http断点续传简单实现（java)

/* 4zoQe>v~  
**SiteFileFetch.java U$OZkHA[  
*/ 39X~<\&'  
package NetFox; }%|ewy9|CW  
import java.io.*; J&xZN8jW   
import java.net.*; .GrOdDK$ns  
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public class SiteFileFetch extends Thread { 2JfSi2T  

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SiteInfoBean siteInfoBean = null; //文件信息Bean b($hp%+yJ  
long[] nStartPos; //开始位置 H1bR+2s  
long[] nEndPos; //结束位置 QaWS%0go  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -k'<6op  
long nFileLength; //文件长度 $Z]&3VxxY  
boolean bFirst = true; //是否第一次取文件 xcB\Y:   
boolean bStop = false; //停止标志 iGyetFqKw  
File tmpFile; //文件下载的临时信息 o<G 9t6~  
DataOutputStream output; //输出到文件的输出流 }9fa]D-a?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =nEP:7~{  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4E$MhP  
{ 1!#N-^qk  
siteInfoBean = bean; `Q@7,z=f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M(-)\~9T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ca2r<|uA  
if(tmpFile.exists ()) LPvp (1  
{ UC!mp?   
bFirst = false; tB_le>rhl  
read_nPos(); ai!u+L  
} v3-/ [-XB:  
else /$~1e7W  
{ RN$vKJk  
nStartPos = new long[bean.getNSplitter()]; ,B
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nEndPos = new long[bean.getNSplitter()]; a'J0}j!  
} vm [lMx  
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} ,-UF5U  
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public void run() NRRJlY S  
{ o@meogkL  
//获得文件长度 O. * 0;5  
//分割文件 SuE~Wb5&  
//实例FileSplitterFetch h]4xS?6O  
//启动FileSplitterFetch线程 xR+vu>f  
//等待子线程返回 WtM%(8Y[]  
try{ 74%vNKzc~  
if(bFirst) ~1G^IZ6  
{ ptCF))Zm'  
nFileLength = getFileSize(); \:vF FK4a  
if(nFileLength == -1) "{0G,tdA  
{ c{q+h V=  
System.err.println("File Length is not known!");
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} &#p1ogf:  
else if(nFileLength == -2) %cF`x_h[j  
{ 4]d^L>  
System.err.println("File is not access!"); #xIg(nG  
} N?\X2J1  
else DB vM.'b$  
{ Q):#6|u+  
for(int i=0;i<nStartPos.length;i++) |x}TpM;ni  
{ Wf~^,]9N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Jh"[ug  
} l}nVWuD  
for(int i=0;i<nEndPos.length-1;i++) Iiy5;:CX:q  
{ 1/dL-"*0  
nEndPos = nStartPos[i+1]; QV|6"4\  
} K?.~}82c  
nEndPos[nEndPos.length-1] = nFileLength; {yn,u)@r9S  
} oz!)x\m*H  
} ~ 'ZwD/!e  
h:Pfiw]  
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//启动子线程 %ZVYgtk;*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; % km<+F=~  
for(int i=0;i<nStartPos.length;i++) |$WH
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{ bT:u|/I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /~LE1^1&U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i"Jy>'  
nStartPos,nEndPos,i); |rx5O5p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `YOYC  
fileSplitterFetch.start(); O8;/oL4 U  
} gM96RY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H,> }t S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sI,cX#h&Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !LKxZ"  
nEndPos = " + nFileLength); "P! .5B  
// fileSplitterFetch[nPos.length-1].start(); Ym'h vK  
,TBOEu."4  
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//等待子线程结束 /?.?1-HM  
//int count = 0; E'6>3n  
//是否结束while循环 >a"J);p  
boolean breakWhile = false; Dk `&tr  

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while(!bStop) c=sV"r?  
