http断点续传简单实现（java)

/* z TM1 e  
**SiteFileFetch.java etPb^&#$  
*/ Tr} r` %  
package NetFox; k70o=}  
import java.io.*; OjUZ-_J  
import java.net.*; c5($*tTT  
**%/Ke[  
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public class SiteFileFetch extends Thread { 
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SiteInfoBean siteInfoBean = null; //文件信息Bean W6d[v/+K+  
long[] nStartPos; //开始位置 \}:&Hl+  
long[] nEndPos; //结束位置 ?0U.1N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3%g\)Cs  
long nFileLength; //文件长度 bm &$wf  
boolean bFirst = true; //是否第一次取文件 L~,x~sLd  
boolean bStop = false; //停止标志 P{'T9U|O-  
File tmpFile; //文件下载的临时信息 p\7(`0?8VN  
DataOutputStream output; //输出到文件的输出流 N<e=!LV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zB8 @Wl  
public SiteFileFetch(SiteInfoBean bean) throws IOException " ^t3VjN  
{ aBH!K   
siteInfoBean = bean; &at^~o  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jlf.~vt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xUiSAKrcM  
if(tmpFile.exists ()) 4490l"  
{  &Ow[  
bFirst = false; z/B[quSio  
read_nPos(); KKPQ[3g  
} Y6>@zznk  
else #LGAvFA*_F  
{ fO;#;p.  
nStartPos = new long[bean.getNSplitter()]; q13bV  
nEndPos = new long[bean.getNSplitter()]; fG+/p 0sJ?  
} Q*W`mFul  
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} ?gp:uxq,.  
* [\H)Lz  
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public void run() pCE,l'Xa  
{ K>"]*#aBv  
//获得文件长度 'Mfn:n+  
//分割文件 7)2Co[t  
//实例FileSplitterFetch u9TiEEof3  
//启动FileSplitterFetch线程 r34q9NFT5  
//等待子线程返回 o@&Hc bN^  
try{ Rh[%UNl  
if(bFirst) w:|BQ,  
{ 5gdsV4DH$  
nFileLength = getFileSize(); dB{VY+!  
if(nFileLength == -1) :y>$N(.8f  
{ 1Qc>A8SU  
System.err.println("File Length is not known!"); -3z$~ {  
} tX<. Ud  
else if(nFileLength == -2) ?89K [D|  
{ yX-h|Cr"  
System.err.println("File is not access!"); bJ~@ k,'  
} p\"WX  
else BIBBp=+  
{ 1>KZ1Kf  
for(int i=0;i<nStartPos.length;i++) B 66-l!xa  
{ O&]P
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); sX8?U,u  
} 4 Qo(Wl
 
for(int i=0;i<nEndPos.length-1;i++) #@i1jZ  
{ %,Pwo{SH  
nEndPos = nStartPos[i+1]; STr&"9c  
} Id<3'ky<N  
nEndPos[nEndPos.length-1] = nFileLength; {JJq/[j  
} VGHy|5K$  
} +d$l1j  
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//启动子线程 e=8z,.Xk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _&U5 u  
for(int i=0;i<nStartPos.length;i++) BEm~o#D  
{ ;;*'<\lP.j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @CxXkR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2l8TX#K  
nStartPos,nEndPos,i); Ykt{]#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ",qcqG(  
fileSplitterFetch.start(); b8>2Y'X  
} JfrPK/Vn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !6yyX}%o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'ot,6@~x>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OYj4G?c  
nEndPos = " + nFileLength); viLK\>>  
// fileSplitterFetch[nPos.length-1].start(); Ot^<:\<`G  
"#3p=}]  
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//等待子线程结束 4!I;U>b b  
//int count = 0; F+lsza  
//是否结束while循环 S~Z`?qHWh  
boolean breakWhile = false; pE^jUxk6  
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while(!bStop) !,I530eh7  
{ aDae0$lc.S  
write_nPos(); 2E*k@  
Utility.sleep(500); WgV'T#*  
breakWhile = true; ftw@nQNU  
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for(int i=0;i<nStartPos.length;i++) SU {
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{ B(omD3jzN  
if(!fileSplitterFetch.bDownOver) ;'|Mt)\  
{ 3hPj;-u  
breakWhile = false; }gfs  
break; ~@v<B I
 
} ?)60JWOJ1  
} MgP6ki1z  
if(breakWhile) nVK`H@5fw  
break; Gx$rk<;ZW  
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#U=}Pv~wM  
//count++; '(qVA>S  
//if(count>4) :kaHvf  
// siteStop(); Py3Y*YP  
} 0VA$ Ige  
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System.err.println("文件下载结束！"); S>'S4MJE`  
} EE^ N01<"\  
catch(Exception e){e.printStackTrace ();} ckZZ)lW`*  
} .ZB/!WiF  
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//获得文件长度 }EW@/; kC  
public long getFileSize() 9qqzCMrI0e  
{ X53TFRxnT  
int nFileLength = -1; }`SXUM_sD`  
try{ +yh-HYo`  
URL url = new URL(siteInfoBean.getSSiteURL()); 9aE.jpN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H/eyc`  
httpConnection.setRequestProperty("User-Agent","NetFox"); S!u`V3-s  
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int responseCode=httpConnection.getResponseCode(); bhIyq4N  
if(responseCode>=400) ^J([w~&  
{ Tt0:rQ.  
