http断点续传简单实现（java)

/* \]a uSO  
**SiteFileFetch.java Oy'0I,  
*/ _W+Q3Jx-(  
package NetFox; $~o3}&az  
import java.io.*; 
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import java.net.*; fv|%Ocm  
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public class SiteFileFetch extends Thread { It\BbG=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [;F{
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long[] nStartPos; //开始位置 VD4S_qx  
long[] nEndPos; //结束位置 GU#Q}L2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !h/
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long nFileLength; //文件长度 pP oxVvG{  
boolean bFirst = true; //是否第一次取文件 e5qvyUJM  
boolean bStop = false; //停止标志 VVN# $  
File tmpFile; //文件下载的临时信息 }!knU3J  
DataOutputStream output; //输出到文件的输出流 aKOf;^@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `E%(pjG  
public SiteFileFetch(SiteInfoBean bean) throws IOException |w,^"j2R  
{ +DxifXtB  
siteInfoBean = bean; *vXDuhQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1l~.R#WG&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PIpWa$b  
if(tmpFile.exists ()) nO:HB.&@  
{ CH#kvR2  
bFirst = false; W9+h0A-  
read_nPos(); y8D 8Y8B  
} * T\>  
else $uTlbAuv  
{ X%35XC.n  
nStartPos = new long[bean.getNSplitter()]; & ]%\.m  
nEndPos = new long[bean.getNSplitter()]; c}8 -/P=  
} _we3jzMW  
|'@V<^GR  
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} sF
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public void run() JN)"2}SE  
{ B ;;cbY  
//获得文件长度 P$F#,Cn  
//分割文件 MsSoX9A{D  
//实例FileSplitterFetch +:b(%|  
//启动FileSplitterFetch线程 QZ:v  
//等待子线程返回 ;7)OSGR
 
try{ T+3k$G[e/  
if(bFirst) 3me<~u  
{ $<14JEU  
nFileLength = getFileSize(); J;7s/YH^  
if(nFileLength == -1) @b8X%0B7  
{ 9PWm@ Nlf  
System.err.println("File Length is not known!"); u`nt\OF  
} EqYz,%I%  
else if(nFileLength == -2) 0.3^  
{ +-'`Q Ae  
System.err.println("File is not access!"); |zg=+  
} #fJwC7 4  
else J~fuW?a]r  
{ 5=Zp%[#  
for(int i=0;i<nStartPos.length;i++) nJW_a&'  
{ -.^=Z!=M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `g2&{)3k  
} 6{lG1\o  
for(int i=0;i<nEndPos.length-1;i++)
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{ ;cnnqT6  
nEndPos = nStartPos[i+1]; ,q/tyGj  
} \;'_|bu3.  
nEndPos[nEndPos.length-1] = nFileLength; ;}$Z 80  
} k`{RXx  
} m]Hb+Y=;h  

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r=xTs,xx  
//启动子线程 ZKZl>dDuh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |2[S/8g!  
for(int i=0;i<nStartPos.length;i++) )Fw @afE~  
{ AfuXu@UZ_/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nmTm(?yE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zK[ 7:<  
nStartPos,nEndPos,i); 5/zf x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fpI;`s  
fileSplitterFetch.start(); ;*n_N!v  
} pE~9o 9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [BJ$|[11  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rDK;6H:u{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $:T<IU[E  
nEndPos = " + nFileLength); Xv`2hf  
// fileSplitterFetch[nPos.length-1].start(); XPGL3[w\V  
BLWA!-  
|Gf1^8:C9  
//等待子线程结束 s@.`"TF.7  
//int count = 0; UZ[/aq  
//是否结束while循环 "u .)X3  
boolean breakWhile = false; yBJ/>SAcG  
w++B-_  
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while(!bStop) Tz+HIUIxF  
{ uEc0/a :.  
