http断点续传简单实现（java)

/* x<'(b7{U0  
**SiteFileFetch.java .!ThqYo  
*/ { jnQoxN  
package NetFox; *^XfEO  
import java.io.*; "x.|'  
import java.net.*; e>-a\g  
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public class SiteFileFetch extends Thread { 7gR8Wr ^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (~~*PT-  
long[] nStartPos; //开始位置 !%' 1x2?  
long[] nEndPos; //结束位置 =v4;t'_^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q
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long nFileLength; //文件长度 K|-?1)Um  
boolean bFirst = true; //是否第一次取文件 pSQ)DqW  
boolean bStop = false; //停止标志 =)Cqjp  
File tmpFile; //文件下载的临时信息 ffuV158a&  
DataOutputStream output; //输出到文件的输出流 PQ`p:=~>:i  
=#N;ZG  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lMu}|d  
public SiteFileFetch(SiteInfoBean bean) throws IOException c?qg i"kS  
{ 3"O)"/"Q.  
siteInfoBean = bean; CKShz]1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UXz0HRRS0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B!|<<;Da6  
if(tmpFile.exists ()) ~c>*3*  
{ C3n_'O  
bFirst = false; 2\flTO2Ny  
read_nPos(); ;}!hgyq  
} g">E it*[  
else K-&&%Id6R  
{ ""[(e0oA  
nStartPos = new long[bean.getNSplitter()]; ~429sT(  
nEndPos = new long[bean.getNSplitter()]; <#U9ih 2  
} sh []OSM
 
e
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} ;P9P2&c8c  
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public void run() (9_~R^='y  
{ cqzd9L6=  
//获得文件长度 ~f&lQN'1  
//分割文件 OI3UC=G  
//实例FileSplitterFetch 0n25{N  
//启动FileSplitterFetch线程 Wq_#46P-  
//等待子线程返回 S^,1N4  
try{ fk%yi[  
if(bFirst) mX78Av.z!  
{ N=J$+  
nFileLength = getFileSize(); xjHOrr OQ  
if(nFileLength == -1) I\JJ7/S`t  
{ 5!2^|y4r  
System.err.println("File Length is not known!"); $d1+d;Mn  
} =VMV^[&>  
else if(nFileLength == -2) -LF0%G  
{ +u1meh3u  
System.err.println("File is not access!"); 7\sJ=*  
} D8a[zXWnc  
else c+l1#[Dnc  
{ DPuz'e*  
for(int i=0;i<nStartPos.length;i++) _qg)^M6  
{ *={` %  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hLyD#XCFA  
} x0^O?UR  
for(int i=0;i<nEndPos.length-1;i++) x!klnpGp  
{ ZCJOh8  
nEndPos = nStartPos[i+1]; 3.q%?S}*  
} tGGv 2TCEy  
nEndPos[nEndPos.length-1] = nFileLength; #%CbZw@hJ9  
} Z:VqBqK  
} s#,~Zb=  
[
h "*>J{  
yc.Vm[!  
//启动子线程 
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lv_|ws  
for(int i=0;i<nStartPos.length;i++) acuch  
{ (pBOv:6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i"=6n>\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y5_`<lFv  
nStartPos,nEndPos,i); Sa!r ,l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]3@6o*R;  
fileSplitterFetch.start(); pkjf5DWp  
} bWzv7#dd=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z=TaB^-)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }mRus<Ax  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", > Y <in/  
nEndPos = " + nFileLength); `ReTfz;o  
// fileSplitterFetch[nPos.length-1].start(); QJc3@  
~b+TkPU   
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//等待子线程结束 8'Dp3x^W>  
//int count = 0; W=T3spV  
//是否结束while循环 KlMrM% ;y  
boolean breakWhile = false; %} WSw~X  
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while(!bStop) P(I`^x  
{ 'P{0K?{H-4  
write_nPos(); BKDs3?&  
Utility.sleep(500); {9sA'5  
breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) rj qX|  
{ tx}}Kd  
if(!fileSplitterFetch.bDownOver) J(*qOG
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{ aY8"Sw|4  
breakWhile = false; l2uh"!
 
break; wjk-$p  
} sS5 ]d8  
} )3<|<jwcx  
if(breakWhile) EL!V\J`S_  
break; DA)+)PhY7K  
V{17iRflf  
8<(qN>R  
//count++; E~?0Yrm F  
//if(count>4) "dfq
  
