http断点续传简单实现（java)

/* $u&|[vcP0  
**SiteFileFetch.java 6,a%&1_  
*/ ujow?$&  
package NetFox; 9ec0^T  
import java.io.*; v<%]XHN  
import java.net.*; XEa~)i{O  
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public class SiteFileFetch extends Thread { /XjN%|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :mzCeX8 *  
long[] nStartPos; //开始位置 #fO*ROe  
long[] nEndPos; //结束位置 QZ?O;K1|y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H'D#s;SlR  
long nFileLength; //文件长度 HqB|SWyK  
boolean bFirst = true; //是否第一次取文件 VVgsLQd  
boolean bStop = false; //停止标志 Ko@zk<~"[  
File tmpFile; //文件下载的临时信息 +tPx0>p;  
DataOutputStream output; //输出到文件的输出流 *ZX!EjICk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） P4i3y{
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public SiteFileFetch(SiteInfoBean bean) throws IOException w<v1N  
{ _F3KFQ4,S-  
siteInfoBean = bean; ]v<d0"2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); CGCQa0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u0wn=Dg  
if(tmpFile.exists ()) #"|"cYi,  
{ iJEB?y  
bFirst = false;  dD:  
read_nPos(); T4Xtu
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} _r~!O$2  
else G OH  
{ e21E_exM0  
nStartPos = new long[bean.getNSplitter()]; U8EJC .e&O  
nEndPos = new long[bean.getNSplitter()]; ;5-R=e(KA  
} !-F^VGD(8  
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} sg+ZQDF{x  
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public void run() 44Q6vb?  
{ '" ^ B&W  
//获得文件长度 UwZu:[T6H  
//分割文件 :U!'U;uQ  
//实例FileSplitterFetch H&~5sEGa  
//启动FileSplitterFetch线程 ]z+*?cc  
//等待子线程返回 ROPC |  
try{ "xL;(Fqu  
if(bFirst) f37ji  
{ e 4 p*51ra  
nFileLength = getFileSize(); q-A`/9  
if(nFileLength == -1) ~8XX3+]z:X  
{ hN Z4v/  
System.err.println("File Length is not known!"); 14mXx}O  
} N>Vacc_[  
else if(nFileLength == -2) R.91v4J  
{ Y')O>C0~  
System.err.println("File is not access!"); TP{>O%b  
} S`ax*`  
else 'bZMh9|  
{ YgO aZqN  
for(int i=0;i<nStartPos.length;i++) YtV |e|aD  
{ fG X1y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #;5[('&[  
} #>7')G  
for(int i=0;i<nEndPos.length-1;i++) pg}~vb"  
{ !w @1!Xpn1  
nEndPos = nStartPos[i+1]; =Jsg{vI  
} P%.`c?olbs  
nEndPos[nEndPos.length-1] = nFileLength; ,Wz[tYL*  
} 6U;Jg
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} C/{nr-V3u  
*p""YEN  
Wv6z%r<  
//启动子线程 CPc"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >2]Eaw&W  
for(int i=0;i<nStartPos.length;i++) dE 3i=  
{ I;`Ko_i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "bHtf_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~AEqfIx*^&  
nStartPos,nEndPos,i); L4\SBO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y_}K?  
fileSplitterFetch.start(); ~C}
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} ?2JS&i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z*Myokhf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9\AEyaJFZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  1m&!l6Jk  
nEndPos = " + nFileLength); ^U-vD[O8  
// fileSplitterFetch[nPos.length-1].start(); C1ZFA![  
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zF[3%qZE:T  
//等待子线程结束 bs<WH`P  
//int count = 0; Y{%4F%Oy  
//是否结束while循环 )ZS:gD  
boolean breakWhile = false; Qh)|FQ[s$r  
g`%ED0aR  
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while(!bStop) ^2&O3s
  
{ Uq9,(tV`6g  
write_nPos(); wQF&GGYR  
Utility.sleep(500); <7vIh0  
breakWhile = true; &,m'sQ  
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for(int i=0;i<nStartPos.length;i++) b5iIV1g  
{ hN>('S-cq  
if(!fileSplitterFetch.bDownOver) JxX jDYrU  
{ 0C7thl{Dms  
breakWhile = false; *Gk<"pEeS  
break; 3Ew"[FUs  
} DiZ!c"$  
} 7i-W*Mb:  
if(breakWhile) <Z\MZ&{k{*  
break; C5
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[JX}1%NA  
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//count++;
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//if(count>4) 'DL;c@}37  
// siteStop(); *
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} oyKt({  
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System.err.println("文件下载结束！"); +XU$GSw3(  
} n.Ur-ot  
catch(Exception e){e.printStackTrace ();} %0ll4"  
} D{,[
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/{eih]`x(  
p%1xj2 ?nN  
//获得文件长度 R`I8Ud4=  
public long getFileSize() 6nY )D6$JG  
{ #`N6<nb  
int nFileLength = -1; q5?
