http断点续传简单实现（java)

/* Y]VLouzl  
**SiteFileFetch.java 3FY87R   
*/ j[CXIz?c  
package NetFox; <c3Te$.  
import java.io.*; +R"Y~ m{F  
import java.net.*; L9{y1'')  
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public class SiteFileFetch extends Thread { B@k2lHks(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *Za'^Z2  
long[] nStartPos; //开始位置 AcP d(Pc  
long[] nEndPos; //结束位置 ?k`UQi]Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'D'H)J  
long nFileLength; //文件长度 "O~7s}  
boolean bFirst = true; //是否第一次取文件 H7FOf[3'  
boolean bStop = false; //停止标志 9CG&MvF c  
File tmpFile; //文件下载的临时信息 ^u(-v/D9  
DataOutputStream output; //输出到文件的输出流 v`hn9O  
[nA1WFfM  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %0Ibi  
public SiteFileFetch(SiteInfoBean bean) throws IOException xL [3R   
{ mor[AJ  
siteInfoBean = bean; p(>D5uN_}5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s}qtM.^W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p~WX\;  
if(tmpFile.exists ()) "^Vnnb:Z*o  
{ &6e A.  
bFirst = false; .;F%k,!v  
read_nPos(); zJ)`snN|  
} t|P+^SL  
else 6L"b O'_5K  
{ !&},h=  
nStartPos = new long[bean.getNSplitter()]; ;;S9kNp^v  
nEndPos = new long[bean.getNSplitter()]; }Qa  
} H1c>3c  
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} %mAwK<MY`  
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public void run() "[ieOFI  
{ M1=eS@  
//获得文件长度 {>UT'fa-  
//分割文件 3/y"kl:<-  
//实例FileSplitterFetch :28[k~.bo  
//启动FileSplitterFetch线程 f}EsS  
//等待子线程返回 RK/>5  
try{ :}-VLp4b
 
if(bFirst) OP|X-  
{ IdoS6  
nFileLength = getFileSize(); !5 ?<QKOe  
if(nFileLength == -1) 3N?"s1U  
{ iUbcvF3aP  
System.err.println("File Length is not known!"); iD.p KG  
} cx[[K.  
else if(nFileLength == -2) i0u`J  
{ RdB,;Um9f  
System.err.println("File is not access!"); fI,2l   
} `(r0+Qx  
else yU>ucuF  
{ +~EnrrT+W  
for(int i=0;i<nStartPos.length;i++) ;6$W-W _  
{ uSJLIb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =gC% =  
} WDI3*  
for(int i=0;i<nEndPos.length-1;i++) FqZD'Uu7  
{ v6H!.0  
nEndPos = nStartPos[i+1]; XMzQ
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} P{HR='2  
nEndPos[nEndPos.length-1] = nFileLength; JkI|Ojmm/  
} hcpe~spz9|  
} .pG`/[*a  
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J| 1!4R~  
//启动子线程 `YY07(%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FE1'MUT_  
for(int i=0;i<nStartPos.length;i++) Y.q$"lm7k  
{ cqaq~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *^KEb")$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <sn,X0W  
nStartPos,nEndPos,i); PZY6 I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X/buz  
fileSplitterFetch.start(); tkmzOc H  
} /]?e^akA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i|0!yID0@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ju!V1ky  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G.r=fNP  
nEndPos = " + nFileLength); 411z-aS  
// fileSplitterFetch[nPos.length-1].start();
~R\ $Z  
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..x2  
//等待子线程结束 #7"";"{z|  
//int count = 0; J\FLIw4  
//是否结束while循环 oBs5xH7@-  
boolean breakWhile = false; G^Y^)pc]   
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while(!bStop) .@\(ay  
{ ]f5vk  
write_nPos(); K+d{R=s^  
Utility.sleep(500); (:^YfG~e  
breakWhile = true; {P3gMv;  
%_G '#Bn<  
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for(int i=0;i<nStartPos.length;i++) K"!U&`T  
{ (1[Z#y[  
if(!fileSplitterFetch.bDownOver) lR/Uboyy  
{ XtE O)  
breakWhile = false; {b-SK5%]L  
break; nkz<t   
} xVrLoAw  
} ]z2x`P^oI  
if(breakWhile) t~$8sG\  
break; ^)o]hE|  
@V&HE:P  
*\_>=sS x;  
//count++; [ {HTGz@(  
//if(count>4) ;Aheeq746  
// siteStop(); og_ylCh:  
} BjHp3-A'  
8bf@<VTO_  
b>9?gmR{  
System.err.println("文件下载结束！"); 7q{yLcC"  
} dA<SVk*0Q  
catch(Exception e){e.printStackTrace ();} '@zMZc!  
} <tm=  
+jS<n13T  
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//获得文件长度
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public long getFileSize() RjR+'<7E^  
{ E>:#{%  
int nFileLength = -1; f%JM a]yV  
try{ =
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URL url = new URL(siteInfoBean.getSSiteURL()); xTqP`ljX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O]?\<&y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5k?xBk=
<  
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int responseCode=httpConnection.getResponseCode(); +U>Y.YP  
if(responseCode>=400) \w&R`;b8w  
{ Iu(]i?Y  
processErrorCode(responseCode); ZXf&pqmG  
return -2; //-2 represent access is error lv~ga2>z  
} tv2k&\1  
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String sHeader; )TBm?VMe  
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for(int i=1;;i++) \?|^w.  
{ 0g Hd{H=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Zqv  
//Utility.log(in.readLine()); yTNHM_P  
sHeader=httpConnection.getHeaderFieldKey(i); B,` `2\B  
if(sHeader!=null) N7GZ'-t^Er  
{ \^!<Y\\  
if(sHeader.equals("Content-Length")) 3Vk\iJ
  
