http断点续传简单实现（java)

/* (?#"S67  
**SiteFileFetch.java M6"a w6  
*/ .[S\&uRv  
package NetFox; SfUbjs@a  
import java.io.*; 7 MG<!U  
import java.net.*; F tay8m@f  
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public class SiteFileFetch extends Thread { ~A,(D-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \x=!'  
long[] nStartPos; //开始位置 tW"s^r=95  
long[] nEndPos; //结束位置 z9ZS&=>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k;pU8y6Y  
long nFileLength; //文件长度 XrN]}S$N  
boolean bFirst = true; //是否第一次取文件 o5<w2(  
boolean bStop = false; //停止标志 `k~w 14~w  
File tmpFile; //文件下载的临时信息 =[IKwmCX  
DataOutputStream output; //输出到文件的输出流 LqoH]AcN  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :[bpMP<bz;  
public SiteFileFetch(SiteInfoBean bean) throws IOException jP"yG#  
{ s5u  
siteInfoBean = bean; P B"nf|pm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ms/Q-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "In$|A\?E  
if(tmpFile.exists ()) s Vg89I&  
{ -59;Zn/  
bFirst = false; G[\3)@I  
read_nPos(); .oz(,$CS"  
} RbJbVFz8C  
else 2[5z6oG  
{ iK9#{1BpML  
nStartPos = new long[bean.getNSplitter()]; bh UghHT  
nEndPos = new long[bean.getNSplitter()]; 3Qu Ft~@@  
} 'T*h0xX  
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} Y\{&chuF  
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# 3gdT  
public void run() ]M/*Beh  
{ .$s=E8fW  
//获得文件长度 sr`)l&t?  
//分割文件 Wj\< )cH]  
//实例FileSplitterFetch q=_tjg  
//启动FileSplitterFetch线程 6cbIs_g  
//等待子线程返回 @-Ln* 3n  
try{ gclw>((5  
if(bFirst) JsbH'l  
{ Rb_+C  
nFileLength = getFileSize(); z)
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if(nFileLength == -1) r_e]sOCb  
{ Ar1X mHq  
System.err.println("File Length is not known!"); L_ 2R3w  
} L6"?p-:@'  
else if(nFileLength == -2) c9axzg UA  
{ hwdZP=X  
System.err.println("File is not access!"); eHHqm^1z  
}
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else %XK<[BF  
{ R9O[`~BA2  
for(int i=0;i<nStartPos.length;i++) ulxy 4] h  
{ =1h> N/VJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _chX {_Hu-  
} =%$BFg1a(  
for(int i=0;i<nEndPos.length-1;i++) _U/CG<n  
{ YlEV@  
nEndPos = nStartPos[i+1]; IL N0/eH  
} \A/??8cgXs  
nEndPos[nEndPos.length-1] = nFileLength; .T }q"  
} +hKH\]  
} L'$;;eM4  
R|O."&CAB  
</7_T<He.  
//启动子线程 g;PZ$|%&s>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {1]/ok2k5  
for(int i=0;i<nStartPos.length;i++) R.B3  
{ x\2N @*I:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), coFQu ;i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gCc::[}\Y  
nStartPos,nEndPos,i); 3rQ;}<*M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !'T,%8']  
fileSplitterFetch.start(); TWAt
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} hp)k[|u;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k>dzeH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )#_:5^1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ve\=By-a|  
nEndPos = " + nFileLength); u+/1ryp  
// fileSplitterFetch[nPos.length-1].start(); E A}Vb(2  
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//等待子线程结束 
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//int count = 0; *^b<CZd9  
//是否结束while循环 #K_E/~  
boolean breakWhile = false; p{k^)5CR/  
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while(!bStop) 5u3SP?.&  
{ ( [m[<  
write_nPos(); {&Es3+{A  
Utility.sleep(500);
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breakWhile = true; skRI\  
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for(int i=0;i<nStartPos.length;i++) q"sD>Yh&  
{ ??tNMr5{[  
if(!fileSplitterFetch.bDownOver) C].w)B  
{ m^rrbU+HM?  
breakWhile = false; _onEXrM  
break; .qjdi`v  
} KJ&~z? X  
} ;^`WX}]C(  
if(breakWhile) ubvXpK:.  
break; eED@Z/~
6  
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//count++; :0)nL  
//if(count>4) uk)6%  
// siteStop(); +GqV9x 8  
} !WD~zZ|  
n:P5m9T  
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System.err.println("文件下载结束！"); ,\cO>y@  
} [C TR8  
catch(Exception e){e.printStackTrace ();} GE0,d  
} 4M4oI .  
