http断点续传简单实现（java)

/* y %$O-q  
**SiteFileFetch.java 7+TiyY]K  
*/ "N:XzG  
package NetFox; I\?9+3 XnQ  
import java.io.*; )Dp/('Z2  
import java.net.*; "jecsqCgK0  
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*rZ^^`4R  
public class SiteFileFetch extends Thread { iGDLZE+
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*tOG*hwdT  
SiteInfoBean siteInfoBean = null; //文件信息Bean #eU.p&Zc  
long[] nStartPos; //开始位置 ;?}l  
long[] nEndPos; //结束位置 {k.MS-q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ultG36.x  
long nFileLength; //文件长度 ?T_3n:  
boolean bFirst = true; //是否第一次取文件 z)XRx:YU;$  
boolean bStop = false; //停止标志 t&5%?QyM  
File tmpFile; //文件下载的临时信息 <D&)OxEn\  
DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kpbm4t  
public SiteFileFetch(SiteInfoBean bean) throws IOException mDGn:oRj  
{ aw?=hXR!  
siteInfoBean = bean; Zn,>]X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HIGq%m=-x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !/ y!QXj  
if(tmpFile.exists ()) t:JI!DR  
{ Z=4{
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bFirst = false; B .TB\j  
read_nPos(); /sR%]q |L  
} H* ,,^  
else 2M)]!lYy  
{ Y $g$x<7  
nStartPos = new long[bean.getNSplitter()]; ~Au,
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nEndPos = new long[bean.getNSplitter()]; mD:IO  
} (vR 9H(#  
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} E6Rz@"^XV  
7z\m; 1  
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public void run() @ZN^1?][  
{ =H0vE7{*  
//获得文件长度 _qvK*nE  
//分割文件 J
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//实例FileSplitterFetch 9/SXs0  
//启动FileSplitterFetch线程 KPSh#x&I  
//等待子线程返回 d;Hn#2C  
try{ Z') pf  
if(bFirst) kE.x+2  
{ BY\:dx)mK  
nFileLength = getFileSize(); nqR?l4 DX  
if(nFileLength == -1) lX:|iB  
{ TUL_TR  
System.err.println("File Length is not known!"); 2:}fe}  
} %I!:ITa  
else if(nFileLength == -2) N-lGa@ j  
{ y AF+bCXo  
System.err.println("File is not access!"); gw+9x<e  
} [LT^sb  
else ^n#1<K[E  
{ GZ!|}$8  
for(int i=0;i<nStartPos.length;i++) R cY>k  
{ f0+2t.tj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Kzy/9  
} /)N@M  
for(int i=0;i<nEndPos.length-1;i++) He0=-AR8  
{ "`}~~.q  
nEndPos = nStartPos[i+1]; =9L$L|W  
} `\=Gp'&Q+  
nEndPos[nEndPos.length-1] = nFileLength; 4!$ M q;U  
} (VyNvB  
} @J[6,$UVu  
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//启动子线程 3[p_!eoW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y<W8Q<9  
for(int i=0;i<nStartPos.length;i++) hf!|\f  
{ R~L0{` 0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \^+ILYO:$  
nStartPos,nEndPos,i); f<i7
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sK$wN4k  
fileSplitterFetch.start(); fnzy5+9"  
} @ \.;b9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !2Dy_U=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NW$H"}+o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G" b60RQ  
nEndPos = " + nFileLength); TGT$ >/w >  
// fileSplitterFetch[nPos.length-1].start(); maMHZ\Q  
z^* '@  
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//等待子线程结束 ,7]k fB  
//int count = 0; >Dm8m[76  
//是否结束while循环 #$S}3 o  
boolean breakWhile = false; a<XCNTaVT  
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~%w~-O2  
while(!bStop) @}FAwv^f  
{ ]*"s\ix  
write_nPos(); S{F-ttS"  
Utility.sleep(500); *a}(6Cx  
breakWhile = true; T*2C_oW  
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=Cf]  
for(int i=0;i<nStartPos.length;i++) &!.HuRiuC  
{ 4Wel[]  
if(!fileSplitterFetch.bDownOver) )yee2(S  
{ -*VKlZ8-  
breakWhile = false;  ~m=EM;  
break; *}b]rjsj  
} SDJH;c0  
} O0~vf[i];  
if(breakWhile) >.9eBz@  
break; a^nAZ  
u/^|XOy  
;|ub!z9GG  
//count++; eBB:~,C^q.  
