http断点续传简单实现（java)

/* g>Y|9Y  
**SiteFileFetch.java *#E FsUw  
*/ 6;u$&&c(  
package NetFox; ~T9/#-e>BF  
import java.io.*; |y&*MTfV4L  
import java.net.*; Z8zmHc"IH  
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public class SiteFileFetch extends Thread { q ]M+/sl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s@9vY\5[9  
long[] nStartPos; //开始位置 { D^{[I  
long[] nEndPos; //结束位置 _]yn"p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HIQ_%L4]  
long nFileLength; //文件长度 0KYEb%44  
boolean bFirst = true; //是否第一次取文件  UmNa[s  
boolean bStop = false; //停止标志 )T';qm0w  
File tmpFile; //文件下载的临时信息 RMK"o?  
DataOutputStream output; //输出到文件的输出流 eb.O#Y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |rJ=Ksc
 
public SiteFileFetch(SiteInfoBean bean) throws IOException t0o`-d(  
{ =o Xsb  
siteInfoBean = bean; ZNf6;%oGG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {)
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '>&^zgr  
if(tmpFile.exists ()) } ~h3c
|  
{ M*z~gOZ  
bFirst = false; U@gn;@\  
read_nPos(); d\p,2  
} ;gBRCZ
 
else 0*rQ3Z  
{ N03HQ
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nStartPos = new long[bean.getNSplitter()]; 2r!s*b\Ix  
nEndPos = new long[bean.getNSplitter()]; Zw
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} )^m%i]L_  
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} ERpnuMb  
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public void run() V=zi >o`   
{ Y,WuBH  
//获得文件长度 #cnq(S=.  
//分割文件 L[^9E'L$  
//实例FileSplitterFetch {p;zuCF1  
//启动FileSplitterFetch线程 ~;1l9^N|  
//等待子线程返回 ~KW,kyXBnD  
try{ Qj,]N@7  
if(bFirst) 7[I}*3Q'  
{ 4kG,*3&2  
nFileLength = getFileSize(); S/^"@?z,vE  
if(nFileLength == -1) X}tVmO?  
{ N$h{Yvbn  
System.err.println("File Length is not known!"); &0NFb^8+  
} 'XZ)!1N  
else if(nFileLength == -2) O$IEn/%+  
{ F{EnOr`,m=  
System.err.println("File is not access!"); 
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} w9NHk~LHKF  
else jqv-D  
{ ?%`@ub$  
for(int i=0;i<nStartPos.length;i++) '@p['#\uI  
{ v'VD0+3[H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &z>e5_.  
} V>ieh2G(  
for(int i=0;i<nEndPos.length-1;i++) 5#> 8MU?&  
{ pV20oSJNt  
nEndPos = nStartPos[i+1]; T'4z=Z]w  
} *8#i$w11M  
nEndPos[nEndPos.length-1] = nFileLength; %1O;fQL  
} p$
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} _h X]%  
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//启动子线程 AI,(
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Sg6"WV{<  
for(int i=0;i<nStartPos.length;i++) V#cqRE3XNi  
{ x
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]T;EdK-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {) Q@c)'  
nStartPos,nEndPos,i); R,F[XI+=N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q>mE< (-M  
fileSplitterFetch.start(); !R1.7}O  
} qjf[zF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mH Ic f{RG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dZi(&s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '[C.|)"  
nEndPos = " + nFileLength); H2um|6>  
// fileSplitterFetch[nPos.length-1].start(); 7Garnd b  
dgA-MQ5{  
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//等待子线程结束 -TM0]{  
//int count = 0; Eo#u#IY  
//是否结束while循环 Q(<)KZIK  
boolean breakWhile = false; VJdIHsI  
ZCB_  
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while(!bStop) /C>wd   
{ COW}o~3-4  
write_nPos(); MxY/`9>E|+  
Utility.sleep(500); u>TZt]h8  
breakWhile = true; -[6z 1"*  
*d"DA[(  
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for(int i=0;i<nStartPos.length;i++)  ))&;}2{  
{ m|=H#  
if(!fileSplitterFetch.bDownOver) 0KGY\,ae:;  
{ (N&lHLy  
breakWhile = false; ,`gl&iB  
break; d/bEt&  
} mnmP<<8C,  
} =$nB/K,8AX  
if(breakWhile) .G+Pe'4a  
break; P@,nA41,j  
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//count++; &|!7Z4N  
//if(count>4) T}"6wywM  
// siteStop(); b@S Cn9  
}
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System.err.println("文件下载结束！"); Gi "941zVl  
} <L`"!~Q  
catch(Exception e){e.printStackTrace ();} 7.Z@Wr?  
} i{ \%e  
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cG?cUw).E  
//获得文件长度 n84GZ5O>7  
