http断点续传简单实现（java)

/* O D5qPovsd  
**SiteFileFetch.java &^&0,g?To  
*/ j8Q_s/n  
package NetFox; ^vh!1"T  
import java.io.*; N68]r3/K  
import java.net.*; V1Ft3Msq  
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public class SiteFileFetch extends Thread { < (9 BO&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _)pOkS  
long[] nStartPos; //开始位置 *eXs7"H  
long[] nEndPos; //结束位置 OSuQ7V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KgYQxEbIW  
long nFileLength; //文件长度 3bGU;2~}  
boolean bFirst = true; //是否第一次取文件 HrLws95'  
boolean bStop = false; //停止标志 _~1O#*|4  
File tmpFile; //文件下载的临时信息 21<Sfsc$  
DataOutputStream output; //输出到文件的输出流 bRFZ:hu l  
~~WY?I-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |Z>}#R!,P  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1:7fV@jw  
{ %! S
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siteInfoBean = bean; GZ5DI+3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4VF]tX?o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (JOR: 1aT  
if(tmpFile.exists ()) Z
! /_H($  
{ ,*V%  
bFirst = false; >G?*rg4  
read_nPos(); zO9WqP_`iR  
} +#>nOn(B  
else n|.eL8lX.<  
{ zvnd@y{[  
nStartPos = new long[bean.getNSplitter()]; , DuyPBAms  
nEndPos = new long[bean.getNSplitter()]; OP(om$xm  
} fi'zk  
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} wmbG$T%k  
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public void run() 7/]Ra  
{ }`0=\cKqn  
//获得文件长度 k;Qm%B  
//分割文件 2GigeN|1N  
//实例FileSplitterFetch :Eg4^,QX  
//启动FileSplitterFetch线程 T|$tQgY^  
//等待子线程返回 X6!KFc  
try{ T{3-H(-gA  
if(bFirst) }#Ji"e  
{ {O=_c|u{N  
nFileLength = getFileSize(); ze8MFz'm  
if(nFileLength == -1) 'g<FL`iP  
{ 
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System.err.println("File Length is not known!"); g("[wqgG  
} .db:mSrL  
else if(nFileLength == -2) UBnHtsM  
{ yJ; ;&  
System.err.println("File is not access!"); #K-O<:s=y  
} Qdc#v\B  
else oO &%&;[/A  
{ Sng3B  
for(int i=0;i<nStartPos.length;i++) CC`#2j  
{ >A L^y(G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0LHge7482  
} ygV-Fv>PQ  
for(int i=0;i<nEndPos.length-1;i++) S[/D._5QD%  
{ >"]t4]GVf  
nEndPos = nStartPos[i+1]; <c(%xh46  
} 1X&scVw  
nEndPos[nEndPos.length-1] = nFileLength; apxq] ! `  
} U6nC <3f F  
} KAT^vbR  
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//启动子线程 up?S (.*B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v~!_DD au  
for(int i=0;i<nStartPos.length;i++) )Y1+F,C  
{ L_zB/(h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (iO/@iw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2+YM .Zl  
nStartPos,nEndPos,i); S U P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u69G #  
fileSplitterFetch.start(); :N4?W}r.  
} ,{RWs^W2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LwI4 2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); P=4o)e7E!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1[Jv9S*f/  
nEndPos = " + nFileLength); ]A_A4=[w  
// fileSplitterFetch[nPos.length-1].start(); 2+\@0j[q  
0)|;uW  
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//等待子线程结束 U4y ?z  
//int count = 0; _cc9+o  
//是否结束while循环 wqQrby<  
boolean breakWhile = false; rY=dNK]d  
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while(!bStop) _~b]/]|z#N  
{ Oim
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write_nPos(); (Vy`u)gG  
Utility.sleep(500); +oa>k 0  
breakWhile = true; <;E>1*K}8  
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for(int i=0;i<nStartPos.length;i++) c~Z\|Y`#B  
{ lJ4&kF=t  
if(!fileSplitterFetch.bDownOver) EK^["_*A  
{ j2!^iGS}  
breakWhile = false; z]M
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break; EDGAaN*Q  
} p~t5PU*(  
} sCRmLUD  
if(breakWhile) b@N*W]  
break; bdyE9t   
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[JX=
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//count++; mr#XN&e  
//if(count>4) zJtB?<  
// siteStop(); /{\mV(F(  
} \]p[DYBY#  
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System.err.println("文件下载结束！"); .:+&2#b  
} 8` f=Eh  
catch(Exception e){e.printStackTrace ();} Eh?,-!SUQn  
} C'//(gjQ-G  
c9xc@G!  
,W&::/2<7  
//获得文件长度 RVe UQ%  
public long getFileSize() [=KA
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{ A^hFRAg4  
int nFileLength = -1; hQDZ%>  
try{ hXsH9R  
URL url = new URL(siteInfoBean.getSSiteURL()); P<gr=&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %N-f9o8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mhj.3nN  
#Q_ d  

