http断点续传简单实现（java)

/* |>1
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**SiteFileFetch.java 2<r\/-#pU  
*/ @*O?6>  
package NetFox; |b.z*G  
import java.io.*; a.kbov(  
import java.net.*; K+d2m9C=  
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public class SiteFileFetch extends Thread { :tj-gDa\Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8q^o.+9  
long[] nStartPos; //开始位置 7"2b H  
long[] nEndPos; //结束位置 p EusTP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q]c5MlJXF  
long nFileLength; //文件长度
ALT^8c&K  
boolean bFirst = true; //是否第一次取文件 nCnjq=  
boolean bStop = false; //停止标志 )D@~|j:  
File tmpFile; //文件下载的临时信息 E^V|  
DataOutputStream output; //输出到文件的输出流 6|;Uq'  
}nrXxfu  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {aOkV::  
public SiteFileFetch(SiteInfoBean bean) throws IOException !xK=#pa  
{ eSy(~Y
 
siteInfoBean = bean; [kB `  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5ukp^OxE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WlVl[/qt  
if(tmpFile.exists ()) pGGmA;TC1  
{ ?S[Y:<R{:  
bFirst = false; wWjG JvJ  
read_nPos(); i
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} @wN G  
else lj[,|[X7`  
{ M]rO;^;6?  
nStartPos = new long[bean.getNSplitter()]; gPXa>C  
nEndPos = new long[bean.getNSplitter()]; j,-C{ K  
} 93Yn`Av;  
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} 0!GAk  
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public void run() q9*MNHg}  
{ U~f4e7x*O  
//获得文件长度 5LW}h^N  
//分割文件 6(V /yn~  
//实例FileSplitterFetch E4%j.  
//启动FileSplitterFetch线程 Ib`-pRU;  
//等待子线程返回 O<*5$,K9  
try{ E5GJi  
if(bFirst) 5er@)p_  
{ qRB7Ec_  
nFileLength = getFileSize(); l]LxL  
if(nFileLength == -1) p.K*UP  
{ fw-\|fP  
System.err.println("File Length is not known!"); C"pB"^0  
} XEH}4;C'{  
else if(nFileLength == -2) k5BXirB  
{ 2.I^Xf2  
System.err.println("File is not access!"); [0;buVU.  
} GF<[}  
else JgfVRqm   
{ t'qL[
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for(int i=0;i<nStartPos.length;i++) ^rAa"p9  
{ k3Cz9Vt%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ub$n |xn  
} YV'pVO'_+  
for(int i=0;i<nEndPos.length-1;i++) vp)Vb^K>  
{ p.JXSn  
nEndPos = nStartPos[i+1]; n(ir[w#,]"  
}
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nEndPos[nEndPos.length-1] = nFileLength; m?CZQq,  
} 4mYCSu14:`  
} ?8V UOx  
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//启动子线程 #Z,E><t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ':h =*v8a  
for(int i=0;i<nStartPos.length;i++) Rd&9E  
{ kyYLP"oB=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _r Y,}\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;@mRo`D`  
nStartPos,nEndPos,i); Gs0H@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _'0 @%P%
 
fileSplitterFetch.start(); X"asfA[6K  
} },-*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tenf:Hm/k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q3e8#R)l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }(FPV*mS  
nEndPos = " + nFileLength); r`'y?Bra;  
// fileSplitterFetch[nPos.length-1].start(); R=)55qu  
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//等待子线程结束 VDF)zA1V  
//int count = 0; e)^j+ l  
//是否结束while循环 X*eW#|$\  
boolean breakWhile = false; uBnoQ~Qd[z  
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while(!bStop) f{#j6wZM  
{ {d3<W N  
write_nPos(); NaUr!s  
Utility.sleep(500); O~Wt600{E  
breakWhile = true; 9]'&RyH=#  
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for(int i=0;i<nStartPos.length;i++) b-5y9K  
{ xG2+(f#C1  
if(!fileSplitterFetch.bDownOver) m#e3%150{  
{ ]88];?KS}  
breakWhile = false; xJ8%<RR!t  
break; ,zTb<g  
} ?`_jFj+<\S  
} L5YnG_M&  
if(breakWhile) ,,L2(N  
break; Kn;D?ioY  
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//count++; * *H&+T/B  
//if(count>4) Y.#:HRtg
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// siteStop(); u+t$l^S  
} po9 9 y-  
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System.err.println("文件下载结束！"); z&8un%Jt  
} |R/.r_x,V?  
