http断点续传简单实现（java)

/* uf,4GPo,  
**SiteFileFetch.java :bMCmY  
*/ XtfO;`  
package NetFox; 9&5\L  
import java.io.*; 06 gE;iT  
import java.net.*; 5,>1rd<B  
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public class SiteFileFetch extends Thread { N1WP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]B0>r^  
long[] nStartPos; //开始位置 [wl:"rm  
long[] nEndPos; //结束位置 .['@:}$1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V#!ihL/>  
long nFileLength; //文件长度 "Iu[)O%  
boolean bFirst = true; //是否第一次取文件 W;*rSK|(Sc  
boolean bStop = false; //停止标志 `pY\Mmgv1  
File tmpFile; //文件下载的临时信息 i%H_ua  
DataOutputStream output; //输出到文件的输出流 (5?5? <  
Okca6=2"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0B)l"$W[)/  
public SiteFileFetch(SiteInfoBean bean) throws IOException #"d.D7nA  
{ ^pMjii8IZ  
siteInfoBean = bean; 48M)A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xI'<4lo7Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \/4ipU.  
if(tmpFile.exists ()) w\=zTHo88  
{ ;nG"y:qq  
bFirst = false; eN{[T PPCq  
read_nPos(); hb9X<N+p  
} u814ZN}  
else 8Q^yh6z  
{ }[Uh4k8P  
nStartPos = new long[bean.getNSplitter()]; Q^/5hA  
nEndPos = new long[bean.getNSplitter()]; -yeQQ4b  
} 0m,A`*o  
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} La?q>  
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public void run() )F&@ M;2p'  
{ _:0<]<x?  
//获得文件长度 }5bh,'  
//分割文件 I#@iA!  
//实例FileSplitterFetch ?ECmPS1  
//启动FileSplitterFetch线程 T^NY|Y/  
//等待子线程返回 ,5'LbO-  
try{ l.1)%q&@^  
if(bFirst) B?-RzWB\3  
{ +Uq9C-Iu  
nFileLength = getFileSize(); g~.,
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if(nFileLength == -1) uOc>~ITPS  
{ MQE=8\  
System.err.println("File Length is not known!"); mp0p#8txi  
} +] B  
else if(nFileLength == -2) sW+YfJT  
{ PC/fb-J  
System.err.println("File is not access!"); KgVit+4u/  
} GmtMA|  
else 2.}<VivT  
{ 8,YF>O&  
for(int i=0;i<nStartPos.length;i++) ]R}#3(]1  
{ &T]+g8''  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b>E%&sf  
} C=@BkneQ  
for(int i=0;i<nEndPos.length-1;i++) zy4AFW  
{ shxr^  
nEndPos = nStartPos[i+1]; IGT~@);  
} (}O)pqZ>  
nEndPos[nEndPos.length-1] = nFileLength; a*CP1@O  
} 3/:O8H  
} fOJk+? c  
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93x.b]]"  
//启动子线程 [{N i94:d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  ?1r@r  
for(int i=0;i<nStartPos.length;i++) 7GfgW02  
{ SDiZOypS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), COFs?L.`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jM1_+Lm1  
nStartPos,nEndPos,i); EVNTn`J_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (U2G"  
fileSplitterFetch.start(); )(*A1C[  
} Di9yd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aRq7x~j )\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8_>\A= E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dJ?VN!B0  
nEndPos = " + nFileLength); Y+iC/pd  
// fileSplitterFetch[nPos.length-1].start(); b@^M|h.Va  
lZ0+:DaP2  
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//等待子线程结束 ?Li^XONz  
//int count = 0; ]?-56c,  
//是否结束while循环 T =3te|fv  
boolean breakWhile = false; 5h1!E  
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while(!bStop) X~0l1 @!  
{ kR^7Z7+#*  
write_nPos(); aen(Mcd3bg  
Utility.sleep(500); 8jqt=}b  
breakWhile = true; 2P$lXGjh  
5YC56,X  
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for(int i=0;i<nStartPos.length;i++) FO_nS  
{ ,p1 (0i  
if(!fileSplitterFetch.bDownOver) )oTEB#J  