processErrorCode(responseCode); vE9M2[TJA  
return -2; //-2 represent access is error jMT];%$[  
} *@C4~Zo  
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String sHeader; ^w+jPT-n  
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for(int i=1;;i++) E rf$WPA  
{ =h083|y>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +hz^( I7  
//Utility.log(in.readLine()); )<6zbG  
sHeader=httpConnection.getHeaderFieldKey(i); Rv ]?qJL  
if(sHeader!=null) xTnd9'Pk`:  
{ f[@M  
if(sHeader.equals("Content-Length")) :\0q\2e[<  
{ Se o3a6o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i>Cxi ZT  
break; ")q{>tV  
} ~/@5&ajz  
} "!yKX(aTX  
else  9"@P.8_  
break; jJpSn[{  
} iw,F)O  
} >PsP y.  
catch(IOException e){e.printStackTrace ();} doCWJ   
catch(Exception e){e.printStackTrace ();} kXj%thDx  
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Utility.log(nFileLength); gc'C"(TO(  
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return nFileLength; =jik33QV<  
} ,RkL|'1l  
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//保存下载信息（文件指针位置） s[yIvlHw`  
private void write_nPos() u@`)u#  
{ mGQgy[gX  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Tl#Jf3XY}  
output.writeInt(nStartPos.length); I5"ew=x#  
for(int i=0;i<nStartPos.length;i++) M
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{ CS 7"mE`{  
// output.writeLong(nPos);  s*gyk  
output.writeLong(fileSplitterFetch.nStartPos); z.H*"r  
output.writeLong(fileSplitterFetch.nEndPos); XUD/\MoV  
} Y$^x.^dT,  
output.close(); kT(}>=]g  
} {__Z\D2I  
catch(IOException e){e.printStackTrace ();} 1}E`K#  
catch(Exception e){e.printStackTrace ();} JJnZbJti  
} SL;\S74  
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//读取保存的下载信息（文件指针位置） wz*QB6QtU  
private void read_nPos() 2a;
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{ +$)C KC  
try{ B|IQ/g?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r<;bArs-u  
int nCount = input.readInt(); d[.kGytUt  
nStartPos = new long[nCount]; 2`#jw)dM;}  
nEndPos = new long[nCount]; $'f<4  
for(int i=0;i<nStartPos.length;i++) @!\g+z_"  
{ p{j }%)6n  
nStartPos = input.readLong(); x@+m_y  
nEndPos = input.readLong(); -jB1tba  
} oZO6J-ea  
input.close(); =&*:)  
} e`Xy!@`_  
catch(IOException e){e.printStackTrace ();} Sti)YCXH  
catch(Exception e){e.printStackTrace ();} ?Z@FxW  
} XA~Rn>7&H  
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private void processErrorCode(int nErrorCode) d7A08l{  
{ pRtxyL"y  
System.err.println("Error Code : " + nErrorCode); \s2hep  
} -ob_]CKtJ~  
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//停止文件下载 0(s0<9s%  
public void siteStop() d\`A ^  
{ t"`LJE
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bStop = true; &nk6_{6 c  
for(int i=0;i<nStartPos.length;i++) 6Q,-ZM=Z_p  
fileSplitterFetch.splitterStop(); ND
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} Qp7|p  
} {&G7 Xa  
//负责部分文件的抓取 w,NK]<dU@  
**FileSplitterFetch.java %T*lcg  
*/ T0WB  
package NetFox; p.q:vI$J  
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import java.io.*; sXI_!)H  
import java.net.*; 65VnH=  
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public class FileSplitterFetch extends Thread { UYH;15s  
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String sURL; //File URL Nt#zr]Fz  
long nStartPos; //File Snippet Start Position TH2D
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long nEndPos; //File Snippet End Position .