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try{ bWX[<rh'  
URL url = new URL(siteInfoBean.getSSiteURL()); k$UzBxR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~xlMHf  
httpConnection.setRequestProperty("User-Agent","NetFox"); +LQs.*  
:=iM$_tp'  
!T#8N7J
>  
int responseCode=httpConnection.getResponseCode(); /ygUd8@  
if(responseCode>=400) >,] eL  
{ [T}%q"<  
processErrorCode(responseCode); %#S"~)  
return -2; //-2 represent access is error r|JiGj^om  
} ?c=R"Yg$  
 r
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String sHeader; *6sJ*lh  
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for(int i=1;;i++) wB1|r{  
{ U&Sbm~Qi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^B&ahk  
//Utility.log(in.readLine()); ^ RcIE (  
sHeader=httpConnection.getHeaderFieldKey(i); ReHd~G9  
if(sHeader!=null) ZZ]OR;8  
{ @MlU!oR&  
if(sHeader.equals("Content-Length")) UgnsV*e&  
{ /QV. U.>G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SBN_>;$c5}  
break; Dj,+t+|  
} &G7)s%q  
} 0bnVIG2q  
else C%95~\Ds  
break; zP{<0o  
} NU)`js  
} Dvq*XI5  
catch(IOException e){e.printStackTrace ();} gT5Ji~xI  
catch(Exception e){e.printStackTrace ();} _ RT"1"r  
JucxhjV#,  
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Utility.log(nFileLength); HYI1 o/}  
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return nFileLength; _Pfx_+  
} #v~S",*.f  
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>F\rBc&  
//保存下载信息（文件指针位置） .Kh(F6 s  
private void write_nPos() ok\/5oz  
{ ?;.1fJU>  
try{ &,Zz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -u3SsU)_%N  
output.writeInt(nStartPos.length); ?ck^? p7  
for(int i=0;i<nStartPos.length;i++) 1EAVMJ  
{ jy__Y=1}  
// output.writeLong(nPos);  'QekQ];  
output.writeLong(fileSplitterFetch.nStartPos); FSYjp{z5  
output.writeLong(fileSplitterFetch.nEndPos); @]ptY*   
} %<ptkZK#  
output.close(); ^7s6J{<  
} :#W>S
O  
catch(IOException e){e.printStackTrace ();} zfr(dQ  
catch(Exception e){e.printStackTrace ();} ?%za:{  
} r"u(!
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//读取保存的下载信息（文件指针位置） 6(<~1{ X%  
private void read_nPos() ]=86[A-2N  
{ UTK.tg  
try{ ev;5?9\E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "-j@GCme  
int nCount = input.readInt(); I3zitI;  
nStartPos = new long[nCount]; ,QHx*~9  
nEndPos = new long[nCount]; M#lVPXS  
for(int i=0;i<nStartPos.length;i++) uZ2v;]\Y6  
{ s=y9!rr  
nStartPos = input.readLong(); Eip~~2  
nEndPos = input.readLong(); sNk>0 X[  
} \")YKN=W  
input.close(); wkZ2Y-#='  
} 1z};"A  
catch(IOException e){e.printStackTrace ();} WJFTy+bD  
catch(Exception e){e.printStackTrace ();} qq9tBCk

 
} `.sIZku  
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.J6j"  
private void processErrorCode(int nErrorCode) fssL'DD  
{ ?j4,^K3  
System.err.println("Error Code : " + nErrorCode); )oxP.K8q)U  
} sei!9+bZr  
bU4+PA@$  
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//停止文件下载 /?dQUu^z  
public void siteStop() RY/ Z~]  
{ AFm*60C  
bStop = true; BE2\?q-  
for(int i=0;i<nStartPos.length;i++) MTITIecw=  
fileSplitterFetch.splitterStop(); Mi/'
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 RoM*Qjw  
} |z7Crz  
} TaHi+  
//负责部分文件的抓取 ;,B@84'  
**FileSplitterFetch.java +zdq+<9X  
*/ 1'U%7#;E  
package NetFox; -ZoOX"N}  
;k41+O:f@  
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import java.io.*; %"KWjwp  
import java.net.*; l-h7ksRs  
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public class FileSplitterFetch extends Thread { E~g}DKs_5  
)RCqsFjK  
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String sURL; //File URL K?OX  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position /h.3<HI."*  
int nThreadID; //Thread's ID wsGq>F~  
boolean bDownOver = false; //Downing is over NMY!-Kv 5  
boolean bStop = false; //Stop identical &qI5*aQ8T  
FileAccessI fileAccessI = null; //File Access interface }?qnwx.  
