http断点续传简单实现（java)

/* J6)efX)j-p  
**SiteFileFetch.java {E3xI2  
*/ Ne &Xf  
package NetFox; o,?!"*EP  
import java.io.*; ]regi- LGU  
import java.net.*; DAjG*K{  
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public class SiteFileFetch extends Thread { x r-;,W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )ZT6:)  
long[] nStartPos; //开始位置 5z1\#" B[  
long[] nEndPos; //结束位置 ~
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 q%OcLZ<,  
long nFileLength; //文件长度 4t&gW  
boolean bFirst = true; //是否第一次取文件 FjD,8^SQW  
boolean bStop = false; //停止标志 Z{Vxr*9oO  
File tmpFile; //文件下载的临时信息 FovE$Dj]  
DataOutputStream output; //输出到文件的输出流 OZ(Dpx
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Ho|o,XvLv  
public SiteFileFetch(SiteInfoBean bean) throws IOException N7e`6
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{ ~gu=x&{  
siteInfoBean = bean; I*^5'N'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); siZr@g!L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C-Nuy1o  
if(tmpFile.exists ()) lbQ6 a  
{ AI&qU/}  
bFirst = false; \bU`  
read_nPos(); yJDeX1+,  
}
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else O{PW  
{ nAIH`L"X  
nStartPos = new long[bean.getNSplitter()]; rlR !&  
nEndPos = new long[bean.getNSplitter()]; 9wAA. -"  
} "Z;~Y=hC13  
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} ki\B!<uv  
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public void run() J4YT)-  
{ *R5`.j =  
//获得文件长度 t:\l&R&  
//分割文件 _~tm7o+js  
//实例FileSplitterFetch fZ[kh{|  
//启动FileSplitterFetch线程 y&1%1 #8F  
//等待子线程返回 i][f#e4  
try{ ID)^vwn  
if(bFirst) t2"@Ps&1|  
{ qv *3A?uzr  
nFileLength = getFileSize(); g.9L)
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if(nFileLength == -1) As0 B\  
{ F7\BF  
System.err.println("File Length is not known!"); Takt_N  
} gXLCRn!iR  
else if(nFileLength == -2) A'GlCp  
{ 5gSylts8  
System.err.println("File is not access!"); {1jpLdCbV^  
} q^5yk=2fq  
else X` ATH^S  
{ >L^xlm%7o  
for(int i=0;i<nStartPos.length;i++) |
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{ q7|:^#{av  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J5;5-:N  
} xZX`%f-  
for(int i=0;i<nEndPos.length-1;i++) s8^~NX(xdy  
{ Q8;#_HE  
nEndPos = nStartPos[i+1]; (/&;jV2DD[  
} ^pj>9%  
nEndPos[nEndPos.length-1] = nFileLength; /-Wuq`P/ T  
} ;>DHD*3X  
} (qUK7$  
}g>kpa0c  
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//启动子线程 @}(SR\~N]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; flP>@i:e6  
for(int i=0;i<nStartPos.length;i++) zDB
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{ h}h^L+4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s D_G)c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b4C
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nStartPos,nEndPos,i); I FsE!oDs4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  r@k"4ce-  
fileSplitterFetch.start(); #,&8&  
} ]BfS270  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -^Xy%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -j&
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .Rvf/-e  
nEndPos = " + nFileLength); 8.yCA  
// fileSplitterFetch[nPos.length-1].start(); za T_d/?J  
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//等待子线程结束 jJia.#.Ze  
//int count = 0; qz`rL#W]  
//是否结束while循环 Q/py qe G  
boolean breakWhile = false; qEQAn/&  
\]8VwsP  
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while(!bStop) `a >?UUT4  
{ qp>N^)>
 
write_nPos(); -(9O6)Rs$  
Utility.sleep(500); 7Lg7ei2mN7  
breakWhile = true; D,Lp|V  
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for(int i=0;i<nStartPos.length;i++) F;P5D<  
{ hU"F;4p  
if(!fileSplitterFetch.bDownOver) o\4CoeG  
{ SNab   
breakWhile = false; 0/Z !5-.  