// siteStop(); ,]?Xf>  
} H.EgL@;mb  
:USN`"  
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System.err.println("文件下载结束！"); 3V:{_~~  
} 44bTx y  
catch(Exception e){e.printStackTrace ();} j.Ro(0%  
} %VG;vW\V  
[r'P
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//获得文件长度 SH>L3@Za  
public long getFileSize() Az4+([  
{ Jlw<%}r  
int nFileLength = -1; 9{{QdN8  
try{ DDk
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URL url = new URL(siteInfoBean.getSSiteURL()); VXt8y)?a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;AV[bjRE\  
httpConnection.setRequestProperty("User-Agent","NetFox"); %bo0-lnp  
3`PPTG  
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int responseCode=httpConnection.getResponseCode(); F"2v5F@  
if(responseCode>=400) mdxa^#w  
{ p2T%Zl_  
processErrorCode(responseCode); % 1Y!|306  
return -2; //-2 represent access is error ( ONn{12Q  
} P3|_RHIb  
4\'1j|nS[  
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String sHeader; UhuEE  
b%`^KEvwfo  
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for(int i=1;;i++) pvL)BD  
{ eliT<sw8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A/n-.ci  
//Utility.log(in.readLine()); i^j1i  
sHeader=httpConnection.getHeaderFieldKey(i); 0$)CWah  
if(sHeader!=null) 2e_ssBbb  
{ 0TA{E-A   
if(sHeader.equals("Content-Length")) DBDHe-1[+  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^Rr0)4ns  
break; Pw`26mB  
} O@;;GJ  
} =zw=Jp  
else Sa5+_TW  
break; -dXlGOD+C  
} ? b;_T,S[  
} #clOpyT*  
catch(IOException e){e.printStackTrace ();} Jt79M(Hp!  
catch(Exception e){e.printStackTrace ();} r0ml|PX  
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Utility.log(nFileLength); MB]8iy8  
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return nFileLength; o&]b\dV  
} nulCk33x'=  
t)|*-=  
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//保存下载信息（文件指针位置） yWI30hW  
private void write_nPos() Vfkm{*t)  
{ H#pl&/+  
try{ g)7~vm2/,
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3vx5dUgl,  
output.writeInt(nStartPos.length); )?35!s6  
for(int i=0;i<nStartPos.length;i++) AF ,*bb  
{ Rf*we+  
// output.writeLong(nPos); RT
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output.writeLong(fileSplitterFetch.nStartPos); cM&5SyxiuE  
output.writeLong(fileSplitterFetch.nEndPos); ~JjL411pG  
} +/u)/ey  
output.close(); E`#m0Q(8  
} h`O"]2  
catch(IOException e){e.printStackTrace ();} Z05kn{<a8  
catch(Exception e){e.printStackTrace ();} <9zzjgzG{c  
} ?f@g1jJP  
DONXq]f:,"  
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//读取保存的下载信息（文件指针位置） ;pk4Voo$  
private void read_nPos() eqvbDva^  
{ 8MIn~  
try{ uw'>tb@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ><<(6  
int nCount = input.readInt(); >eX&HSoy  
nStartPos = new long[nCount]; GM&< ?K1  
nEndPos = new long[nCount]; HgH\2QL3&  
for(int i=0;i<nStartPos.length;i++) =MQpYX  
{ 0ws1S(pq  
nStartPos = input.readLong(); SU,S1C_q8  
nEndPos = input.readLong(); gc~nT/lfK  
} "R8:s  
input.close(); Ul"9zTH  
} w>-@h>Ln  
catch(IOException e){e.printStackTrace ();} [ .]xy  
catch(Exception e){e.printStackTrace ();} p mv6m  
} 0,1x- yD  
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{wUbr^  
private void processErrorCode(int nErrorCode) _v~c3y).  
{ BE,XiH;  
System.err.println("Error Code : " + nErrorCode); ?`9XFE~a!  
} m\9R;$\  
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//停止文件下载 _+c' z  
public void siteStop() Be~__pd  
{ nV/8u_  
bStop = true; yT[CC>]l  
for(int i=0;i<nStartPos.length;i++) Ew`(x30E  
fileSplitterFetch.splitterStop(); Xe;Eu  
;<=Z\NX  
@bPR"j5D  
} /j7e q  
} &j}08aK%  
//负责部分文件的抓取 hw2'.}B"(  
**FileSplitterFetch.java 6I)[6R  
*/ 0tA~Y26  
package NetFox; b2L9%8h  
@#HB6B  
8 $5 y]%!  
import java.io.*; uD'yzR!]+  
import java.net.*; w&c6iFMd0  
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public class FileSplitterFetch extends Thread { }kJfTsFS  
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String sURL; //File URL &%@e6..Ex  
long nStartPos; //File Snippet Start Position rV{:'"=y-  
long nEndPos; //File Snippet End Position 1omjP`]|,  
int nThreadID; //Thread's ID TJYup%q  
boolean bDownOver = false; //Downing is over Q#kSp8  
boolean bStop = false; //Stop identical }j+Af["W?  
FileAccessI fileAccessI = null; //File Access interface (Dat`
:  
3
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #%Hk-a=>)#  
{ =g.R?H8cj5  
this.sURL = sURL; Ux[2 +Cf  
this.nStartPos = nStart; KjWF;VN*[3  
this.nEndPos = nEnd; 9Wu c1#  
nThreadID = id; _ MsO2A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t`M4@1S"'  
} Cs:?9G  
8 x=J&d  
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public void run() Fb2,2Px  
{ i2+r#Hw#5R  
while(nStartPos < nEndPos && !bStop) h.Y&_=Gc  
{ d
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try{ $&25hvK,  
URL url = new URL(sURL); UWW^g@d4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uBp,_V?  
httpConnection.setRequestProperty("User-Agent","NetFox"); <mrvuWg0  
String sProperty = "bytes="+nStartPos+"-"; LoUHStt  
httpConnection.setRequestProperty("RANGE",sProperty); W)X" G3  
Utility.log(sProperty); #!0=I s^  
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InputStream input = httpConnection.getInputStream(); xNrPj8V<Y  
//logResponseHead(httpConnection); lQS(\}N  
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3# g"Z7/  
byte[] b = new byte[1024]; 1 5heLnei  
int nRead; ._E 6?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c>|1%}"?  
{ cp:U@Nh(  
nStartPos += fileAccessI.write(b,0,nRead); )_&P:;N  
//if(nThreadID == 1) ndmsXls  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o5@d1A  
} JpRn)e'Z  
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Utility.log("Thread " + nThreadID + " is over!"); Ao )\/AR'  
bDownOver = true; ybC0Ee@  
//nPos = fileAccessI.write (b,0,nRead); Aaw]=8 OI  
} -lY,lC>{  
catch(Exception e){e.printStackTrace ();} m >Rdsn~l  
} A_!N,<-  
} H9\,;kM)  
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/Hs\`Kg"!  
//打印回应的头信息 I[6ft_*  
public void logResponseHead(HttpURLConnection con) w4Uo-zr@  
{ h]Y,gya[yk  
for(int i=1;;i++) +C}s"qrb@  
{ 9xN`  
String header=con.getHeaderFieldKey(i); `@<~VWe5  
if(header!=null) n2(`O^yd7C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aMJW__,  
Utility.log(header+" : "+con.getHeaderField(header)); 1gA^Qv~?  
else XtZeT~/7RT  
break; ]+k]Gbty6  
} Yu}[RXC(=  
} 4C#r=Uw`  
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public void splitterStop() w61*jnvi@  
{ WK.K-bd  
bStop = true; */APe#  
} Ueu~803~  
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} w)XnMyD(P  
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#AR$'TE#  
/* DO 0  
**FileAccess.java R0#'t+7^  
*//文件访问(定位，写) dw-o71(1d  
package NetFox; X:/7#fcG8  
import java.io.*; ?$Dc>  
jK]An;l{
Z  