write_nPos(); ^aGZJiyJ  
Utility.sleep(500); 3P%w-qT!N  
breakWhile = true; )Ix-5084  
@>qx:jx(-S  
a!TBk=P  
for(int i=0;i<nStartPos.length;i++) 4r68`<mn[  
{ 6M O|s1zk  
if(!fileSplitterFetch.bDownOver) 3ybK6!g`[  
{ @&!=m]D*  
breakWhile = false; U)O?| VN^o  
break; Gp?ToS2^d  
} Z%,\+tRe  
} o|z
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if(breakWhile) JL}hOBqfI  
break; {mCKTyN+  
+#de8/x  
8MYLXW6  
//count++; e;&{50VY  
//if(count>4) vkDZv@  
// siteStop(); 3I(dC|d  
} f}Ne8]U/Hc  
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System.err.println("文件下载结束！"); l(3'Re  
} se^NQ=  
catch(Exception e){e.printStackTrace ();} s$SU vo1J  
} XvfcPI6  
7eaA]y~H  
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//获得文件长度 1kz
9>;Ud6  
public long getFileSize() #;qFPj- v  
{ doxdRYKL  
int nFileLength = -1; |o;j0  
try{ glOqft&>`  
URL url = new URL(siteInfoBean.getSSiteURL()); }mtC6G41Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [[/ }1%  
httpConnection.setRequestProperty("User-Agent","NetFox"); wHBHkz  
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int responseCode=httpConnection.getResponseCode(); k"3Z@Px:  
if(responseCode>=400) "/ a*[_sV  
{ LV[66<T  
processErrorCode(responseCode); 4U LJtM3  
return -2; //-2 represent access is error ?9wFV
/  
} !4qp
s$p{  
fY)4]=L  
$DABR  
String sHeader; q:EzKrE  
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v;N1'  
for(int i=1;;i++) @&i#S}%/  
{ +7U A%q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'NG^HLD/  
//Utility.log(in.readLine()); (7rz:  
sHeader=httpConnection.getHeaderFieldKey(i); `[C v-  
if(sHeader!=null) Q*mMF@-:  
{ a6#{2q  
if(sHeader.equals("Content-Length")) p ?Ij-uo"o  
{ WcZo+r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *tbpFk4/  
break; x 1%J1?Fp  
} yPzULO4  
} I9Edw]  
else FJn~ =hA  
break; Sug~FV?k$e  
} do?S,'(g  
} (:j+[3Ht  
catch(IOException e){e.printStackTrace ();} +_-)0[+p  
catch(Exception e){e.printStackTrace ();} BW;=i.  
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prF  

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Utility.log(nFileLength); UL@5*uiX  
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return nFileLength; ki*79d"$  
} "I}'C^gP  
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//保存下载信息（文件指针位置） 6/V{>MTZg  
private void write_nPos() Qn'r+X5t  
{ 3 4A&LBwC  
try{ l b1sV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [6RV'7`Abj  
output.writeInt(nStartPos.length); +*:x#$phx  
for(int i=0;i<nStartPos.length;i++) !Wdt:MUI8  
{ ]X"i~$T1S  
// output.writeLong(nPos); [6/%V>EM  
output.writeLong(fileSplitterFetch.nStartPos); T`RQUJO  
output.writeLong(fileSplitterFetch.nEndPos); "oj
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} x=)30y3*;  
output.close(); WW8L~4Zy  
} ]' "^M  
catch(IOException e){e.printStackTrace ();} 8^~ZNU-~v  
catch(Exception e){e.printStackTrace ();} kw-
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} ^RFmRn  
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[ ;3EzZL  
//读取保存的下载信息（文件指针位置） U7f&N  
private void read_nPos() v^lm8/}NO  
{ Vp{RX8?.  
try{ Ygkd~g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :;h
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int nCount = input.readInt(); h.s<0.  
nStartPos = new long[nCount]; )8N)Z~h  
nEndPos = new long[nCount]; x"C93ft[  
for(int i=0;i<nStartPos.length;i++) b#\kZ/W  
{ zm)CfEF 8  
nStartPos = input.readLong(); UNZVu~WnF  
nEndPos = input.readLong(); 8L9S^ '  
} U}vtVvx  
input.close(); (EF$^FYPK  
} 1rm$@L  
catch(IOException e){e.printStackTrace ();} omUl2C  
catch(Exception e){e.printStackTrace ();} ;ZqD60%\  
} \<MTY:  
a\.OL}"   
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private void processErrorCode(int nErrorCode) Dk{nOvZu<  
{ "6Hjji@A  
System.err.println("Error Code : " + nErrorCode); Vo9)KxR  
} abk:_  
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{*=5qV}  
//停止文件下载 C7*Yg$`{  
public void siteStop() B=RKi\K6a  
{ /*R' xBr  
bStop = true; G3?a~n^b  
for(int i=0;i<nStartPos.length;i++) Nno={
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fileSplitterFetch.splitterStop(); ~pBxFA  
B& f~.UH  
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} }";hz*a  
} #.G>SeTn2}  
//负责部分文件的抓取 { G>+.  
