http断点续传简单实现（java)

/* C:}1r  
**SiteFileFetch.java \Vroz=IT:  
*/ ~[dL:=?c  
package NetFox; }A,!|m4  
import java.io.*; KvEv0L<ky  
import java.net.*; `GW&*[.7  
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public class SiteFileFetch extends Thread { *4NY"EwjN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J(@" 7RX  
long[] nStartPos; //开始位置 8h }a:/  
long[] nEndPos; //结束位置 qg=`=]j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {?Y\T  
long nFileLength; //文件长度 r5ldK?=k+*  
boolean bFirst = true; //是否第一次取文件 [DDe}D3C  
boolean bStop = false; //停止标志 /RMtCa~  
File tmpFile; //文件下载的临时信息 4v |i\V>M  
DataOutputStream output; //输出到文件的输出流 D!! B4zt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ib#rT{e  
public SiteFileFetch(SiteInfoBean bean) throws IOException @'):rFr@F  
{ 3<"j/9;K'  
siteInfoBean = bean; @&`^#pok  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OylUuYy~j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yj#FO'UY  
if(tmpFile.exists ()) ZJU %&@  
{ sS;)d  
bFirst = false; k}qQG}hB
 
read_nPos(); 1.k=ji$D0  
} |9\i+)C  
else k ,ldi  
{ G+Z ,ic  
nStartPos = new long[bean.getNSplitter()]; s>I]_W)Pt  
nEndPos = new long[bean.getNSplitter()]; #b;k+<n[X  
} mRRZ/m?A(  
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} :Ae#+([V  
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{<@ud0A:\  
public void run() .\T!oSb4[  
{ W_E^+Wl@  
//获得文件长度 ][tR=Y#&y5  
//分割文件 &V$cwB  
//实例FileSplitterFetch WZn;u3,R  
//启动FileSplitterFetch线程 ;Ivv4u  
//等待子线程返回 %(p9AE  
try{ `ovMfL.u  
if(bFirst) KJ32L  
{ Q"D  
nFileLength = getFileSize(); 
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if(nFileLength == -1) jT$J~MpHh  
{ {*F =&D  
System.err.println("File Length is not known!"); COu5Tu^  
} xWXLk )A  
else if(nFileLength == -2) @ Do.Wgt  
{ O50<h O]l  
System.err.println("File is not access!"); _b&26!gl  
} 1uN;JN `_  
else (}6\_k[}m  
{ MnqT?Cc4$j  
for(int i=0;i<nStartPos.length;i++) _q#pEv  
{ EjFpQ|-L|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Vm\zLWNB  
} ukEJD3i  
for(int i=0;i<nEndPos.length-1;i++) ;lb  
{ r>ed/<_>m;  
nEndPos = nStartPos[i+1]; 9v`sSTlSd  
} <(@S;?ZEW  
nEndPos[nEndPos.length-1] = nFileLength; 8Cp@k=  
} 5NUaXQ  
} O2ktqAWx@  
>I5Wf/$  
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//启动子线程 ?xH{7)dO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wU!-sf;]y  
for(int i=0;i<nStartPos.length;i++) BXU0f%"8U  
{ 0+op|bdj  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n@ba>m4{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G!sfp}qW  
nStartPos,nEndPos,i); ,LxZbo!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9uWg4U  
fileSplitterFetch.start(); n/(}|xYU  
} N8At N\e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IMbF]6%p(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qd YYWD   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u28$V]
 
nEndPos = " + nFileLength); \3^V-/SJf  
// fileSplitterFetch[nPos.length-1].start(); ],0I`!\  
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//等待子线程结束 ;f[##=tm  
//int count = 0; 3Fn}nek  
//是否结束while循环 hx&fV#m  
boolean breakWhile = false; _[z)%`kay  
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while(!bStop) qOy(dG g  
{ N[3Y~HX!q  
write_nPos(); yH-&o,  
Utility.sleep(500); !Whx^B:  
breakWhile = true; K)   
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for(int i=0;i<nStartPos.length;i++) +C7E]0!r  
{ pXlqE,  
if(!fileSplitterFetch.bDownOver) :Bt,.uNC  
{ YYFS ({  
breakWhile = false; ibZ[U p?  
break; 1G12FV>M  
} @fmp2!?6  
} aW dI  
if(breakWhile) lJ=EP.T  
break; /cx'(AT  
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//count++; Z7pX%nj_  
//if(count>4) 5EQ)pH+  
// siteStop(); aWRi`poZT
 