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public class FileAccessI implements Serializable{ kz"QS.${  
h+!@`c>)Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2M>`W5  
RandomAccessFile oSavedFile; ]PlLy:(  
long nPos; U
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public FileAccessI() throws IOException V2SHF  
{ =D`:2k~ ,  
this("",0); FN<Sagj  
} cX#U_U~d  
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8
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public FileAccessI(String sName,long nPos) throws IOException Zg4kO;r08  
{ $!vK#8-&{  
oSavedFile = new RandomAccessFile(sName,"rw"); z?Cez*.h>  
this.nPos = nPos; [VE>{4]W  
oSavedFile.seek(nPos); T<%%f.x[s  
}
)&$mFwf  
aM4-quaG]  
4 'DEdx,&f  
public synchronized int write(byte[] b,int nStart,int nLen) z?t75#u9.  
{ goOw.~dZ'  
int n = -1; -cWGF  
try{ !A:d9 k  
oSavedFile.write(b,nStart,nLen); iOtf7.@  
n = nLen; }OqP`B  
} xnDst
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catch(IOException e) 6@;sOiN+  
{ ,FwJ0V  
e.printStackTrace (); HF<h-gX  
} X>i{288M3  
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return n; !-m 'diE  
}  (F&o!W  
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!E6QED"  
} H@te!EE  
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/* [ut[W9  
**SiteInfoBean.java txiX1o!/L  
*/  Cwl:  
package NetFox; \[d~O>k2  
`PT'Lakf;3  
:eH\9$F`x;  
public class SiteInfoBean { YH&q5W,KX  
!ou;yE&<,  
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private String sSiteURL; //Site's URL m7u" awM^  
private String sFilePath; //Saved File's Path yUN>mD-  
private String sFileName; //Saved File's Name *#1
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private int nSplitter; //Count of Splited Downloading File nE56A
#,Q,  
G1Vn[[%k  
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public SiteInfoBean() P9x':I$  
{//nSplitter的缺省值为5 x@@bC=iY$  
//default value of nSplitter is 5 6
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this("","","",5); 3:>hHQi  
} M}$Td_g  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?z0W1a  
{ yG^pND>_df  
sSiteURL= sURL; `i!fg\qnK  
sFilePath = sPath; VONC<wC  
sFileName = sName; \x|8  
this.nSplitter = nSpiltter; Cg8  
}^ =f%EjV  
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} Os*s{2OvO  
qYQ vjp  
pq:[`  
public String getSSiteURL() rl x6a@MiD  
{ pwRCfR)"X  
return sSiteURL;  7gx?LI_e  
} o?^Rw*u0/  
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public void setSSiteURL(String value) Lf`<4 P  
{ vSY YetL  
sSiteURL = value; 1--Ka&H  
} _}cD_$D  
gfKv$~  
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public String getSFilePath() i7e_~K  
{ M^lP`=sSv  
return sFilePath; 6`X}Z'4.Ox  
} i v.G  
:x3xeVtY  
i0Rj;E=:]  
public void setSFilePath(String value) UjMWSPEBy  
{ ZSr!L@S  
sFilePath = value; ?
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} W\<HUd  
bq9/d4
  
