http断点续传简单实现（java)

/* "B3&v%b  
**SiteFileFetch.java 3Eu;_u_  
*/ +\/1V`  
package NetFox; #[$zbZ(I>:  
import java.io.*; TQ&1!~L*  
import java.net.*; HBp$   
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public class SiteFileFetch extends Thread { xN CU5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [8v>jQ)  
long[] nStartPos; //开始位置 OLs<]0H  
long[] nEndPos; //结束位置 4Mck/i2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b<E+5;u  
long nFileLength; //文件长度 #Bo3:B8  
boolean bFirst = true; //是否第一次取文件 A-*y[/  
boolean bStop = false; //停止标志 J_`a}ox  
File tmpFile; //文件下载的临时信息 u/ZV35z  
DataOutputStream output; //输出到文件的输出流 Q@0Zh,l  
]TX"BH"2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） WNo7`)Kx  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1<;RI?R[9  
{ X`JoXNqm  
siteInfoBean = bean; U ljWBd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x +]ek  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |A,<m#C  
if(tmpFile.exists ()) XmAun  
{ 4l rKU^-  
bFirst = false; VKMgcfbHr/  
read_nPos(); CEh!X=Nn  
} aE 2=  
else 0T
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{ K3xt,g  
nStartPos = new long[bean.getNSplitter()]; w:nLm,  
nEndPos = new long[bean.getNSplitter()]; FxdWJ|rN9D  
} /1h ${mo~  
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} Hj97&C{Q^  
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public void run() T6nc/|Ot  
{ tUT:
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//获得文件长度 (i;,D-  
//分割文件 ;Z.sK-NJ4  
//实例FileSplitterFetch p)Fi{%
bc  
//启动FileSplitterFetch线程 'y&DOy/|  
//等待子线程返回 sv)4e)1  
try{ *-X`^R  
if(bFirst) 0iI|eE o  
{ !QlCt>{  
nFileLength = getFileSize(); t03T1.:(Mg  
if(nFileLength == -1) !:c_i,N  
{ q+2v9K@  
System.err.println("File Length is not known!"); F60?%gg  
} _%KRZx}  
else if(nFileLength == -2) p]rV\,Yss  
{ hMyN$7Z  
System.err.println("File is not access!"); 5}TTf2&Xo#  
} c)Ne/E{!0  
else 3,0b<vfSv  
{ k>F>y|m  
for(int i=0;i<nStartPos.length;i++) Nz>xilU'  
{ w1LZ\nA<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L),r\#Y(v  
} Ctbc!<@o  
for(int i=0;i<nEndPos.length-1;i++) LKgo(&mY  
{ U#`2~Qv/1  
nEndPos = nStartPos[i+1]; w\a6ga!xt"  
} qwq5yt?  
nEndPos[nEndPos.length-1] = nFileLength; xAr&sGMA  
} QBd4ok:R  
} ko"xR%Q  
&q +l5L"  
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//启动子线程 xy4P_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <8^ws90Y  
for(int i=0;i<nStartPos.length;i++) "A0y&^4B@  
{ 0,B"p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h-\Ov{~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _<'?s>(U'  
nStartPos,nEndPos,i); T1%}H3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xT-`dS0u  
fileSplitterFetch.start(); OHt^e7\  
} TLq^5,qG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6?
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Zr(eH2}0D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eQ*zi9na  
nEndPos = " + nFileLength); "q KVGd  
// fileSplitterFetch[nPos.length-1].start(); rDGrq9  
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\  
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//等待子线程结束 n<1*cL:8B  
//int count = 0; D^6Q`o  
//是否结束while循环 jp|*kBDq\  
boolean breakWhile = false; 4I#@xm8)  
h]/3doP  
gAgF$H .  
while(!bStop) E=91k.  
{ \Nk578+AA  
write_nPos(); 3R)|DGql=1  
Utility.sleep(500); )4N1EuD6  
breakWhile = true; 7g:Lj,Z4L  
-@@ O<M^  
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for(int i=0;i<nStartPos.length;i++) s1tkiX{>  
{ 1jE {]/Y7&  
if(!fileSplitterFetch.bDownOver) !x!1H5"  
{ bXA%|7*  
breakWhile = false; K"ly\$F  
break; @>&b&uj7T  
} /qFY$vj  
} = ?BhtW  
if(breakWhile) E{}J-_oS45  
break; #CcEI  
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o#WECs>  
//count++; (M<l}pl)  
//if(count>4) gf}*}8D  
// siteStop(); ^^< C9  
} yYrFk^  
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System.err.println("文件下载结束！"); #fk1'c2  
}  ^Vf@J  
catch(Exception e){e.printStackTrace ();} .m.