catch(Exception e){e.printStackTrace ();} IeX^4rc(  
} (h-*_a}F4  
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//获得文件长度 ?(6mVyIe  
public long getFileSize()
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{ MTGiAFE  
int nFileLength = -1; "L&'Fd@ZU  
try{ :wqC8&V  
URL url = new URL(siteInfoBean.getSSiteURL()); F|bYWYED;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ikBYd }5  
httpConnection.setRequestProperty("User-Agent","NetFox"); G$zL)R8GE|  
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int responseCode=httpConnection.getResponseCode(); 1k%k`[VC  
if(responseCode>=400) 0yM[Z':i'{  
{ bAk&~4Y_"  
processErrorCode(responseCode); C#;jYBtT7?  
return -2; //-2 represent access is error b#)UUGmI  
} $h[QQ-  
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String sHeader; aA`/E  
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for(int i=1;;i++) FbnO/! $8  
{ cXMhq<GkAA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G.'+-v=\]  
//Utility.log(in.readLine());  6Si-u  
sHeader=httpConnection.getHeaderFieldKey(i); s^OO^%b  
if(sHeader!=null) OYC_;CP  
{ DmVP  
if(sHeader.equals("Content-Length")) h4pTq[4*  
{ V==z"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RE$`YCs5  
break; 8x{B~_~  
} ZPN roCK`  
} >gKh  
else 88"Sai  
break; tGdf/aTjy  
} j;_c+w!P  
} \o-&f:
 
catch(IOException e){e.printStackTrace ();} D0(xNhmKz  
catch(Exception e){e.printStackTrace ();} Z|9
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=$8nUX`  
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Utility.log(nFileLength); CBQhIvq.d  
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return nFileLength; :!;'J/B@..  
} ]9=h%5Ji>  
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//保存下载信息（文件指针位置） "TV(H+1,z  
private void write_nPos() 3($"q]Y  
{ @=]~\[e\  
try{ vkS)E0s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e6X[vc|Y}  
output.writeInt(nStartPos.length); o[ENp'r  
for(int i=0;i<nStartPos.length;i++) ultG36.x  
{ 3lLMu B+  
// output.writeLong(nPos); ._wkj  
output.writeLong(fileSplitterFetch.nStartPos); 5WqXo{S  
output.writeLong(fileSplitterFetch.nEndPos); 5G0
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} i`/+,<  
output.close(); =K&\E2kA4  
} 6qe*@o  
catch(IOException e){e.printStackTrace ();} $wYtyN[  
catch(Exception e){e.printStackTrace ();} cw&Hgjj2  
} .*$
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; UiwH  
//读取保存的下载信息（文件指针位置） MRr</o  
private void read_nPos() \ 6EKgC1  
{ LAx4Xp/  
try{ 1iL'V-y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0w'j+  
int nCount = input.readInt(); Et"?8\"n7  
nStartPos = new long[nCount]; zJM S=r  
nEndPos = new long[nCount]; Sx*oo{Kk%  
for(int i=0;i<nStartPos.length;i++) "'^4*o9  
{ j7FN\ cz  
nStartPos = input.readLong(); 2#X4G~>#h  
nEndPos = input.readLong(); 1[*UYcD  
} Nf3.\eR  
input.close(); C8#@+Q.  
