http断点续传简单实现（java)

/* VZ8HnNAbX  
**SiteFileFetch.java 3M{/9rR[  
*/ } .cP  
package NetFox; v1Lu.JQC$  
import java.io.*; (s`yMUC+  
import java.net.*; /a$RJ6t&3  
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public class SiteFileFetch extends Thread { RWi~34r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S:GX!6>  
long[] nStartPos; //开始位置 EV 8}C=  
long[] nEndPos; //结束位置 XZeZqBr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Td5;bg6Qy  
long nFileLength; //文件长度 yA+:\%y$  
boolean bFirst = true; //是否第一次取文件 0g@ 8x_3  
boolean bStop = false; //停止标志 8j}CP  
File tmpFile; //文件下载的临时信息 4W9#z~'  
DataOutputStream output; //输出到文件的输出流 "7pd(p *C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'i|z>si[*  
public SiteFileFetch(SiteInfoBean bean) throws IOException iVt*N$iZ  
{ 7usf^g[dh  
siteInfoBean = bean; +SSF=]4+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }pa@qZXh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tF<|Eja*  
if(tmpFile.exists ()) V[Jd1T  
{ FU|c[u|z  
bFirst = false;
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read_nPos(); 6*/o  
} H`$s63  
else {%5tqF  
{ Fss7xP'  
nStartPos = new long[bean.getNSplitter()]; u"\HBbBx  
nEndPos = new long[bean.getNSplitter()]; S/|'ggC  
} X#mppMU  
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} ruL
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public void run() x62b=k}  
{ MeqW/!72$L  
//获得文件长度 Fa$ pr`  
//分割文件 6Uk[_)1  
//实例FileSplitterFetch zR_#c3o  
//启动FileSplitterFetch线程 f#a ~av9rC  
//等待子线程返回 VGY#ph%  
try{ L "L@4B  
if(bFirst) zhI} p.  
{ "|S \J5-%  
nFileLength = getFileSize(); 2!/_Xh  
if(nFileLength == -1) ;9pOtr  
{ xGq,hCQHV  
System.err.println("File Length is not known!"); H/p<lp  
} QUp()B1  
else if(nFileLength == -2) xoD5z<<  
{ [{ak&{R,9{  
System.err.println("File is not access!"); #k1%}k=  
} `}KK@(Y  
else is%qG?,P  
{ B1oy,'  
for(int i=0;i<nStartPos.length;i++) dwKre#4F  
{ sY=fS2b#)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _'k?9eN`  
} EnJAHgRV;e  
for(int i=0;i<nEndPos.length-1;i++) 4Wq{ch  
{ `Njv#K} U  
nEndPos = nStartPos[i+1];  '._8  
} #e0tT+  
nEndPos[nEndPos.length-1] = nFileLength; !6ZkLE[XJ<  
} 3VbQDPG  
} %Ysu613mz  
+pJ;}+  
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//启动子线程 A\Q]o#U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w8*+l0  
for(int i=0;i<nStartPos.length;i++) ?w1_.m|8u  
{ m&DDz+g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2Av3.u8%u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ud0%O  
nStartPos,nEndPos,i); P.P3/,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >A|6kzC  
fileSplitterFetch.start(); h3D8eR.  
} *Wv]DV=\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SI3ek9|XU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4`G":nE?We  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4w^B
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nEndPos = " + nFileLength); e@s+]a8D-k  
// fileSplitterFetch[nPos.length-1].start(); Xi_>hL+R(  
:cop0;X:Wm  
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//等待子线程结束 |n3PznV  
//int count = 0; W|3XD-v@  
//是否结束while循环 qtTys gv  
boolean breakWhile = false; `,4"[6S  
. zvF!!z  
HH3WZ^0>  
while(!bStop) ehI*cf({  
{ Qw.""MLmN8  
write_nPos(); ;uNcrv0J  
Utility.sleep(500); t<9oEjk["  
breakWhile = true; 0 ]U ;5  
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for(int i=0;i<nStartPos.length;i++) 0ANqEQX  
{ b5 YE4h8%  
if(!fileSplitterFetch.bDownOver)
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{ g>x2[//pk  
breakWhile = false; H1f){L97wR  
break; /] ce?PPC  
} _CPe  
} {Q?AIp6u|  
if(breakWhile) ;VM/Cxgep  
break; UXoaUW L  
{%@zQ|OO0  
}-k<>~FA  
//count++; Lw?4xerLsb  
//if(count>4) =L9sb!  
// siteStop(); ErJi  
} ' eO4h^  
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System.err.println("文件下载结束！"); <O&L2E @~f  
} M~;mamTP  
catch(Exception e){e.printStackTrace ();} ZebXcT ,41  
} uh%%MhTjv  

