http断点续传简单实现（java)

/* W~.1f1)  
**SiteFileFetch.java LV0g *ng  
*/ {ogGi/8  
package NetFox; lD6hL8[  
import java.io.*; x/~V ZO  
import java.net.*; !a[ voUS  
IJD'0/R'c  
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public class SiteFileFetch extends Thread { |D$U{5}Mv  
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H_ .@{8I  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0jrcXN~  
long[] nStartPos; //开始位置 Fq&@dxN3  
long[] nEndPos; //结束位置 tU!"CX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KOV^wSwS  
long nFileLength; //文件长度 P{)&#HXUVb  
boolean bFirst = true; //是否第一次取文件 wS%I.  
boolean bStop = false; //停止标志 7xVI,\qV  
File tmpFile; //文件下载的临时信息 S!#7]wtbP  
DataOutputStream output; //输出到文件的输出流 M86
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4^w>An6  
public SiteFileFetch(SiteInfoBean bean) throws IOException *=MC+4E  
{ CmJI"   
siteInfoBean = bean; G( nT.\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #fG!dD42  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _Eq:Qbw#  
if(tmpFile.exists ()) lc>nUhj.  
{ X3!btxa%t  
bFirst = false; c<A@Op"A  
read_nPos(); #|A @  
} NqkRR$O  
else 00%$?Fyk  
{ :&2RV_$>=  
nStartPos = new long[bean.getNSplitter()]; w]"Y1J(i  
nEndPos = new long[bean.getNSplitter()]; ~Msee+ZZ :  
} M_T$\z;,  
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} ;T"}dJel#  
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public void run() uTbI\iq  
{ +m:U9K(\h  
//获得文件长度 \r324Bw>2  
//分割文件 mmwwz  
//实例FileSplitterFetch k:m~'r8z  
//启动FileSplitterFetch线程 ^^jF*)DT@  
//等待子线程返回 V F6OC4 K  
try{ %Q1v8l.}  
if(bFirst) x\3 ` W  
{ +SrE  
nFileLength = getFileSize(); MZ=U} &F  
if(nFileLength == -1) 0w8Id . ,  
{ WB6g i2  
System.err.println("File Length is not known!"); x2Y1B  
} }s}b]v  
else if(nFileLength == -2) .oaW#f}0P  
{ KKGAk\X  
System.err.println("File is not access!"); @`wBe#+\  
} .DHZs#R  
else GQ2&D}zh  
{ 0AJ6g@t[  
for(int i=0;i<nStartPos.length;i++) tI*u"%#t  
{ TkWS-=lNH0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _#f/VE  
} X2dTV}~i  
for(int i=0;i<nEndPos.length-1;i++) iBN,YPo~  
{ {'"A hiR/  
nEndPos = nStartPos[i+1]; ;L(W'+  
} Ad@))o2  
nEndPos[nEndPos.length-1] = nFileLength; %lv2
;-  
} "!E(=W?  
} 8Dhq_R'r  
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Ip.5I!h[Xb  
//启动子线程 |WXu;uf$.u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |oSyyDYWP  
for(int i=0;i<nStartPos.length;i++) b[GZ sXD-  
{ .X_k[l9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4%\L8:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), FxM`$n~K  
nStartPos,nEndPos,i); (LL4V 3)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \
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fileSplitterFetch.start(); u\Fq
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} p
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q!GB^P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1kb?y4xeJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b'Mg  
nEndPos = " + nFileLength); pA(@gisg  
// fileSplitterFetch[nPos.length-1].start(); !uO|1b  
3t68cdFlz  
"4`h -Y  
//等待子线程结束 )P:TVe9`  
//int count = 0; J^n(WnM*F  
//是否结束while循环 xzW]D0o0  
boolean breakWhile = false; ThJLaNS  
-HZvz[u  
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while(!bStop) q6H90Zb  
{ "*%=k%'
 
write_nPos(); L)8;96  
Utility.sleep(500); wd..{j0&  
breakWhile = true; ^Bm9yR  
aina6@S  
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for(int i=0;i<nStartPos.length;i++) "LP4)hr_`  
{ RUX!(Xw  
if(!fileSplitterFetch.bDownOver) `5[VO  
{ FT`y3~
 
breakWhile = false; \&@Tq-o  
break; 78dmXOZ'_h  
} *|_u~v:)|5  
} 'PV,c|f>  
if(breakWhile) Gp;[WY\  
break; &vdGKYs 6  