{ -~*kAh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &i6JBZ#~,  
break; A<(Fn_&W  
} m
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} "*S_wN%  
else XsSDz}dg  
break; fo<nk|i  
} TkIiO>  
} E 0OHl  
catch(IOException e){e.printStackTrace ();} -Vs;4-B{9  
catch(Exception e){e.printStackTrace ();} =>&~p\Aw  
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Utility.log(nFileLength); o#D'"Tn!  
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return nFileLength; IR&b2FTcU  
} 6BZi4:PDx  
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k4!p))ql  
//保存下载信息（文件指针位置） H`yUSB IP  
private void write_nPos() '5A&c(
  
{ _bv9/#tR  
try{ V0*MY{x#S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KI].T+I  
output.writeInt(nStartPos.length); x]608I T  
for(int i=0;i<nStartPos.length;i++) +:/.\3v71  
{ Zeq^dV5y77  
// output.writeLong(nPos); \Hq=_}]F  
output.writeLong(fileSplitterFetch.nStartPos); A'D2u
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output.writeLong(fileSplitterFetch.nEndPos); p S|  
}
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output.close(); kX*.BZI}C  
} k9&W0$I#  
catch(IOException e){e.printStackTrace ();} ^rGuyW#  
catch(Exception e){e.printStackTrace ();} ];eJ'#  
} d"a\`#  
9)n3f^,Oj*  
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//读取保存的下载信息（文件指针位置） %fXgV\xY  
private void read_nPos() R <&U]%FD  
{ &#9HV  
try{ ]6MXG%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DZ:$p.  
int nCount = input.readInt(); =(bTS n  
nStartPos = new long[nCount]; \_)mWK,h  
nEndPos = new long[nCount]; 
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for(int i=0;i<nStartPos.length;i++) \ >#y*W<  
{ <W^>:!?w  
nStartPos = input.readLong(); ^e8
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nEndPos = input.readLong(); j#
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} 7c<_j55(  
input.close(); &
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} K]^Jl0  
catch(IOException e){e.printStackTrace ();} RF~c/en  
catch(Exception e){e.printStackTrace ();} #8%~u+"N  
} 821 6_Qm  
P` Gb}]rW  
@# .a5  
private void processErrorCode(int nErrorCode) roIc1Ax:  
{ a,:Nlr3  
System.err.println("Error Code : " + nErrorCode);  Sg(\+j=  
} 51;Bc[)%  
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<AHdz/N  
//停止文件下载 v5FfxDvw  
public void siteStop() mAe)Hy %  
{
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bStop = true; bE jQMlb  
for(int i=0;i<nStartPos.length;i++) m$g{&  
fileSplitterFetch.splitterStop(); =7S\
-{  
;9)=~)  
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} mhNgXp)_56  
} >^v,,R8j  
//负责部分文件的抓取 }To-c'  
**FileSplitterFetch.java 7!e kINQ  
*/ z:0
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package NetFox; !1<>][F  
`R-VJR 2"  
c=Zurqj  
import java.io.*; 3)l<'~"z<  
import java.net.*; o%h[o9i  
#BI6+rfv|  
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public class FileSplitterFetch extends Thread { }dEf |6_  
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String sURL; //File URL %.:]4jhk  
long nStartPos; //File Snippet Start Position 3B4C@ {  
long nEndPos; //File Snippet End Position i}C%`1+(  
int nThreadID; //Thread's ID zB6&),[,v  
boolean bDownOver = false; //Downing is over 9"dZ4{\!  
boolean bStop = false; //Stop identical ,!98VJmr  
FileAccessI fileAccessI = null; //File Access interface OV-#8RXJ  
.0dx@Sbv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ALKzR433/  
{  >6'brb  
this.sURL = sURL; )2F%^<gZ#  
this.nStartPos = nStart; hM8FN  
this.nEndPos = nEnd; HZ89x|Hk_  
nThreadID = id; ?u{D-by%&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f%%'M.is  
} ]/Cu,mX  
2'?C  
<7j"CcJzZ  
public void run() "g1Fg.o  
{ @nM+*0 $d  
while(nStartPos < nEndPos && !bStop) D Z=OZ.v  
{ Gx(%AB~9$  
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try{ %vU
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URL url = new URL(sURL); x' 3kHw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %;O# y3,  
httpConnection.setRequestProperty("User-Agent","NetFox"); %z["TVH  
String sProperty = "bytes="+nStartPos+"-"; eGI&4JgJ.  
httpConnection.setRequestProperty("RANGE",sProperty); 'uLYah  
Utility.log(sProperty); ZC&4uNUr  
Bs<LJzS{V  
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InputStream input = httpConnection.getInputStream(); 1tH#QZIT  
//logResponseHead(httpConnection); z|zd=3c  
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byte[] b = new byte[1024]; QaAMiCZFR  
int nRead; N||s#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A~'p~@L  
{ 5:l"*  
nStartPos += fileAccessI.write(b,0,nRead); 2/l4,x  
//if(nThreadID == 1) 9<*<-x{A17  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cx8  H  
}
_;k))K^  
L$}'6y/@  
@Hst-H.l<l  
Utility.log("Thread " + nThreadID + " is over!"); |d_ rK2  
bDownOver = true; ~#iAW@  
//nPos = fileAccessI.write (b,0,nRead); ~VJP:Y{[  
} rB3b  
catch(Exception e){e.printStackTrace ();} O9)k)A]`O  
} .%mjE'  
} [,mcvO;  
6 ZVD<C:\  
b'4r5@GO  
//打印回应的头信息 SrXuiiK  
public void logResponseHead(HttpURLConnection con) BsN~Z!kd  
{ A;Uw b  
for(int i=1;;i++) 8hvh xp  
{ ]\:l><  
String header=con.getHeaderFieldKey(i); "yxBD 7  
if(header!=null) ~8G cWy6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WFpR@53Db  
Utility.log(header+" : "+con.getHeaderField(header)); ^ px)W,O  
else pXHeUBY.  
break; 1V1T1  
} F6#U31Q=  
} SQx:`{O  
n!y}p q6  
|)u|@\{  
public void splitterStop() @GE:<'_:{  
{ FI(M 1iJ  
bStop = true; WjMP]ND#c  
} @5(HRd
 