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//获得文件长度 a'pJg<  
public long getFileSize() !gfz4f&  
{ ~wdKO7fs  
int nFileLength = -1; {_{&t>s2  
try{ JG=U@I]  
URL url = new URL(siteInfoBean.getSSiteURL()); "uthFE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [8J/#!B  
httpConnection.setRequestProperty("User-Agent","NetFox"); VP<_~OLc  
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int responseCode=httpConnection.getResponseCode(); DY~zi  
if(responseCode>=400) edW:(19}  
{ [qEd`8V(  
processErrorCode(responseCode); ^8#;>+7R  
return -2; //-2 represent access is error %`~?w'  
} YdI&OzaroE  
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String sHeader; ;1&7v  
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for(int i=1;;i++) #q5 L4uM9  
{ gZ^NdDBO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o1"-x  
//Utility.log(in.readLine()); 6,*o;<k[  
sHeader=httpConnection.getHeaderFieldKey(i); y_=},a  
if(sHeader!=null) k7\h- yn{  
{ t*&O*T+fgy  
if(sHeader.equals("Content-Length")) C6XZZ  
{ o y'GAc/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #z*-  
break; 1gZW~6a}  
} -PI_*  
} V_SZp8  
else 7:h8b/9  
break; 3%JPJuNVw  
} Zu$30&U  
} <~[A  
catch(IOException e){e.printStackTrace ();} z}" Xt=G?  
catch(Exception e){e.printStackTrace ();} ^@&RJa-kb  
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Utility.log(nFileLength); v/4Bt2J  
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return nFileLength; 22|a~"Z  
} ^E5[~C*o3  
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bOi`JJ^  
//保存下载信息（文件指针位置） 8?L7h\)-  
private void write_nPos() Felu`@b  
{ yH<^txNF  
try{ Uv(THxVh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P(1bd"Q  
output.writeInt(nStartPos.length); 6<h?%j(  
for(int i=0;i<nStartPos.length;i++) (5SN=6O  
{ !;YmLJk;hN  
// output.writeLong(nPos); 0<{+M`G/  
output.writeLong(fileSplitterFetch.nStartPos); )V}u}5  
output.writeLong(fileSplitterFetch.nEndPos);
=)B@`"  
} QsaaA MGY  
output.close(); _VeZlk7k  
} vKzq7E  
catch(IOException e){e.printStackTrace ();} f$lf(brQ:  
catch(Exception e){e.printStackTrace ();} 50:$km\  
} 8?lp:kM  
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//读取保存的下载信息（文件指针位置） K%) K$/A  
private void read_nPos() xwwy9:ze*l  
{ uZe|%xK$y  
try{ B rGaCja  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7*e7P[LQU  
int nCount = input.readInt(); S$!)Uc\)A  
nStartPos = new long[nCount]; <c[+60p"  
nEndPos = new long[nCount]; N5ityJIgQ  
for(int i=0;i<nStartPos.length;i++) {xm^DT  
{ tN'-4<+  
nStartPos = input.readLong(); QMGMXa  
nEndPos = input.readLong(); Wx;`=9  
} cxhS*"Ph  
input.close(); KJ Gh)  
} SBBDlr^P  
catch(IOException e){e.printStackTrace ();} -q9`Btz  
catch(Exception e){e.printStackTrace ();} niZ/yW{w  
} \($EYhx  
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private void processErrorCode(int nErrorCode) ':kj\$U  
{ RO-ABFEi(  
System.err.println("Error Code : " + nErrorCode); *5DOTWos  
} %&L]k>n^  
l
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//停止文件下载 2k,!P6fgl  
public void siteStop() DP=4<ES%+  
{ .".xNHR#  
bStop = true; ?QGAiu0  
for(int i=0;i<nStartPos.length;i++) sK~d{)+T  
fileSplitterFetch.splitterStop(); xm@vx}O:  
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*I0{1cST  
} w$~|/UrLf  
} @D!KFJ  
//负责部分文件的抓取 \Uun2.K  
**FileSplitterFetch.java |];s[^$#  
*/ }(AgXvRq  
package NetFox; -ec~~95  
w(kN0HD  
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import java.io.*; 5}3Q}o#  
import java.net.*; krkRP%jy  
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public class FileSplitterFetch extends Thread { \BC|`)0h  
#/'5N|?  