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@_1$ <8  
//count++; ^a<=@0|  
//if(count>4) UupQ*,dJ  
// siteStop(); ;[gv-H  
} 8 l}tYl`|  
N5%~~JRO  
N7+K$)3  
System.err.println("文件下载结束！"); Tk.MtIs)V}  
} 1m}'Y@I  
catch(Exception e){e.printStackTrace ();} _f^q!tP&d  
} W 86S)+h  
9DKmX
L  
Fypqf|  
//获得文件长度 P*I
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public long getFileSize()
;S,g&%N  
{ hLx*$Z>  
int nFileLength = -1; vQu) uml  
try{ OEdp:dW|  
URL url = new URL(siteInfoBean.getSSiteURL()); G\jr^d\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "9kEqz4a  
httpConnection.setRequestProperty("User-Agent","NetFox"); -_>c P  
7
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int responseCode=httpConnection.getResponseCode(); mUcHsCszH  
if(responseCode>=400) c7wza/r>  
{ /~gM,*  
processErrorCode(responseCode); ~g1@-)zYxK  
return -2; //-2 represent access is error !l.Rv_o<O  
} IG
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m='+->O*'l  
String sHeader; /*rMveT  
=jg
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for(int i=1;;i++) -W+dsZ Sv8  
{ `n5RDz/f0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6u8`,&U  
//Utility.log(in.readLine()); ^Ud`2 OW;2  
sHeader=httpConnection.getHeaderFieldKey(i); 8ne5 B4  
if(sHeader!=null) IQ2<Pinv  
{ iDHmS6_c  
if(sHeader.equals("Content-Length")) ,ZMYCl]  
{ `z+:Z>>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -#rFCfPy^  
break; Br-y`s~cP  
} BtU,1`El5  
} LoBKR c2t  
else B: {bmvy  
break; c!w4N5aM  
} pjjs'A*y  
} hDmVv;M:  
catch(IOException e){e.printStackTrace ();} 2Q1* Xq{  
catch(Exception e){e.printStackTrace ();} J0o U5d=3  
\?g)
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Utility.log(nFileLength); 0qR;Z{k  
5 0~L(<  
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return nFileLength; #-e3m/>  
} ~jF5%Gu  
^0X86  
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//保存下载信息（文件指针位置） K")-P9I6-f  
private void write_nPos() ;]<$p[m  
{ b3Y9  
try{ y6:=2(]w<p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9dKrE_zK:  
output.writeInt(nStartPos.length); atl0#FBd  
for(int i=0;i<nStartPos.length;i++) !u4oo-  
{ d&R/fIm  
// output.writeLong(nPos); ^IQC:21  
output.writeLong(fileSplitterFetch.nStartPos); dzbzZ@y  
output.writeLong(fileSplitterFetch.nEndPos); D5AKOM!`  
} Y*J`Wf(w  
output.close(); I:mJWe  
} ~^Vt)/}Q  
catch(IOException e){e.printStackTrace ();} 3ck;~Ncj<  
catch(Exception e){e.printStackTrace ();} A:
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} Q v{q:=k  

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//读取保存的下载信息（文件指针位置） `[o^w(l:5@  
private void read_nPos() wXNFL9F8  
{ C7qbofoV  
try{ :2?i9F0_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); LuQ=i`eXx  
int nCount = input.readInt(); /i^b;?/1  
nStartPos = new long[nCount]; '1.T-.4>&  
nEndPos = new long[nCount]; <M+ZlF-`  
for(int i=0;i<nStartPos.length;i++) 2
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{ NUx%zY  
nStartPos = input.readLong(); :Q&8DC#]  
nEndPos = input.readLong(); .F 3v)  
} .&}}ro48
  
input.close(); :/Sx\Nz78  
} LvW9kL+WiQ  
catch(IOException e){e.printStackTrace ();} }tj@*n_  
catch(Exception e){e.printStackTrace ();} &x;v&  
} jsi\*5=9p<  
^>k[T.  
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private void processErrorCode(int nErrorCode) skZxR5v3~L  
{ 2}509X(*  
System.err.println("Error Code : " + nErrorCode); cB?HMLbG>  
} | LfH,6  
A")B<BK  
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//停止文件下载 H!oP!rzEo  
public void siteStop() m=j7 vb  
{ =b !f  
bStop = true; =@{H7z(p&  
for(int i=0;i<nStartPos.length;i++) KvktC|~?  
fileSplitterFetch.splitterStop(); m0un=>{  
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} fqvA0"tv  
} \JN<"/  
//负责部分文件的抓取 ~?[@
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**FileSplitterFetch.java nm\n\j~  
*/ l+YpRx/T\  
package NetFox; ~u}[VP  
&)\0mpLK9  
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import java.io.*; p~=%CG^5  
import java.net.*; BflF*-s ^  
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public class FileSplitterFetch extends Thread { 6RzTSb  
Ct"h.rD]  
8+gSn  
String sURL; //File URL yUNl)E  
long nStartPos; //File Snippet Start Position \<;/)!Nmw  
long nEndPos; //File Snippet End Position #T !YFMh;  
int nThreadID; //Thread's ID "FG6R'  
boolean bDownOver = false; //Downing is over ?^,GaZ^V  
boolean bStop = false; //Stop identical ^R K[-tVV  
FileAccessI fileAccessI = null; //File Access interface Q"QrbU  
5l{_E:.1  
)+\e+Ad}H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N"HN]Y@w  
{ }Y<(1w  
this.sURL = sURL; =\oNu&Q^  
this.nStartPos = nStart; i-tX5Md|  
this.nEndPos = nEnd; 5+,&9;'Y^  
nThreadID = id; uXK$5"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0=-h9W{zI  
} 9)H~I/9Y  
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public void run() @bD,^3U  
{ Z$6W)~;,
 