break; hsz^rZ  
} Qs l80~n_7  
} Q_]~0PoH  
if(breakWhile) 6aY>lkp  
break;  q>-R3HB  
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//count++; 4&{!M _  
//if(count>4) w{`Acu  
// siteStop(); PNpu*#Z`  
} qnJ50 VVW  
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System.err.println("文件下载结束！"); &yU>2=/T  
} 5/?P|T  
catch(Exception e){e.printStackTrace ();} ]JdJe6`Mc  
} ,?(ciO)  
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P
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//获得文件长度 uw33:G  
public long getFileSize() 514Z<omrK  
{ mb1Vu  
int nFileLength = -1; MQ`%``  
try{ YJ,*(A18  
URL url = new URL(siteInfoBean.getSSiteURL()); (.?ZKL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ubbnFE&PD  
httpConnection.setRequestProperty("User-Agent","NetFox"); GoIQ>n
 
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. I==-|  
int responseCode=httpConnection.getResponseCode(); ,h&a9:+i  
if(responseCode>=400) ?:igumeYX  
{ E'EcP4eL  
processErrorCode(responseCode); gn)R^  
return -2; //-2 represent access is error !D:Jbt@R<n  
} S!hXf|*0[  
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,mKObMu  
String sHeader; yMxT
fR  
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for(int i=1;;i++) f%XJ;y\,9H  
{ H0>yi[2f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f~ZEdq8  
//Utility.log(in.readLine());  hw=GR_,  
sHeader=httpConnection.getHeaderFieldKey(i); 0V`[Zgf  
if(sHeader!=null) dv!r.  
{ L:@fP~Erh  
if(sHeader.equals("Content-Length")) }y6q\#G  
{ #U ASH&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bL1m'^r  
break; VagT_D  
} zzIr2so  
} ~<)vKk  
else HBiBv-=,  
break; ho
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} <)U4Xz?  
} 5 1dSFr<#  
catch(IOException e){e.printStackTrace ();} `1+F,&e  
catch(Exception e){e.printStackTrace ();} fS=hpL6]@  
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Utility.log(nFileLength); QyGnDomQ  
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return nFileLength; nidr\oFUIn  
} , ZFE(  
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//保存下载信息（文件指针位置） Riry_   
private void write_nPos() lzhqcL"  
{ vmX"+sHz$]  
try{ Hd &{d+B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f p[,C1U  
output.writeInt(nStartPos.length); z|N3G E(.@  
for(int i=0;i<nStartPos.length;i++) rHz||jjU  
{ Q5a)}6-5  
// output.writeLong(nPos); ?LP9iY${  
output.writeLong(fileSplitterFetch.nStartPos); u:dx;*  
output.writeLong(fileSplitterFetch.nEndPos); cWLqU  
} BVpO#c~I  
output.close(); ~*.-  
} '@=PGpRF  
catch(IOException e){e.printStackTrace ();} $`J_:H%  
catch(Exception e){e.printStackTrace ();} X}A'Cg0y  
} V/%~F6e  
V diJ>d[  
=,V|OfW  
//读取保存的下载信息（文件指针位置） /4irAG% Oj  
private void read_nPos() M(Zc^P}N  
{ I#rubAl  
try{ $}o b,i^W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sa&) #Z:  
int nCount = input.readInt(); bC6oqF'#  
nStartPos = new long[nCount]; l"+Jc1\X  
nEndPos = new long[nCount]; SA"8!soY3  
for(int i=0;i<nStartPos.length;i++) *d*,Hqn  
{ H/fUM  
nStartPos = input.readLong(); ?cy4&]s  
nEndPos = input.readLong(); @It>*B yB.  
} & E}mX]t  
input.close(); ZH 6\><My  
} fV\]L4%  
catch(IOException e){e.printStackTrace ();} DN] v_u+}  
catch(Exception e){e.printStackTrace ();} "TOa=Tt{,  
} p&b5% 4P  
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</`yd2>
 
private void processErrorCode(int nErrorCode) g(E"4M@t!  
{ v|';!p|  
System.err.println("Error Code : " + nErrorCode); ^Q}eatEn  
} gl%`qf6:O  
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v6=-g$FG  
//停止文件下载 j2 %^qL  
public void siteStop() \cJa;WM>  
{ Dt|)=a  
bStop = true; EHf\L  
for(int i=0;i<nStartPos.length;i++) `'S0*kMT  
fileSplitterFetch.splitterStop(); *%5{'  
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} *m+BuGt|  
} }T_Te?<&  
//负责部分文件的抓取 p9eRZVy/  
**FileSplitterFetch.java c3TKl/  
*/ #FxPj-3(ix  
package NetFox; jM)C4ii.-$  
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import java.io.*; f58?5(Dc|  
import java.net.*; 2{|$T2?e  
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public class FileSplitterFetch extends Thread { ;q>9W,jy  
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String sURL; //File URL Xd `vDgD  
long nStartPos; //File Snippet Start Position $A_]:qI2  
long nEndPos; //File Snippet End Position %kshQ%P)?  
int nThreadID; //Thread's ID Q>< 0[EPj3  
boolean bDownOver = false; //Downing is over T1WWK'  
boolean bStop = false; //Stop identical *iA4:EIP  
FileAccessI fileAccessI = null; //File Access interface (qMj-l  
,M5}4E7L%s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !~i' -4]  
{ bC!`@/  
this.sURL = sURL; OX]V)QHVZ  
this.nStartPos = nStart; c
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this.nEndPos = nEnd; =@x`?oev  
nThreadID = id; &DG->$&|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o`S?  