**FileSplitterFetch.java },QFyT  
*/ ])ZJ1QL1  
package NetFox; BKjPmrZ|  
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import java.io.*; Sm I8&c  
import java.net.*; z )}wo3  
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public class FileSplitterFetch extends Thread { XuAc3~HAd  
u #QSa$P  
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String sURL; //File URL 1MzB?[gx  
long nStartPos; //File Snippet Start Position eEds-&_  
long nEndPos; //File Snippet End Position ~[X:twidkL  
int nThreadID; //Thread's ID t-ReT_D|;  
boolean bDownOver = false; //Downing is over "e};?|y  
boolean bStop = false; //Stop identical vR.6^q  
FileAccessI fileAccessI = null; //File Access interface 6I.+c
 
'~6CGqU*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E":":AC#  
{ [`nyq)  
this.sURL = sURL; PT*@#:MA  
this.nStartPos = nStart; <HX-qN
A?  
this.nEndPos = nEnd; [(^''*7r+T  
nThreadID = id; HBkQ`T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E6IL,Iq9  
} *q9$SDm  
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@P*P8v8:  
public void run() ).#D:eO[~  
{ R8Ei:f}  
while(nStartPos < nEndPos && !bStop)
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{ M(f*hOG{Y  
/ z>8XM&  
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try{
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URL url = new URL(sURL); a{YVz\?d}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I)4|?tb?  
httpConnection.setRequestProperty("User-Agent","NetFox"); z&G3&?Z  
String sProperty = "bytes="+nStartPos+"-"; bX1! fa  
httpConnection.setRequestProperty("RANGE",sProperty); RPqn#B  
Utility.log(sProperty); ZFw743G  
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InputStream input = httpConnection.getInputStream(); '`VO@a  
//logResponseHead(httpConnection); ;iI2K/ 3  
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byte[] b = new byte[1024]; .3SjkC4I  
int nRead; )W7H{#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *>H'@gS  
{ 4>eg@sN  
nStartPos += fileAccessI.write(b,0,nRead); 8k}CR)3@C  
//if(nThreadID == 1) \A"a>e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vb2O4%7tw  
} |"&4"nwa  
.:Xe*Q  
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Utility.log("Thread " + nThreadID + " is over!"); ~9 nrS9)  
bDownOver = true; t#Yh!L6>  
//nPos = fileAccessI.write (b,0,nRead); S^_yiV S  
} E*]L]vR  
catch(Exception e){e.printStackTrace ();} :EAfD(D{)  
} BiAcjN:Z  
} 3gXUfv2ID  
#3jZ7RqzQ  
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//打印回应的头信息 'n`$c{N<tM  
public void logResponseHead(HttpURLConnection con) , Vr6  
{ w0OK.fj  
for(int i=1;;i++) lcLxqnv  
{ m/c~2?-;  
String header=con.getHeaderFieldKey(i); T>?1+mruM  
if(header!=null) u"3cSuqy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <t2?Oii;  
Utility.log(header+" : "+con.getHeaderField(header)); D#(Pg  
else }=R|iz*,!  
break; M4]|(A  
} 1Ee>pbd  
} ov}{UP]a?  
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public void splitterStop() _$x *CP0(  
{ dTNgrW`4  
bStop = true; 0a;zT O/"v  
} 4ov~y1Da)  
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} .j,&/y&  
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/* *Fs^T^ ?r  
**FileAccess.java Msdwv.jM  
*//文件访问(定位，写) FiH!)6T  
package NetFox; !S<~(Ujyw  
import java.io.*; U4/$4.'
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`OK }q  
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public class FileAccessI implements Serializable{ ?Io2lFvI@Y  
eS+LFS7*k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =swcmab;  
RandomAccessFile oSavedFile; m)2U-3*iX  
long nPos; N($]))~3&  
=sJHnWL[  
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public FileAccessI() throws IOException =1uI >[aN  
{ Np)!23 "  
this("",0); {RO=4ba{J  
} &}?e:PEy  
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public FileAccessI(String sName,long nPos) throws IOException od|.E$B  
{ vDL/PXNC  
oSavedFile = new RandomAccessFile(sName,"rw"); sRG3`>1  
this.nPos = nPos; m]vr|:{6/  
oSavedFile.seek(nPos); Sy~Mh]{E  
} %?y`_~G  
EZFWxR/  
YDL)F<Y  
public synchronized int write(byte[] b,int nStart,int nLen) Gj?q+-d!(5  
{ ]].21  
int n = -1; O2B$c\pw  
try{ r3)t5P*_  
oSavedFile.write(b,nStart,nLen); %dQX d]  
n = nLen; w,$17+]3  
} @ vudeaup  
catch(IOException e) C$;~=  
{ EtG)2)  
e.printStackTrace (); 1gr jK.x  
} gr7_oJ:R  
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return n; cPYQ<Y=  
}
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} ]vrs?  
