http断点续传简单实现（java)

/* iW-t}}Z>B  
**SiteFileFetch.java U-ULQ|6U  
*/ y0y+%H-  
package NetFox; b8e*Pv/  
import java.io.*; acy"ct*I  
import java.net.*; iI}nW  
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public class SiteFileFetch extends Thread { %WmZ ]@M  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [@zkv)D6  
long[] nStartPos; //开始位置 E8 \\X  
long[] nEndPos; //结束位置 TiTYs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R<t&F\>  
long nFileLength; //文件长度 8@Q"YA3d+  
boolean bFirst = true; //是否第一次取文件 fA;x{0CAMX  
boolean bStop = false; //停止标志 JfR kp  
File tmpFile; //文件下载的临时信息 "hfw9Qm  
DataOutputStream output; //输出到文件的输出流 zcZ^s v>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） DU(X,hDBF  
public SiteFileFetch(SiteInfoBean bean) throws IOException }
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{ rC~_:uXtE  
siteInfoBean = bean; f)qPFM]%z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :E}6S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x={kjym L  
if(tmpFile.exists ()) w:n(pLc<  
{ (1OW6xtfG  
bFirst = false; ;Kt'Sit  
read_nPos(); EwC5[bRjUp  
} zv&ePq\#  
else F1zT )wW  
{ 0,+EV,  
nStartPos = new long[bean.getNSplitter()]; 6 bYC  
nEndPos = new long[bean.getNSplitter()]; -i2D#i'  
} iz,]%<_PE  
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} dVij <! Lu  
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public void run() X^u4%O['  
{ pW`ntE#L  
//获得文件长度 CD*f4I#d  
//分割文件 !k4 }v'=  
//实例FileSplitterFetch p`shYyE  
//启动FileSplitterFetch线程 [P(rY  
//等待子线程返回 >aNbp  
try{ };4pZceV  
if(bFirst) `M towXj  
{ $K5ni{M;  
nFileLength = getFileSize(); @'6S[zU  
if(nFileLength == -1) Krt$=:m|1  
{ cg>!<T*  
System.err.println("File Length is not known!"); aUsul'e;M  
} @2-Hj~  
else if(nFileLength == -2) ]?v?Q
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{ ~R
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System.err.println("File is not access!"); v4nvZ6  
} ~xsb5M5  
else 6{Krw\0  
{ z(8)1#(n7  
for(int i=0;i<nStartPos.length;i++) F(?Fz8  
{ LC~CPV'F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \<0G kp  
} :mCw.Jz<
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for(int i=0;i<nEndPos.length-1;i++) }3 fLV  
{ G_4K+ -K  
nEndPos = nStartPos[i+1]; ~z-?rW  
} Fjb4BdZP  
nEndPos[nEndPos.length-1] = nFileLength; x9FLr}e  
} wdN>KS2!  
} A)O_es2  
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//启动子线程 %RfY`n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Zi2Eu4p l{  
for(int i=0;i<nStartPos.length;i++) ,6y-.m7>  
{ tkm~KLWV&7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sK""  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -$sl!%HO%  
nStartPos,nEndPos,i); d=xI   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |,M#8NOp:  
fileSplitterFetch.start(); t wa(M?  
} +Tgy,oD0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JN;TGtB^p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &"~,V6,q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HlOAo:8'  
nEndPos = " + nFileLength); Q+y-*1   
// fileSplitterFetch[nPos.length-1].start(); EA%#/n  
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9}'l=b:Jms  
//等待子线程结束 (F4dFh  
//int count = 0; /jK17}j  
//是否结束while循环 $h|I7`  
boolean breakWhile = false; "R\\\I7u  
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while(!bStop) ^Xt]wl*]+  
{ gOES2 4$2  
write_nPos(); ~,`\D7Z3  
Utility.sleep(500); VfE^g\Ia  
breakWhile = true; .H[Lo>  
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for(int i=0;i<nStartPos.length;i++) D/!eov4"  
{ LzEE]i  
if(!fileSplitterFetch.bDownOver) p[k9C$@e}  
{ HPd+Bd  
breakWhile = false; (`uC"MLk  
break; ,pGCgOG#}c  
}
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} ~;O=
7  
if(breakWhile) Is*0?9qU  
break; S*DBY~pZy  
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//count++; Lu#@~  
//if(count>4) 5>z:[OdY*  
// siteStop(); 3Oig/KZ  
} *{D:1S
  
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System.err.println("文件下载结束！"); 'mY,>#sT  
} :BZx)HxQ  
catch(Exception e){e.printStackTrace ();} +D{*L0$D"  
} ,[K)E  
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//获得文件长度 me}Gb a  
public long getFileSize() 5+Zx-oWq_  
{ DHujpZXQ  
int nFileLength = -1; VkP:%-*#v  
try{ ZZ.0'   
URL url = new URL(siteInfoBean.getSSiteURL()); !^"!fuoNC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0.+Z;j  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z@aL"@2]a  

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int responseCode=httpConnection.getResponseCode(); aKU8" 5  
if(responseCode>=400) bFdg'_  
{ &l}xBQAL  
processErrorCode(responseCode); WMRgf~TY=2  
return -2; //-2 represent access is error O09g b[  
} ~322dG  
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String sHeader; *wZV*)}  
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for(int i=1;;i++) P*=3$-`  
{ r\- k/0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZaV66Y>  
//Utility.log(in.readLine()); 8}b[Q/h!  