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//获得文件长度 w"bQxS~$y  
public long getFileSize() gQgG_&xkC  
{ g4P059  
int nFileLength = -1; 9zEO$<e o  
try{ s"p}>BjMIC  
URL url = new URL(siteInfoBean.getSSiteURL()); I)V2cOrXM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tS8*l2Y`   
httpConnection.setRequestProperty("User-Agent","NetFox"); =U!'v X d  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) fzRzkn:=  
{ mKtZ@r)u  
processErrorCode(responseCode); (tP>z+  
return -2; //-2 represent access is error *j2P#et  
} EYd`qk3  
+?[TH?2c+  
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String sHeader; [ECSJc&i  
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for(int i=1;;i++)
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{ zFqH)/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |!i3Y=X  
//Utility.log(in.readLine()); RO=[Rr!   
sHeader=httpConnection.getHeaderFieldKey(i); b[?6/#N  
if(sHeader!=null) /d9I2~}B  
{ [#kfl  
if(sHeader.equals("Content-Length")) F*
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{ MQ5#6vJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NwoBM6 #  
break; ++F #Z(p  
} 7m{
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} gfw,S;  
else dY68wW>d|  
break; n>)CCf@H  
} kdmannM  
} 1bF aQ50t  
catch(IOException e){e.printStackTrace ();} ]T}G-  
catch(Exception e){e.printStackTrace ();} 9}iEEI  
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Utility.log(nFileLength); cBBc^SR  
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return nFileLength; $)vljM<<  
} FF6[qSV  
|8c3%jve  
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//保存下载信息（文件指针位置） }H!c9Y  
private void write_nPos() m:d P,  
{ a[]=*(AZI  
try{ _)O1v%]"4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9xyj,;P>  
output.writeInt(nStartPos.length); +^Eruv+F  
for(int i=0;i<nStartPos.length;i++) $GNN*WmHw  
{ ~dC)EG  
// output.writeLong(nPos); {=PO`1H  
output.writeLong(fileSplitterFetch.nStartPos); )&+j#:  
output.writeLong(fileSplitterFetch.nEndPos); thDQ44<#)  
} s[NkPh9&  
output.close(); 6A;V[3  
} HsGXb\  
catch(IOException e){e.printStackTrace ();} HhhN8t  
catch(Exception e){e.printStackTrace ();} D'ZR>@w@  
} L TZ3r/  
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//读取保存的下载信息（文件指针位置） a&6 3[p.<}  
private void read_nPos() AIR,XlD  
{ {3@f(H m  
try{ H ifKa/}P8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G)]'>m<y  
int nCount = input.readInt(); 5'd$TC  
nStartPos = new long[nCount]; 0=#:x()e  
nEndPos = new long[nCount]; *BH*   
for(int i=0;i<nStartPos.length;i++) X#'DS&{  
{ L/_h5Q:'W  
nStartPos = input.readLong(); [-_3Zr  
nEndPos = input.readLong(); IP7j)SM!  
} [5e}A&  
input.close(); sI7d?+  
} iagl^(s  
catch(IOException e){e.printStackTrace ();} KPSFy<  
catch(Exception e){e.printStackTrace ();} q.U` mtS  
} 9u^PM  
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private void processErrorCode(int nErrorCode) $~!%Px)  
{ a\ fG)Fqp  
System.err.println("Error Code : " + nErrorCode); C$(US8:{  
} g(B&A P_e  
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//停止文件下载 K#_&}C^-jY  
public void siteStop() <{GpAf8-  
{ SE.r 'J0  
bStop = true; KiAWr-~gJ  
for(int i=0;i<nStartPos.length;i++) 3p6QJuSB  
fileSplitterFetch.splitterStop(); Oq@+/UWX
 
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} "XlNKBgM  
} ukpbx;O:hc  
//负责部分文件的抓取 [Ul"I-K  
**FileSplitterFetch.java "s]r"(MX  
*/ T\I}s"d  
package NetFox; XLb lVi@
 