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int nThreadID; //Thread's ID %R5APMg1  
boolean bDownOver = false; //Downing is over n.C.th >Y1  
boolean bStop = false; //Stop identical =+q9R`!L]  
FileAccessI fileAccessI = null; //File Access interface BVxg=7%St  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BQv+9(:fQB  
{ |XxA Fje  
this.sURL = sURL; h&J6  
this.nStartPos = nStart; 2%N$Y]  
this.nEndPos = nEnd; ]{
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nThreadID = id; k,M%/AXd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `pF|bZ?v  
} $rDeI-)S  
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public void run() Nm%&xm  
{ Qvs}{h/  
while(nStartPos < nEndPos && !bStop) @(PYeXdV6&  
{ AwB ]0H  
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try{ m/n_e g  
URL url = new URL(sURL); bp2l%A;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R-J\c+C>W  
httpConnection.setRequestProperty("User-Agent","NetFox"); Nh~ Hh(  
String sProperty = "bytes="+nStartPos+"-"; "<0BCJJ  
httpConnection.setRequestProperty("RANGE",sProperty); $<2r;'?0D  
Utility.log(sProperty); |c,":R  
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InputStream input = httpConnection.getInputStream(); H r?G_L  
//logResponseHead(httpConnection); *. l,_68  
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byte[] b = new byte[1024]; AD=@  
int nRead; /j./  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {gluK#Qm  
{ Dna0M0   
nStartPos += fileAccessI.write(b,0,nRead); $"C]y$}  
//if(nThreadID == 1) bLGgu#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ex7zg!  
} l]inG^s  
/ZZo`   
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Utility.log("Thread " + nThreadID + " is over!"); OBi9aFoQ  
bDownOver = true; _)Q)tOW  
//nPos = fileAccessI.write (b,0,nRead); (=0W[@k  
} 2}>jq8Y47  
catch(Exception e){e.printStackTrace ();} ^ruS  
} QIF|pZ+^  
} ;!&A  
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|
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//打印回应的头信息 n[lf==R  
public void logResponseHead(HttpURLConnection con) Qn(e[ C6\  
{ szMh}q"u  
for(int i=1;;i++) LYNd^}  
{ :U)q(.53  
String header=con.getHeaderFieldKey(i); cjsQm6  
if(header!=null) {S(?E_id5b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q17c)]<"  
Utility.log(header+" : "+con.getHeaderField(header)); r]Bwp i%  
else :}TT1@  
break;
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} AU}e^1h  
} \v{tK;  
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public void splitterStop() mf6?8!O}>  
{ Ev%4}GwO4  
bStop = true; 5Tluxt71  
} XP *pYN  
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} 2]C`S,)  
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/* 6c>t|=Ss(  
**FileAccess.java 1HL}tG?+#  
*//文件访问(定位，写) U|6ME%xm  
package NetFox; Sx+.<]t2A  
import java.io.*; L.>tJ.I
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public class FileAccessI implements Serializable{ p>h B&h  
Teu4;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "AP''XNi  
RandomAccessFile oSavedFile; ~ z*  
long nPos; VS@o_fUx)  
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public FileAccessI() throws IOException .]0B=w* Z  
{ /ZHuT
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this("",0); l;}D| 6+_W  
} )VQ:L:1t(  
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public FileAccessI(String sName,long nPos) throws IOException ;!DUNzl  
{ E9HA8  
oSavedFile = new RandomAccessFile(sName,"rw"); P\KP)bkC  
this.nPos = nPos; K/79Tb-  
oSavedFile.seek(nPos); (h7 rW3  
} HiCNs;t  
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public synchronized int write(byte[] b,int nStart,int nLen) qY`)W[  
{ [5,aBf)X  
int n = -1; > xkl7D  
try{ 1s8v E f  
oSavedFile.write(b,nStart,nLen); 5t#+UR  
n = nLen; su/l'p'  
} )Y}t~ Zfx  
catch(IOException e) Gp'rN}i^  
{ $r*7)/  
e.printStackTrace (); st P~/}  
} csz/[*  
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return n; 2MQgTFM9  
} ]?S\
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} <KqZ.7XfB  
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/* 9KRHo%m  
**SiteInfoBean.java _O2},9L n  
*/ K,bv\j;f  
package NetFox; UhYeyT  
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public class SiteInfoBean { I>o+INb:  
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private String sSiteURL; //Site's URL rM#jxAb  
private String sFilePath; //Saved File's Path 6js94ko[  
private String sFileName; //Saved File's Name 8o#*0d|  
private int nSplitter; //Count of Splited Downloading File Iq0_X7:{QI  
T`7;Rl'Q  
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public SiteInfoBean() _*h,,Q  
{//nSplitter的缺省值为5 V.#,dDC@j  
//default value of nSplitter is 5 Ls)y.u  
this("","","",5); l-xKfp`  
} b|U&{I>TH  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zQM3n =y  
{ ce th)Xm  
sSiteURL= sURL; BM!\U 6  
sFilePath = sPath; >B/ jTn5=  
sFileName = sName; a_XM2dc%  
this.nSplitter = nSpiltter; "-GjwB  
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} IJ2]2FI  
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public String getSSiteURL() *#-X0}'s  
{ DKgwi'R  
return sSiteURL; 4V9DP
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} WL$Ee=  
By(:%=.  