//if(count>4) vL_zvXA  
// siteStop(); S
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} I?Y d   
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~&G4)AM  
System.err.println("文件下载结束！"); w*LbH]l<-  
} Z_z#QX>=D  
catch(Exception e){e.printStackTrace ();} Y)HbxFF`/  
} iSp  
*$,+`+  
t\y-T$\\  
//获得文件长度 LVtu*k   
public long getFileSize() IhonnLLW  
{ q=c/B(II!  
int nFileLength = -1; Ub)I66  
try{ )qM|3],  
URL url = new URL(siteInfoBean.getSSiteURL()); $3 8gs{+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `7Ug/R<  
httpConnection.setRequestProperty("User-Agent","NetFox"); B!,yfTk]  
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int responseCode=httpConnection.getResponseCode(); r2eQ{u{nX  
if(responseCode>=400) iyM^[/-R6  
{ qc8Ta"  
processErrorCode(responseCode); n.$(}A  
return -2; //-2 represent access is error Q7Ij4  
} UmP'L!  
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String sHeader; mvTb~)  
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for(int i=1;;i++) WcGXp$M  
{ 9N Le&o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f'{>AKi=C  
//Utility.log(in.readLine()); $Ub}p[L  
sHeader=httpConnection.getHeaderFieldKey(i); *BOBH;s  
if(sHeader!=null) rihlae5Kz  
{ UC!5 wVY  
if(sHeader.equals("Content-Length")) ^ }#f()  
{ %W;u}`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c4|so=  
break;  KOSyh<&  
} epVH.u%  
} xH$%5@~  
else Z{}+)Q*Q  
break; G[6=u|(M  
} 878tI3-  
} |R~;&x:  
catch(IOException e){e.printStackTrace ();} eTZ`q_LfI1  
catch(Exception e){e.printStackTrace ();} raQYn?[  
s/S+ ec3  
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Utility.log(nFileLength); 4(m3c<'P  
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return nFileLength; MZ^Ch   
} #$uZDQY_  
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@Z2/9K%1'  
//保存下载信息（文件指针位置） -s~p}CQ.  
private void write_nPos() >@Khm"/T  
{ 6DZ2pT:  
try{ SRk7gfP*q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m/N(%oMWB=  
output.writeInt(nStartPos.length); DZAH"
sb  
for(int i=0;i<nStartPos.length;i++) N[{]iQ  
{ :eLLDp<  
// output.writeLong(nPos); H2]BMkum  
output.writeLong(fileSplitterFetch.nStartPos); HjPH  
output.writeLong(fileSplitterFetch.nEndPos); zf")|9j  
} | VRq$^g  
output.close(); qq>44k\|)  
} _Fvsi3d/  
catch(IOException e){e.printStackTrace ();} ^ N_`^m  
catch(Exception e){e.printStackTrace ();} k7[)g]u  
} c=<v.J@K  
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//读取保存的下载信息（文件指针位置） fa.f(c
  
private void read_nPos() dK7 ^  
{ 0Cv4/Ar(  
try{ <sF!]R&4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,DQ >&_D
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int nCount = input.readInt(); L/%xbm~  
nStartPos = new long[nCount]; 33S`aJ  
nEndPos = new long[nCount]; PE +qYCpP9  
for(int i=0;i<nStartPos.length;i++) 0MhxFoFO  
{ "URVX1#(r  
nStartPos = input.readLong(); j[BgP\&,  
nEndPos = input.readLong(); f(W,m >.;  
} JCBnFrP  
input.close(); 4>d[qr*<  
} |oB]6VS`  
catch(IOException e){e.printStackTrace ();} !FO:^P  
catch(Exception e){e.printStackTrace ();} f61]`@Bk  
} P}b Dn;  
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private void processErrorCode(int nErrorCode) 1gO//fdI  
{ ook' u}h  
System.err.println("Error Code : " + nErrorCode); P/HHWiD`D  
}
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//停止文件下载 ',<{X(#(  
public void siteStop() vsxvHot=  
{ nT(!HD
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bStop = true; }qTv&Z3$  
for(int i=0;i<nStartPos.length;i++) 
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fileSplitterFetch.splitterStop(); 9Vh_XBgP  
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} }"!6Xm  
} ~r7DEy|+  
//负责部分文件的抓取 7 B4w.P,B  
**FileSplitterFetch.java &n,xGIG  
*/ aA!@;rR<yU  
package NetFox; xUV_2n+  
;w>Q{z  
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import java.io.*; +;{rU&  
import java.net.*; ~M|NzK_9  
R|d^M&K,  
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public class FileSplitterFetch extends Thread { (Qw`%B  