} 4E8JT#&  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} N3t0-6$_  
} H9 C9P17  
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private void processErrorCode(int nErrorCode) lcON+j  
{ kE.x+2  
System.err.println("Error Code : " + nErrorCode); 4fh^[\  
} 3`O?16O  
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//停止文件下载 H@X oqgI  
public void siteStop() IUGz =%[  
{ 6*9}4`  
bStop = true; ~5ZvOX6L2  
for(int i=0;i<nStartPos.length;i++) 3qHQX?a  
fileSplitterFetch.splitterStop(); nmlPX7!{$  
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} Xqp|VbDca  
} w)E@*h<Z  
//负责部分文件的抓取 A6<C-1 N}j  
**FileSplitterFetch.java 6nDV1O5  
*/ j^`X~gE  
package NetFox; d "BW/%m|g  
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import java.io.*; PYB+FcR6?n  
import java.net.*; fQWIw  
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public class FileSplitterFetch extends Thread { 0uVv<Q~  
)/4(e?%=  
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String sURL; //File URL >-T`0wI  
long nStartPos; //File Snippet Start Position \^+ILYO:$  
long nEndPos; //File Snippet End Position y$Zj?Dd#  
int nThreadID; //Thread's ID I9$c F)zk  
boolean bDownOver = false; //Downing is over XA0(f*  
boolean bStop = false; //Stop identical ;y?);!g  
FileAccessI fileAccessI = null; //File Access interface fLN!EDq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vY6W|<s  
{ m:tiY [c>W  
this.sURL = sURL; S6nhvU:  
this.nStartPos = nStart; k>4qkigjc  
this.nEndPos = nEnd; NQTnhiM7$  
nThreadID = id; ?9j{V7h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3K/Df#  
} HCA{pR`  
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public void run() +\`vq"e  
{ a+41|)pt  
while(nStartPos < nEndPos && !bStop) .r|*Ch#;P  
{ %:6?Y%`*[  
7D"%%|: h  
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try{ iCG`3(xL  
URL url = new URL(sURL); :bM+&EP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -xmf'c9P  
httpConnection.setRequestProperty("User-Agent","NetFox"); H(u+#PIIw  
String sProperty = "bytes="+nStartPos+"-"; O0l^*nZ46t  
httpConnection.setRequestProperty("RANGE",sProperty); rp! LP#*  
Utility.log(sProperty); ,#u\l>&$  
$j` $[tX6l  
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InputStream input = httpConnection.getInputStream(); 0O@_cW  
//logResponseHead(httpConnection); Go\VfLLw  
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byte[] b = new byte[1024]; |g)FA_#|<  
int nRead; ND]S(C"?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $`Nd?\$  
{ N{akg90  
nStartPos += fileAccessI.write(b,0,nRead); _j#SpL'P  
//if(nThreadID == 1) Rc$h{0K8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <HoAj"xf  
} nnCug  
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Utility.log("Thread " + nThreadID + " is over!"); s3t!<9[m  
bDownOver = true; Ub)I66  
//nPos = fileAccessI.write (b,0,nRead); ksI>IW  
} )q^ Bj$  
catch(Exception e){e.printStackTrace ();} ;b~~s.+  
} ziL^M"~2  
} Hhv$4;&X  
# mT]j""  
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//打印回应的头信息 bkQ3c-C<  
public void logResponseHead(HttpURLConnection con) IsYP0(L  
{ X-Ycz 5?  
for(int i=1;;i++) 2_pz3<,\  
{ :EHQ .^  
String header=con.getHeaderFieldKey(i); #}o<v|;  
if(header!=null) T%I&txl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c~tAvDX  
Utility.log(header+" : "+con.getHeaderField(header)); xb^Mo.\[  
else =MSu3<y,  
break; [&VxaJ("3  
} 'DAltr<  
} h5onRa*
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public void splitterStop() \iZ1W  
{ :C%47qv  
bStop = true; h~ha  
} @d)a~[pm  
T
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} yiT{+;g^  
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/* Nmf#`+7gCI  
**FileAccess.java v MWC(m  
*//文件访问(定位，写) qJMp1DC  
package NetFox; Yq;&F0paK  
import java.io.*; %+8  
z(UX't (q  
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public class FileAccessI implements Serializable{ rk|a'&  
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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 b-b;7a\N  
RandomAccessFile oSavedFile; '%O\E{h  
long nPos; KgU[  
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public FileAccessI() throws IOException f[M"EMy  
{ :wCC^Y]  
this("",0); :+A;TV  
} <w11nB)  
YD+QX@  
#ZwY?T x  
public FileAccessI(String sName,long nPos) throws IOException _Fvsi3d/  
{ ^ N_`^m  
oSavedFile = new RandomAccessFile(sName,"rw"); {lKEZirO  
this.nPos = nPos; mZ&]  
oSavedFile.seek(nPos); &@Yoj%%  
} L`bo#,eg6  
v_.j/2U  
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public synchronized int write(byte[] b,int nStart,int nLen) t9n'!  
