http断点续传简单实现（java)

/* , :10  
**SiteFileFetch.java S~Z`?qHWh  
*/ &3o[^_Ti  
package NetFox; W@T_-pTCjK  
import java.io.*; !,I530eh7  
import java.net.*; 3RW3<n  
:epjJ1mW  

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public class SiteFileFetch extends Thread { %+1;iuDL  
*<5zMSZO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +FYQ7UE  
long[] nStartPos; //开始位置 !6d6b@Mv  
long[] nEndPos; //结束位置 bsn.HT"5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,pg\5b  
long nFileLength; //文件长度 +RuPfw{z  
boolean bFirst = true; //是否第一次取文件 G T3wJQ5N  
boolean bStop = false; //停止标志 A18&9gY  
File tmpFile; //文件下载的临时信息 #Fl5]> |  
DataOutputStream output; //输出到文件的输出流 nJ ZQRRa:C  
=` %iv|>r0  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :.K#=ROP  
public SiteFileFetch(SiteInfoBean bean) throws IOException Py3Y*YP  
{ xpzQ"'be  
siteInfoBean = bean; ~kkwPs2V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fG^#G/n2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -%h0`hOG{  
if(tmpFile.exists ()) s-z*Lq*  
{ S>'S4MJE`  
bFirst = false; 4raKhN"  
read_nPos(); On^jHqLaE  
} YXBU9T{r  
else m V U(b,  
{ ,J(+%#$UT  
nStartPos = new long[bean.getNSplitter()]; )Q!3p={S*  
nEndPos = new long[bean.getNSplitter()]; b')Lj]%;k  
} EZz`pE  
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} N@z+h  
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public void run() ~I+}u]J  
{ ~MgU"P>  
//获得文件长度 L&i_  
//分割文件 TDMyZ!d  
//实例FileSplitterFetch P/'9k0zs)  
//启动FileSplitterFetch线程 =36e&z-#  
//等待子线程返回 X+:>&&9  
try{ q*h1=H52  
if(bFirst) bc".R]  
{ wl*"Vagb  
nFileLength = getFileSize(); K~?M?sa  
if(nFileLength == -1) gEE6O%]g  
{ )bM #s">Y  
System.err.println("File Length is not known!");
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} frYPC Irj  
else if(nFileLength == -2) mp{r$tc  
{ vfh0aW-O  
System.err.println("File is not access!");  h,D6MP  
} s`bC?wr5h  
else  `#m>3  
{ ]/_GHG9  
for(int i=0;i<nStartPos.length;i++) ^w+jPT-n  
{ Tath9wlv6;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w'Kc#2  
} mNvK|bTUT  
for(int i=0;i<nEndPos.length-1;i++) zW@OSKq4  
{ dwQ*OxFl  
nEndPos = nStartPos[i+1]; dXe. 5XC  
} /!r#=enG7  
nEndPos[nEndPos.length-1] = nFileLength; 0'DlsC/`*  
} ATeXOe
 
} Rv ]?qJL  
s1[_Pk;!  
.45XS>=z#  
//启动子线程 f[@M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %7_c|G1  
for(int i=0;i<nStartPos.length;i++) gAx8r-` `  
{ +3c!.] o;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !`B
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H& #Od?  
nStartPos,nEndPos,i); 5>XrNc91  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '.@'^80iQ  
fileSplitterFetch.start(); u%^Lu.l_c  
} [ imC21U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~dIb>[7wy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !~'\Ey  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dh7PpuN{  
nEndPos = " + nFileLength); sFEkxZi<  
// fileSplitterFetch[nPos.length-1].start(); [_3Rhp:  
;x[F4d  
*>=vSRL0_  
//等待子线程结束 _{EO9s2FG  
//int count = 0; =A6/D    
//是否结束while循环 u@`)u#  
boolean breakWhile = false; :'OC
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hIj[#M&6  
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while(!bStop) |~! R5|Q  
{ '~-Lxvf'  
write_nPos(); 67I6]3[Z  
Utility.sleep(500); eQk ~YA]K  
breakWhile = true; vT<q zN  
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for(int i=0;i<nStartPos.length;i++) CI+dIv>  
{ tQ7DdVdix  
if(!fileSplitterFetch.bDownOver) 0Fw0#eE  
{ ~P*t_cpZ  
breakWhile = false; VV(>e@Bc4  
break; H=vrF-#  
} Lw=.LN  
} J&{qe@
^
 