6T5A31 Q  
F='jmiVJ  
String sURL; //File URL #w[q.+A  
long nStartPos; //File Snippet Start Position uk>q\j  
long nEndPos; //File Snippet End Position |^>L`6uo  
int nThreadID; //Thread's ID [U_Q 2<H  
boolean bDownOver = false; //Downing is over g%KGF)+H  
boolean bStop = false; //Stop identical D~t"9Z\  
FileAccessI fileAccessI = null; //File Access interface 'npT+p$V  
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o)$Q]N##  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hj-<{#,  
{ wjw<@A9  
this.sURL = sURL; FN8=YUYK%  
this.nStartPos = nStart; ]y$V/Ij=qK  
this.nEndPos = nEnd; iLI.e rm  
nThreadID = id; UGezo3}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +A.a~Stt  
} -hJ>wGI  
8/kx3  
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public void run() ._F6-pl  
{ A(_^_p.|  
while(nStartPos < nEndPos && !bStop) <LOx.}fv  
{ .P0Qs&i  
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try{ cVv4gQD\  
URL url = new URL(sURL); !<UEq`2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +X|m>9  
httpConnection.setRequestProperty("User-Agent","NetFox"); k(vEp]  
String sProperty = "bytes="+nStartPos+"-"; dOYmt,  
httpConnection.setRequestProperty("RANGE",sProperty); 6{,K7FL  
Utility.log(sProperty); ~_^o?NE,  
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InputStream input = httpConnection.getInputStream(); | 9\7xT  
//logResponseHead(httpConnection); ~jCpL@rS  
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byte[] b = new byte[1024]; 3I{ta/(  
int nRead; o-e,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *Yk8Mj^_h  
{ r{N{!"G  
nStartPos += fileAccessI.write(b,0,nRead); ws=9u-  
//if(nThreadID == 1) i2%m}S;D9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^xkppN2  
} O]r3?=  
0)]C&;}_M  
aSj1P/A  
Utility.log("Thread " + nThreadID + " is over!"); QGCdeE$K  
bDownOver = true; G]NtX4'4  
//nPos = fileAccessI.write (b,0,nRead); +` Y ?-  
} D``NQ`>A  
catch(Exception e){e.printStackTrace ();} 'Tan6Qa  
} cPBy(5^  
} L)nVpqm   

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&)f++(i  
//打印回应的头信息 5\kZgX
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public void logResponseHead(HttpURLConnection con) -O>mY)  
{ qLi1yH  
for(int i=1;;i++) eYSGxcx  
{ !DUg"o3G>  
String header=con.getHeaderFieldKey(i); 0<]!G|;|  
if(header!=null) iYQy#kO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); huD\dmQ:]  
Utility.log(header+" : "+con.getHeaderField(header)); _x|8U'|Ce  
else EKS<s82hF&  
break; J]^gF|  
} G~hILW^  
} ~aR='\<  
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public void splitterStop() y^|3]G3  
{ 1YD.jU^;HD  
bStop = true; IV#f}NrfD  
} CZ%"Pqy&1L  
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} b0=AQ/:  
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/* 2DqHqq9m  
**FileAccess.java M~Dc5\T  
*//文件访问(定位，写) AS"|r  
package NetFox; 0bL=l0N$W  
import java.io.*; k*6eZ7  
g UAPjR  
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public class FileAccessI implements Serializable{ WY~[tBi\  
/Z_ [)PTH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]H'82
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RandomAccessFile oSavedFile; \iSBLU  
long nPos; ZGvNEjff  
y'wW2U/1-  
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public FileAccessI() throws IOException |i}g
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{ 9T
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this("",0); '
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} \)kAhKtG  
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public FileAccessI(String sName,long nPos) throws IOException RA67w&  
{ > o`RPWs  
oSavedFile = new RandomAccessFile(sName,"rw"); X_8NW,  
this.nPos = nPos; 6x8|v7cMH  
oSavedFile.seek(nPos); wIHz TL  
} %d\+(:uu/  
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public synchronized int write(byte[] b,int nStart,int nLen) &}=,8Gt1G  
{ ,OAWGFKOp  
int n = -1; - $/{V&?t  
try{ %=eD)p7l-  
oSavedFile.write(b,nStart,nLen); YWF<2l.  