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} "Q<*H<e  
&,@wLy^T  
hTbot^/  
/* H0i\#)Xs  
**FileAccess.java U9p^?\-=  
*//文件访问(定位，写) YJ^TO\4WM  
package NetFox; oJTsrc_-  
import java.io.*; Nm/Fc
 
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8RR6f98FF  
public class FileAccessI implements Serializable{ ;F<)BEXC<  
3 ,?==?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >#\&%0OZw  
RandomAccessFile oSavedFile; h/%Hk;|9  
long nPos; ;i><03  
3M&75OE  
>, }m=X8  
public FileAccessI() throws IOException {m%X\s;ni  
{ kY6))9 O  
this("",0); d.&~n`Rv!p  
} BOp&s>hI  
{L8(5  
}`9}Q O  
public FileAccessI(String sName,long nPos) throws IOException V-w[\u  
{ f V.(v&  
oSavedFile = new RandomAccessFile(sName,"rw"); =>CrZ23B"  
this.nPos = nPos; /vB%gqJvX  
oSavedFile.seek(nPos); 7M1*SC  
} rLcQG  
LHWh-h(s  
KV0e^c;  
public synchronized int write(byte[] b,int nStart,int nLen) \0pJ+@\T9  
{ UmU=3et<Wj  
int n = -1; 7c6-S@L  
try{ pz^"~0o5  
oSavedFile.write(b,nStart,nLen); V@K}'f~  
n = nLen; ls6ywLP{  
} 8L 9;VY^Y  
catch(IOException e) [M2,bc8SJV  
{ xZmKKKd0*  
e.printStackTrace (); !{SU G+.2  
} MT#9x>  
N_r*Ig  
][b
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return n; DD'<zL[  
} 9#6ilF:F  
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s$:]$&5  
} J\
  