} @0PWbs$  
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System.err.println("文件下载结束！"); "}1cQ|0a  
} km9#lK  
catch(Exception e){e.printStackTrace ();} /KC^x=Xv:  
} BNE:,I*&  
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//获得文件长度 G)[gLD{g?  
public long getFileSize() xLFMC?I  
{ K]B`&ih  
int nFileLength = -1; |pBFmm*  
try{ :TP4f ?FA  
URL url = new URL(siteInfoBean.getSSiteURL()); R'tvF$3=i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $eT[`r  
httpConnection.setRequestProperty("User-Agent","NetFox"); ./3/3&6  
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int responseCode=httpConnection.getResponseCode(); {
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if(responseCode>=400) 6(7{|iY  
{ Q~ Ad{yC  
processErrorCode(responseCode); %hBwc#^  
return -2; //-2 represent access is error :}fA98S  
} (D?4*9=  
}z/%b<o_  
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String sHeader; zQ,M795@EA  
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for(int i=1;;i++) BjPU@rS.U  
{ jf1GYwuW*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PE6,9i0ee  
//Utility.log(in.readLine()); /^jl||'H,:  
sHeader=httpConnection.getHeaderFieldKey(i); :oW 16m1`  
if(sHeader!=null) XSN=0N!GB  
{ P8h|2
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if(sHeader.equals("Content-Length")) q>K3a1x  
{ XaE*$:   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H)Me!^@[D  
break; 'j{o!T0  
} p ]jLs|tat  
} n05GM.|*s  
else A9]&w  
break; \}n_Sk  
} 0S>L0qp  
} J,:;\Xhl  
catch(IOException e){e.printStackTrace ();} CF-tod  
catch(Exception e){e.printStackTrace ();} l?_Fy_fBt  
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Utility.log(nFileLength); /DHV-L  
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return nFileLength; tN)t`1_j  
} )f^^hEIS  
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\v=@'  
//保存下载信息（文件指针位置） K% snE7X?)  
private void write_nPos() LDU4 D  
{ bFL2NH5  
try{
' e!WZvr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M6A0D+08  
output.writeInt(nStartPos.length); tmBt[  
for(int i=0;i<nStartPos.length;i++) iyR"O1]  
{ 9dAtQwGR"6  
// output.writeLong(nPos); `S-%}eUv  
output.writeLong(fileSplitterFetch.nStartPos); {"$[MYi:  
output.writeLong(fileSplitterFetch.nEndPos); CGK]i.N  
} { Dm@_&  
output.close(); $.w$x1  
} C,mfA%63  
catch(IOException e){e.printStackTrace ();} &M3KJ I0L  
catch(Exception e){e.printStackTrace ();} yDZm)|<.  
} Fkpaou  
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//读取保存的下载信息（文件指针位置） .)bNi*&  
private void read_nPos() 3'i(wI~
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{ %LmsywPPp  
try{ =6 zK1Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P4{~fh(  
int nCount = input.readInt(); E8nj_^Z  
nStartPos = new long[nCount]; x3U>5F@  
nEndPos = new long[nCount]; .I#_~
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for(int i=0;i<nStartPos.length;i++) iWA?FBv  
{ gxUa-R  
nStartPos = input.readLong(); GNrRc3dr$  
nEndPos = input.readLong(); l. cp[  
} cvT@`1  
input.close(); rx9y^E5T`;  
} ?>V>6cDQ  
catch(IOException e){e.printStackTrace ();} T fIOS]  
catch(Exception e){e.printStackTrace ();} [Pjitw/?  
} v#s*I/kw  
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private void processErrorCode(int nErrorCode) gzKMGL?%?  
{ :O&jm.2m  
System.err.println("Error Code : " + nErrorCode); [iO8R-N8d  
} eGpKoq7a  
[\h?mlG?  
PP!-*~F0Jr  
//停止文件下载 I#;dS!W"'  
public void siteStop() [ "3s  
{ .Oc j|A6  
bStop = true; (.Ak*  
for(int i=0;i<nStartPos.length;i++)  CDuA2e  
fileSplitterFetch.splitterStop(); *pnaj\  
|`o1B;lc  
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} ;&}z L.!jo  
} (jyufHm  
//负责部分文件的抓取 f9kd&#O&  
**FileSplitterFetch.java (4ZO[Ae  
*/ FAM:; F30  
package NetFox; o^"OKHU,S0  
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import java.io.*; ir{ 4k  
import java.net.*; $- %um  
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public class FileSplitterFetch extends Thread { $YY{|8@kjv  
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String sURL; //File URL ;Sg.E8  
long nStartPos; //File Snippet Start Position m0h,!  
long nEndPos; //File Snippet End Position 52#6uBe  
int nThreadID; //Thread's ID } d8\ Jg  
boolean bDownOver = false; //Downing is over LA2/<:  
boolean bStop = false; //Stop identical &hL2xx=  
FileAccessI fileAccessI = null; //File Access interface (^g XO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cqs.[0 z#B  
{ 7 wEv`5  
this.sURL = sURL; puWMgvv  
this.nStartPos = nStart; 6~W@$SP,F  
this.nEndPos = nEnd;
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nThreadID = id; :KXI@)M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 , u%V%  
} <pHm=q/U  
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z^&$6c_  
public void run() ZbdGI@  
{ >D~8iuy]8.  
while(nStartPos < nEndPos && !bStop) |%F4`gz8KP  
{ &^HVuYa.0  
0
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try{ nIfAG^?|*  
URL url = new URL(sURL); F|5Au>t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S|LY U!IWZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); $^?VyHXvY  
String sProperty = "bytes="+nStartPos+"-"; p19@t
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httpConnection.setRequestProperty("RANGE",sProperty); TKsP#Dt/  
Utility.log(sProperty); >s"/uo  