if(breakWhile) UarU.~Uqi  
break; <v?9:}  
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//count++; p{j }%)6n  
//if(count>4) 8wz
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// siteStop(); rK*s/mX <  
} l`2X'sw[/  
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R v9?<]  
System.err.println("文件下载结束！"); ;Ef:mr"Nu  
} W{Cc wq  
catch(Exception e){e.printStackTrace ();} ;lS
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} "C$z)  
3G9YpA_}X  
"(}xIsy  
//获得文件长度 i0uBb%GMT  
public long getFileSize() QD LXfl/  
{ iTU
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int nFileLength = -1; 4BG6C'`%  
try{ &nk6_{6 c  
URL url = new URL(siteInfoBean.getSSiteURL()); #&.&Uu$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1<
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httpConnection.setRequestProperty("User-Agent","NetFox"); O6P0Am7s  
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int responseCode=httpConnection.getResponseCode(); 7?K?-Oj  
if(responseCode>=400) v]g/ 5qI&  
{ p.q:vI$J  
processErrorCode(responseCode); rt%.IQdY  
return -2; //-2 represent access is error xm>RLx}9  
} XG"&\FL{T  
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String sHeader; <@n/[ +3  
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for(int i=1;;i++) aG?ko*A
;  
{ KO(+%>^R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -@%*~^~z'  
//Utility.log(in.readLine()); =+q9R`!L]  
sHeader=httpConnection.getHeaderFieldKey(i); P}o:WI4.cB  
if(sHeader!=null) SU"-%}~O#,  
{ $}<+~JpGfP  
if(sHeader.equals("Content-Length")) DO(-)izC  
{ XOO!jnQu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v
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break; 9Y1&SEsNX  
} zpr`  
} i TY4X:x  
else PYqx&om  
break; ;]?1i4p)  
} Pze$QBNoRd  
} \pZ,gF;y  
catch(IOException e){e.printStackTrace ();} KzZ! CB\  
catch(Exception e){e.printStackTrace ();} :(?joLA  
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Utility.log(nFileLength); Qvs}{h/  
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return nFileLength; {zBf*x  
} Eom|*2vWIC  
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)  
//保存下载信息（文件指针位置） Mw
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private void write_nPos() km'3[}8o&  
{ ,St#/tu  
try{ =)m2u2c M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $<2r;'?0D  
output.writeInt(nStartPos.length); A] pLq`  
for(int i=0;i<nStartPos.length;i++) ZAzn-n  
{ J&S$F:HM  
// output.writeLong(nPos); CfQOG7e@  
output.writeLong(fileSplitterFetch.nStartPos); "aK3 ylz;  
output.writeLong(fileSplitterFetch.nEndPos); Ixg.^>62  
} 9_[TYzpB!  
output.close(); r]?ZXe$
;  
} Gvv~P3Dm  
catch(IOException e){e.printStackTrace ();} -WwFUm  
catch(Exception e){e.printStackTrace ();} }kI-UEn$EP  
} ~WU _u,:  
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X>EwJ"q#  
//读取保存的下载信息（文件指针位置） !7@IWz(,"  
private void read_nPos() %TdZ_  
{ O^|dc=  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0/S|P1!b  
int nCount = input.readInt(); ;oVdkp  
nStartPos = new long[nCount]; p!>FPS  
nEndPos = new long[nCount]; V0z.w:-  
for(int i=0;i<nStartPos.length;i++) pj&vnX6O^  
{ 0G1?  
nStartPos = input.readLong(); cjsQm6  
nEndPos = input.readLong(); jZS6f*$  
} g}0}$WgH:  
input.close(); :\L{S  
} H1rge<  
catch(IOException e){e.printStackTrace ();} ]p:x,%nm  
catch(Exception e){e.printStackTrace ();} r9'lFj  
} EcrM`E#kaZ  
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private void processErrorCode(int nErrorCode) aB"W6[  
{ ;$l!mv7  
System.err.println("Error Code : " + nErrorCode); :pcKww|V  
} h<\o[n7j  
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2]C`S,)  
//停止文件下载 X{\>TOk  
public void siteStop() H7?C>+ay  
{ g<{/m
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bStop = true; lZZ4 O(  
for(int i=0;i<nStartPos.length;i++) BbUZ,X*Y  
fileSplitterFetch.splitterStop(); :.f =>s]  
:XcU@m  
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} N,V%/O{Y  
} 5c($3Pno=  
//负责部分文件的抓取 ?Q;8D@   
**FileSplitterFetch.java QgO@oV*S  
*/ ZdeRLX  
package NetFox; S*Un$ngAh  
/lkIbmV  
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import java.io.*; [[P?T^KT  
import java.net.*; \Xc6K!HJM  
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public class FileSplitterFetch extends Thread { rcMVYSj0  
> n
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String sURL; //File URL Q\&FuU  
long nStartPos; //File Snippet Start Position @|(mR-Jj  
long nEndPos; //File Snippet End Position P;bl+a'gu  
int nThreadID; //Thread's ID y_M<\b  
boolean bDownOver = false; //Downing is over #P=rP=  
boolean bStop = false; //Stop identical <iunDL0  
FileAccessI fileAccessI = null; //File Access interface } *|_P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zg+78  
{ csz/[*  
this.sURL = sURL;
/1ooOq]  
this.nStartPos = nStart; lHv;C*(_=  
this.nEndPos = nEnd; .x5Yfe  
nThreadID = id; &!]$#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a_4Ny  
} )Q9m,/F  
\.2?951}  
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public void run() =i
}  
{ K,bv\j;f  
while(nStartPos < nEndPos && !bStop) ~4y&]:I  
{ DZ5%-  
<:0649ZB  
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try{ :TJv<NZi'  
URL url = new URL(sURL); H!Z=}>TN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WM5s  
httpConnection.setRequestProperty("User-Agent","NetFox"); (f^WC,  
String sProperty = "bytes="+nStartPos+"-"; T`7;Rl'Q  
httpConnection.setRequestProperty("RANGE",sProperty); -;&aU;k  
Utility.log(sProperty); n3t1'_/TU}  
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InputStream input = httpConnection.getInputStream(); ~[dU%I>L^  
//logResponseHead(httpConnection); )$Xd#bzD|  
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byte[] b = new byte[1024]; BM!\U 6  
int nRead; ~Z!!wDHS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |F[E h ~  
{ /uS(Z-@  
nStartPos += fileAccessI.write(b,0,nRead); \?7)oFNz  
//if(nThreadID == 1) L ?g|:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (M5w:qbR  
} JUXIE y^  
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Utility.log("Thread " + nThreadID + " is over!"); Y~EKMowI&e  
bDownOver = true; {.pR$]6B"+  
//nPos = fileAccessI.write (b,0,nRead); 2.CjjI  
} 7yo/sb9h  
catch(Exception e){e.printStackTrace ();} l?v`kAMR
 