} 7r#ymQ  
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public void run() lCd@jB{  
{ }n:?7  
while(nStartPos < nEndPos && !bStop) >R,'5:Rw  
{ _*M42<wcO  
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try{ HvwYm.$zE  
URL url = new URL(sURL); `mfq 2bVc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y*oDO$6  
httpConnection.setRequestProperty("User-Agent","NetFox"); uP $Cj  
String sProperty = "bytes="+nStartPos+"-"; [(kB 5 a  
httpConnection.setRequestProperty("RANGE",sProperty); CG\tQbum  
Utility.log(sProperty); CK+d!Eg  
@&F@I3`{  
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InputStream input = httpConnection.getInputStream(); 2NGeC0=  
//logResponseHead(httpConnection); E_z;s3AXQ  
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#65^w=Sp}  
byte[] b = new byte[1024]; {@Yb%{+  
int nRead; 8LkP)]4^sO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IA zZ1#/3  
{ W<ZK,kv  
nStartPos += fileAccessI.write(b,0,nRead); `$LWmm#  
//if(nThreadID == 1) 6DIZ@oi  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~5 N)f UI\  
} -/C)l)V}  
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Utility.log("Thread " + nThreadID + " is over!"); lT&wOm3  
bDownOver = true; ^g1f X1  
//nPos = fileAccessI.write (b,0,nRead); S{]7C?4`  
} u9woEe?  
catch(Exception e){e.printStackTrace ();} Jq.lT(E8D  
} $3T_.  
} ,fDEz9-,  
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//打印回应的头信息 3f Xv4R;!:  
public void logResponseHead(HttpURLConnection con) Am0{8
'  
{ Qhi '')Q  
for(int i=1;;i++) KOq
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{ lASL8O&\  
String header=con.getHeaderFieldKey(i); n]_[NR) i  
if(header!=null) rPNb\Ri  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 63|+2-E2Q  
Utility.log(header+" : "+con.getHeaderField(header)); O%~jop7#6  
else `vG,}Pt]  
break; v44}%$  
} XKA&XpF  
} 5vAf7\*  
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rB~W Iu  
public void splitterStop() j:T/iH!YF  
{ AUVgPXOwd  
bStop = true; lE8&..~l$+  
} qW:)!z3\  
1 2++RkL#  
up
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} -4rDbDsr  
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/* 1axQ)},o@p  
**FileAccess.java Ab%;Z5$fr  
*//文件访问(定位，写) jCAC `  
package NetFox; 4(neKr5\#  
import java.io.*; =p^He!  
jr7C}B-Fb^  
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public class FileAccessI implements Serializable{ H7Uli]e3  
p^nL&yIW,%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E9|eu\  
RandomAccessFile oSavedFile; 4h!f/aF'  
long nPos; ,/&'m13b/L  
l.\r
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public FileAccessI() throws IOException 1aVa0q<  
{ J`q]6qf#  
this("",0); pMg3fUIM  
} zsU=sTsL  
n%R;-?*v  
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public FileAccessI(String sName,long nPos) throws IOException zl-2$}<a  
{ cfox7FmW  
oSavedFile = new RandomAccessFile(sName,"rw"); ]eQV,Vt  
this.nPos = nPos; {8,<ZZ_  
oSavedFile.seek(nPos); 5(W"-A}  
} J89Dull  
@~<j&FTT  
& gJV{V5Ay  
public synchronized int write(byte[] b,int nStart,int nLen) ""Zp:8o  
{ =1I#f  
int n = -1; 50TA:7  
try{ ~U(,TjJb  
oSavedFile.write(b,nStart,nLen); {e|*01hE  
n = nLen; .6O"| Mqb  
} o-xDh7v  
catch(IOException e) di)*-+  
{ 9!9Z~/*m  
e.printStackTrace (); ZvYLL{>}w  
} j*
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return n; ZKQ hbNT  
} }>^Q'BW;65  
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{7cX#1  
} EM7+VO(  
6Ao%>;e*  
LA_3=@2.H  
/* n .!Ym X4  
**SiteInfoBean.java *`j-i  
*/ _A<u#.yd  
package NetFox; }?cGf-c  
tt%MoQ)  
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public class SiteInfoBean { JOjoiA  
5Zmw} M  
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private String sSiteURL; //Site's URL tNsPB6Z  
private String sFilePath; //Saved File's Path ,D\GGRw  