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public void setSSiteURL(String value) {2G9>'  
{ S453oG"  
sSiteURL = value; l?v`kAMR
 
} &cztUM(  
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public String getSFilePath() A]"$O&l  
{ WV}<6r$e  
return sFilePath; RpPbjz~  
} .| CcUmx  
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public void setSFilePath(String value)
}ozlED`E  
{ sG`||Kb;n  
sFilePath = value; 6wC|/J^  
} fH~InDT^  
3&'ll51t  
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public String getSFileName() 7|LJwXQ-  
{ qawb9Iud0  
return sFileName; XlIRedZ{  
} .r[b!o^VR  
6}wXNTd  
=KqcWN3k  
public void setSFileName(String value) `RDlk  
{ CAyV#7[0  
sFileName = value; EM]~yn!+  
} 1
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7^,C=2  
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public int getNSplitter() HPl!r0 h  
{ 834(kw+#9  
return nSplitter; yL/EIN  
} IB:eyq-+  
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public void setNSplitter(int nCount) M,@\*qlEJ  
{ {;0j9rr  
nSplitter = nCount; +g,:!5pg  
} Gc2sY 0  
} S!Ue+jW  
._
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/* BE. v+'c"  
**Utility.java Jcf'Zw"\  
*/ vRa|lGeW  
package NetFox; p6m](Jg  
*n mr4Q'v{  
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public class Utility { #~?Q?"  
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public Utility() 9Axk-c  
{ p'UYHt  
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} ,ButNBv  
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//线程睡眠 l'=H,8LfA  
public static void sleep(int nSecond) , f9V`Pz)  
{ 2KVMQH`B9  
try{ L4`bGZl55  
Thread.sleep(nSecond); pOP`n3m0  
} UMR0S5`}  
catch(Exception e) >m='#x0>Y  
{ |_L\^T|6  
e.printStackTrace (); !xm
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} WccTR aq  
} 3a PCi>i!_  
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//日志 x*td nor&  
public static void log(String sMsg) cF!ygz//  
{ RM\it"g  
System.err.println(sMsg); K +n  
} %T@3-V_  
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public static void log(int sMsg) [of{~  
{ \Z9+U:n  
System.err.println(sMsg); hZNS$  
} 7=C$*)x  
} *izPLM}+  
*sK")Q4N  
kKr|PFz  
/* I>ks H  
**TestMethod.java X`bN/sI  
*/ _j{^I^P  
package NetFox; {~NiGHY  
@wO"?w(  
\jLn5$OW  
public class TestMethod { 0S8v41i6  
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JJ@O5  
public TestMethod() eh_{-  
{ ///xx/weblogic60b2_win.exe g4USKJ19.  
try{ U-/-aNJ]U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @+II@[_lT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lM ]n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &}}
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fileFetch.start(); 1SIhW:C  
} }T=0]u4,  
catch(Exception e){e.printStackTrace ();} S9kagiFX\  
8a{S*  
BeP]M1\?>  
} 4AdZN5  
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:m*
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public static void main(String[] args) k(l  
{ MT
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new TestMethod(); d*3;6ZLy  
} tlhYk=yq  
} "e]1|~  
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