} :L#t?~  
} 8Kt_irD  
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//打印回应的头信息 6I GUp  
public void logResponseHead(HttpURLConnection con) sc'QNhrW  
{ u,e'5,`N  
for(int i=1;;i++) J/S 47J~  
{ xO)vn\uJ  
String header=con.getHeaderFieldKey(i); YYU Di@K  
if(header!=null) M-1 VB5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nlJ~Q_E(  
Utility.log(header+" : "+con.getHeaderField(header)); oV
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else rU<NHFGj4  
break; 2:'C|  
} $~vy,^  
} 7_C;-  

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public void splitterStop() fmZ5rmw!  
{ |P7c {  
bStop = true; ?#?[6t  
} Dz/I"bZLC  
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} maQE Bi,  
@Aa$k:_  
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/* meunAEe  
**FileAccess.java WF\ hXO  
*//文件访问(定位，写) +;~JHx.~X  
package NetFox; HL$}Gh]q  
import java.io.*; {|?OKCG{  
#k2&2W=x  
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public class FileAccessI implements Serializable{ wjh[}rTV*  
_"n1"%Ns  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2`>/y  
RandomAccessFile oSavedFile; ?hUC#{  
long nPos; .|Y2'TWQ  
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public FileAccessI() throws IOException <"w;:Zs  
{ :q=u+h_  
this("",0); (\m4o   
} 'teToE<i  
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q !\Ht2$b  
public FileAccessI(String sName,long nPos) throws IOException ,9<}V;(  
{ UMR0S5`}  
oSavedFile = new RandomAccessFile(sName,"rw"); H&jK|]UXoO  
this.nPos = nPos; ^2E\{$J
 
oSavedFile.seek(nPos); ry9%Y3  
} `<&RZB2  
tWR>I$O8F  
*(6vO{  
public synchronized int write(byte[] b,int nStart,int nLen) ETvn$ Jdp  
{ kbzzage6L  
int n = -1; t"M&Yy  
try{ )W9W8>Cc5_  
oSavedFile.write(b,nStart,nLen); i? 5jl&30  
n = nLen; !|6M,Rk_  
} G)5w_^&%  
catch(IOException e) pQ%~u3  
{ JU+Uzp   
e.printStackTrace (); yf`Nh  
} ~]f+  
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return n; .),ql_sXr  
} HqNM31)  
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} =au7'i|6  
<#AS[Q[N  
l H:Y8j  
/* ; (I(TG  
**SiteInfoBean.java $YuVM  
*/ l/9V59Fv9  
package NetFox; >zcR ?PPs  
iu!j#VO  
 fp!Ba  
public class SiteInfoBean { sYnf #'  
\| qr&(PG  
#T<<{ RA  
private String sSiteURL; //Site's URL ERcj$ [:T(  
private String sFilePath; //Saved File's Path pvCn
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private String sFileName; //Saved File's Name ELoE-b)Cb  
private int nSplitter; //Count of Splited Downloading File 6 ,jp-`  
&?L K>QV  
I4'mU$)U  
public SiteInfoBean() 4oW6&1  
{//nSplitter的缺省值为5 9x;CJhX
 