{ Qat%<;P2  
breakWhile = false; FvG9PPd  
break; 8)5n  
} 34YYw@?}Y  
} Mn>dI@/gM  
if(breakWhile) FtM7+>Do
.  
break; z"}k\B-5  
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//count++;
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//if(count>4) 7b+
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// siteStop(); H!F'I)1  
} )FWF T:P~  
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System.err.println("文件下载结束！"); gywI@QD%#  
} l]WV?^*  
catch(Exception e){e.printStackTrace ();} [.6>%G1C  
} mI9h| n  
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]
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//获得文件长度 "oz@w'rG  
public long getFileSize() Pdf_{8r  
{ sB0+21'R  
int nFileLength = -1; cnLC>_hY  
try{ ivoPl~)J  
URL url = new URL(siteInfoBean.getSSiteURL()); ~e{2Y%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WcH^bAY6  
httpConnection.setRequestProperty("User-Agent","NetFox"); <$?:|  
C| Mh<,~E  
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int responseCode=httpConnection.getResponseCode(); ~|DF-t V  
if(responseCode>=400) T:)>Tcv}:  
{ f
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processErrorCode(responseCode); n!
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return -2; //-2 represent access is error QMtt:f]?i  
} {)b`fq  
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String sHeader; ^]U2Jd  
!-N!80  
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for(int i=1;;i++) *D AgcB  
{ ]VwAHT&je  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '')G6-c/  
//Utility.log(in.readLine()); H~ks"D1  
sHeader=httpConnection.getHeaderFieldKey(i); M<ad>M  
if(sHeader!=null) l$zNsf.  
{ YvYavd  
if(sHeader.equals("Content-Length")) >F+:ej  
{ bzJKoxU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6:B5PJq  
break; 4aV3x&6X  
} *s%s|/  
} AP@xZ%;K  
else N.64aL|1  
break; aNqVs|H  
} RLKO0 #  
} 50I6:=
@\\  
catch(IOException e){e.printStackTrace ();} mceSUKI;L  
catch(Exception e){e.printStackTrace ();} 1Rczf(,aT  
=x7ODBYW^  
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Utility.log(nFileLength); iGhapD  
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return nFileLength; |HG%o 3E]  
} SQ.4IWT(hR  
htF&VeIte  
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//保存下载信息（文件指针位置） R(zsn;  
private void write_nPos() wz, \zh  
{ \]9;c6(  
try{ #5H@/o8!s=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KDXo9FzF  
output.writeInt(nStartPos.length); Iewq?s\Fo  
for(int i=0;i<nStartPos.length;i++) wZC'BLD  
{
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// output.writeLong(nPos); 26Yg?:kP  
output.writeLong(fileSplitterFetch.nStartPos); >)N#n`  
output.writeLong(fileSplitterFetch.nEndPos); }2\"(_  
} plf<O5'  
output.close(); JHQ8o5bEQp  
} 4;*V^\',9  
catch(IOException e){e.printStackTrace ();} mD=?C  
catch(Exception e){e.printStackTrace ();} `3+U6>U [  
} ^M80 F7  
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t =*K?'ly  
//读取保存的下载信息（文件指针位置） Wt`D  
private void read_nPos() 3%P?1s  
{ ScTqnY$v  
try{ bkM$ Qo  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z N t7DK  
int nCount = input.readInt(); t{7l.>kf  
nStartPos = new long[nCount]; b~Ruhi[E  
nEndPos = new long[nCount]; S1B
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for(int i=0;i<nStartPos.length;i++) m_Rgv.gE^  
{ R80R{Ze  
nStartPos = input.readLong(); TtvS|09p;  
nEndPos = input.readLong(); E$1^}RGT)  
} |.S;z"v![  
input.close(); [%@zH
  