private String sFileName; //Saved File's Name nA|.t  
private int nSplitter; //Count of Splited Downloading File <APB11  
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>FhK#*Pa  
public SiteInfoBean() ,f}UGd[a  
{//nSplitter的缺省值为5 ug{R 3SS  
//default value of nSplitter is 5 7NC=*A~  
this("","","",5); < B_Vc:Q  
} K =.%$A  
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s[8@*/ds  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2&+#Vsm`V  
{ Auy_K?he]  
sSiteURL= sURL; T081G`li  
sFilePath = sPath; J7C4V'_  
sFileName = sName; yCJFo  
this.nSplitter = nSpiltter; r]W  
7nbB^2  
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} >0{S  
U yw-2]!n  
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public String getSSiteURL() pLMRwgzr  
{ KXV[OF&J  
return sSiteURL; AtR?J"3E  
} <I}2k  
t}v2$<!I  
b{fQ|QD{^E  
public void setSSiteURL(String value) @fuM)B1"  
{ X7,
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sSiteURL = value; Q'k\8'x  
} [4fU+D2\d  
p8
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"<}&GcJbz  
public String getSFilePath() J5h+s-'  
{ &V|>dLT>A  
return sFilePath; 5Z4-Z  
} "Jjs"7  
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public void setSFilePath(String value) j)t+jcMUI  
{ & cNy  
sFilePath = value; Mv c`)_Md  
} +0),xu   
;['[?wk  
0&ByEN99  
public String getSFileName() @!&}}"<  
{ O]f/r,4@  
return sFileName; \rykBxs  
} m
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public void setSFileName(String value) lTU$0CG  
{ E~<`/s  
sFileName = value; IrMl:+t\  
} RE.r4uOJg  
uxg9yp@|  
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public int getNSplitter() dD<fn9t  
{ \c[IbL07  
return nSplitter; Mg#j3W}]  
} 2MA]jT  
#_mi `7!B#  
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public void setNSplitter(int nCount) qS&%!  
{ r_EcMIuk  
nSplitter = nCount; TpA\9N#$  
} fQLt=Lrp  
} _Lw
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/* >;z<j$;F<  
**Utility.java iCP/P%  
*/ CE15pNss  
package NetFox; VF&Z%O3n  
]pEV}@7  

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public class Utility { a?yMHb{F  
yT{8d.Rh  
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public Utility() ~x{.jn  
{ {_RWVVVe  
6z,&i  
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} KRJLxNr  
~.%K/=wK@  
//线程睡眠 `V[!@b:  
public static void sleep(int nSecond) ;Ut+yuy  
{ $3D'4\X~?  
try{ K;7f?52  
Thread.sleep(nSecond); o;b0m;~   
} Lp5U"6y  
catch(Exception e) W)(^m},*8D  
{ xf%4, JQ  
e.printStackTrace (); }FF W|f  
} y}C`&nW[=  
} J/7R\;q`~o  
?=GXqbS"  
//日志 ;M]C1!D9#  
public static void log(String sMsg) yGg,$WM  
{ E&yD8=vw  
System.err.println(sMsg); @`FCiHM  
} fAZiC+  
sBv>E}*R  
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public static void log(int sMsg) 4`#F^2r!  
{ vi@Lz3}::  
System.err.println(sMsg); (h']a!  
} IPuA#C  
} `P
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/* (I@bkMp  
**TestMethod.java E^w:KC2@  
*/ ZxGP/D  
package NetFox; 2/,0iwj-  
uH3D{4   
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3  
public class TestMethod { lq.Te,Y%w  
3Q/#T1@  
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public TestMethod() 4YZS"K'E  
{ ///xx/weblogic60b2_win.exe ~-a'v!  
try{ wPbkUVO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x*oWa,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &iN--~}!$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 79zJ\B_  
fileFetch.start(); .@iFa3  
} 3M5#4n\v$  
catch(Exception e){e.printStackTrace ();} }U@m*dEG  
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c= UU"  
} 8#R
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\Mv":Lm1  
public static void main(String[] args) dQezd-y*  
{ Y}6n]n;uR  
new TestMethod(); DN4#H`  
} %}2@rLP  
} 4^6.~6a  
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