//default value of nSplitter is 5 IG@.WsM_  
this("","","",5); P5 GM s  
} UHr0J jQK  
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_  dFZR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r;:5P%:  
{ [/_M!&zz2  
sSiteURL= sURL; <P&~k\BuF{  
sFilePath = sPath; j8/rd
 
sFileName = sName; s}Y_og_c  
this.nSplitter = nSpiltter; F-i`GMWC  
pzcV[E1  
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} u&MlWKCi  
t(3<w)r2  
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public String getSSiteURL() DY2r6bcn`  
{ &"!s+_  
return sSiteURL; 5!
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} [@ExR*  
-*q:B[d  
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public void setSSiteURL(String value) ,\*PpcU  
{ c_$9z>$  
sSiteURL = value; . ] =$((  
} E.*TJ  
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public String getSFilePath() EC[2rROn\  
{ vrVb/hhG  
return sFilePath; +#qW 0g  
} O
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i4 BCm/h  
a/d'(]  
public void setSFilePath(String value) _86pbr9  
{ 9qyA{ |3  
sFilePath = value; 1rs`|iX5  
} + 3+^J?N  
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public String getSFileName() lwS6"2q  
{ ^kg[n908Nw  
return sFileName; qs\O(K
8  
} n_G< /8  
&?~OV:r9  
7.hgne'<  
public void setSFileName(String value) r>v_NKS]t  
{ MUo}Qi0K  
sFileName = value; dWR0tS6vR`  
} M4hzf  
c
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7;cb^fi/  
public int getNSplitter() x13t@b  
{ S`,(10Y  
return nSplitter; pqaQ%|<  
} 4-P'e%S  
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7:fC,2+  
public void setNSplitter(int nCount) B>kx$_~  
{ eWjLP{W  
nSplitter = nCount; J*)Vpk  
} 5|l&` fv`  
} A`
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^,@!L-<~(b  
sT|$@$bN  
/* IN
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**Utility.java U`gQ7
 
*/ h.\V;6ly  
package NetFox; lq2Ah=FuN  
u,<#z0R|;$  
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public class Utility { Z i-)PK^  
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9f ,$JjX[  
public Utility() <DG=qP6O  
{ bLMN9wGOgK  
:1Jg;G  
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} Jb'l.xN  
y,$kU1yH7  
//线程睡眠 0(A(Vb5J.T  
public static void sleep(int nSecond) _M n7zt1^  
{ `% sKF  
try{ T7f>u}
T  
Thread.sleep(nSecond); HCP'V  
} xE/r:D#  
catch(Exception e) GX4HW \>a  
{ o&2(xI2  
e.printStackTrace (); Fb#_(I[aj  
} 63b?-.!b  
} Kyy CS>  
_yje"  
//日志 y8T%g(  
public static void log(String sMsg) ]MjQr0&M  
{ E. @n Rj#  
System.err.println(sMsg); r5
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} B%HG7  
zyNg?_SM  
_tE`W96J  
public static void log(int sMsg) j6wdqa9!~  
{ aa!o::;  
System.err.println(sMsg); |G.|ocj;  
} =]r<xON%S  
} D[) Z$+D4f  
HorFQ?8  
m'h`%0Tc  
/* }K\]M@  
**TestMethod.java `Q d_Gu,M  
*/ \(9hg.E  
package NetFox; B4k~~;|  
>"qnuv G  
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public class TestMethod { p|Po##E}g^  
(ly4[G1y  
#Z8=z*4  
public TestMethod() W79wz\a  
{ ///xx/weblogic60b2_win.exe 3D3/\E#'o  
try{ U8_<?H
d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8
c-r;DE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b(8#*S!U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N%Gb  
fileFetch.start(); ZTV|rzE   
} h$`P|#V&  
catch(Exception e){e.printStackTrace ();} Ba$&4?8  
Kj|l]'  
9&R. <I  
} G]Fp},  
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;c1ar)G7  
public static void main(String[] args)
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{ zTODV<-`  
new TestMethod(); "F nH>g-  
} "M.\Z9BCt  
} p8CDFLuV  
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