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} O8Z+g{  
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H?,Dv>.#*  
//获得文件长度 Z?'?|vM  
public long getFileSize() ,/kZt!  
{ nw#AKtd@x  
int nFileLength = -1; Nw(hN+_u  
try{ Qg0%rbE  
URL url = new URL(siteInfoBean.getSSiteURL()); U.h2 (-p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =uEpeL~d;+  
httpConnection.setRequestProperty("User-Agent","NetFox"); nW<nOKTnk_  
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int responseCode=httpConnection.getResponseCode(); &[SFl{fx>-  
if(responseCode>=400) brG!TJ  
{ *IIA"tC  
processErrorCode(responseCode); s3 fQGbU  
return -2; //-2 represent access is error `TH\0/eE  
} !yr4B"kz  
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String sHeader; /F46Ac}I  
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for(int i=1;;i++) *.KVrS<B1  
{ eI-SWwmv/u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #f%fY%5q  
//Utility.log(in.readLine()); FA := )  
sHeader=httpConnection.getHeaderFieldKey(i); 947;6a%$  
if(sHeader!=null) vif)g6,  
{ w'XN<RWA  
if(sHeader.equals("Content-Length")) j\zlp  
{ Z9|A"[b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s0:M'wA  
break; j@Pd" Z9  
} 7GS4gSd3  
} 5ArgM%  
else PKC0Dt;F.  
break; y%x:~.  
} r;"D>IM\  
} 4O.R=c2}7>  
catch(IOException e){e.printStackTrace ();} PgA1:i&'  
catch(Exception e){e.printStackTrace ();} 8aKS=(Z!j  
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Utility.log(nFileLength); bC98<if  
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return nFileLength; 587;2  
} <Q"G aqZ  

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//保存下载信息（文件指针位置） JYmYX-  
private void write_nPos() [zXC\)&!  
{
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try{ !^s -~`'\~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cP\z*\dS  
output.writeInt(nStartPos.length); @vX
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for(int i=0;i<nStartPos.length;i++) ew~?&=  
{ U@
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// output.writeLong(nPos); B}.:7,/0  
output.writeLong(fileSplitterFetch.nStartPos); n
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output.writeLong(fileSplitterFetch.nEndPos); !uO@4]:Y  
} kjB'WzZ8  
output.close(); Qe-Pg^PS]  
} D~Ef%!&  
catch(IOException e){e.printStackTrace ();} KUK.;gG*Z  
catch(Exception e){e.printStackTrace ();} 1P'A*`!K  
} 'Bxj(LaV-  
0 f$96sl  
{2mF\A#.  
//读取保存的下载信息（文件指针位置） -84%6p2-  
private void read_nPos() R4P&r=?  
{ d:>'c=y  
try{ uK`gveY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R
9Wr?  
int nCount = input.readInt(); J/:U,01  
nStartPos = new long[nCount]; Gqc6]{  
nEndPos = new long[nCount]; oylQCbT  
for(int i=0;i<nStartPos.length;i++) .MRN)p  
{ 5f?GSHA}  
nStartPos = input.readLong(); Di27=_J  
nEndPos = input.readLong(); )UpVGT
)  
} ryw%0H18  
input.close(); !#WQ8s!?o  
} g5"I{ol5T~  
catch(IOException e){e.printStackTrace ();} TJZ/lJU  
catch(Exception e){e.printStackTrace ();} t'0&n3  
} w4CcdpR  
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private void processErrorCode(int nErrorCode) BfCn
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{ GDe,n  
System.err.println("Error Code : " + nErrorCode); 4b((,u$  
} @"A 5yD5
  
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/$]S'[5uF  
//停止文件下载 4o;;'P  
public void siteStop() <DPRQhNW]  
{ jkta]#O  
bStop = true; 6<>1,wbq  
for(int i=0;i<nStartPos.length;i++) }{j@q~w>$  
fileSplitterFetch.splitterStop(); Mis B&Ok`k  
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} ],[<^=|  
} ?e4H{Y/M  
//负责部分文件的抓取 U`8Er48X  
**FileSplitterFetch.java WagL8BpLx  
*/ XP0;Q;WF}  
package NetFox; rQGInzYp  
i+in?!@G:  
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import java.io.*; q :~/2<o  
import java.net.*; je2"D7D  
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public class FileSplitterFetch extends Thread { W)J5
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[tJn!cMs  
String sURL; //File URL u-s*k*VHoc  
long nStartPos; //File Snippet Start Position ,}@4@ >?K  
long nEndPos; //File Snippet End Position #NGtba  
int nThreadID; //Thread's ID On~KTt3Mp  
boolean bDownOver = false; //Downing is over WcS`T?Xa  
boolean bStop = false; //Stop identical d4ld-y  
FileAccessI fileAccessI = null; //File Access interface tKcC{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tP*GYWI48  
{ !sEhjJV^7  
this.sURL = sURL; 1 I.P7_/  
this.nStartPos = nStart; ~Ey+  
this.nEndPos = nEnd; Wa.xm_4s2  
nThreadID = id; 8Dtpb7\o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 53ZbtEwhwr  
}  <82&F  
+WR?<*_  
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public void run() oIx|)[  
{ >`a^E1)  
while(nStartPos < nEndPos && !bStop) Vp~ cN  
{ ,dK)I1"C  
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try{ _[rQt8zn  
URL url = new URL(sURL); dQ-shfTr]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j$XaO%y)  
httpConnection.setRequestProperty("User-Agent","NetFox"); v=hn# U  
String sProperty = "bytes="+nStartPos+"-"; 60$;Q,]o  
httpConnection.setRequestProperty("RANGE",sProperty); _h  \L6.  