sHeader=httpConnection.getHeaderFieldKey(i); )s[S.`STz  
if(sHeader!=null) ;xC~{O  
{ T{xo_u{Q  
if(sHeader.equals("Content-Length")) QF6JZQh<  
{ Pb&+(j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gG>^h1_o~  
break; weadY,-H8  
} yFtf~8s3  
} 6? ly.h$  
else >V=@[B(0  
break; jmVy4* P_  
} jJC((1|  
} TTak[e&j3  
catch(IOException e){e.printStackTrace ();} nezbmpL4  
catch(Exception e){e.printStackTrace ();} ;XuEMq,Di  
n 9M6wS  
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Utility.log(nFileLength); vK~KeZ\,p=  
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return nFileLength; 6MQ:C'8T&=  
} _ 9]3S>Rn  
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,1+_k ="Z  
//保存下载信息（文件指针位置） ="E V@H?U  
private void write_nPos() nL~ b   
{ /hR]aw  
try{ Jtk(yp{Zz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]`9K|v  
output.writeInt(nStartPos.length); 'mR+W{r  
for(int i=0;i<nStartPos.length;i++) W4Q]<<6&  
{ Q(7l<z  
// output.writeLong(nPos); .q}k  
output.writeLong(fileSplitterFetch.nStartPos); yt,;^o^  
output.writeLong(fileSplitterFetch.nEndPos); j)*nE./3  
} 6%1o<{(%f  
output.close(); ?QVI'R:Z
?  
} KK|Jach  
catch(IOException e){e.printStackTrace ();} VHNiTp  
catch(Exception e){e.printStackTrace ();} 4+bsG6i  
} NQ=YTRU  
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//读取保存的下载信息（文件指针位置） . %7A
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private void read_nPos() 2wvDC@  
{ 5,Zn$zosJC  
try{ s50ln&2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q>X2=&1  
int nCount = input.readInt(); gp2)35  
nStartPos = new long[nCount];
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nEndPos = new long[nCount]; b"9,DQB=i  
for(int i=0;i<nStartPos.length;i++) W -&5 v  
{ TaG-^bX8B  
nStartPos = input.readLong(); P#PQ4uK \  
nEndPos = input.readLong(); ~G:7*:[b  
} c @R6p+  
input.close(); O2f2Fb$B7  
} 2=EKAg=S  
catch(IOException e){e.printStackTrace ();} ?C3cPt"  
catch(Exception e){e.printStackTrace ();} [*t EHW  
} ak[)+_k_  
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private void processErrorCode(int nErrorCode) <&iBR  
{ +_Z/VQv  
System.err.println("Error Code : " + nErrorCode); H;1}Nvvd  
} (P-<9y@  
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v!Z9T  
//停止文件下载 $(U|JR@  
public void siteStop() C+5nft6:  
{ A$cbH.  