{ c>bns/f  
write_nPos(); C'#KTp4!1  
Utility.sleep(500); y##h(y  
breakWhile = true; CW1l;uwtU  
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for(int i=0;i<nStartPos.length;i++) !2t7s96  
{ CCTU-Xz/  
if(!fileSplitterFetch.bDownOver) +\=g&G,  
{ '
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breakWhile = false; h&4s%:_4  
break; LL<xyg
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} t$BjJ -G  
} x?AG*' h&  
if(breakWhile) ;Gr {  
break; 1I%u)[;>  
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//count++; sH6;__e  
//if(count>4) (.-4Jn  
// siteStop(); -
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} D07M!U  
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System.err.println("文件下载结束！"); #*h\U]=VS  
} Vb,VN?l  
catch(Exception e){e.printStackTrace ();} %a/3*vz/I%  
} /A9RmTb  
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//获得文件长度 snaAn?I4  
public long getFileSize() CX]1I|T5  
{ ,X!6|l8  
int nFileLength = -1; :^7w  
try{ xQ
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URL url = new URL(siteInfoBean.getSSiteURL()); 0F[f%2j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Cm[}DB  
httpConnection.setRequestProperty("User-Agent","NetFox"); e:O,$R#g  
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int responseCode=httpConnection.getResponseCode(); ^hLr9k   
if(responseCode>=400) oSCaP,P  
{ Sa g)}6+  
processErrorCode(responseCode); W )FxN,  
return -2; //-2 represent access is error ~qinCIj  
} 9c^,v_W@  
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String sHeader; YTTyMn  
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for(int i=1;;i++) D:T]$<=9  
{ +byOThuE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &ijz'Sg3  
//Utility.log(in.readLine()); kcfT|@:MK"  
sHeader=httpConnection.getHeaderFieldKey(i); Mj@2=c  
if(sHeader!=null) 6n]+(=  
{ >.meecE?Q  
if(sHeader.equals("Content-Length")) XPdmz!,b  
{ |5 V0_79  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <YvXyIs  
break; 6H|1IrG  
} kY)Vr3uGA  
} ?i _ACKpw  
else Z"8lW+r*  
break; 9@|52dz%  
} ! I:N<  
} gG?@_ie  
catch(IOException e){e.printStackTrace ();} E@GYl85fI  
catch(Exception e){e.printStackTrace ();} &N^j }^ Z  
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Utility.log(nFileLength); }Ulxt:}   
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return nFileLength; =v:?rY}  
} s!IIvF  
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//保存下载信息（文件指针位置） A|ZT;\  
private void write_nPos() HPphTu}`  
{ :;_
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try{ 9tHK_),9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ||:>&  
output.writeInt(nStartPos.length); F{x+1hct0  
for(int i=0;i<nStartPos.length;i++) >+{WiZ`  
{ .I^4Fc}&4  
// output.writeLong(nPos); FI^Wh7J  
output.writeLong(fileSplitterFetch.nStartPos); AlQhKL}|s  
output.writeLong(fileSplitterFetch.nEndPos); fOi Rstci  
} SA<\n+>q^  
output.close(); }#^Cj;  
} [QnN1k  
catch(IOException e){e.printStackTrace ();} >M#@vIo?<6  
catch(Exception e){e.printStackTrace ();} ':n`0+Eh  
}
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//读取保存的下载信息（文件指针位置） Cfi4~&  
private void read_nPos() xeF>"6\  
{ %6[,a  
try{ Tf3CyH!k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S/E&&{`ls  
int nCount = input.readInt(); "WKOlfPa  
nStartPos = new long[nCount]; QATRrIj{e  
nEndPos = new long[nCount]; Bc8&-eZ,  
for(int i=0;i<nStartPos.length;i++) J.UNw8z  
{ {]\7 M|9\  
nStartPos = input.readLong(); wa@Rlzij>  
nEndPos = input.readLong(); !Q>xVlPVu  
} { {\oC$  
input.close(); $UzSPhv[  
} EGl<oxL*R2  
catch(IOException e){e.printStackTrace ();} ZS.=GjK  
catch(Exception e){e.printStackTrace ();} M@T{uo  
} as@8L|i*  
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private void processErrorCode(int nErrorCode) 3S3 a|_+%  
{ +<Gp >c  
System.err.println("Error Code : " + nErrorCode); MnD}i&k[  
} <{W{ Y\_A>  
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//停止文件下载 ^=x/:0  
public void siteStop() ;n't:yQW  
{ #]dm/WzY  
bStop = true; 4ior  
for(int i=0;i<nStartPos.length;i++) b|
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fileSplitterFetch.splitterStop(); M+:5gMB'  
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} X2V+c
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} I7_lKr3  
//负责部分文件的抓取 48-j  
**FileSplitterFetch.java ;Ci:d*  
*/ 76D$Nm  
package NetFox; \lg ^rfj  
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import java.io.*; suQTi'K1  
import java.net.*; $R'?OK(`  
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public class FileSplitterFetch extends Thread { N'y<<tTA
 
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String sURL; //File URL -;g
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long nStartPos; //File Snippet Start Position , >WH)+a  
long nEndPos; //File Snippet End Position F`4W5~`  
int nThreadID; //Thread's ID x:-NTW -g  
boolean bDownOver = false; //Downing is over :Fhk$?/r  
boolean bStop = false; //Stop identical :WRD<D_4  
FileAccessI fileAccessI = null; //File Access interface &vmk!wAs  
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r]Hrz'C`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [.>=>KJ_  
{ \V'fB5  
this.sURL = sURL; :C^{L
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this.nStartPos = nStart; Wj3i*x$  
this.nEndPos = nEnd; fwUvFK1G  
nThreadID = id; M5RN Z%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *# <%04f  
} ;4-$C=&  
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public void run() <- sr&  
{ D|U bh]  
while(nStartPos < nEndPos && !bStop) FnVW%fh  
{ \="U|LzG  
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try{ ,6^Xn=o #  
URL url = new URL(sURL); *\+oe+3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9;n*u9<  
httpConnection.setRequestProperty("User-Agent","NetFox"); {[bpvK  
String sProperty = "bytes="+nStartPos+"-"; YVHf-uP  
httpConnection.setRequestProperty("RANGE",sProperty); M4;M.zxJv  
Utility.log(sProperty); ON{a'H  
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InputStream input = httpConnection.getInputStream(); r.u\qPT&  
//logResponseHead(httpConnection); ~[aV\r?  