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String sURL; //File URL .W{\wkn  
long nStartPos; //File Snippet Start Position gd>Op  
long nEndPos; //File Snippet End Position ShAI6j  
int nThreadID; //Thread's ID PJu)%al  
boolean bDownOver = false; //Downing is over >#z*gCO5,  
boolean bStop = false; //Stop identical *bu/Ko]  
FileAccessI fileAccessI = null; //File Access interface @DYxxM-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )>q.!
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{ 3
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this.sURL = sURL; a%>p"4WL  
this.nStartPos = nStart; "WOY`su>  
this.nEndPos = nEnd; lJ!+n<K+  
nThreadID = id; L*tn>AO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HVzG }r(J  
} wXf_2qB9  
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public void run() BgLK}p^  
{ kKnz F  
while(nStartPos < nEndPos && !bStop) ckRWVw   
{ 1,fjdd8OM;  
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try{ 9aT#7B  
URL url = new URL(sURL); $-9m8}U(Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T'2(sHk  
httpConnection.setRequestProperty("User-Agent","NetFox"); s 
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String sProperty = "bytes="+nStartPos+"-"; u= ( kii=/  
httpConnection.setRequestProperty("RANGE",sProperty); ;3NA,JA#Y  
Utility.log(sProperty); N?0T3-/K  
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InputStream input = httpConnection.getInputStream(); 2bU3*m^M  
//logResponseHead(httpConnection); -G2'c)DR  
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byte[] b = new byte[1024]; DPIiGRw  
int nRead; u(\O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v0`E lkaN  
{ p;Kw$fQ?  
nStartPos += fileAccessI.write(b,0,nRead); *b9=&:pU(  
//if(nThreadID == 1) s)W^P4<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n *|F=fl  
} x]6OE]]8L  
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Utility.log("Thread " + nThreadID + " is over!"); gS~QlW V  
bDownOver = true; !u@e^J{Ao  
//nPos = fileAccessI.write (b,0,nRead); -sl] funRy  
} XJTY91~R  
catch(Exception e){e.printStackTrace ();} 62Yi1<kV@  
} CGvU{n,"  
} <hgt{b4  
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//打印回应的头信息 D_@WB.eL  
public void logResponseHead(HttpURLConnection con) %g}ri8  
{ yU3fM?
a  
for(int i=1;;i++) dM8`!~#&PI  
{ 85YE6^y  
String header=con.getHeaderFieldKey(i); 
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if(header!=null) %{g<{\@4(;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oVyOiWo\Z  
Utility.log(header+" : "+con.getHeaderField(header)); 5O<7<OB  
else  Hrm^@3  
break; LC)-aw>-  
} fEF1&&8^  
} &m_4#  
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public void splitterStop() f}b= FV{  
{ NL%5'8F>,  
bStop = true; >.N?y@  
} {H{u[XR[z
 
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} 2bwf(  
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+]P??`,R;  
/* X-O/&WRYQ  
**FileAccess.java 86$9)UI  
*//文件访问(定位，写) 1TeYA6 t  
package NetFox; :clMO|  
import java.io.*; (<!Yw|~  
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public class FileAccessI implements Serializable{ P 0v&*y3Y  
6jT+kq)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v1wMXOR  
RandomAccessFile oSavedFile; }DiMt4!ZC!  
