http断点续传简单实现（java)

/* ]@_M
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**SiteFileFetch.java RGh`=D/yE  
*/ (cJb/|?3  
package NetFox; GY 4?}T^s  
import java.io.*; MB;<F  
import java.net.*; N
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public class SiteFileFetch extends Thread { 9^l_\:4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4L\bT;dQ|.  
long[] nStartPos; //开始位置 $$`E@\5P  
long[] nEndPos; //结束位置 i2`i5&*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "mr;|$Y  
long nFileLength; //文件长度 i3g;B?54  
boolean bFirst = true; //是否第一次取文件 9NLO{kN  
boolean bStop = false; //停止标志 e#]=-^  
File tmpFile; //文件下载的临时信息 ](c[D9I!8  
DataOutputStream output; //输出到文件的输出流 SOQm>\U'i  
8 St`,Tq)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +Z[(s!  
public SiteFileFetch(SiteInfoBean bean) throws IOException /~*U'.V  
{ aY7kl  
siteInfoBean = bean; P[-2^1P
"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5\/h3i"I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j;@7
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if(tmpFile.exists ()) l<0BMwS8  
{ LQ pUyqR  
bFirst = false; *+TIF"|1  
read_nPos(); U&#1qRm\h  
} +*-u_L\'  
else Q?rb(u(  
{ C=2"*>lTn  
nStartPos = new long[bean.getNSplitter()]; 4Sv&iQ=vh  
nEndPos = new long[bean.getNSplitter()]; ,p6X3zY  
} [X[d`@rXv  
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} tn};[r  
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public void run() &qqS'G*  
{ Uv'.]#H<  
//获得文件长度 GWa_^  
//分割文件 "QA <5P  
//实例FileSplitterFetch sxcpWSGA^  
//启动FileSplitterFetch线程 bAv>?Xqa  
//等待子线程返回 O.4ty)*  
try{ (m|w&oA/  
if(bFirst) SAswP  
{ xh Sp<|X_  
nFileLength = getFileSize(); tj@IrwC^e"  
if(nFileLength == -1) 5at\!17TY  
{ ;i|V++$_  
System.err.println("File Length is not known!"); +FiM?,G  
} /N(L52mz  
else if(nFileLength == -2) diN5*CF'~  
{ _
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System.err.println("File is not access!"); %9hzz5#  
} o(5Xj$Z  
else JJlwzH  
{ ;7CE{/Bq.p  
for(int i=0;i<nStartPos.length;i++) D/C,Q|Ya6  
{ y1P KoN|K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `iuo([E d  
} }ybveZxv5A  
for(int i=0;i<nEndPos.length-1;i++) Fa78y
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{ #MYhKySku  
nEndPos = nStartPos[i+1];
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} qXmkeidb&W  
nEndPos[nEndPos.length-1] = nFileLength; $8#zPJR&  
} A\J|eSG'$  
} !DFT}eu  
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//启动子线程 b}63?.M{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xJ H]>#XJ  
for(int i=0;i<nStartPos.length;i++) ><9E^ k0.  
{ {iiHeSD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jeM %XI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n|5+HE4@  
nStartPos,nEndPos,i); 4r5trquC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !IlsKMZ  
fileSplitterFetch.start(); a!YpSFr  
}  mD`
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <}x_F)E[t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); eglcf z%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tpp.
9  
nEndPos = " + nFileLength); =9@{U2 =l  
// fileSplitterFetch[nPos.length-1].start(); !}fq%8"-  
t>;u;XY!;  
>-fOkOWXy  
//等待子线程结束 !_<zK:`-L  
//int count = 0; Ig*68M<  
//是否结束while循环 xu[6h?u(h8  
boolean breakWhile = false; 8/cD7O  
Y(QLlJ*)/  
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while(!bStop) E'qGKT  
{ >g8H  
write_nPos(); v:0.  
Utility.sleep(500); ~_^#/BnAl  
breakWhile = true; k fS44NV  
0 =#)-n  
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for(int i=0;i<nStartPos.length;i++) t3%[C;@wB  
{ #T_m|LN7  
if(!fileSplitterFetch.bDownOver) B ^>}M  
{ .: ~);9kj  
breakWhile = false; RL0,QC)e#@  
break; GZgu1YR
 
} z/zUb``  
} r}ZL{uWMW  
if(breakWhile) O!#yPSq?  
break; >R"]{y  
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//count++; fW^\G2Fk  
//if(count>4) NUH;\*]8s  
// siteStop(); ,{=pFs2  
} c zTr_>
  