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byte[] b = new byte[1024]; -d2)  
int nRead; 8.%wnH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C\Ob!sv%H  
{ RV]QVA*i  
nStartPos += fileAccessI.write(b,0,nRead); E@Ewx;P5  
//if(nThreadID == 1) WcXNc`x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \Lbwfd=  
} Az(,Q$"|5  
l  ~xXy<  
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Utility.log("Thread " + nThreadID + " is over!"); gQ{<2u  
bDownOver = true; I"8Z'<|/\q  
//nPos = fileAccessI.write (b,0,nRead); ?#doH,  
} Jp8,s%  
catch(Exception e){e.printStackTrace ();} +wHa)A0MW  
} QYj 4D  
} 'm<L}d  
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//打印回应的头信息 ;Hp78!#,  
public void logResponseHead(HttpURLConnection con) wT3D9N.  
{ 9qzHy}A  
for(int i=1;;i++) wpNb/U  
{  YOfYa  
String header=con.getHeaderFieldKey(i); E+ XR[p  
if(header!=null) Dl\0xcE
  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :.{d,)G  
Utility.log(header+" : "+con.getHeaderField(header)); gtY7N>e  
else ojJuac4  
break; OB+cE4$  
} ^4[QX -_2  
} E=bZ4 /  
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public void splitterStop() gId :IR  
{ $fPiR  
bStop = true; <I?f=[  
} *Hv d  
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} b+dmJ]c  
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/* tPw7zFy6r  
**FileAccess.java ,&@FToR  
*//文件访问(定位，写) k<o<!   
package NetFox; ep l1xfr  
import java.io.*; >;s2V_d  
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public class FileAccessI implements Serializable{ IpKI6[2{`f  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V Kc`mE  
RandomAccessFile oSavedFile; #TgP:t]p  
long nPos; An BM*5G  
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public FileAccessI() throws IOException %P*b&H^0  
{ /pGx!  
this("",0); V%^d~^m,H  
} K$$%j"s
 
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public FileAccessI(String sName,long nPos) throws IOException e.|t12)L "  
{ B+'w'e$6  
oSavedFile = new RandomAccessFile(sName,"rw"); U71A#OD^U  
this.nPos = nPos; +J !1z  
oSavedFile.seek(nPos); )VG_Y9;Xk:  
} ggHl{cl)  
z+?48}  
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public synchronized int write(byte[] b,int nStart,int nLen) y8|}bd<Sr  
{ <FvljKuq+  
int n = -1; h*mKS -TC  
try{ }sfvzw_  
oSavedFile.write(b,nStart,nLen); tkdyR1-  
n = nLen; ZZ].h2=K  
} tQ2S*]"f  
catch(IOException e) {6wy}<ynC+  
{ y$?O0S%F  
e.printStackTrace (); SsIN@  
} 8WG_4e  
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return n; @])}+4D(S  
} 0MOn>76$N  
X
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} c=IjR3F  
l @r`NFWD@  
9
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/* #Xun>0  
**SiteInfoBean.java Ozc9yy!%  
*/ }ev+WIERQV  
package NetFox; V8z*mn
D  
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`)1qq @  
public class SiteInfoBean { R!_1*H$  
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private String sSiteURL; //Site's URL S2 YxA  
private String sFilePath; //Saved File's Path z&A#d  
private String sFileName; //Saved File's Name A@I3:V  
private int nSplitter; //Count of Splited Downloading File toC|vn&P  
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public SiteInfoBean() > ,P,{"  
{//nSplitter的缺省值为5 :J6FI6  
//default value of nSplitter is 5 [N*`3UZk"  
this("","","",5); LQa1p  
} q62U+o9G  
kX'a*AG  
!Ka~X!+\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X0%BE!  