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InputStream input = httpConnection.getInputStream(); h:?qd  
//logResponseHead(httpConnection); );t+~YPS  
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byte[] b = new byte[1024]; c@}t@k  
int nRead; >ZG$8y 'j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qsbo"29  
{ R@tEC)Zn  
nStartPos += fileAccessI.write(b,0,nRead); ;A7JX:*?y=  
//if(nThreadID == 1) xypgG;`\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  SvvNk  
} w <"mS*Q  
&$_!S!Sa/  
+By'6?22  
Utility.log("Thread " + nThreadID + " is over!"); <)(W7#Ks  
bDownOver = true; i}v.x  
//nPos = fileAccessI.write (b,0,nRead); oS9Od8  
} ~@xPoD&  
catch(Exception e){e.printStackTrace ();} .n YlYY'   
} Y&Fg2_\">  
} H7;,Kr  
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^E)  
//打印回应的头信息 Z^as ?k(iM  
public void logResponseHead(HttpURLConnection con) Mz2TwU_  
{ JJbd h \  
for(int i=1;;i++) g.hYhg'KUh  
{ {GnZ@Q:F  
String header=con.getHeaderFieldKey(i); vGh>1U:  
if(header!=null) 2/s42 FoG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~AX~z)  
Utility.log(header+" : "+con.getHeaderField(header)); GCO: !,1  
else NjEi.]L*fX  
break; xYYa%PhIC  
} ?0*[ L  
} C:5d/9k  
'#LzQ6Pn  
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public void splitterStop() QdQ1+*/+U  
{ Y.Z:H!P);$  
bStop = true;  @,k5T51m  
} (Y7zaAG]  
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} L_vl%ii-  
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$,, PF/N8c  
/* F
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**FileAccess.java ; xp-MK  
*//文件访问(定位，写) ZnI15bsDx  
package NetFox; id5`YA$  
import java.io.*; gz[3xH~  
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public class FileAccessI implements Serializable{ v]F4o1ckk  
t4v'X}7q]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Q#SQ@oUzD  
RandomAccessFile oSavedFile; $>O~7Nfst7  
long nPos; !R\FCAW[x  
!f5
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2 Kjd!~Z$  
public FileAccessI() throws IOException 7G-?^  
{ `{Q'iydU  
this("",0); bK~Toz<k  
} *OFG3uM  
1a{r1([)  
B^P&+,\[}  
public FileAccessI(String sName,long nPos) throws IOException &*+$38XE^  
{ f?k0(rl  
oSavedFile = new RandomAccessFile(sName,"rw"); h L [eA  
this.nPos = nPos; W>d)(  
oSavedFile.seek(nPos); 0g|5s  
} vZTXvdF  
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public synchronized int write(byte[] b,int nStart,int nLen) U6@c)_* <  
{ ~YCH5,  
int n = -1; o68i0aFW  
try{ T pF[-fO  
oSavedFile.write(b,nStart,nLen); DWKQ>X6  
n = nLen; *1`X}  
} QE[<
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catch(IOException e) .aY$-Y<  
{ !KK
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e.printStackTrace (); Y 2ANt w@  
} I)FFh%m<}a  
/^nIOAeE  
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return n; fy"}# 2  
} J}xM+l7uY  
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} \'j(@b,  
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/* /v5A)A$7  
**SiteInfoBean.java 8ex;g^e  
*/ 2Wluc37  
package NetFox; ,k4pW&A  
oxc;DfJ_  
PJN9[Y{^3  
public class SiteInfoBean { B1nm?E 0i  
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private String sSiteURL; //Site's URL r4*H96l  
private String sFilePath; //Saved File's Path `K.B`  
private String sFileName; //Saved File's Name (Fzy8 s  
private int nSplitter; //Count of Splited Downloading File 96V8R
<   
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public SiteInfoBean() G'/GDN^j  
{//nSplitter的缺省值为5 +M I{B="7.  
//default value of nSplitter is 5 4DCh+|r  
this("","","",5); _<.VP  
} 8~C}0
H  
}bS1M  
*GE6zGdN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }UW*[dCf>C  
{ ?{f6su@rW  
sSiteURL= sURL; o1(;"5MM  
sFilePath = sPath; Wds>'zzS  
sFileName = sName; c 1F^Gj!8  
this.nSplitter = nSpiltter; X13+n2^8]  
'M"z3j]m-,  
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} KUZi3\p9W>  
I &iyj99n  
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public String getSSiteURL() WkA47+DsV  
{ (t@)`N{  
return sSiteURL; ~3:hed7:  
} YTefEG]|q  
# `E  
C
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public void setSSiteURL(String value) m6e(Xk,)  
{ :P_h_Tizv  
sSiteURL = value; 8+oc4~!A@n  
} 7w)8s  
Ly2,*\7  
!FP ]  
public String getSFilePath() l.pxDMY  
{ 9abUh
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return sFilePath; a[~[lk=7  
} 3pWav 1"  
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|9S8sfw  
public void setSFilePath(String value) <h/q^|tZ{  
{ M{24MF   
sFilePath = value; g.9C>>tj  
} h8Uhr
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u/j\pDl.  
Hu<]*(lK%  
public String getSFileName() I(~([F2  
{ *bFWNJ}`q  
return sFileName; ;F@Sz/  
} *x2!N$b  
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:.g/=Q(T~  
public void setSFileName(String value) 8`+=~S  
{ |=IJ^y(x|  
sFileName = value; y+iRZ%V^  
} 75Z|meG~  
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np^&cY]  
public int getNSplitter() b_ZvI\H  
{ a.%ps:  
return nSplitter; 6NV592  
} P I"KY@>H  
ZUHW*U.  
@~hy'6/  
public void setNSplitter(int nCount) 9]=J+ (M  
{ jq)Bj#'7  
nSplitter = nCount; o i'iZX  
} ),N,!15j,  
} %W D^0U|  
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/* 8+w*,R
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**Utility.java ]}/Rl}_  
*/ /a32QuS  
package NetFox; G$Mf(S'f  
7(o`>7x*
 