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System.err.println("文件下载结束！"); ge*(w{|x  
} +RLHe]9&  
catch(Exception e){e.printStackTrace ();} \[</|]'[  
} =ZdP0l+V=k  
7!.#:+rg5#  
/.!ytHw8  
//获得文件长度 o'nju.'  
public long getFileSize() _ZUtQ49  
{ Y] Q=kI  
int nFileLength = -1; NYopt?Xg  
try{ !bEy~.  
URL url = new URL(siteInfoBean.getSSiteURL()); oCD#Gmr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `uL^!-  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~Y=v@] 2/  
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6
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int responseCode=httpConnection.getResponseCode(); E#'JYz@  
if(responseCode>=400) zq ;Y
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{ ^~iu),gu  
processErrorCode(responseCode); >jI(^8?  
return -2; //-2 represent access is error \va'>?#o1  
} ('yBIb\ue  
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String sHeader; Fy(-.S1  
|#hj O3  
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for(int i=1;;i++) @lvvI<U  
{ I9J
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o/Z  
//Utility.log(in.readLine()); &fH;A X.  
sHeader=httpConnection.getHeaderFieldKey(i); tNsiokOm  
if(sHeader!=null) <\i}zoPO  
{ v
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if(sHeader.equals("Content-Length")) Af'L=0  
{ p9c`rl_N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ID+o6/V8  
break; r3.A!*!  
} M[aF3bbN  
} 1eiV[z$?  
else IK#W80y  
break; "`Y.N$M`k  
} ~fL:pVp  
} (J!FW(Ma|=  
catch(IOException e){e.printStackTrace ();} Mf [v7\  
catch(Exception e){e.printStackTrace ();} '9O4$s1  
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Utility.log(nFileLength); & w%%{lM  
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return nFileLength; "Me)'  
} k 4|*t}o7  
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//保存下载信息（文件指针位置） _," -25a  
private void write_nPos() cE}y~2cH
 
{ ]xJ5}/  
try{ fb8"hO]s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6]`XW0{C  
output.writeInt(nStartPos.length); kGaK(^w  
for(int i=0;i<nStartPos.length;i++) QL_~E;U  
{  {@XzY>  
// output.writeLong(nPos); (?luV#{5  
output.writeLong(fileSplitterFetch.nStartPos); vAeh#V~#  
output.writeLong(fileSplitterFetch.nEndPos); ]#)1(ZE  
} RPH]@  
output.close(); Ps<6kQ(  
} !Db0r/_:G  
catch(IOException e){e.printStackTrace ();} -Fi{[%&u  
catch(Exception e){e.printStackTrace ();} n%N|?!rB  
} tCkKJ)m  
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//读取保存的下载信息（文件指针位置） Z^P]-CB|6A  
private void read_nPos() :wlX`YW+e  
{ B.:DW3  
try{ kzZdYiC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N*d )<8_  
int nCount = input.readInt(); {Pi+VuLE  
nStartPos = new long[nCount]; }B-@lbK6)  
nEndPos = new long[nCount]; ;'^5$q  
for(int i=0;i<nStartPos.length;i++) EN OaC  
{ `jl 1Q,~2r  
nStartPos = input.readLong(); irqNnnMGEa  
nEndPos = input.readLong(); cQ:Y@f 9  
} r3OTU$t?  
input.close(); 'g3!SdaLF  
} FbvwzZ  
catch(IOException e){e.printStackTrace ();} S1_X@[t  
catch(Exception e){e.printStackTrace ();} xR9<I:^&  
} NF/@'QRT  
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+59tX2@Q  
private void processErrorCode(int nErrorCode) p([g/Q  
{ e|ChCvk  
System.err.println("Error Code : " + nErrorCode); cP >MsUZWl  
} &4g]#A>@  
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//停止文件下载 [&IJy  
public void siteStop()  bnll-G|  
{ z|';Y!kQ  
bStop = true; `5VEGSP]  
for(int i=0;i<nStartPos.length;i++) ~d+.w%Z`  
fileSplitterFetch.splitterStop(); yJ(BPSt  
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} P!;%DI!<b  
} SV-M8Im73z  
//负责部分文件的抓取 QG~4<zy  
**FileSplitterFetch.java *}yOL [  
*/ :n1^Xw0q  
package NetFox; ?Hb5<,1u3  
p&Os5zw;|  
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import java.io.*; }3G`f> s  
import java.net.*; /h/f&3'h  
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public class FileSplitterFetch extends Thread { fpCkT[&m  
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String sURL; //File URL Q
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long nStartPos; //File Snippet Start Position _;o)MTw|'  
long nEndPos; //File Snippet End Position ccLTA  
int nThreadID; //Thread's ID O$'BJKj-4  
boolean bDownOver = false; //Downing is over ?*2DR:o>@  
boolean bStop = false; //Stop identical v'x)AbbC  
FileAccessI fileAccessI = null; //File Access interface ^lF'
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s7x&x;-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0nz=whS{  
{ U"Gg ,  
this.sURL = sURL; HnDz4eD  
this.nStartPos = nStart; i_ha^mq3  
this.nEndPos = nEnd; p};B*[ki  
nThreadID = id; [| \Z"   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -k$
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} 5>E]C=maD  
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public void run() WtT* 1Z  
{ z>\vYR$  
while(nStartPos < nEndPos && !bStop) "OIra2O  
{ ||M;[-JoJ  
}8H_^G8  
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try{ n^HKf^]  
URL url = new URL(sURL); M Y2=lT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a>3#z2#  
httpConnection.setRequestProperty("User-Agent","NetFox"); O
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String sProperty = "bytes="+nStartPos+"-"; U Bo[iZ|%  
httpConnection.setRequestProperty("RANGE",sProperty); F\!Va  
Utility.log(sProperty); G5C=p:o{/  
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InputStream input = httpConnection.getInputStream(); Y[(U~l,a+  
//logResponseHead(httpConnection); hJkP_(+J\  
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byte[] b = new byte[1024]; .3yoDab  
int nRead; /| nZ)?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  b7]MpL  
{ 0j=xWC  
nStartPos += fileAccessI.write(b,0,nRead); <{t*yMr   
//if(nThreadID == 1) f
!|$!r*q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?9Lp@k~TO  
} P^wDt14>  
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Utility.log("Thread " + nThreadID + " is over!"); D*!UB5<>/t  
bDownOver = true; !$q *~F"S  
//nPos = fileAccessI.write (b,0,nRead); cO&(&*J r  
} 4,nUCT  
catch(Exception e){e.printStackTrace ();} V^v?;f?  
} f WUFCbSU  
} z5V~m_RO  
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_TGv"c@V  
//打印回应的头信息 Q1cM{$}M  
public void logResponseHead(HttpURLConnection con) !x%$xC^Iz  
{ yvQRr75
  