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import java.io.*; qq.M]?Z  
import java.net.*; Z8E-(@`q5Q  
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public class FileSplitterFetch extends Thread { (RVe,0y  
o}$uP5M8q  
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String sURL; //File URL S"'0lS   
long nStartPos; //File Snippet Start Position ?!^ow5"8  
long nEndPos; //File Snippet End Position O 7RIcU  
int nThreadID; //Thread's ID ,%"!8T  
boolean bDownOver = false; //Downing is over h?R{5?RxK  
boolean bStop = false; //Stop identical JJ_b{ao<  
FileAccessI fileAccessI = null; //File Access interface G%^jgr)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]<L(r,@,  
{ k#F |  
this.sURL = sURL; s|F}Ab
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this.nStartPos = nStart; })W9=xO~  
this.nEndPos = nEnd; <|Srbs+  
nThreadID = id; 7]W6\Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "@^Pb$BLY  
} %]
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public void run() Q2yD4>qy  
{ Z,zkm{9*  
while(nStartPos < nEndPos && !bStop) }py)EI,U  
{ B-^r0/y;  
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try{ c?5?TJpm  
URL url = new URL(sURL); @<kY,ox@~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LNp{lC  
httpConnection.setRequestProperty("User-Agent","NetFox"); "Vh3hnS~  
String sProperty = "bytes="+nStartPos+"-"; A,67)li3  
httpConnection.setRequestProperty("RANGE",sProperty); -Zq\x'  
Utility.log(sProperty); 6_|iXs(&
 
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InputStream input = httpConnection.getInputStream(); +t*V7nW  
//logResponseHead(httpConnection); j9gn7LS  
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byte[] b = new byte[1024]; !Gob `# r  
int nRead; ]1hyvm3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qm^|7m^  
{ O6*2oUKqK  
nStartPos += fileAccessI.write(b,0,nRead); ( jACLo  
//if(nThreadID == 1) GuK3EM*_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S[ch/  
} L~oy|K67  
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#($~e|  
Utility.log("Thread " + nThreadID + " is over!"); V>Dqw!  
bDownOver = true; ^h\(j*/#X  
//nPos = fileAccessI.write (b,0,nRead); F m?j-'  
} b@QCdi,u  
catch(Exception e){e.printStackTrace ();} <fHJ9(5$V  
} mR["xDHD  
} ^'9.VVyz  
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dG&^M".(
 
//打印回应的头信息 >{6U1ft):  
public void logResponseHead(HttpURLConnection con) UQZl:DYa  
{ [Ef6
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for(int i=1;;i++) QB uX#bDV  
{ Emy=q5ryl  
String header=con.getHeaderFieldKey(i); b?{MX
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if(header!=null) |L/EH~|
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); a\m_Q{:  
Utility.log(header+" : "+con.getHeaderField(header)); n6AA%? 5  
else g(_xo\  
break; "QD>m7  
} W4;/;[/L  
} GCf,Gfmr  
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public void splitterStop() Mj&G5R~_  
{ LBxmozT  
bStop = true; Vv54;Js9  
}  `j1oxJm  
azz=,^U#  
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} *\.8
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/* +7\d78U  
**FileAccess.java '-U&S  
*//文件访问(定位，写) ]p8zT|bv  
package NetFox; * N]^(+/A  
import java.io.*; SZ29B  
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public class FileAccessI implements Serializable{ X+1Mv  
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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 /#WvC;B  
RandomAccessFile oSavedFile; V7b;qC'  
long nPos; %afN&T  
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public FileAccessI() throws IOException Zg$S% 1(Q  
{ i;rcgd  
this("",0); H;R~d%!b  
} 6hMKAk  
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public FileAccessI(String sName,long nPos) throws IOException Lqdapx"Z_  
{ }DQTy.d;P  
oSavedFile = new RandomAccessFile(sName,"rw"); 78 w  
this.nPos = nPos; 5(gWK{R)*  
oSavedFile.seek(nPos); EugRC  
} tr5j<O  
k#bG&BF  
<UF0Xc&X'  
public synchronized int write(byte[] b,int nStart,int nLen) Xp] jF^5  
{ j7U&a}(  
int n = -1; 1fvN[  
try{ PB *v45  
oSavedFile.write(b,nStart,nLen); e|?eY)_  
n = nLen; 2eHVl.C5  
} q
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catch(IOException e) =z;]FauR!  
{ h%U}Y5Ps~  
e.printStackTrace (); 3.@LAF  
} $ay!'MK0d  
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return n; Lb)rloca  
} 6DU~6c=)  
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} n$`+03a  
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:hT.L3n,  
/* e!PB3I  
**SiteInfoBean.java %ufh  
*/ "={*0P  
package NetFox; ]J[d8S5  
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public class SiteInfoBean { Pz34a@%"  
=[8K#PZ$w  
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private String sSiteURL; //Site's URL =\_gT=tZ  
private String sFilePath; //Saved File's Path m% 3D  
private String sFileName; //Saved File's Name HdgNy\  
private int nSplitter; //Count of Splited Downloading File x!fG%o~h  
QyxUK}6mr  