Utility.log(sProperty); &Wb"/Hn2  
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 $RRX-  
InputStream input = httpConnection.getInputStream(); }N(gP_?n  
//logResponseHead(httpConnection); %Cqp88]  
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byte[] b = new byte[1024]; yvzH}$!]  
int nRead; yp^k;G?_d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^VG].6  
{ 1P1h);*Z  
nStartPos += fileAccessI.write(b,0,nRead); |39,n~"o&  
//if(nThreadID == 1) -P|claO0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W^xO/xu1/  
} Cd=$XJ-b  
7}~w9jK"F  
IvkYM`%  
Utility.log("Thread " + nThreadID + " is over!"); ::#[lw  
bDownOver = true; N\Lu+ x5  
//nPos = fileAccessI.write (b,0,nRead); PX/{!_mM  
} 7=u Gf$/  
catch(Exception e){e.printStackTrace ();} +^esL9RG:  
} X0^@E  
} Ri_2@U-  
~CV.Ci.dG  
:;+_<pk  
//打印回应的头信息 (>ze{T|  
public void logResponseHead(HttpURLConnection con) F<6(Hw#>  
{ }v|_]   
for(int i=1;;i++) \<`oW>  
{ XR7v
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String header=con.getHeaderFieldKey(i); rFzj\%xa[  
if(header!=null) tN\I2wm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )D/,QWk  
Utility.log(header+" : "+con.getHeaderField(header)); w}OBp^V^  
else cUG^^3!  
break; F@q9UlfB-  
} 6s~B2t:Y  
} dm=?o  
r"
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,<#Rk'y$  
public void splitterStop() ys`oHSf  
{ 3T0-RP*  
bStop = true; fR@Cg sw  
} 0k16f3uI   
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} uHZ4 @w:  

6.
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/* ^W:a7cMw  
**FileAccess.java : Bo
  
*//文件访问(定位，写) xxl|j$m  
package NetFox; e/:?9  
import java.io.*; hI*v)c  
0KgP'oWvY  
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public class FileAccessI implements Serializable{ _Y&.Nw  
6=$<R4B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]j
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RandomAccessFile oSavedFile; xl,% Z~[  
long nPos; |X A0F\  
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public FileAccessI() throws IOException 5m0lk|`  
{ 1~~GF_l?  
