http断点续传简单实现（java)

/* mfCp@1;26  
**SiteFileFetch.java 2U.'5uA"L  
*/ ;G|#i?JJ  
package NetFox; yeqHeZ  
import java.io.*; x,:DL)$1  
import java.net.*; 5~GH*!h%;  
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public class SiteFileFetch extends Thread { 5e}adHjM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &Xh_`*]ox  
long[] nStartPos; //开始位置 &.1qixXIr  
long[] nEndPos; //结束位置 N/6!|F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^Cy=L]  
long nFileLength; //文件长度 <kOdd)X  
boolean bFirst = true; //是否第一次取文件 PQJw"[N/YM  
boolean bStop = false; //停止标志 <`'T#e$  
File tmpFile; //文件下载的临时信息 ;(r,;S_`0  
DataOutputStream output; //输出到文件的输出流 5u=>~yK+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 51-@4E2:l:  
public SiteFileFetch(SiteInfoBean bean) throws IOException kr>4%Ndm7  
{ :erfs}I  
siteInfoBean = bean; V 0z`p"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Cm%|hk>fQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,4--3 MU  
if(tmpFile.exists ()) GW,RE\Q:  
{ <\`qRz0/  
bFirst = false; "el}9OitC  
read_nPos(); ~1:_wni  
} ^2C \--=;  
else yIYQ.-DkS+  
{ _?v&\j  
nStartPos = new long[bean.getNSplitter()]; !q!5D`  
nEndPos = new long[bean.getNSplitter()]; h,|. qfUk  
} >["X(%&w  
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} QERj`/
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public void run() F[KM0t!  
{ H/}W_ h^^  
//获得文件长度 bJoP@s  
//分割文件 +$$5Cv5#<&  
//实例FileSplitterFetch &lnM 1W  
//启动FileSplitterFetch线程 COA*Q  
//等待子线程返回 g&I
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try{ 7sq15oL  
if(bFirst) {PKf]m  
{ xSrjN  
nFileLength = getFileSize(); EGVS8YP>h  
if(nFileLength == -1) %l[]n;
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{ IoZ_zz0  
System.err.println("File Length is not known!"); yT|44 D2j  
} ~,7Tj  
else if(nFileLength == -2) TeRH@oI  
{ *i>hFNLdOM  
System.err.println("File is not access!"); mO2u9?N  
} i}5M'~F  
else .z[#j]k  
{ 2Mu@P8O&  
for(int i=0;i<nStartPos.length;i++) SZvp%hS0  
{ bbT1p:RF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a66Ns7Rb  
} EY^?@D_<  
for(int i=0;i<nEndPos.length-1;i++) ;FJFr*PM  
{ :.u2^*<  
nEndPos = nStartPos[i+1]; Q^*4
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} Irui{%T  
nEndPos[nEndPos.length-1] = nFileLength; %bS1$ v\n  
} p<+Y;,+  
} !P3y+;S  
sQ.t3a3m  
57KrDxE}  
//启动子线程 }W0_eQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NMS+'GRW  
for(int i=0;i<nStartPos.length;i++) YC(X= D  
{ wxJo
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <99/7>#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k$GtzjN
 
nStartPos,nEndPos,i); 2~R%_r+<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Q\ hd*+g  
fileSplitterFetch.start(); wjXv{EsMq  
} #v; :K8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =IKgi-l*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Gk xtGe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wg<t*6&'x  
nEndPos = " + nFileLength); 45k.U$<|  
// fileSplitterFetch[nPos.length-1].start(); <}T7;knO  
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+j %y#_~  
//等待子线程结束 A76HM@Q  
//int count = 0; %aV~RB#  
//是否结束while循环 ^1yD&i'q  
boolean breakWhile = false; !%[fi[p  
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while(!bStop) ^*w}+tB  
{ "T*1C=  
write_nPos(); sX-@ >%l  
Utility.sleep(500); 3m$ck$  
breakWhile = true; axOEL:-|Bu  
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for(int i=0;i<nStartPos.length;i++) N<b~,[yCd>  
{ 7Ck3L6J#  
if(!fileSplitterFetch.bDownOver) ZQ>Q=eCs 1  
{ 9Y@ eXP  
breakWhile = false; B#?rW*yEe  
break; 'S|7<<>4k  
} +,cd$,18  
} \_YDSmjy  
if(breakWhile) wbvOf X  
break; ksTK'7*  
4)8e0L*[B?  