long nPos; ,;9byb  
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public FileAccessI() throws IOException F3j#NCuO=z  
{ @*'$QD,  
this("",0); fH[Yc>(oj  
} dHjJLs_  
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public FileAccessI(String sName,long nPos) throws IOException w3oh8NRs_  
{ GqB]^snh  
oSavedFile = new RandomAccessFile(sName,"rw"); CPGiKE  
this.nPos = nPos; G*.}EoA  
oSavedFile.seek(nPos); AB92R/  
} H]2cw
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public synchronized int write(byte[] b,int nStart,int nLen) X}Heaqn  
{ _)AX/%^%  
int n = -1; NVqJN$z  
try{ zyb
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oSavedFile.write(b,nStart,nLen); Hxe!68{aR  
n = nLen; t;g=@o9YA  
} GcXh V  
catch(IOException e) -'ff0l  
{ |Et8FR3[m  
e.printStackTrace (); >drG,v0qh  
} Fo  K!JX*  
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return n; 4O}ZnE1[  
} a B(_ZX'L  
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} X
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/* {p -q&k&R|  
**SiteInfoBean.java SvE3E$*  
*/ Vqr#%.N  
package NetFox; 
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fGK=lT$  
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public class SiteInfoBean { K9\p=H^T7  
>J4Tk1//b  
t}$WP&XRG<  
private String sSiteURL; //Site's URL cOz8YVR-  
private String sFilePath; //Saved File's Path D}.Pk>5  
private String sFileName; //Saved File's Name +hoZW R  
private int nSplitter; //Count of Splited Downloading File HP/f`8  
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public SiteInfoBean() J3 Y-d7=|  
{//nSplitter的缺省值为5 SQ$|s%)oB  
//default value of nSplitter is 5 Nu}x`Qkmr  
this("","","",5); /#WRd}IjK  
} e u{  
1#]0\Y(  
. }#R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _SVIY@K|/  
{ V?_:-!NJ(  
sSiteURL= sURL; k 5~#_D>  
sFilePath = sPath;
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sFileName = sName; o p{DPUO0  
this.nSplitter = nSpiltter; I%
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} E;I'b:U`  
.k_> BD];  
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public String getSSiteURL() F},#%_4  
{ =I(F(AE  
return sSiteURL; 1$+-?:i C  
} *O5Ysk^|  
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*#{V^}  
public void setSSiteURL(String value) Npr<{}ZE  
{ F=T};b  
sSiteURL = value; !L|}/u3v  
} Bz7rf^H`Z  
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public String getSFilePath() 9Q*T'+V  
{ cN{(XmX5n  
return sFilePath; Xyz w.%4c  
} v@qU<\Y>  
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public void setSFilePath(String value) AlVBhR`  
{ fV>12ici  
sFilePath = value; WVa-0;  
} ktEdbALK  
[B2g{8{!  
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public String getSFileName() OV.f+_LS  
{ %}`zq8Q
;  
return sFileName; be->ofUYgs  
} sY%nPf~9q'  
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public void setSFileName(String value) ukInS:7  
{ L-,C5^  
sFileName = value; 0
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}  l,lfkm  
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public int getNSplitter() CGp7 Tx#  
{ DwNEqHi  
return nSplitter; @OB7TI_/
 
} _U<r@  
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public void setNSplitter(int nCount) Zr#\>h'c  
{ |ctcY*+  
nSplitter = nCount; $xK*TJ(k  
} "NMSLqO  
} 9sId2py]W  
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/* #Aver]e
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**Utility.java TGSkJ 1Lx  
*/ d95 $w8>  
package NetFox; I #bta  
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T
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public class Utility { vxt<}h5J/!  
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'<!T'l:R:/  
public Utility() Pe`eF(J  
{ XPfheV G  
5f-eWW]!  
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} y7@q]~%  
z:JQ3D7/we  
//线程睡眠 %h^ f?.(:  
public static void sleep(int nSecond) >J['so2Bf  
{ g?1! /+  
try{ ~}@cSv'(1  
Thread.sleep(nSecond); Xt$o$V  
} DRy,n)U&  
catch(Exception e) =P)H3|AdIm  
{ [R%Pf/[Fr  
e.printStackTrace (); NU/:jr.W#  
} '.5_
L8  
} J5j3#2l  
`F,*NESv  
//日志 UgC{  
public static void log(String sMsg) [[A}MF*@  
{ UtzM+7r@  
System.err.println(sMsg); eW/sPQ-  
} u~7 ,v  
?_BK(kL_  
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public static void log(int sMsg) /{sFrEMP\  
{ 7 yp}  
System.err.println(sMsg); xwe^_7  
} :J~sz)n4  
} i&',g  
>j}.~$6dj_  
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/* 79G& 0 P\  
**TestMethod.java v
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*/ Fo$'*(i  
package NetFox; G~FAChI8![  
c_dg/!Iu  
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public class TestMethod { v#`7,::  
Api<q2@R  
5rPK7Jh`B  
public TestMethod() 'rSP@  
{ ///xx/weblogic60b2_win.exe m{{8#@g  
try{ bS"zp6Di  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :W*']8 M-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `p\@b~GM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Xn3 \a81  
fileFetch.start(); Kjfpq!NYE  
} n"dYN3dE  
catch(Exception e){e.printStackTrace ();} o@j)clf  
9n!IdqKN  
w$j!89@)  
} OHyB
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public static void main(String[] args) SZ3UR  
{ {- Y.C
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new TestMethod(); /\e&nYz  
} c$AwJhl^]  
} lVR a{._m  
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