while(nStartPos < nEndPos && !bStop) &8~U&g6C  
{ Vf O0 z5&  

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[.3M>,)+-  
try{ mufF_e)  
URL url = new URL(sURL); Lo9+#ITyx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ydoCoD w  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3#5sj >  
String sProperty = "bytes="+nStartPos+"-"; `?`\!uP"  
httpConnection.setRequestProperty("RANGE",sProperty); >f}rM20Vm  
Utility.log(sProperty); +O\6p  
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InputStream input = httpConnection.getInputStream(); lD 9'^J  
//logResponseHead(httpConnection); s}/YcU
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byte[] b = new byte[1024]; LH0\Sm
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int nRead; ^Z2%b>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ><^A4s  
{ .XY
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nStartPos += fileAccessI.write(b,0,nRead); kw?RUt0-V  
//if(nThreadID == 1) 0( /eSmet  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5E}0
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} GRlA9Q  
-OVJ]  
q
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Utility.log("Thread " + nThreadID + " is over!"); JWH}0+1*  
bDownOver = true; #YhKAG@|  
//nPos = fileAccessI.write (b,0,nRead); QWfwoe&;R:  
} tA'i-D&  
catch(Exception e){e.printStackTrace ();} .RoO6:T6  
} 31J7# S2  
} :'.-*Ew  
1!BV]&,[  
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//打印回应的头信息 9;JUc0%  
public void logResponseHead(HttpURLConnection con) 24|:VxO  
{ */?L_\7  
for(int i=1;;i++) f)N67z6  
{ dp_J*8  
String header=con.getHeaderFieldKey(i); q;Qpd]H  
if(header!=null) .DCp)&m l;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l.b  
Utility.log(header+" : "+con.getHeaderField(header)); YHCXVu<.b  
else =a7m^e7  
break; <6-(a;T!7  
} `| R8WM  
} iY.~N#Q  
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public void splitterStop() ]FQ4v.7  
{ "ve?7&G7U  
bStop = true; pmHd1 Wub  
} rA{h/T"  
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} ed*=p l3.  
j:U>V7Kn3~  
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/* _v]I6<!5U  
**FileAccess.java $+*ZsIo   
*//文件访问(定位，写) 1&wZJP=  
package NetFox; Zad+)~@!tq  
import java.io.*; G|Q}.v  
=fG(K!AQ  

;|9VPv/  
public class FileAccessI implements Serializable{ 7+=j]+O  
1\zI#"b ^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L\hPw{)  
RandomAccessFile oSavedFile; Ig$5Ui  
long nPos; y]cx}9~  
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public FileAccessI() throws IOException Hk3HzN3  
{ "
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this("",0); a$;+-Y  
} I+u=H2][2  
T
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public FileAccessI(String sName,long nPos) throws IOException L~vNW6#W  
{ =X+DC&]%!  
oSavedFile = new RandomAccessFile(sName,"rw"); ^{Syg;F=  
this.nPos = nPos; \k;raQR4t*  
oSavedFile.seek(nPos); $OjsaE%  
} vs6`oW"{#  
}yB@?  

rr9HC]63  
public synchronized int write(byte[] b,int nStart,int nLen) f_;3|i  
{
n=hz7tjaz  
int n = -1; Z< uwqA  
try{ G-,PsXSwe  
oSavedFile.write(b,nStart,nLen); ?A2EuvQH]  
n = nLen; VFG)|Z  
} hM>xe8yE  
catch(IOException e) wl(}F^:/`  
{ )xTp7YnZ;  
e.printStackTrace (); &TC  
} '7_'s1  
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return n; 5{cA
awU.  
} "q]v2t  
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} Q^0K8>G^  
{/B) YR  
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/* Rzb663d  
**SiteInfoBean.java Of:e6N  
*/ U/jJ@8
 
package NetFox; `=CF |I  
EH4WR/x  
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public class SiteInfoBean { "gK2!N|#  
X}p4yR7'  