.HyiPx3^  
O7CYpn4<7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ']6#7NU  
{ !RUo:b+  
this.sURL = sURL; \-iUuHP  
this.nStartPos = nStart; a3 _0F@I  
this.nEndPos = nEnd; g$T_yT''  
nThreadID = id; 1]3bx N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  {e  
} 4a\+o]  
]jY)M<:J4  
y $DB  
public void run() |b;M5w?  
{ 6C51:XQO  
while(nStartPos < nEndPos && !bStop) H=BR -  
{ j83Y'VJJC  
~V- o{IA  
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try{ +p}Xmn  
URL url = new URL(sURL); oJu4vGy0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r~Ubgd ]U  
httpConnection.setRequestProperty("User-Agent","NetFox"); z4fK{S  
String sProperty = "bytes="+nStartPos+"-"; ]:#$6D"  
httpConnection.setRequestProperty("RANGE",sProperty); wkpVX*DfRE  
Utility.log(sProperty); Mc3h  R0  
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d\Z4?@T<5  
InputStream input = httpConnection.getInputStream(); !<PTsk F  
//logResponseHead(httpConnection); :3*oAh8|  
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byte[] b = new byte[1024]; v;qL?_:=c  
int nRead; Oc+L^}elJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $I0a2Z=dP  
{ Q)X\VQcgj  
nStartPos += fileAccessI.write(b,0,nRead); 3K:Xxkk  
//if(nThreadID == 1) XBt0Ez  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); knZd}?I*  
} `/Jr8J_  
$`{q =  
]"vdC}  
Utility.log("Thread " + nThreadID + " is over!"); iw;Alav"x  
bDownOver = true; Cr
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//nPos = fileAccessI.write (b,0,nRead); kRa$jD^?  
} H
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catch(Exception e){e.printStackTrace ();} pR7G/]U$A  
} 2xBGs9_Y  
} G%/cV?18  
/38Pp%
 
\/%Q PE8  
//打印回应的头信息 BU\NBvX$  
public void logResponseHead(HttpURLConnection con) ^o<Nz8  
{ mYRR==iDL  
for(int i=1;;i++) @,$HqJ  
{ #
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String header=con.getHeaderFieldKey(i); S?WUSx*N  
if(header!=null) 52Ffle8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g@i 4H[k  
Utility.log(header+" : "+con.getHeaderField(header)); OVK(:{PwS  
else 3VgH*vAU}  
break; -
/*{^[  
} *g.,[a0  
} ht!:e>z&4  
_\]UA?0  
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public void splitterStop() %j`]x -aOz  
{ 9Ky,oB  
bStop = true; c
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} duTSU9  
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 KX@Fgs  
} ,peFNpi  
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/* a#@opUn-  
**FileAccess.java $x<-PN  
*//文件访问(定位，写) Va:jMN  
package NetFox; +<#-52br\  
import java.io.*; #7)6X:/O  
9EQ,|zf'  
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public class FileAccessI implements Serializable{ #6nA^K}  
IEj`:]d  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z r*ytbt  
RandomAccessFile oSavedFile; FL}8h/  
long nPos; @bE?WXY  
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public FileAccessI() throws IOException Q0A1N[  
{ e&kg[jU  
this("",0); xr-scdh2  
} "^7Uk#! 7  
qz):YHxT]n  
b ;b1V  
public FileAccessI(String sName,long nPos) throws IOException /_HL&|N_5  
{ pgarGaeq  
oSavedFile = new RandomAccessFile(sName,"rw"); LPClE5  
this.nPos = nPos; ('Pd GV4V  
oSavedFile.seek(nPos); bEJZh%j!  
} }s9J+m  
Sx7xb]3XI"  
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public synchronized int write(byte[] b,int nStart,int nLen) uW|y8 BP $  
{ gfHlY
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int n = -1; 4O'ho0w7  
try{ k3w#^ "i  
oSavedFile.write(b,nStart,nLen); 1F-L(\oKm  
n = nLen; a7R7Ks|q  
} _,QUH"
  
catch(IOException e) j(hC't-  
{ bL<cgtz7)  
e.printStackTrace (); [DviN  
} /6fsh7 \  
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return n; Yp$lc^)c>  
} S45jY=)z  
_`_$UMK;  
od>.