} n-=\n6"P  
catch(IOException e){e.printStackTrace ();} r zvX~B6  
catch(Exception e){e.printStackTrace ();} JxvwquI  
} uVk8KMYU  
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}  
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private void processErrorCode(int nErrorCode) -?]ltn9!  
{ lvN{R{7>  
System.err.println("Error Code : " + nErrorCode); W+eN%w5  
} ;+jp,( 7  
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//停止文件下载 e"2QV vB  
public void siteStop() c[YjGx  
{ zm"\D vN)  
bStop = true; v]J# SlF  
for(int i=0;i<nStartPos.length;i++) i f"v4PHq  
fileSplitterFetch.splitterStop(); a2 SQ:d  
68)^i"DM<  
- VE#:&  
} q1gf9`0  
} G!~BA*
 
//负责部分文件的抓取 =I5XG"",
 
**FileSplitterFetch.java g\l;>  
*/ K]u|V0c  
package NetFox; Lg?'1dg  
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import java.io.*; YNXk32@j@e  
import java.net.*; Om^/tp\  
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public class FileSplitterFetch extends Thread { C1/jA>XW  
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String sURL; //File URL w|HZI,~  
long nStartPos; //File Snippet Start Position Wk|z\OR(  
long nEndPos; //File Snippet End Position w=`z!x![/  
int nThreadID; //Thread's ID O)Qz$  
boolean bDownOver = false; //Downing is over @( t:E`8  
boolean bStop = false; //Stop identical z(WpOD  
FileAccessI fileAccessI = null; //File Access interface H6I #Xj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c|R/,/  
{ R\}YD*  
this.sURL = sURL; _y9P]@Q7%  
this.nStartPos = nStart; ^55?VQB  
this.nEndPos = nEnd; |FFC8R%@]u  
nThreadID = id; HFr3(gNj@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Wy4^mOv  
} A|
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public void run() vo$66A  
{ /4?`F}7)  
while(nStartPos < nEndPos && !bStop) /RM-+D:Y  
{ W,~1KUTc  
78)^vvn5~  
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try{ TJpv"V  
URL url = new URL(sURL); K5>:WiY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `VsGa  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lm|X5RVq  
String sProperty = "bytes="+nStartPos+"-"; S:YL<_oI|  
httpConnection.setRequestProperty("RANGE",sProperty); j 7URg>i0  
Utility.log(sProperty); q?L
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InputStream input = httpConnection.getInputStream(); Elp!,(+&6  
//logResponseHead(httpConnection); GU3/s&9  
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byte[] b = new byte[1024]; 1%"` =$q%  
int nRead; ^rwSbM$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lc-|Q#$3$  
{ Bs?
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nStartPos += fileAccessI.write(b,0,nRead); ?6d4T  
//if(nThreadID == 1) V+24-QWh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =LxmzQO#  
} }NCvaO  
a1SOC=.M
;  
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Utility.log("Thread " + nThreadID + " is over!"); $0}bi:7  
bDownOver = true; rb
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//nPos = fileAccessI.write (b,0,nRead); 'cN#rHPB6  
} }yw;L(3  
catch(Exception e){e.printStackTrace ();} YSo7~^1W"  
} #&83;uys  
} sK0VT"7K  
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//打印回应的头信息 V^I/nuy  
public void logResponseHead(HttpURLConnection con) i[{] LiP  
{
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for(int i=1;;i++) Ki/5xK=s  
{ Xp6*Y1Y  
String header=con.getHeaderFieldKey(i); c)MR+'d\WO  
if(header!=null) ]Cn*C{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [IFRwQ^%_O  
Utility.log(header+" : "+con.getHeaderField(header)); X'7S|J6s  
else jHH  
break; O/9%"m:i  
} WV1
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} |HGb.^f?  
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public void splitterStop() >
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{ "jO3Y/>S  
bStop = true; @O}j:b  
} sLdUrD%  
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} DhNo +"!z  
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/* k(z<Bm  
**FileAccess.java xg,]M/J  
*//文件访问(定位，写) NK9WrUj)  
package NetFox; eD{ @0&
 
import java.io.*; 8='21@wrN  
<nTmZ-;  
19 wqDIE0  
public class FileAccessI implements Serializable{ <ytKf<a%e  
nX\]i~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @gSFvb bc  
RandomAccessFile oSavedFile; 2~WFLD  
long nPos; Pgw%SMEp  
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public FileAccessI() throws IOException 4Sstg57x~  
{ 8o7]XZE=)  
this("",0); -*hb^MvP  
} zc/%1  
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w<~<(5mM5;  
public FileAccessI(String sName,long nPos) throws IOException M
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{ XDdcq]*|  
oSavedFile = new RandomAccessFile(sName,"rw"); &lPBqw  
this.nPos = nPos; Kwl qi]~  
oSavedFile.seek(nPos); e*2&s5 #RT  
} (Ef2 w['  
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w}W@M,.^  
public synchronized int write(byte[] b,int nStart,int nLen) &O6;nJEI  
{ m/hi~.D9  
int n = -1; y|;8:b32  
try{
?FV7|)f  
oSavedFile.write(b,nStart,nLen); dD^_^'i  
n = nLen; j&[.2PW\  
} u1)TG"+0  
catch(IOException e) W]D`f8r9  
{ / }XsuH  
e.printStackTrace (); 1%hM8:)i_  
} VUy)4
*  
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return n; 9VUm=Z#`  
} n`m_S
 