public long getFileSize() |fSe>uVZ  
{ U7I qST  
int nFileLength = -1; x\J#]d.  
try{ /\H>y  
URL url = new URL(siteInfoBean.getSSiteURL()); LE*h9((  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aj?a^}X  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'JNElXqrv  
{W]=~*w  
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int responseCode=httpConnection.getResponseCode();  b^p"|L  
if(responseCode>=400) fH)YFn/  
{ D<Zp!J1o  
processErrorCode(responseCode); oiX+l5`pz  
return -2; //-2 represent access is error tl><"6AIP  
} Clh!gpB c  
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}  
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String sHeader; T'LIrf  
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for(int i=1;;i++) ~i21%$  
{ i:u1s"3~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rr!Y3)f;  
//Utility.log(in.readLine()); 7^Ns&Q  
sHeader=httpConnection.getHeaderFieldKey(i); CE"JS-S?  
if(sHeader!=null) \mV'mZ9>  
{ Zc!@0  
if(sHeader.equals("Content-Length")) 5vw{b
?  
{ ei6AV1| p  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ({NAMc*  
break; Fr%d}g  
} ZeEWp3vW  
} fwBRWr9  
else ;q:jl~  
break; xY$iz)^0&  
} %~jkB.\* )  
} 1?| flK  
catch(IOException e){e.printStackTrace ();} HgBGV0  
catch(Exception e){e.printStackTrace ();} IN,(yaC  
5*0y7K/D  
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Utility.log(nFileLength); &`fhEN  
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return nFileLength; #^4,GLIM  
} l/Vo-#  
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//保存下载信息（文件指针位置） 5bA)j!#)|X  
private void write_nPos() ;/0 Q1-  
{ cW{1 Pz^_  
try{ %eJGte-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /"?HZ
% W  
output.writeInt(nStartPos.length); LC})ciWa  
for(int i=0;i<nStartPos.length;i++) +z9gbcx  
{ b]7GmRekl  
// output.writeLong(nPos); $z$u{  
output.writeLong(fileSplitterFetch.nStartPos); 7Su#Je]  
output.writeLong(fileSplitterFetch.nEndPos); r)T:7zy  
} iA,kX\nK  
output.close(); i@][rdhT  
} *#TYqCc+g  
catch(IOException e){e.printStackTrace ();} 9<vWcq*4  
catch(Exception e){e.printStackTrace ();} ZlHDi!T  
} ~h"/Tce  
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5'Q|EIL  
//读取保存的下载信息（文件指针位置） -!)xQvagD.  
private void read_nPos() TyKWy0x-3  
{ c,Euv>*`  
try{ h!#:$|Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =E&OuX-R  
int nCount = input.readInt(); ](B@5-^  
nStartPos = new long[nCount]; @ a4/ELx  
nEndPos = new long[nCount]; .0G6flD   
for(int i=0;i<nStartPos.length;i++) 8_&CT :u>  
{ l_j4DQBRV  
nStartPos = input.readLong(); KIeT!kmDl  
nEndPos = input.readLong(); zyg:nKQW  
} xBFJ} v  
input.close(); W[[bV  
} ZvGgmLN  
catch(IOException e){e.printStackTrace ();}
KvQ,;A  
catch(Exception e){e.printStackTrace ();} o&hIHfZri  
} \ j.x0/;  
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S}[:;p?F`  
private void processErrorCode(int nErrorCode) 2l(j 4~g  
{ 8(/f!~  
System.err.println("Error Code : " + nErrorCode); 9"lW"lG!  
} *;yMD-=  
2d;xAX]  
"gikX/Co=  
//停止文件下载 >Wit"p  
public void siteStop() 6ym)F!t8l  
{ cTaD{!zm5  
bStop = true; 6`";)T[G9  
for(int i=0;i<nStartPos.length;i++) s
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fileSplitterFetch.splitterStop(); MHyl=5  
2-c0/?_4  
d~Ry>   
} H'\EA(v+  
} bl>b/u7/6  
//负责部分文件的抓取 g?AqC  
**FileSplitterFetch.java R|$`MX}'z  
*/ A}Dpw[Q2@8  
package NetFox; 5YH mp7c-z  
wVJFA1  
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import java.io.*; X|1YGZJ  
import java.net.*; !K~$-jlT  
yj+b/9My   
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public class FileSplitterFetch extends Thread { 71&+
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String sURL; //File URL RZh)0S>J  
long nStartPos; //File Snippet Start Position 4bzn^  
long nEndPos; //File Snippet End Position w]-iM  
int nThreadID; //Thread's ID DF|lUO]:  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical }~'Wz*Gm  
FileAccessI fileAccessI = null; //File Access interface "}+/0$F  
;L%~c4`l~m  
vGHYB1=~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException swq!Sp  
{ fToI,FA
 