HYL['B?Wid  
//count++; 8/T,{J\  
//if(count>4) PEg]z  
// siteStop(); 4Y1dkg1y  
} ZtmaV27s/  
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System.err.println("文件下载结束！"); Te`@{>  
} e^,IZ{  
catch(Exception e){e.printStackTrace ();} TY%=Y=  
} !l]_c5  
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//获得文件长度 " %qr*
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public long getFileSize() :K5?&kT  
{ D)Ep!`Q   
int nFileLength = -1; )U7fPKQ  
try{ 1wm`a  
URL url = new URL(siteInfoBean.getSSiteURL()); ^!x! F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8]oolA:^4s  
httpConnection.setRequestProperty("User-Agent","NetFox"); "0,FB4L[U5  

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int responseCode=httpConnection.getResponseCode(); R:3=!zav  
if(responseCode>=400) IRueq @4  
{ g5RH:]DV  
processErrorCode(responseCode); KMK8jJ  
return -2; //-2 represent access is error ^tjw }sE  
} SUv'cld  
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String sHeader; vCNq2l^CW  
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for(int i=1;;i++) axDa&7%  
{ >rJ**y
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cGR)$:  
//Utility.log(in.readLine()); #C~ </R%  
sHeader=httpConnection.getHeaderFieldKey(i); c*]f#yr?  
if(sHeader!=null) gcB hEw  
{ W#E(?M[r  
if(sHeader.equals("Content-Length")) h"/'H)G7_&  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xs# _AX  
break; JWYe~  
} J@"UFL'^  
} ,RM8D)m\  
else \I-e{'h  
break; #p7gg61  
} QqRF?%7q"q  
} cTS.yN({G  
catch(IOException e){e.printStackTrace ();} \#WWJh"W  
catch(Exception e){e.printStackTrace ();} jvAjnh#  
;]b4O4C\  
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Utility.log(nFileLength); a
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return nFileLength; ?qi~
8.<w  
} K~2sX>l  
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//保存下载信息（文件指针位置） (z.n9lkfi  
private void write_nPos() ZNM9@;7  
{ |TP,  
try{ ^,mN-.W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lM}-'8tt?  
output.writeInt(nStartPos.length); iF":c}$.  
for(int i=0;i<nStartPos.length;i++) /H"fycZ  
{ )Tp"l"(G  
// output.writeLong(nPos); 09trFj$L
 
output.writeLong(fileSplitterFetch.nStartPos); 7(uz*~Z?`0  
output.writeLong(fileSplitterFetch.nEndPos); dP+wcl4  
} U#]J5'i  
output.close(); B :S8{  
} de)4)EzUP  
catch(IOException e){e.printStackTrace ();} c;Tp_e@  
catch(Exception e){e.printStackTrace ();} x,]x>Up  
} U\B9Ab  
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//读取保存的下载信息（文件指针位置） ok0ZI>=,  
private void read_nPos() J*MH`;-  
{ a/J Mg  
try{ 0nL #-`S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Yj*T'<e  
int nCount = input.readInt(); ~CbiKez  
nStartPos = new long[nCount]; pgiZA?r*<  
nEndPos = new long[nCount]; 2O*At%CzW  
for(int i=0;i<nStartPos.length;i++) 6W{Nw<  
{ +Ugy=678Tr  
nStartPos = input.readLong(); > Xh=P%  
nEndPos = input.readLong(); jex\5  
} !=
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input.close(); @TD=or .&  
} O39   
catch(IOException e){e.printStackTrace ();} s~2o<#  
catch(Exception e){e.printStackTrace ();} 7<*0fy5nn  
} _z8"r&  
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private void processErrorCode(int nErrorCode) `B4Ilh"d  
{ ~3M8"}X;L  
System.err.println("Error Code : " + nErrorCode); {6GX ?aw'  
} az:}RE3o  
1 :$#a  
)^AZmUYZ  
//停止文件下载 \8!CKnfs  
public void siteStop() {U$XHG  
{ R]e&JoY  
bStop = true; LH)1IGAx2y  
for(int i=0;i<nStartPos.length;i++) i
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fileSplitterFetch.splitterStop(); axph]o@ y@  
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} /<n7iIK)  
} M>Tg$^lm  
//负责部分文件的抓取 }2LWDQ;po  
**FileSplitterFetch.java u"(NN9s  
*/ Y'~O_coG  
package NetFox; EyVu-4L:#  
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import java.io.*; 7gN;9pc$  
import java.net.*; pZopdEFDK|  
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public class FileSplitterFetch extends Thread { IqFcr
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String sURL; //File URL )
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long nStartPos; //File Snippet Start Position l7jen=(Zb;  
long nEndPos; //File Snippet End Position VgIk'.  