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public SiteInfoBean() *L9v(Kc  
{//nSplitter的缺省值为5 Gbjh|j=  
//default value of nSplitter is 5 >{
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this("","","",5); aW*k,\:e  
} 5[g\.yi2_]  
' Ut4=@)  
) [?xT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #D/*<:q5  
{ hf]m'5pb  
sSiteURL= sURL; .b+ix=:  
sFilePath = sPath; SkMFJ?J/  
sFileName = sName; 4w~%MZA^  
this.nSplitter = nSpiltter; T\n6^@.
>  
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} Pw| h`[h  
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public String getSSiteURL() yhYF "~CM  
{ PcEE`.  
return sSiteURL; Yb-{+H8{J  
} zPND$3&'  
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public void setSSiteURL(String value) |4g0@}nr+W  
{ $:%E<j4Dn  
sSiteURL = value; }04mJY[  
} JLn
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public String getSFilePath() aUzCKX%>C  
{ bq9w@O  
return sFilePath; u1L^INo/  
} }rI:pp^KS  
"5Y6.$Cuf!  
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public void setSFilePath(String value) C&>*~  
{ *s*Y uY%y  
sFilePath = value; IC&P-X_aP  
} ^e_LnJ+  
i? ~-%  
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public String getSFileName() -z~!%4a  
{ Ac|\~w[\  
return sFileName; cd1G.10  
} R8k4?_W?T  
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public void setSFileName(String value) sde>LZet/  
{ }VZExqm)  
sFileName = value; V-}}?c1 F  
} <M@-|K"Eb  
ey=KA
t  

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public int getNSplitter() !*}UP|8  
{ /3,Lp-kp
 
return nSplitter; [K.1 X=O}  
} Q}|K29Y:p  
3y6\0|{1  
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public void setNSplitter(int nCount) X)[tb]U/Wx  
{ }a||@unr  
nSplitter = nCount; |g)C `k  
}  d(o=)!p  
} A}SGw.3  
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/* \jtA8o%n  
**Utility.java 0SQr%:zG  
*/ Fs(PVN  
package NetFox; Z-Qp9G'   
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public class Utility { QM F 
 
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public Utility() :.,9}\LK  
{ ]alc%(=  
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} &bW,N  
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//线程睡眠 Y/kq!)u;%L  
public static void sleep(int nSecond) h6 {vbYj  
{ Nv7-6C6<  
try{ }+9?)f{?@  
Thread.sleep(nSecond); \;)g<
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} k0e}`#t  
catch(Exception e) %hsCB .r>|  
{ i]%f94  
e.printStackTrace (); =Z  
} V ql4*OJW  
} b$,Hlh,^  
<bKtAf  
//日志 z#G
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public static void log(String sMsg) r%?-MGc  
{ Or5?Gt  
System.err.println(sMsg); [j+:2@  
} 1IA1
;  
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public static void log(int sMsg) dtC@cK/,D  
{ ~\_VWXXvIW  
System.err.println(sMsg); TlS? S+  
} B-Jd|UE`u  
} sgp.;h'  
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/* {h?pvH_>  
**TestMethod.java &J6
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*/ N&NBn(  
package NetFox; }`B .(3n  
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@.e X8~3=  
public class TestMethod { R&Y_  
< '5~p$  
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public TestMethod() b_31\  
{ ///xx/weblogic60b2_win.exe <?nIO
  
try{ !4vb{AH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tn}`VW~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6h;(b2p{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8)X9abC  
fileFetch.start(); c* {6T}VZr  
} =Z^5'h~  
catch(Exception e){e.printStackTrace ();} ;5j|B|v  
%":3xj'EEI  
IL].!9
  
} AHb_BgOU*  
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public static void main(String[] args) _Op%H)  
{ &kg^g%%  
new TestMethod(); NKO"'
   
} }`"}eN @,  
} 0^ODJ7  
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