{ <+; cgF!+  
sSiteURL= sURL; 1?#Wg>7'  
sFilePath = sPath; T`|>oX  
sFileName = sName; v|YJ2q?19  
this.nSplitter = nSpiltter; >4AwjS}H  
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4 !M6RL8{  
} SCD;(I~4  
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~2?UEv6  
public String getSSiteURL() R2nDK7j  
{ 'lR
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return sSiteURL; bn"z&g  
} [wjH;f>SQ  
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public void setSSiteURL(String value) 82Nw6om6i  
{ mi{ r7.e5I  
sSiteURL = value; dZjh@yGP.  
} 3ocRq %%K  
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public String getSFilePath() d`4@aoM  
{ 3`\)Qm  
return sFilePath; ~qmu?5  
} +\`t@Ht#  
~6:y@4&F  
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public void setSFilePath(String value) AA0zt N  
{ <\5Y~!)  
sFilePath = value; 834dsl+U  
} H!ISQ8{V  
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public String getSFileName() <E&"]  
{ 7Ke#sW.HN  
return sFileName; db.E-@W.OI  
} vdN0YCXG  
C:d$
 
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public void setSFileName(String value) y[@<goT  
{ )|zna{g\  
sFileName = value; C]+T5W\"<B  
} &OSyU4r  
b/Z0{38  
y:+s*x6Vg  
public int getNSplitter() ,0Y5O?pu\  
{ qP0_#l&  
return nSplitter; )\TI^%s  
} \3@AC7  
\aO.LwYm;:  
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public void setNSplitter(int nCount) %L9A6%gr  
{ mjq
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nSplitter = nCount; ly]n2RK  
} #TX=%x6  
} H-,RzL/  
nC5  
a/wkc*}}/  
/* 5CsJghTw  
**Utility.java IFY,j8~q  
*/ b]h]h1~hHH  
package NetFox; afMIqQ?  
5PQs1B  
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public class Utility { KD~F5aS`[  
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public Utility() SdfrLdi}Y  
{ X=p~`Ar M{  
:>[;XT<  
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} f9FsZD  
fodr1M4J  
//线程睡眠 Ir*,fyl  
public static void sleep(int nSecond) M#qZ0JT4  
{ 1& k_&o  
try{ I^
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Thread.sleep(nSecond); X3:-+]6,d  
} BK'!WX  
catch(Exception e) N3nk\)V\E  
{
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e.printStackTrace (); ,diV;d  
} jBEt!Azur  
} LTY@}o]\U  
Nky%v+r  
//日志 V\kf6E  
public static void log(String sMsg) e3wFi,/@  
{ y)v'0q  
System.err.println(sMsg); x c-=;|s  
} ujcNSX*  
@Ey(0BxNu  
+MQf2|--  
public static void log(int sMsg) ?|:!PF*L~z  
{ UJ)\E ^Hp  
System.err.println(sMsg); mV;Egm{A\  
} ~R)Km`t  
} 1C=}4^Pu  
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/* $Tq-<FbM)  
**TestMethod.java =?57*=]0M  
*/ / GJ"##<  
package NetFox; 5-w6(uu  
;P _`4w3  
FI~)ZhE)]  
public class TestMethod { _qmBPUx  
"31GC7  
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public TestMethod() g?i_10Xlp  
{ ///xx/weblogic60b2_win.exe ^<<( }3  
try{ |n=kYs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (^9q7)n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _q=$L eO5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KL0u:I(lWU  
fileFetch.start(); ,I@4)RSAH|  
} $Kb-mFR  
catch(Exception e){e.printStackTrace ();} :H\6wJ  
tB[(o%k  
~@bCSOIy  
} G+'MTC_  
42Vy#t/HC  
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public static void main(String[] args) N"T~U\R  
{ =o_d2Ak  
new TestMethod(); kd'qYh  
} ,h5.Si>  
} 60teD>Eh,  
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