n = nLen; 8[IifF1M=&  
} q8]k]:r  
catch(IOException e) Bn:sN_N  
{ $ayD55W4  
e.printStackTrace (); a8c]B/  
} #+nv,?@  
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return n; ;r}<o?'RM  
} 2 G{KpM&  
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} =Ybu_>  
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/* "rJL ^ \r  
**SiteInfoBean.java  /9Xf[<  
*/ &ayoT
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package NetFox; '5\1uB PKW  
;oE4,  
+__Rk1CVh  
public class SiteInfoBean { EZV$1pa  
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private String sSiteURL; //Site's URL uv!/DX#  
private String sFilePath; //Saved File's Path tB.9Ov*  
private String sFileName; //Saved File's Name #S)*MT4ke  
private int nSplitter; //Count of Splited Downloading File gK'MUZ()  
`OWB@_u5  
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public SiteInfoBean() T}*'9TB  
{//nSplitter的缺省值为5 >Ko )Z&j9W  
//default value of nSplitter is 5 YX(%jcj*  
this("","","",5); =k z;CS+  
} gMbvH
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#0c`"2t&M  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {ig@Iy~DT  
{ ?W(f%/B#  
sSiteURL= sURL; U Lq%,ca  
sFilePath = sPath; 1N&U{#4  
sFileName = sName; E:ytdaiT  
this.nSplitter = nSpiltter; ~oI49Q&{  
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;S7xJ'H  
} ':=C2x1d|  
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public String getSSiteURL() _rM%N+$&d_  
{ C{D2mSS  
return sSiteURL; >Et?7@   
} vl
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public void setSSiteURL(String value) wcOAyo5(n  
{ $2.DZ  
sSiteURL = value; L%DL n  
} i0P+,U  
"YBA$ef$  
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public String getSFilePath() Z#Fw 1  
{ /c7j@=0  
return sFilePath; E*%{Nn  
} k}/: xN"  
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public void setSFilePath(String value) ;KhYh S(q  
{ -nW{$&5AF  
sFilePath = value; lbPxZ'YO#  
} TcC=_je460  
9#p^Z)[)-  
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public String getSFileName() ,%C$~+xjM  
{ (mEZ4yM
 
return sFileName; IkvH8E  
} (C
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fkYQ3d,`  
public void setSFileName(String value) Vf@/}=X *  
{ 2#R"#Q!  
sFileName = value; FR <wp  
} sOJ~PRA  
t!k 0n&P  
9we=aX5  
public int getNSplitter() rEViw?^KT  
{ S.I<Hs  
return nSplitter; <[q)2 5RL  
}  4@5<B  
X>CYKRtb  
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public void setNSplitter(int nCount) 5u&jNU5m_  
{ mB\5bSFY`  
nSplitter = nCount; _+{s^n=  
} T|m+ULp~  
} 4e:hKv,+4  
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@f$P*_G   
/* B4b UcYk  
**Utility.java czp5M
U_^  
*/ QhZ%<zN  
package NetFox; q"Xls(  
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public class Utility { 9> |rIw  
:sn}D~  
`SVR_  
public Utility() /v8qT'$^  
{ 6e*JCf>  
Y,a.9AWw)  
@.5Ybgn  
} 3drgB;:g`  
Y5;:jYk#<_  
//线程睡眠 q q`UvU  
public static void sleep(int nSecond) 8'YL!moG|  
{ /#XO!%=7  
try{
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Thread.sleep(nSecond); jJf|Ok:G{  
} DJbj@ 2W[  
catch(Exception e) (/)JnBy0  
{ !b7H  
e.printStackTrace (); f ZI
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} 4uv }6&R  
} &O'yhAP] j  
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//日志 @<YZa$`  
public static void log(String sMsg) mdk:
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{ 5p~Z-kU&  
System.err.println(sMsg); tpVtbh1)u  
} )TWf/Lcp  
=gj]R  
_WkK%RYV  
public static void log(int sMsg) :!|xg!|y  
{ 1 4|S^UM$  
System.err.println(sMsg); 0}ZuF.  
} 41:Z8YL(  
} 8-m"]o3  
*Vc}W  
j/W#=\xz  
/* f(3#5288  
**TestMethod.java &38Fj'l  
*/ lmod8B  
package NetFox; 3:C *'@  
/r)d4=1E  
/qz(ra  
public class TestMethod { M--6oR7  
3~ qgvAr  
y_'8m9Qy)  
public TestMethod() WgY3g1C  
{ ///xx/weblogic60b2_win.exe n"Ev25%  
try{ ?6[>HX
;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); { u;ntDr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a E#s#Kv   
SiteFileFetch fileFetch = new SiteFileFetch(bean); =e4,)Wd9&
 
fileFetch.start(); 
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} #de]b  
catch(Exception e){e.printStackTrace ();} 1mB6rp  
U$-FQRM4K  
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} wOOPuCw?  
kt@+UK."  
h rZ\ O?j  
public static void main(String[] args) Qdtfi1_Y1  
{ ";GLX%C!{@  
new TestMethod(); 9eV@v  
} =7jkW (Q  
} tvg7mU]l  
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