for(int i=1;;i++) NCid`a$  
{ i!|OFU6  
String header=con.getHeaderFieldKey(i); 5<Lal^c D  
if(header!=null) 4
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); J)*7JX  
Utility.log(header+" : "+con.getHeaderField(header)); E41ay:duAl  
else )<<}8Fs  
break; i4Ps#R_wx  
} " R=,W{=  
} #it)  
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public void splitterStop() }K rQPg  
{ ,Q7W))j  
bStop = true; C0RnBu  
} `$fKS24u  
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} JemB[  
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/* bL6, fUS  
**FileAccess.java w&b?ze{  
*//文件访问(定位，写) :u ruC
  
package NetFox; I(bxCiRV  
import java.io.*; `vMrlKq  
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>j%4U*  
public class FileAccessI implements Serializable{ <i!:{'%  
MBjo9P(
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E1"H(m&6  
RandomAccessFile oSavedFile; Xb/W[rcs  
long nPos; R&!{3!V  
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w1N-`S:  
public FileAccessI() throws IOException nQHQVcDs8  
{ 54^2=bp  
this("",0); OG!+p}yD]  
} zfm-vU  
t,v=~LE  
[k<w'n*  
public FileAccessI(String sName,long nPos) throws IOException JSCZX:5  
{ ,`su0P\%#.  
oSavedFile = new RandomAccessFile(sName,"rw"); :S_3(/} \  
this.nPos = nPos; 40M/Gu:  
oSavedFile.seek(nPos); $-J=UT2m  
} x2_?B[z  
oiKY2.yW  
n[`KhRN  
public synchronized int write(byte[] b,int nStart,int nLen) D.ajO^[  
{ ?gGmJl  
int n = -1; HW"';M%  
try{ &3_S+.JO  
oSavedFile.write(b,nStart,nLen); ^! r<-J  
n = nLen; J+]W*?m  
} P c'0.4  
catch(IOException e) :JI&ngWK  
{ )W0zu\fL =  
e.printStackTrace (); =KCAHNr4?  
} Vs:x3)m5j  
 mRYM,  
/Y7YyjMi  
return n; ~4}'R_  
} 8b!-2d:*  
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} C5ia9LpRX  
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?Z{:[.  
/* :5 zXW;s  
**SiteInfoBean.java {0?]weN*  
*/
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package NetFox; t:N3k ;k  
UbDRE[^P  
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public class SiteInfoBean { {i!@C(M3  
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private String sSiteURL; //Site's URL % a9C]?  
private String sFilePath; //Saved File's Path ymr#OP$<S  
private String sFileName; //Saved File's Name RY\[[eG  
private int nSplitter; //Count of Splited Downloading File ! ,v!7I  
,|Xib
fw  
{ d*?O  
public SiteInfoBean() 4^>FN"Ve`B  
{//nSplitter的缺省值为5 7c7:B2Lq  
//default value of nSplitter is 5 !#'
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this("","","",5); P+/6-CJ  
} )=EJFQ*v  
!92zC._  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #1#?k  
{ fdCN?p[_  
sSiteURL= sURL; Ac,Qj`'V  
sFilePath = sPath; Ga9^+.j  
sFileName = sName; 7L"Pe'Hw  
this.nSplitter = nSpiltter; ta)'z@V@g  
!}$,) ~<+H  