int nThreadID; //Thread's ID H`fJ<So?  
boolean bDownOver = false; //Downing is over }|2A6^F
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boolean bStop = false; //Stop identical {*F =&D  
FileAccessI fileAccessI = null; //File Access interface 9x!kvB6  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KYw7Jx`l  
{ iY$iL<  
this.sURL = sURL; E56  
this.nStartPos = nStart; ^pd7nr~Y  
this.nEndPos = nEnd; %q3`k#?<  
nThreadID = id; .O'~s/h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aT IzfqCM  
} yP# Y:s  
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public void run() /7\q#qIm:  
{ Qt{){u
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while(nStartPos < nEndPos && !bStop) mY/"rm  
{ Q"~%T@e  
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try{ O2ktqAWx@  
URL url = new URL(sURL); >I5Wf/$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J-'XT_k:iM  
httpConnection.setRequestProperty("User-Agent","NetFox"); J/K~8sc  
String sProperty = "bytes="+nStartPos+"-"; 1}Q9y`65  
httpConnection.setRequestProperty("RANGE",sProperty); &.DRAD)  
Utility.log(sProperty); 7r'_p$  
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InputStream input = httpConnection.getInputStream(); /huh}&NNu  
//logResponseHead(httpConnection); n0co* ]X+k  
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byte[] b = new byte[1024]; aWJ BYw6{L  
int nRead; c8[kL$b;j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OYt_i'Q  
{ 5PZ7-WJ/  
nStartPos += fileAccessI.write(b,0,nRead); L-E?1qhP>  
//if(nThreadID == 1) R|8L'H+1x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .rO~a.kG  
} 2bTS,N/>  
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Utility.log("Thread " + nThreadID + " is over!"); yH-&o,  
bDownOver = true; = FV12(U  
//nPos = fileAccessI.write (b,0,nRead); ,~38IIS>_  
} B*O/>=_  
catch(Exception e){e.printStackTrace ();} 0n6eWwY  
} CKZEX*mPC  
} oY0b8=[  
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//打印回应的头信息 N".BC|r  
public void logResponseHead(HttpURLConnection con) iOEBjj;C  
{ :3R3>o6m  
for(int i=1;;i++) O>hh  
{ `ql8y'  
String header=con.getHeaderFieldKey(i); U4-RI]Cpf  
if(header!=null) ]!sCWR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BC_<1 c  
Utility.log(header+" : "+con.getHeaderField(header)); k6z ]-XG  
else qS! Lt3+  
break; ~=
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} -f ~1Id  
} zE1=P/N  
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public void splitterStop() Ru#pJb(R  
{ tzd!r7  
bStop = true; bcwb'D\a  
} c-&Q_lB  
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} qvo!nr7  
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/* RAu(FJ  
**FileAccess.java '[8w8,v(  
*//文件访问(定位，写) @<$m`^H
 
package NetFox; z.RM85?T  
import java.io.*; b49h @G  
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public class FileAccessI implements Serializable{ V*O[8s%5v  
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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 ;:oJFI#;  
RandomAccessFile oSavedFile; {`*Fu/Upb  
long nPos; +924_,zF  
"2-D[rYZ  
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public FileAccessI() throws IOException mDp8JNJNE  
{ {g[kn^|  
this("",0); ndDF(qHr  
} "AXgT[ O  
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public FileAccessI(String sName,long nPos) throws IOException >)NS U  
{ 'L7u`  
oSavedFile = new RandomAccessFile(sName,"rw"); @N<h`vDa  
this.nPos = nPos; dQrz+_  
oSavedFile.seek(nPos); ;AVIt!(L~V  
} LU8[$.P  
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public synchronized int write(byte[] b,int nStart,int nLen) -&1P2m/46  
{ wsQuJrG  
int n = -1; QX}J
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try{ (U$;0`  
oSavedFile.write(b,nStart,nLen); /%7&De6Xg  
n = nLen; 7D>_<)%d=  
} 95j
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catch(IOException e) Tr}XG  
{ V>obMr^5  
e.printStackTrace (); u' kG(<0Y  
} B0Z>di:  
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return n; X-" +nThMn  
} N}#"o  
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} x)eF{%QB  
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/* {"$[MYi:  
**SiteInfoBean.java h:G>w`X  
*/ :|ahu  
package NetFox; 6XCFL-o-  
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public class SiteInfoBean { 3HcduJntl  
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private String sSiteURL; //Site's URL r: >RH,  
private String sFilePath; //Saved File's Path mqsAYzG  
private String sFileName; //Saved File's Name ^[bFGKE  
private int nSplitter; //Count of Splited Downloading File #UwX~  
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YuIF}mUr"  
public SiteInfoBean() >)diXe}j  
{//nSplitter的缺省值为5 +03/A`PKrB  
//default value of nSplitter is 5 6;s[dw5T  
this("","","",5); W?kJ+1"(  
} tEo-Mj5:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2T?Y  
{ T fIOS]  
sSiteURL= sURL; [Pjitw/?  