this.sURL = sURL; 5t?2B]  
this.nStartPos = nStart; sLqvDH?V  
this.nEndPos = nEnd; X@q1;J  
nThreadID = id; Lbp6I0&n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k[)@I;m  
} E(LE*J  

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public void run() @5G7bY7Nz  
{ ld?.o/  
while(nStartPos < nEndPos && !bStop) -fg
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{ }z-  

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try{ emPm^M5/K
 
URL url = new URL(sURL); 7O^ S.(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bic { H  
httpConnection.setRequestProperty("User-Agent","NetFox"); X hX'*{3k  
String sProperty = "bytes="+nStartPos+"-"; kK|+W,  
httpConnection.setRequestProperty("RANGE",sProperty); !*UdY(  
Utility.log(sProperty); yP4.Z9  
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InputStream input = httpConnection.getInputStream(); PuCA @qY  
//logResponseHead(httpConnection); 8~#Q *  
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byte[] b = new byte[1024]; AK?j1Pk  
int nRead; xU<lv{m`D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NP*0WT_gB  
{ Y<fXuj|&  
nStartPos += fileAccessI.write(b,0,nRead); qJt gnk|  
//if(nThreadID == 1) ZUW>{'[K  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #'h CohL  
} }?kO<)d  
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Utility.log("Thread " + nThreadID + " is over!"); [V0h9!  
bDownOver = true; %pQ o%<d  
//nPos = fileAccessI.write (b,0,nRead); 2<@!m@  
} 695ppiKU  
catch(Exception e){e.printStackTrace ();} S`w)b'B!M  
} !PIdw~YC  
} <j3HT"^[D  
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//打印回应的头信息 ;}'<`(f&nX  
public void logResponseHead(HttpURLConnection con) -V<"Ay  
{ hAyPaS#  
for(int i=1;;i++) lIP<`6=4  
{ IuW10}"9  
String header=con.getHeaderFieldKey(i); (SA*9%  
if(header!=null) L]<4{8H.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); TJ:Lz]l >  
Utility.log(header+" : "+con.getHeaderField(header)); {hR2
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else #K w\r50  
break; 5VbNWrw  
} i%8 sy  
} @ RBwT  
:%MWbnVSC,  
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public void splitterStop() Mwc3@  
{ {2@96o2}  
bStop = true; jMbK7 1K%  
} g>zL{[e!  
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} zUqDX{I8  
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/* |Wk G='02  
**FileAccess.java Q2?qvNZ  
*//文件访问(定位，写) 3/FB>w gt  
package NetFox; OhEL9"\<  
import java.io.*; -m/4\D  
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public class FileAccessI implements Serializable{ #mYxO  
=YIQ _,{u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Hp!F?J7sx  
RandomAccessFile oSavedFile; P7-3Vf_L  
long nPos; IhLfuyFWu  
I r~X#$Upc  
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public FileAccessI() throws IOException }DaYO\:yK*  
{ ]EQ/*ct  
this("",0); yk
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} `l"~"x^Rr  
{eUfwPAa3  
6<Z9p@6  
public FileAccessI(String sName,long nPos) throws IOException lV'83  
{ =w-H )  
oSavedFile = new RandomAccessFile(sName,"rw"); EA.U>5Fq  
this.nPos = nPos; &=bI3-  
oSavedFile.seek(nPos); YyIt-fPZ  
} %>TdTt  
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8t%1x|!  
public synchronized int write(byte[] b,int nStart,int nLen) a0.XJR{T"  
{ <H6Uo#ao  
int n = -1; %R"Fx$tQ  
try{ {wI0 =U  
oSavedFile.write(b,nStart,nLen); I]X<L2  
n = nLen; kZQ;\QL1}  
} UhK,H   
catch(IOException e) GWKefH  
{ plfB}p  
e.printStackTrace (); I2'?~Lt  
} $hio(   
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return n; p<4':s;*  
}
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} ,dBI=D'  
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/* ]mSVjF3l  
**SiteInfoBean.java :Kiu*&{  
*/ 7(H/|2;-d8  
package NetFox; 2dfA}i>k  
J++D\x#@  
)Pq.kn{Sp  
public class SiteInfoBean { K4BMa]/U  
S[M$>  
\X!!(Z;6A  
private String sSiteURL; //Site's URL 0W> ",2|z  
private String sFilePath; //Saved File's Path ;q
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private String sFileName; //Saved File's Name s/V[tEC*z  
private int nSplitter; //Count of Splited Downloading File t&_lpffv  
^^#A9AM  
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public SiteInfoBean() Vs >1%$If  
{//nSplitter的缺省值为5 k:sh:G+=$d  
//default value of nSplitter is 5 J3=jC5=J4  
this("","","",5); R)/w   
} +dfSCs  
sC>8[Jatd  
2 E^P=jU`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #u_-TWVt  
{ d9s"y?8  
sSiteURL= sURL; !SnpesTn  
sFilePath = sPath; 8Ex0[e  
sFileName = sName; bTj,5,8i  
this.nSplitter = nSpiltter; eIJQ|p<v  
M5]wU   
#/T)9=m  
} <3HJkcYGz  
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}  
public String getSSiteURL() a^BD55d?  
{ T~la,>p|}  
return sSiteURL; c}A^0,"z>  
} AOpf
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public void setSSiteURL(String value) [
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{ \gdd
 