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/* t~M_NEPxV  
**SiteInfoBean.java $P~a  
*/ NI)nf;C  
package NetFox; %mJ)pMV  
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public class SiteInfoBean { wOP}SMn  
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private String sSiteURL; //Site's URL HmKE>C/  
private String sFilePath; //Saved File's Path }Q_i#e(S  
private String sFileName; //Saved File's Name v]>(Ps )R  
private int nSplitter; //Count of Splited Downloading File 8'$n|<1X  
y.2 SHn0  
N3)EG6vE*  
public SiteInfoBean() .nJGxz+X"  
{//nSplitter的缺省值为5 <Th.}=  
//default value of nSplitter is 5 j7zQ&ANF  
this("","","",5); <o O_wS@:  
} &iivSc;#  
ljRR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1+Oo Qs  
{ r+2dBp3  
sSiteURL= sURL; }ls>~uN  
sFilePath = sPath; .u&g2Y  
sFileName = sName; jC=_>\<|X*  
this.nSplitter = nSpiltter; P? n`n!qZ  
$hapSrS  
(H7q[UG|  
} Vow+,,oh  
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public String getSSiteURL() 2Qy&V/E ?  
{ BN0))p  
return sSiteURL; |{(ynZ]R  
} z\, w$Ef+  
(J;<&v}Gad  
:1Ay_b_J  
public void setSSiteURL(String value) 4T"P#)z  
{ *(J<~:V?  
sSiteURL = value; (msJ:SG  
} &%<G2x$  
ZZUCwczI  
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public String getSFilePath() "cZ.86gG`:  
{ *
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return sFilePath; <v?-$3YT  
} \BA_PyS?W+  
4I$#R  
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public void setSFilePath(String value) 8oK30?  
{ e5dwq  
sFilePath = value; w$_ooQ(_;Q  
} BTB,a$P/  
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public String getSFileName() d{Z  
{ !Qy3fs  
return sFileName; | =&r) ~  
} pdM|dGq^  
|"arVde  
(Xx @_  
public void setSFileName(String value) NW$Z}?I  
{ &Ef'5  
sFileName = value; \|kU{d0  
} .[7m4iJf  
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public int getNSplitter() ~be&T:7.  
{ `#~@f!';  
return nSplitter; 7J)-WXk  
} /}V9*mD2  
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]0o78(/w2  
public void setNSplitter(int nCount) OF)X(bi4j  
{ fYpy5vc-dm  
nSplitter = nCount; q^gd1K<N  
} 8I*fPf  
} x\lua  
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v+Hu=RZE  
/* U`D"L4},.  
**Utility.java H&I0\upd  
*/ /IgTmXxxj  
package NetFox; 6;ICX2Wq'  
ZC05^  
e_Y>
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public class Utility { 3N?uY2  
xi^_C!*J  
]:F]VRPT  
public Utility() fZgZ  
{ Te;`-EL  
p!=/a)4X  
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} *0Fn C2W1  
v6]lH9c{,  
//线程睡眠 V /|@  
public static void sleep(int nSecond) ]F,5Oh :OY  
{ (UpSi6?\  
try{ XMpPG~XdN  
Thread.sleep(nSecond); @D%VV=N~[  
} 6x_8m^+m  
catch(Exception e) }ZV$_  
{ 4!D!.t~r  
e.printStackTrace (); a&j H9  
} g8^$,  
} qz?9:"~$C  
k9a-\UIMet  
//日志
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public static void log(String sMsg) *T 6<'a  
{ vAX %i(4  
System.err.println(sMsg); @A g=2\9  
} /|Zk$q.\  
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M>-x\[n+  
public static void log(int sMsg) yhZ2-*pTg  
{ .DHPKz`W0  
System.err.println(sMsg); ~zi&u46  
} w<>B4m\  
} Xq9%{'9  
fy7]
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od
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/* I/t2c=f  
**TestMethod.java "H6DiPh.E  
*/ NU81 V0:jG  
package NetFox; L ej3? k  
sOv:/'
 
%<P&"[F]v@  
public class TestMethod { ^dRB(E}|)  
~r+;i,,X  
kz]qk15w  
public TestMethod() %-> X$,Q :  
{ ///xx/weblogic60b2_win.exe  T=9+  
try{ 6~j6M4*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k]w;(<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uPt({H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8KN0z<  
fileFetch.start(); ^C_ ;uz  
} V4iN2  
catch(Exception e){e.printStackTrace ();} 0jG8G
mh!  
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<$R'y6U:  
} SK#;/fav6  
*$
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public static void main(String[] args) iU5M_M$G  
{ kect)=T(  
new TestMethod(); 0"LJ{:plz  
} 5@6F8:x}V  
} U%_BgLwy%  
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