sFilePath = sPath; [.Fq l+  
sFileName = sName; @VG@|BQWa  
this.nSplitter = nSpiltter; tq'ri-c&b  
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1\aTA,  
} dXM8
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public String getSSiteURL() AX1!<K  
{ ?fC9)s  
return sSiteURL; d8 Jf3Mo  
} ?D)$OCS  
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public void setSSiteURL(String value) O8" t.W  
{ o%;ly  
sSiteURL = value; ~a_X 7
 
} /|}yf/^9X  
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public String getSFilePath() 'PFjZGaKR  
{ q`L)^In"  
return sFilePath; Qmo}esb'(  
} #QcRN?s  
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public void setSFilePath(String value) i_r708ep6  
{ jpZq]E9`P  
sFilePath = value; ' i5KRFy-  
} ?Y8hy|`  
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public String getSFileName() kFmtE dhsc  
{ * ]bB7  
return sFileName; QZ;DZMP  
} P,-5af*;  
8>x'. 8  
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public void setSFileName(String value) bE2O[B  
{ R'>@ja*  
sFileName = value; 6H  U*,  
} \~Z%}$ =  
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public int getNSplitter() O_.!qk1R  
{ OyK#Rm2A=  
return nSplitter; eu_ZsseZ  
} C%]qK(9vvd  
f`/('}t  
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public void setNSplitter(int nCount) !'BXc%`x[  
{ O j:I @c  
nSplitter = nCount; X9FO"(J  
} nIfAG^?|*  
} !V/\_P!I  
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/* X;)/<:mX  
**Utility.java ceCO*m~  
*/ qS!N\p~>  
package NetFox; `0M6<e]C  
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public class Utility { u'_}4qhCC;  
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public Utility() Mb\(52`)Q  
{ ,>kVVp
u  
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0hGmOUO  
} UXpp1/d|e  
vF'>?O?  
//线程睡眠 ;sAGTq  
public static void sleep(int nSecond) wik<#ke  
{ C|3Xz[k{  
try{ ZxT E(BQv  
Thread.sleep(nSecond); BQg3+w:>  
} &V(6N%A^U  
catch(Exception e) vS0 ii  
{ !-3;Qj}V  
e.printStackTrace (); Y\B6c
^E)  
} Z^as ?k(iM  
} il!B={  
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//日志 5<v1v
&  
public static void log(String sMsg) ^5TVm>F@3  
{ q jc4IW t~  
System.err.println(sMsg); Cfd* Q  
} ~AX~z)  
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NjEi.]L*fX  
public static void log(int sMsg) xYYa%PhIC  
{ IHd W!q  
System.err.println(sMsg); "P(obk  
} $rr@3H+  
} m26YAcip}  
+>!nqp  
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/* '
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**TestMethod.java *kqC^2t  
*/ t? 6 et1~  
package NetFox; >jIn&s!}  
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public class TestMethod { <Ohi+a%6  
r#)1/`h  
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public TestMethod() kln)7SzPuk  
{ ///xx/weblogic60b2_win.exe Bh cp=#  
try{ ZnI15bsDx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `kQosQV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 457{9k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 81s }4  
fileFetch.start(); w@cW`PlF  
} v]F4o1ckk  
catch(Exception e){e.printStackTrace ();} t4v'X}7q]  
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$>O~7Nfst7  
} !R\FCAW[x  
9.M'FCd~M  
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public static void main(String[] args) \#dacQ2E@  
{ jLVD37 P^  
new TestMethod(); =%IyR  
} 6Nn+7z<*&z  
} 8t*sp-cy|  
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