bStop = true; r8rR_M{P  
for(int i=0;i<nStartPos.length;i++) ZI7<E  
fileSplitterFetch.splitterStop(); jLSZ#H  
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& j43DYw4  
} HV@:!zM  
} UZ#2*PH2E  
//负责部分文件的抓取 "L]_NST  
**FileSplitterFetch.java b3+PC$z2h  
*/ z{\.3G  
package NetFox; Pp2)P7  
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import java.io.*; "|if<
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import java.net.*; /V&Y@j  
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public class FileSplitterFetch extends Thread { )c/] 8KU  
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String sURL; //File URL |wDCIHzQ  
long nStartPos; //File Snippet Start Position U,'n}]=4A3  
long nEndPos; //File Snippet End Position \"SI-`x  
int nThreadID; //Thread's ID J5k%  
boolean bDownOver = false; //Downing is over yWzTHW`)Mr  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface 5S1m&s5k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k;sUDmrO  
{ ~J|0G6H  
this.sURL = sURL; _bX)fnUu  
this.nStartPos = nStart; 7u zN/LAF  
this.nEndPos = nEnd; {-xnBx  
nThreadID = id; DxlX-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {#vo^& B  
} `d8TA#|`  
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public void run() '&9b*u";x(  
{ /SiQw7yp%  
while(nStartPos < nEndPos && !bStop) $)U RY~;i  
{ @:63OLlrG  
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try{ 'Gk|&^  
URL url = new URL(sURL); ps2C8;zT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <t8})
 
httpConnection.setRequestProperty("User-Agent","NetFox"); C
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String sProperty = "bytes="+nStartPos+"-"; yxH[uJpb  
httpConnection.setRequestProperty("RANGE",sProperty); Vh&uSi1V  
Utility.log(sProperty); \?j
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8:f(PN  
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InputStream input = httpConnection.getInputStream(); e.N#+  
//logResponseHead(httpConnection); s SDBl~g  
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byte[] b = new byte[1024]; =#W6+=YN8  
int nRead; K$4Ky&89  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k20tn ew  
{ ="V6z$N  
nStartPos += fileAccessI.write(b,0,nRead); l{<@[foc  
//if(nThreadID == 1) HxjhP(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r;-\z(
h  
} BwR)--75  
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Utility.log("Thread " + nThreadID + " is over!"); #soWX_>  
bDownOver = true; d;`JDT  
//nPos = fileAccessI.write (b,0,nRead); >6c{CYuT  
} !(/dbHB  
catch(Exception e){e.printStackTrace ();} *cf#:5Nl  
} p &A3l  
} "_lSw3  
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&Mol8=V)  
//打印回应的头信息 (f7R~le  
public void logResponseHead(HttpURLConnection con) `On%1%k8  
{ Ls( &.  
for(int i=1;;i++) A," u~6Bn  
{ gF&1e5`i  
String header=con.getHeaderFieldKey(i); BRzrtK  
if(header!=null) F8q|$[nH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |(]XZ!{  
Utility.log(header+" : "+con.getHeaderField(header)); 0y*8;7-|r)  
else P
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break; 3{CXIS  
} ->d3FR  
} }}<^fM  
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public void splitterStop() q>t#5Z81  
{ NbH;@R)L  
bStop = true; nPE{Gp) }  
} jx J5F3d  
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} 51xiX90D  
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/*  (cx Q<5  
**FileAccess.java vr"O9L w  
*//文件访问(定位，写) y2cYRHN[X}  
package NetFox; PY[nnoF"|  
import java.io.*; h:xvnyaI  
''tCtG" Xi  
 Z/RSZ-  
public class FileAccessI implements Serializable{ lxf+$Z`~:  
;?4EVZ#o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B 1jeIk,  
RandomAccessFile oSavedFile; FN\*x:g  
long nPos; }2
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public FileAccessI() throws IOException I'}&s|6  
{ Y7BmW+  
this("",0); @q]4]U)  
} 2u Zb2O  
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public FileAccessI(String sName,long nPos) throws IOException -Gy=1W`09  
{ s5h}MXIXw  
oSavedFile = new RandomAccessFile(sName,"rw"); y*=sboX  
this.nPos = nPos; OYSq)!:  
oSavedFile.seek(nPos); S#kYPe  
} |P@N}P@  
L+N\B@ 0-  
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public synchronized int write(byte[] b,int nStart,int nLen) ;6:9EEd  
{ D%L^[|)c\s  
int n = -1; Jr5dw=B gw  
try{ 't6l@_x  
oSavedFile.write(b,nStart,nLen);  LAkBf  
n = nLen; /%g+|C  
} IdqCk0lVD  
catch(IOException e) ,p{naT%R  
{ =^1jVaAL  
e.printStackTrace (); wx^Det  
} 1w~PHH`~  
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3\2%i6W6  
return n; @R%*;)*F  
} ,OWk[
0/  
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} p[w! SR%=  
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Q 9fK)j1$  
/* 9}%$j  
**SiteInfoBean.java /5)*epF+  
*/ E*O($tS  
package NetFox; NB1KsvD{  
]!ox2m_U  
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public class SiteInfoBean { f`:GjA,J$  
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private String sSiteURL; //Site's URL ,VS(4  
private String sFilePath; //Saved File's Path UAPd["`)y  
private String sFileName; //Saved File's Name  
4d\^  
private int nSplitter; //Count of Splited Downloading File 5mQ@&E~#W  
23P&n(.  
