFileName(String value) I1pnF61U  
{ ,B~5;/|  
sFileName = value; 57wHo[CJ  
} 4aP 96  
$fCKK&Wy  
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public int getNSplitter() /8#e < p  
{ ;9CbioO
 
return nSplitter; aPdEEqc\l  
} {j6$'v)0  
3Ofh#|qc&  
bey:Qj??  
public void setNSplitter(int nCount) %*zV&H   
{ r.q*S4IS.m  
nSplitter = nCount; "4IrW6B$9  
} W:maE9E=  
} ^sKdN-{  
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/* 3,'LW}  
**Utility.java qRSoF04!R  
*/ 0u;a*#V@  
package NetFox; d
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public class Utility { {'Y()p3kl  
;`O9YbP#  
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public Utility() 5X>K#N  
{ %[, R Q">v  
=8vNO
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KE.O>M,I.  
} U!{~L$S  
.-'_At4g  
//线程睡眠 w`DcnQK'  
public static void sleep(int nSecond) -%Rw2@vU  
{ KPVu-{_Fi  
try{ 2"T b><^"  
Thread.sleep(nSecond); ~:L5Ar<  
} #Iu"qu  
catch(Exception e) S{RRlR6Z  
{ ,.kmUd  
e.printStackTrace (); QOX'ZAB`  
} <5E)6c_W)  
} :>}7^1I  
k8\KCKql  
//日志 3@nIoN'z  
public static void log(String sMsg) Q<NQ9lX  
{ ]4ck)zlv   
System.err.println(sMsg); x<`^4|<  
} Y<I
uwS  
b<!' WpY-  
a@Vk(3Rx_  
public static void log(int sMsg) vz(=3C[  
{ -X_\3J  
System.err.println(sMsg); _&(L{cFx6  
} T
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} F Uz1P  
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] g<$f#S  
/* }3, 4B-8!  
**TestMethod.java S\]9mHJI  
*/ .820~b0  
package NetFox; tU$n3Bg  
*<:6A&'D9  
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public class TestMethod { 9B![l=Gh  
}.(DQwC}1k  
z;?ztpa@  
public TestMethod() CDF;cM"td  
{ ///xx/weblogic60b2_win.exe kL8E#  
try{ q{Gh5zg5O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ck%.D%=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xbxzB<yL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {Mj- $G"  
fileFetch.start(); KwV!smi2  
} }9^'etD  
catch(Exception e){e.printStackTrace ();} M)ao}m>  
r;)31Tg  
#eN2{G=4+  
} e|W;(@$<  
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j D*<M/4  
public static void main(String[] args) /NjBC[P  
{ auB 931|  
new TestMethod(); :{^~&
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} c#CV5J\Kk3  
} k]C k%[d  
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