this("",0); a$Ud"  
} ?K:\WW  
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public FileAccessI(String sName,long nPos) throws IOException e<1Ewml(]  
{ ?G',Qtz<K  
oSavedFile = new RandomAccessFile(sName,"rw"); tl!dRV92  
this.nPos = nPos; AQQa6Ce*  
oSavedFile.seek(nPos); gM;m{gXYK  
} /"k[T  
\ZV>5N3hS  
$3p48`.\  
public synchronized int write(byte[] b,int nStart,int nLen) [[<TW}  
{ uQ
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int n = -1; =gJ{75tV3  
try{ nyR<pnuC'  
oSavedFile.write(b,nStart,nLen); 62'9lriQ  
n = nLen; 4Ps;Cor+  
} zw+wq+2"  
catch(IOException e) Hqs-q4G$  
{ A~nqSe  
e.printStackTrace (); sPW:[  
} uk$MQv*D  
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return n;
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} +kYp!00  
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} }MMKOr(  
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/* DDGDj)=`  
**SiteInfoBean.java 8VQ!&^9!U#  
*/ 5;/q[oXI  
package NetFox; }2RbX,0l9  
E+XS7':I  
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sU+  
public class SiteInfoBean { K O\HH  
+l)t5Mg\  
JS m7-p|E  
private String sSiteURL; //Site's URL z)^.ai,:0  
private String sFilePath; //Saved File's Path j~ds)dW%`&  
private String sFileName; //Saved File's Name GEVDXx>@  
private int nSplitter; //Count of Splited Downloading File 'do2n/  
Uq'W<.v5  
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public SiteInfoBean() 9<3}zwJ  
{//nSplitter的缺省值为5 dg#Pb@7a  
//default value of nSplitter is 5 C|Gk}  
this("","","",5); VV$#<D<)  
} j?o6>j
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q~wS2f`)  
{ J`[jub  
sSiteURL= sURL; wI 7gHp  
sFilePath = sPath; #P}n+w_@  
sFileName = sName; w$iPFZC'  
this.nSplitter = nSpiltter; :qj^RcmVPL  
ydOG8EI  
Oj%5FUP~[%  
} jGkDD8K [  
v+g:0 C5 (  
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public String getSSiteURL() mpk+]n@  
{ nTGf  
return sSiteURL; F?a 63,r  
} [+b8 !'|&  
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public void setSSiteURL(String value) pO)EYla9  
{ i;]0>g4  
sSiteURL = value; cjGN=|`u  
} *u|1Z%XO  
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|n;);T(  
public String getSFilePath() xa]yq%  
{ yId1J  
return sFilePath; Y[PC<-fyf  
} aLW3Ub{h  
{Z <`@\K3  
D[]0/+,  
public void setSFilePath(String value) ipGxi[Vav  
{ 9wf"5c  
sFilePath = value; ZZHQ?p-  
} v\G7V  
0wTOdCvmb  
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public String getSFileName() H-e$~vEbP  
{ oKz!Xu%Hl  
return sFileName; ,']CqhL6=R  
} NA0Z~Ug>  
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public void setSFileName(String value) "v0bdaQH3  
{ ,m0M:!hK  
sFileName = value; St!0MdCH  
} c}S<<LR  
+C7W2!I[G2  
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public int getNSplitter() sb_/FE5e  
{ ) 5Ij  
return nSplitter; $E;Tj|W  
} ydY(*]  
+{;wOQ.  
^%Y-~yB-  
public void setNSplitter(int nCount) ps`j>vX*  
{ t&x\@p9  
nSplitter = nCount; 3jW&S  
} 4|cRYZj5  
} g
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/* TT3GGHR  
**Utility.java PvW4%A@0  
*/  6; )5v  
package NetFox; AG%[?1IXW  
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+zDRed_]=_  
public class Utility { zHNBX Rx  
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public Utility() S^D@8<6GJ  
{ oXk6,b"  
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} _~umE/tz  
An?#B4:  
//线程睡眠 2Rwd\e.z  
public static void sleep(int nSecond) `) ],FE*:  
{ sieC7raO  
try{ E&t8nlTx  
Thread.sleep(nSecond); Fx1FxwIJ  
} E^{!B]/oP  
catch(Exception e) *+6iXMwe  
{ (5:pHX`P  
e.printStackTrace (); >y#qn9rV1  
} pih 0ME}z  
} r.Z g<T  
e9Gu`$K  
//日志 I!kR:Z  
public static void log(String sMsg) RZnmia
 
{ ]D,_<Kk  
System.err.println(sMsg); u+6D|  
} KC:6^h'.  
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public static void log(int sMsg) 74 )G.!  
{ Tu}EAr  
System.err.println(sMsg); \=|=(kt)  
} vQ2{+5!|  
} H!"TS-s`  
PX23M|$!  
^ )!eiM  
/* '+iLW~   
**TestMethod.java (I
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*/ km^ZF<.@  
package NetFox; SS_6VE*sI  
.ej+?QYwC  
k5Q1.;fW76  
public class TestMethod { jxhZOLG  
}?6;;d#  
pz/W#VN  
public TestMethod() !v%>W< 3Q  
{ ///xx/weblogic60b2_win.exe G8?Do+[  
try{ VhMVoW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }|M:MJ`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
,(sE|B#s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `]4(Z"R  
fileFetch.start(); QKVOc,Fp7i  
} <u# 7K\:  
catch(Exception e){e.printStackTrace ();} @ %q>Jd  
ve.P{;;Ky  
~FXq%-J  
} 7\nXJ381  
S&[
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glROT@  
public static void main(String[] args) gzW{h0iRr  
{ 8*B+@`  
new TestMethod(); $txF|Fj]^A  
} uz$p'Q  
} rADzJ#CU\  
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