OKAU*}_  
public SiteInfoBean() ele@xl  
{//nSplitter的缺省值为5 L/Q[N^ (^  
//default value of nSplitter is 5 XHekz
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this("","","",5); g:z<CSIq/  
} H.\`(`6  
9Q=VRH:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D3cJIVM  
{ g35!a<JW  
sSiteURL= sURL; Iz1x|EQ  
sFilePath = sPath; iP0m1  
sFileName = sName; tGgxID  
this.nSplitter = nSpiltter; q)i %*IY  
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} }9+;-*m/  
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public String getSSiteURL() &cL1 EQ(  
{ ~f h  
return sSiteURL; >x{("``D0y  
} Jqj!k*=/  
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5Jbwl$mZ  
public void setSSiteURL(String value) iX$G($[l(  
{ [3jJQ3O,  
sSiteURL = value; rZKfb}ANQ  
} BB6[(Z  
r,Uk)xa/^  
7v*gwBH  
public String getSFilePath() $Z:O&sD{  
{ C`hdj/!A  
return sFilePath; Kcm+%p^  
} 1uAjy(
y  
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f' ?/P~[  
public void setSFilePath(String value) hx9{?3#  
{ )i~AXBt}  
sFilePath = value; )A\ ZS<@Z7  
} /W/e%.  
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public String getSFileName() FJ_7<4ET  
{ ;Z]Wj9iY  
return sFileName; `,qft[1  
} P.y +jyu  
3YHEH\60^  
z&6_}{2,]  
public void setSFileName(String value) gQ_<;'m)2  
{ N&HI)X2&  
sFileName = value; jE*{^+n  
} aKDY_D  
\N9=13W<lK  
2? qC8eC  
public int getNSplitter() PVIOe}N  
{ Fi/iA%,  
return nSplitter; qX,q*hr-  
} V&*IZt&  
~*HQPp?v  
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public void setNSplitter(int nCount) k+J%o%* <  
{ MgXZN{  
nSplitter = nCount; AY /9Io
-  
} ;z'&$#pA  
} ?()*"+N(ck  
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$ VT)  
/* M+ +Dk7B  
**Utility.java J :O!4gI  
*/ $94lF~  
package NetFox; S2$66xr#  
g88k@<Y  
vNSUrf,r  
public class Utility { `NIb?/!f  
I~&*^q6 |  
/HdXJL9B  
public Utility() L^JU{\C  
{ %Psg53N  
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} i]ZGq7YJ%  
t/[2{'R4  
//线程睡眠 'gY?=,dF>  
public static void sleep(int nSecond) f Fi=/}  
{ A[l )>:  
try{ Va?]:Q  
Thread.sleep(nSecond); xm{?h,U,  
} QNbZ)  
catch(Exception e) G#%Sokkb'  
{ n*\o. :f  
e.printStackTrace (); Fl)nmwOc  
} T
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} $n<1D -0!r  
O~5t[  
//日志 *$9U/  d  
public static void log(String sMsg) !KI^Z1dP(  
{ 3eUi
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System.err.println(sMsg); _WS8I>  
} ThV>gn5  
0Z2XVq~T$  
JZ}zXv  
public static void log(int sMsg) "mn?*  
{ Zq4%O7%  
System.err.println(sMsg); aj4ZS  
} k~)CJ6}
 
} ozY$}|sjDT  
F > rr.  
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/* : ;8L1'  
**TestMethod.java FRxR/3&  
*/ y{M7kYWtHV  
package NetFox; Kb]}p  
ICz:>4M-dn  
Tv#d>ZSD  
public class TestMethod { S:{xx`6K  
reR@@O  
<oXBkCi0r  
public TestMethod() Ko&4{}/  
{ ///xx/weblogic60b2_win.exe 3^P;mQ$p1  
try{ 2=?3MXcjy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0=&S?J#!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4M%|N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8pEA3py  
fileFetch.start(); Wu6'm&t  
} sSh." H  
catch(Exception e){e.printStackTrace ();} 9qDM0'W
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*ELU">!}G  
0xZ^ f}@L  
} JFI*Pt;X9  
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public static void main(String[] args)  kMW9UUw  
{ P84YriLo  
new TestMethod(); ts<\n-f  
} gaC4u,Zb  
} 48z%dBmTT*  
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