sSiteURL = value; Z,*VRuA  
} ; ?!sU  
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||qW'kNWM  
public String getSFilePath() ?G@%haqn6  
{ ;Bm{_$hf=  
return sFilePath; IcB>Hg5  
} \a<E3 <  
?pFHpz  
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public void setSFilePath(String value) ]BA8[2=m  
{ '2NeuK-KD  
sFilePath = value; --FvE|I  
} yDPek*#^"q  
/)~McP3  
bz1\EkLL  
public String getSFileName() bkb}M)C  
{ {+!_; zzZ  
return sFileName; q;rU}hAzG0  
} ^VA)vLj@  
_QQO&0Z  
=&vV$UtV  
public void setSFileName(String value) jsuQR  
{ r_)*/  
sFileName = value; }G]]0Oi2  
} # aC}\  
x[]n\\a?  
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public int getNSplitter() sviGS&J9h  
{ 9rhz#w  
return nSplitter; bp }~{]:b  
} 17-K~ybc  
m
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public void setNSplitter(int nCount) W_?S^>?l/  
{ 0'gJSrgNI  
nSplitter = nCount; )pg?ZM9  
} lm$T`:c  
} dme_I
vt  
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/* 'E9\V\bi  
**Utility.java Q WOd&=:  
*/ G*ecM`Bl  
package NetFox; STO6
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public class Utility { 6b@:La  
!y6 D+<k*]  
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public Utility() <=WQs2  
{ q?`bu:yS
 
0 ~VniF^  
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} O`*}N1No[  
*edB3!!  
//线程睡眠 o
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public static void sleep(int nSecond) |@Bl?Bs+  
{ (%tKGeb
  
try{ vFQ'sd]C  
Thread.sleep(nSecond); b?y3m +V`  
} +g(QF
  
catch(Exception e) >xT8[  
{ -e30!A  
e.printStackTrace (); tv5SQ+AI3  
} L.>`;`dmY  
} ZZ#S\*  
g^=p)h3  
//日志 p9 %7h.  
public static void log(String sMsg) A%pcPzG;  
{ $Die~rPU  
System.err.println(sMsg); gz8<&*2  
} ~h -0rE  
c'[l%4U8[  
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public static void log(int sMsg) p;g$D=2  
{ :dK/}S0  
System.err.println(sMsg); 4\3Z$%2^LZ  
} |*Hw6m  
} c{zQX0  
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+Ibcc8Qud  
/* L9"V$MO  
**TestMethod.java 5Osx__6$t  
*/ -|
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package NetFox; SO9j/  
2ACN5lyUS  
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public class TestMethod { I6~.sTl  
$0 eyp]XC\  
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f}  
public TestMethod() BZe x  
{ ///xx/weblogic60b2_win.exe 4Z,MqG>  
try{ ?(H/a-(:v}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,F]Y,"x:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YP/BX52v  
fileFetch.start(); 6Gwk*%sb  
} m!V ?xGKJ  
catch(Exception e){e.printStackTrace ();} d[J
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>T=($:n  
} vdV@G`)HPr  
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public static void main(String[] args) Y:XE4v/)@L  
{ > X<pzD3u  
new TestMethod(); r
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} ,E<(K8  
} R_`i=>Z-  
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