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} 827)
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/* 1x\VdT  
**SiteInfoBean.java \
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*/ ]~\SR0  
package NetFox; lv00sa2z  
F8S~wW=\w  
,dZ#,<  
public class SiteInfoBean { ^%oG8z,L  
LZQFj/,Jg  
20/
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private String sSiteURL; //Site's URL i|c`M/) h:  
private String sFilePath; //Saved File's Path ST:
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private String sFileName; //Saved File's Name UN*dU  
private int nSplitter; //Count of Splited Downloading File pY)j0tdd  
jA-5X?!In  
hmBnV  
public SiteInfoBean() g<2lPH  
{//nSplitter的缺省值为5 5:l*Ib:s7  
//default value of nSplitter is 5 ^A11h6I  
this("","","",5); yZ;k@t_WRD  
} q!hy;K`Jd  
''(fH$pY  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $kkp*3{ot  
{ |D;"D  
sSiteURL= sURL; ZSF=  
sFilePath = sPath; hy$M
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sFileName = sName; 8K@"B  
this.nSplitter = nSpiltter; B:3+',i1  
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} (>rS _#^  
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public String getSSiteURL() b`h%W"|2L  
{ ]]J#7L#  
return sSiteURL; h/ LR+XX!  
} iot.E%G  
RwAbIXG{0  
Yg=E@F   
public void setSSiteURL(String value) 9n>$}UI\  
{ ]RH=s7L  
sSiteURL = value; ><;l:RGK|  
} GOYn\N;V2  
%aj7-K6:t  
kyW6S+#-  
public String getSFilePath() +A8=R%&b)[  
{ Kk!6B  
return sFilePath; >a&?AP #  
} ]]p19[4s  
5,HCeN  
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public void setSFilePath(String value) g.[+yzuE6  
{ )l+XDI  
sFilePath = value; #&^ZQs<  
} H$~M`Y9I~  
N?qIpv/a.  
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public String getSFileName() nB cp7e  
{ \6`v.B&v  
return sFileName; 2 ) TG  
} $ZQlIJZ  
j~,h)C/v  
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public void setSFileName(String value) 4R&*&GZ#  
{ )u39}dpeu  
sFileName = value; <@u0.-]  
} 5TXg;v#Z  
Sk8%(
JD7  
-W|*fKN`3  
public int getNSplitter() u^`eKak"l  
{ Z|2Eb*  
return nSplitter; &mh Ln4^  
} d^KBIz8$5l  
]s*5[=uc2  
3C277nx  
public void setNSplitter(int nCount) YHs?QsP  
{ 5a=nF9/  
nSplitter = nCount;
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} "DVt3E  
} 25xcD1*  
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/* +?qf`p.{  
**Utility.java n=f`AmF;  
*/ iKg75%;t  
package NetFox; "#*
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public class Utility { !+m@AQ:,  
j.k@6[R>?  
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public Utility() C=>B_EO
 
{ FQ+8J7  
}C=Quy%Z<  
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} ^fkCyE;=  
,/~[S  
//线程睡眠 )yHJ[  
public static void sleep(int nSecond) @(Z( /P;:  
{ E::L?#V  
try{ m])Lw@#9W  
Thread.sleep(nSecond); jyNb(Z  
} LFCTr/,  
catch(Exception e) 2bWUa~%B  
{ -r!42`S  
e.printStackTrace (); 7nm}fT z7  
} &kb\,mQ  
} Q`N18I3  
%>i@F=O2<  
//日志 zCBplb  
public static void log(String sMsg) >W'j9+Va  
{ GOGt?iw*<  
System.err.println(sMsg); ICk(z~D~  
} WS5A Y @(~  
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]K7`-p~T  
public static void log(int sMsg) x7f:
F.  
{ !;i*\ a  
System.err.println(sMsg); 5!~!j "q  
} S0F@#mSQ?  
} fVYiwE=F  
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k,T_e6(  
/* |H:<:*=6c  
**TestMethod.java s,w YlVYf!  
*/ 9GThyY  
package NetFox; 0Su_#".-*  
9X3yp:>V  
\
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public class TestMethod { Y:wF5pp;  
Khj=llo,  
h77IWo6%  
public TestMethod() 9[kX/#~W*  
{ ///xx/weblogic60b2_win.exe 8\DME  
try{ w$b~x4y%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3x![8 x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `0?^[;[u[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m*gj|1k  
fileFetch.start(); E[UO5X  
} u^l*5F%DK  
catch(Exception e){e.printStackTrace ();} 7gm:ZS   
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} mY`@'  
3q
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public static void main(String[] args) Yc d3QRB  
{ rhIGOk1k  
new TestMethod(); ]/_G-2.R  
} ~6kJ~R4  
} M\dO({o  
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