-e>Z!0  
public String getSFileName() [c XSk  
{ \uO^wJ}  
return sFileName; =2YXh,i  
} :? s{@7  
Y ` Z,52  
8T[<&<^-  
public void setSFileName(String value) Cu_-QE  
{ yq1G6hw  
sFileName = value; '<>?gE0Cd  
} !L<z(dV|(  
Xpt9$=d  
hZw8*H^tP  
public int getNSplitter() }Syd*%BR[  
{ IZGRQmi"  
return nSplitter; QP<.~^ao  
} zN=s]b=
/  
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public void setNSplitter(int nCount) 5#y_EpL"  
{ Zy.3yQM9i  
nSplitter = nCount; B*9?mcP\  
} u\"/EaQ{  
} d%RH]j4  
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#$]8WSl  
/* ou{V/?rb  
**Utility.java :, 3S5!(y  
*/ c^&4m[?C[u  
package NetFox; ~,Yd.?.TI  
IfT: 9 &  
dkqyn"^  
public class Utility { c?KIHZ0  
#<s"?Y%-  
@}Q!K*  
public Utility() ] g8z@r"b  
{ ML0_Uc3en  
'ka$@,s:  
9Q*:II  
} g1:%986jv  
bR;.KC3C
 
//线程睡眠 G_zK .N  
public static void sleep(int nSecond) ZAn9A>5_  
{ t/3HX]B_  
try{ J#q^CWN3R  
Thread.sleep(nSecond); ,gM:s}l!dJ  
} ,6o tm  
catch(Exception e) @sW!g;\T  
{ PIdGis5G  
e.printStackTrace (); < +kdL  
} &aa3BgxyE  
} -%Rbd0gVH\  
awjAv8tPO!  
//日志 }Oqt=Wm  
public static void log(String sMsg) kB%.i%9\\  
{ `m#i|8  
System.err.println(sMsg); gf>GK/^HH  
} ]h=5d09z  
@= =)  
URt+MTU[  
public static void log(int sMsg) j)#yyK{k2s  
{ 7j29wvSp5  
System.err.println(sMsg); @1' Y/dCyD  
} EWY'E;0@5  
} ZE= Yn~XM  
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Xbrc_V\_  
/* WJ
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**TestMethod.java }%<_>b\  
*/ 9XhH*tBn7(  
package NetFox; M%RH4%NZ0  
&pR 8sySu  
]EUQMyR  
public class TestMethod { Z[B:6\oQ  
E|jU8qz>P  
l2YA/9.  
public TestMethod() ,?HM5c{'[Y  
{ ///xx/weblogic60b2_win.exe )jt?X}  
try{ 0c8_&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u} +?'B)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c=QN!n:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -@Urq>^v T  
fileFetch.start(); Qpj[]c5  
} ReL+V  
catch(Exception e){e.printStackTrace ();} rl&.|;5uH;  
)4.-6F7U?  
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} 71ab&V i
l  
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public static void main(String[] args) `%EcQ}Nr  
{ *-uzsq.W  
new TestMethod(); wh2E$b(-  
} @,-D P41g  
} _ n1:v~  
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