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} XooAL0w  
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5Dd;?T>  
/* qIl@,8T  
**SiteInfoBean.java m"5gzH  
*/ +VDB\n  
package NetFox; c'C2V9t  
%$Uw]a  
*^]ba>  
public class SiteInfoBean { idQr^{  
ZzY6M"eUXD  
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private String sSiteURL; //Site's URL (plOV
)  
private String sFilePath; //Saved File's Path k
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private String sFileName; //Saved File's Name & |r)pl0$  
private int nSplitter; //Count of Splited Downloading File bZ=d!)%P-{  
]dH;+3}  
;C3](  
public SiteInfoBean() ;iWCV&>w  
{//nSplitter的缺省值为5 &F)lvtt|  
//default value of nSplitter is 5 *@< jJP4  
this("","","",5); jw H)x  
} p("do1:  
W/+0gh7`,(  
}5|uA/B  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y}8j_r  
{ >A6lX)  
sSiteURL= sURL; 'k hJ
Z:  
sFilePath = sPath; L3S,*LnA  
sFileName = sName; e |!i1e!  
this.nSplitter = nSpiltter; vU_#(jZ  
b=sc2)3?  
.Q7z<Q  
} oVs&r?\Z  
hhpH)Bi=  
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public String getSSiteURL() i4l?q#X  
{ 6w'^,V  
return sSiteURL; D0~mu{;c$  
} 4IVCTz[  
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D n^RZLRhy  
public void setSSiteURL(String value) 9 HuE'(wQ  
{ MQAb8 K:e  
sSiteURL = value; Ood&cP'c  
} ^#Shs^#  
\;~>AL*  
y3lsAe#  
public String getSFilePath() r'j*f"uAm  
{ Oo,<zS=ICk  
return sFilePath; aX~7
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} {?82>q5F  
6+>q1,<  
(%".=x-  
public void setSFilePath(String value) _d:l1jD  
{ n@xU5Q  
sFilePath = value; ]cbY@U3!2  
} 1L3L!@  
mwBOhEefNJ  
<EJC.WWJa  
public String getSFileName() Pr" 2d\  
{ HyB!
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return sFileName; ~qRP.bV%f  
} i-$]Tg  
(@]{=q<  
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public void setSFileName(String value) hC,EO&  
{ ">|fB&~A  
sFileName = value; hl8[A-d(R  
} wTG6>l]H  
, j7&(V~  
Z{|wjZb(  
public int getNSplitter() JpN+'/  
{ 2 g,UdG  
return nSplitter; }k$2r3  
} b8(94t|;U  
@#;2P'KL  
40+
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public void setNSplitter(int nCount) ><+wHb  
{ ;>bcI).  
nSplitter = nCount; h?jKq2`  
} rz5AIe>Hm  
} v="i0lL_  
dL!PpLR$2  
qq G24**9v  
/* @uApm~}  
**Utility.java .}C pX  
*/ [5yLg  
package NetFox; P`0}( '"U  
@uXF(KDX  
Yv\>\?865  
public class Utility { N$i!25F`  
qX>mOW^gT8  
')
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public Utility() X|++K;rtfE  
{ 8tJB/Pw`S  
0CX2dk"UB^  
K 0R<a~  
} ?hHVawt  
{oOzXc
6o  
//线程睡眠 hV_bm@f/y  
public static void sleep(int nSecond) %|Sh|\6A!  
{ ZjLuqo  
try{ 0ZcvpR?G  
Thread.sleep(nSecond); [z
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} sF[7pE  
catch(Exception e) <A"[Wk  
{ Xy0*1$IS]  
e.printStackTrace (); SHWD@WLE4  
} +es|0;Z4yP  
} 9}G.Fr  
AUBZ7*VO  
//日志 j S~Wcu  
public static void log(String sMsg) DC+p s  
{ 3 vr T`  
System.err.println(sMsg); W~b->F  
} f-$%Ck$%,  
I54`}Npp  
"h58I)O  
public static void log(int sMsg) 2Tt^^Lb  
{ 2z#gn9Wb  
System.err.println(sMsg); oy{ {d  
} (@X].oM^y  
} =r=?N\7I  
c{4Y?SSx  
q.I  
/* 6)5Akyz4V  
**TestMethod.java PLoD^3uG)  
*/ Oc A;+}>  
package NetFox; O S?S$y  
pT ]:TRPS  
5=@q!8a*  
public class TestMethod { % XvJJ  
!I)wI~XF)5  
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public TestMethod() >_esLsPWh]  
{ ///xx/weblogic60b2_win.exe ?azi(ja  
try{ `!- w^~c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $<DcbJW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JA!?vs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >/J!:Htk+K  
fileFetch.start(); 0*y|k1  
} _|1m]2'9  
catch(Exception e){e.printStackTrace ();} Wy:xiP  
^V
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ip)gI&kN`z  
} HnlCEW,^o  
P80mK-Iyv_  
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public static void main(String[] args) V;@kWE>3  
{ qE:/~Q0  
new TestMethod(); Cr&,*lUo  
} =pa F6!AB  
} R%EpF'[~[  
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