{ ^)'||Ly  
int n = -1; p!V)55J*  
try{ C890+(D~  
oSavedFile.write(b,nStart,nLen); @) ]t8(  
n = nLen; )S"o{N3B  
} q .)^B@}_  
catch(IOException e) ;W =by2x*  
{ {S# 5g2  
e.printStackTrace ();  K oL%}u&  
}
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return n; >EyvdX#v  
} )z|_*||WU^  
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} +# A|Zp<  
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/* -U&098}<K  
**SiteInfoBean.java 6YB-}>?  
*/ __Vg/C!W  
package NetFox; %Gnd"SGs  
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6!i( \Q*  
public class SiteInfoBean { qsQ]M^@>  
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private String sSiteURL; //Site's URL r< N-A?a  
private String sFilePath; //Saved File's Path s2kGU^]y  
private String sFileName; //Saved File's Name $v2S;UB v*  
private int nSplitter; //Count of Splited Downloading File &n,xGIG  
aA!@;rR<yU  
9}IVNZc  
public SiteInfoBean() jTGS6{E  
{//nSplitter的缺省值为5 gt(X!iN]  
//default value of nSplitter is 5 .CB"@.7  
this("","","",5); #h}
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} pRb+'v&_k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `"-`D!U?$  
{ H"kc^G+(R"  
sSiteURL= sURL; j X^&4f  
sFilePath = sPath; T=iZ9w  
sFileName = sName; 6ba2^3GH  
this.nSplitter = nSpiltter; mRix0XBI~  
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} rVc zO+E  
;+#za?w  
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public String getSSiteURL() 3/#
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{ `t/@ L:  
return sSiteURL; /;]B1T7  
} iLI.e rm  
I*`=[nR  
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public void setSSiteURL(String value) 9Le/'ovq  
{ \I`=JKYT  
sSiteURL = value; ~ L i%  
} Sj=69>m]5  
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public String getSFilePath() 8M(|{~~3:  
{ 0'`8HP  
return sFilePath; cxF?&0[mY  
} WPh |~]by<  
:w&)XI34  
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public void setSFilePath(String value) 9^[5!SMzCj  
{ ~_^o?NE,  
sFilePath = value; j@_) F^12  
} 8bKWIN g_n  
:6Pc m3  
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public String getSFileName() 6XxG1]84  
{ Ubos#hP  
return sFileName; O%Gsk'mo  
} ^5'/ }iR2N  
&s}@7htE  
>[P7Zlwv4  
public void setSFileName(String value)  lN`_0  
{ g,GbaaXH  
sFileName = value; YO!7D5rV#  
} la"A$Tbu~  
q9]^+8UP  
?GD?J(S  
public int getNSplitter() J7xT6Q=  
{ |% YzGgp7  
return nSplitter; LK-6z w5=(  
} "VVR#H}{  
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public void setNSplitter(int nCount)
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{ &)f++(i  
nSplitter = nCount; 5\kZgX
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} )s7Tv#[  
} en#g<on  
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/* O> ^~SO  
**Utility.java /E  yg*#  
*/ gwB>oi*OE  
package NetFox; RDZh>K PG  
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public class Utility { Jz3<yQ-  
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public Utility() }(%}"%$  
{ |b@A:8ss  
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h|uP=0   
} l )V43  
1~u\]Zi=D  
//线程睡眠 sU_4+Mk  
public static void sleep(int nSecond) #2'&=?J1r  
{ }fMFQA)  
try{ ./*,Thc  
Thread.sleep(nSecond); @
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} bme#G
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catch(Exception e) e6xjlaKb  
{ z>g& ?vo2  
e.printStackTrace (); "/-v 9  
} 1xV1#'@[Jd  
} iKH T  
/2V',0  
//日志 b%t9a\0V  
public static void log(String sMsg) 7Bd_/A($  
{ MCpK^7]k  
System.err.println(sMsg); X.Y)'qSf  
} H0NyxG<  
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?
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public static void log(int sMsg) v86`\K*0Y  
{ w7V W  
System.err.println(sMsg);  #X_M  
} TBfl9Q  
} U.h PC3  
(uz!:dkvx  
.u3W]5M|  
/* n:
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**TestMethod.java $gK>R5^G>  
*/  :!FwF65  
package NetFox; TL:RB)- <  
%d\+(:uu/  
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public class TestMethod { 6RodnQ  
=B%e0M  
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public TestMethod() Vo8"/]_h  
{ ///xx/weblogic60b2_win.exe {0{$.L  
try{ bvTkSEN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9DE)5/c`v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bn:sN_N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $ayD55W4  
fileFetch.start(); "!?Ya{  
} K#m o+n5-;  
catch(Exception e){e.printStackTrace ();} }epN<DL  
F\<i>LWT'  
n8,/olqwW  
} [wYQP6Cyy  
^[akB|#\9  
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public static void main(String[] args) Pw.+DA  
{ n_glYSV!  
new TestMethod(); ]h@:Y]  
} ,/9|j*9H  
}  /9Xf[<  
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