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private String sSiteURL; //Site's URL 1b_->_9  
private String sFilePath; //Saved File's Path drb_GT  
private String sFileName; //Saved File's Name B5tJ|3!  
private int nSplitter; //Count of Splited Downloading File ;39{iU.m  
gb@!Co3  
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public SiteInfoBean() u# %7>=  
{//nSplitter的缺省值为5 ;>Z#1~8  
//default value of nSplitter is 5 kW-5H;>  
this("","","",5); [3/P EDkw  
} XP{ nf9&  
nq6]?ZJ  
dB_\,%vAd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EH,uX{`e  
{ .h7b 4J  
sSiteURL= sURL; <GoE2a4Va  
sFilePath = sPath; )
;,#H`'  
sFileName = sName; {]Lc]4J  
this.nSplitter = nSpiltter; ?*4]LuK6  
4J I;NN  
0udE\/4!^  
} ?Bh}  
=}Cb?C[;  
 *riGi  
public String getSSiteURL() ?m~x%[Vn  
{ mTs[3opg  
return sSiteURL; ]B5\S  
} )<3WVvB  
5_`.9@eh.  
5[Q44$a{  
public void setSSiteURL(String value) FPcgQ v;p  
{ F htf4  
sSiteURL = value; lezdJ  
} _L: /2  
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public String getSFilePath() 4vy!'r@  
{ qv,|7yw{  
return sFilePath; y"){?  
} y:v0&9L  
moc_}(  
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public void setSFilePath(String value) n P69W  
{ ?rv+ydR/q  
sFilePath = value; !(o)*S  
} gzC\6ca
 
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^  
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public String getSFileName() E^|b3G6T  
{ ZN
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return sFileName; ,:,c kul  
} sN;U,{  
#s]]\  
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public void setSFileName(String value)
rW1>t+  
{ 
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sFileName = value; qed; UyN  
} }7&;YAt  
]Mtb~^joG  
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public int getNSplitter() 4q~l?*S  
{ P}aJvFlmP  
return nSplitter; -R:1-0I$  
} -`Z5#8P  
KK7Y"~ 9&-  
,ciNoP*-~%  
public void setNSplitter(int nCount) qWP1i7]=/  
{ ^ ]`<nO  
nSplitter = nCount; 6?hv,^  
} x9@%L{*  
} `;i| %$TU  
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qOk4qbl[  
/* dnN"  
**Utility.java g\X"E>X  
*/ 8LiRZ"  
package NetFox; O>'o;0  

g*^"x&  
/#Ew{RvW'  
public class Utility { B4J^ rzK  
4;j#7  
}F@`A?k  
public Utility() *h]qh20t  
{ D./e|i?  
ImvkB~8N  
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} a
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]C]tLJ!M  
//线程睡眠 *d(wOl5[  
public static void sleep(int nSecond) La3f{;|u5M  
{ FJ#V"|}  
try{ bt~-=\  
Thread.sleep(nSecond); drN^-e  
} _}Z*%sT  
catch(Exception e) A0&~U0*(~  
{ mp@JsCU  
e.printStackTrace (); aeP4%h  
} %f, 9  
} T@k&YJ  

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//日志 M@csB.'  
public static void log(String sMsg) nA+[[(6  
{ ;'cv?3Y  
System.err.println(sMsg); |=GRPvvi  
} MA"iM+Ar  
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@dcW0WQ\  
public static void log(int sMsg) }S%a]  
{ V ;>{-p  
System.err.println(sMsg); !%5{jO1  
} {feS-.Khv  
} QmgwIz_  
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IO,kP`Wcx  
/* Fbk<qQH  
**TestMethod.java yP[GU| >(  
*/ cL=P((<K?  
package NetFox; vy-{BH  
]kKf4SJZFU  
9>zN27  
public class TestMethod { TcRnjsY$  
a>s v  
b6]M}ixK  
public TestMethod() ]kc_wFT<  
{ ///xx/weblogic60b2_win.exe *TMg.  
try{ vqL{~tR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6"%[s@C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R[#5E|` `9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oNiS"\t  
fileFetch.start(); s"a*S\a;b  
} x<= ;=893  
catch(Exception e){e.printStackTrace ();} {uckYx-A  
cYGZZC8|K  
w7%N=hL1
 
}  W#??fae  
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5B98}N  
public static void main(String[] args) 40@KL$B=  
{ |,yS>kjp  
new TestMethod(); 2TAy'BB;)  
} d$Mj5w
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} =z@'vu$Fh  
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