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/* &H5 6mL{  
**SiteInfoBean.java zAB-kE\)  
*/ rf1nC$Sop  
package NetFox; n]coqJ  
Yjk A^e  
,-DE;l^Q=  
public class SiteInfoBean { ? *I9  
|_[mb(<|  
(DKpJCx  
private String sSiteURL; //Site's URL oRWsi/Zf  
private String sFilePath; //Saved File's Path )vGRfFjw_  
private String sFileName; //Saved File's Name N'
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private int nSplitter; //Count of Splited Downloading File )_2!1  

gYzKUX@  
KS(T%mk\  
public SiteInfoBean() sQihyq6U;  
{//nSplitter的缺省值为5 J;q3 fa  
//default value of nSplitter is 5 JG}U,{7(  
this("","","",5); xI:;%5{LN  
} <JH0 &  
"l +Jx|h\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x=au.@psBS  
{ V`fh,(:  
sSiteURL= sURL; J;_JHlK  
sFilePath = sPath; nVyb B~.=  
sFileName = sName; 9'5,V{pj  
this.nSplitter = nSpiltter; |+`hS
A  
W+K=M*^D;c  
&*)tqQeQf  
} BTd'bD~EA  
6/#= dv  
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public String getSSiteURL() Vj?.'(  
{ GF/p|I D  
return sSiteURL; UN>hJN;c  
} {&h&:  
>MP PYVn7  
O&w$  
public void setSSiteURL(String value) wH${q@z_  
{ 06Hn:IT18  
sSiteURL = value; 3&?Tc|F+  
} BxZop.zwE(  
vCpi|a_eCu  
am"/Anml|  
public String getSFilePath() .PAkW2\#  
{ uqO51V~  
return sFilePath; J0=`n(48B  
} HWefuj  
M$~h(3
  
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public void setSFilePath(String value) iPFYG  
{ BEI/OGp  
sFilePath = value; |
[{;*wtv  
} GO?-z0V  
~l}TlRqL  
^c(PZ,/#JB  
public String getSFileName() BklB3*n  
{ E$ngmm[  
return sFileName; g3Xz-  
} <hK$Cf_  
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|t]9RC.;7  
public void setSFileName(String value) ToMX7xz6  
{ .i=%gg  
sFileName = value; D{l.WlA.  
} uRL3v01?H0  
AV2q*  
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public int getNSplitter() Y?5yzD:  
{ VUnEI oKM  
return nSplitter; e:,.-Kvzp`  
} ?xf;#J+{8  
wl{p,[
]  
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public void setNSplitter(int nCount) 3,F/i+
@  
{ mm{U5
  
nSplitter = nCount; +I Ze`M%n  
} -y\N9  
} eLC&f}  
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/* 7K;dVB  
**Utility.java XsG]-Cw  
*/ _L=vK=,  
package NetFox; c\]L  
"w'YZO]>  
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public class Utility { ROjjN W`W  
:>;psR  
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public Utility() LN
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{ oOL3O@)w>  
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} $3[cBX.=  
#y*=UV|h  
//线程睡眠 K?;p:  
public static void sleep(int nSecond) - dOT/%Ux  
{ L$Leo6<3a  
try{ ]8_h9ziz
 
Thread.sleep(nSecond); H3c=B /+  
} w7Pe<vT  
catch(Exception e) RYV6hp)|  
{ >=`c [=:Z_  
e.printStackTrace (); 4bxkp3~h;  
} Xou#38&p>  
} 5"gRz9Ta`  
ATzNV=2s  
//日志 ZKR z=(  
public static void log(String sMsg) ~r!5d@f.6  
{ -+9x 0-P  
System.err.println(sMsg); wrO>#`Z  
} vW{cBy  
i]53A0l  
_$'Mx'IC=  
public static void log(int sMsg) ^kl9U+  
{ cyhD%sB[D9  
System.err.println(sMsg); >b["T+  
} 5j{@2]i  
} epR~Rlw>2  
)PG,K4z  
C}h@El  
/* r;XQ i  
**TestMethod.java NI1HUUZz  
*/ &V?q d{39  
package NetFox; v2n0[b0  
>Y/[zfI2  
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public class TestMethod { S[a5k;8GL  
O|>1~^w  

#c^Q<&B  
public TestMethod() 2&Byq  
{ ///xx/weblogic60b2_win.exe 7RP_ ^Cr+  
try{ yo*iv+l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
/,Rc
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~t:b<'/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Qsntf.fT  
fileFetch.start(); P*PL6UQ  
} mU=6"A0 U  
catch(Exception e){e.printStackTrace ();} |\a:]SlH  
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nF'xV44"  
} >-w=7,?'?z  
BJ9sR.yX62  
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public static void main(String[] args) u3wC}Zo  
{ ;-?ZI$  
new TestMethod(); {}pqxouE  
} kppRQ Q*[  
} +?iM$}8!U  
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