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} 0)Wrfa  
/CT g3Q"KQ  
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public String getSSiteURL() A@H
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{ >i:hdcxe  
return sSiteURL; G|,'6|$jE  
} F/(z3Kf  
g~Hmka_fD1  

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public void setSSiteURL(String value) %Q2<bj]  
{ iAWd 9x  
sSiteURL = value; __Tg1A  
} qyl9#C(a  
/"LcW"2;N  
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public String getSFilePath() 54geU?p0  
{ x,~ys4  
return sFilePath; =yy7P[D  
} OY?x'h  
]!=,8d
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0**.:K<i  
public void setSFilePath(String value) \A'tV/YAd  
{ D$OUy}[2`.  
sFilePath = value; WXgGB[x  
} bf2B  
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public String getSFileName() <`/22S"  
{ fZ6"DJZ  
return sFileName; 1p%75VW  
} (='e9H!3D  
ra[*E4P9L*  
#rs]5tx([  
public void setSFileName(String value) b+rn:R  
{ I_\#(  
sFileName = value; (tLAJ_v!.K  
} )kl(}.9X  
@9X+ BdQU  
'U8% !  
public int getNSplitter() o7A+O%dX  
{ oTjsiXS  
return nSplitter; ;xKPa6`E  
} WU" Lu  
ha -KfkPFE  
=Co[pt  
public void setNSplitter(int nCount) q0a8=o"|  
{ I\FBf&~  
nSplitter = nCount; =8!FY"c*  
} Munal=wL  
}
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/* G7yR&x^  
**Utility.java e71dNL'$  
*/ bWe_<'N  
package NetFox; ]?$eBbt  
PAUepO_  
{"x>ewAf  
public class Utility { {|Pg]#Wi&  
\F }s"#  
+ yF._Ie=  
public Utility() P nxxW?  
{ R | &+g\{;  
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Oz:J8l%  
} #,4CeD|(D,  
^G~C#t^  
//线程睡眠 },;ymk|g[  
public static void sleep(int nSecond) A3Lfh6O  
{ jZ5 mpYUO  
try{ K\2UwX  
Thread.sleep(nSecond); 5,,b>Z<  
} F^mMyK  
catch(Exception e) cp&- 6 w+  
{ @-ms_Z  
e.printStackTrace (); NPFrn[M$  
} :nPLQqXGQ  
} pg4J)<t#  
*NEA(9  
//日志 \`!M5FJ  
public static void log(String sMsg) \
>%.ktG  
{ F.%g_Xvk:  
System.err.println(sMsg); =%\y E0#  
} !4blX'<w  
i3s,C;7[2  
L#|,_j=9  
public static void log(int sMsg) yl#(jb[?1  
{ 5^}"Tn4I  
System.err.println(sMsg); ycr\vn t  
} T/$6ov+K  
} Z^ e?V7q  
I\|x0D  
n> >!dg Og  
/* wy1xZQ<5  
**TestMethod.java X4D>  
*/ 8!T6N2O6d  
package NetFox; aUBGp: (  
f.~-31  
wj'5D0  
public class TestMethod { tsLi5;KA]  
_^;;vR%   
\U0p?wdr:  
public TestMethod() >\x   
{ ///xx/weblogic60b2_win.exe <Kq4thR  
try{ O$2'$44HX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZMI!Sl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YXdd=F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w[A$bqz  
fileFetch.start(); `h:$3a:5  
} J'%  
catch(Exception e){e.printStackTrace ();} <DM /"^*  
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&f:"p*=a\  
} '4L0=G:A<q  
2[#7YWs  
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public static void main(String[] args) ,Qd;t  
{ 4Hk eXS.  
new TestMethod(); <yxEGjm  
} =xa:>Vh#  
} |Zn|?#F  
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