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public class Utility { moxmQ>xoH  
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public Utility() JR`$t~0t  
{ xwD`R*  
ir.RO7f  
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} *RS/`a;,  
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//线程睡眠 A;rk4)lij  
public static void sleep(int nSecond) $BehU  
{ c9EtUv~  
try{ _$$.5?4  
Thread.sleep(nSecond); }w4OCN\1  
} F,S)P`?  
catch(Exception e) u=nd7:bv  
{ K
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e.printStackTrace (); zl8M<z1`1  
} i=<;$+tW  
} cu>(;=  
&'^.>TJ\  
//日志 )@DDs(q=i  
public static void log(String sMsg) 1]''@oh{6U  
{ Ld.9.d]  
System.err.println(sMsg); nQV0I"f]?]  
} ShC$ue?Q  
j({L6</x  
+Q_Gm3^  
public static void log(int sMsg)  L_Ai/'
 
{ Ri-wbYFaP  
System.err.println(sMsg); $S cjEG:6  
} d ly 0874  
} &k{@:z  
AU$5"kBE  
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/* 42Ffx?Qmv  
**TestMethod.java {5z?5i ?D  
*/ 9hp0wi@W}  
package NetFox; pcl_$2_  
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6ensNr~ea  
public class TestMethod { `") I[h  
6<~y!\4;F  
,zyrBO0 Eq  
public TestMethod() _bz,G"w+:  
{ ///xx/weblogic60b2_win.exe Zd%\x[f9ck  
try{ n<$I,IRE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); nMbV{h ,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ohyUvxvj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p]g/iLDZ  
fileFetch.start(); 2I4P":q  
} q B2#EsZ  
catch(Exception e){e.printStackTrace ();} 1Q$ M/}  
xX>448=  

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} 4'8.f5  
/ q!&I  
@<sP1`1  
public static void main(String[] args) Z,&ywMm/G  
{ 5LK>n-  
new TestMethod(); 4%{m7CK}  
} \%VoX`B  
} g?+P&FL#I  
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