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int responseCode=httpConnection.getResponseCode(); &o*f*(C2  
if(responseCode>=400) 095ZZ20  
{ dWAKIBe  
processErrorCode(responseCode); 0hx EI  
return -2; //-2 represent access is error :f58JLX  
} Rd{#cW~  
)o@-h85";  
lCMU{)  
String sHeader; 9zK5Y+!  
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/MQI5Djg  
for(int i=1;;i++) LZG~1tf  
{ #}{1>g{sXt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DU%j;`3  
//Utility.log(in.readLine()); V:8ph`1  
sHeader=httpConnection.getHeaderFieldKey(i); yzQ^KqLH  
if(sHeader!=null) A#B6]j)  
{ XT 'v7  
if(sHeader.equals("Content-Length")) MX{p)(HW  
{ VY=c_Gl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *w;=o}`  
break; AmmUoS\
 
} 27!9LU  
} w %sHA  
else [J.-gN$X@  
break; <MH| <hP  
} 5+[`x']l  
} )cX6o[oia  
catch(IOException e){e.printStackTrace ();} 406.6jmv  
catch(Exception e){e.printStackTrace ();} _U`_;=(  
1"Z61gXrz  
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Utility.log(nFileLength); $'2yPoR  
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return nFileLength; Tv{X$`%  
} ekj@;6 d]  
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//保存下载信息（文件指针位置） #D-L>7,jA  
private void write_nPos() c_xo6+:l  
{ _XqD3?yH4  
try{ ,^UNQO*{GI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Uxq9H  
output.writeInt(nStartPos.length); 62X;gb  
for(int i=0;i<nStartPos.length;i++) ag$mc8-p[  
{ 6(`Bl$M9  
// output.writeLong(nPos); hKtc  
output.writeLong(fileSplitterFetch.nStartPos); ~#b&UR  
output.writeLong(fileSplitterFetch.nEndPos); .WR+)^&zz  
} Z+< zKn}  
output.close(); k-b0Eogp]  
} 2vit{  
catch(IOException e){e.printStackTrace ();} PfI~`ke  
catch(Exception e){e.printStackTrace ();} 9aE!! (E  
} 6_# >s1`R  
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//读取保存的下载信息（文件指针位置） V.RG=TVS  
private void read_nPos() *@|EaH/  
{ + W ? /A]  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Cku&s  
int nCount = input.readInt(); q>T7};5m2  
nStartPos = new long[nCount]; 8yH*  
nEndPos = new long[nCount];  ?vgHu  
for(int i=0;i<nStartPos.length;i++) SV4a_m?  
{ 2<*DL6  
nStartPos = input.readLong(); =jX'FNv#  
nEndPos = input.readLong(); ;c'9Xyl-  
}
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input.close(); FBYAd@="2  
} 75t\= 6#  
catch(IOException e){e.printStackTrace ();} mE"?{~XVL  
catch(Exception e){e.printStackTrace ();} HY,+;tf2r  
} Q]Fm4  
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private void processErrorCode(int nErrorCode)
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{ \k{UqU+s  
System.err.println("Error Code : " + nErrorCode); e>Vr#a4  
} 2[W1EQI  
5y
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//停止文件下载 G &'eP  
public void siteStop() KrhAObK  
{ i>n.r_!E  
bStop = true; s^X(G!V{c  
for(int i=0;i<nStartPos.length;i++) ?G[<~J3-E  
fileSplitterFetch.splitterStop(); @?A39G{  
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} 8:%=@p>$  
} :&#HrD[KT  
//负责部分文件的抓取 k\T,CZ<  
**FileSplitterFetch.java tdTD!'  
*/ 
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package NetFox; 5} 9}4e  
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import java.io.*; "#H@d+u  
import java.net.*; J`T1 88  
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public class FileSplitterFetch extends Thread { =v4;t'_^  
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String sURL; //File URL pSQ)DqW  
long nStartPos; //File Snippet Start Position 3@ a  
long nEndPos; //File Snippet End Position x/NR_~Rnk  
int nThreadID; //Thread's ID SMr ]Gf.  
boolean bDownOver = false; //Downing is over 5:mS~  
boolean bStop = false; //Stop identical 03ol!|X"9  
FileAccessI fileAccessI = null; //File Access interface VJ`c/EVIt  
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1]HEwTT/1_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FE+Y#  
{ H[ 6L!  
this.sURL = sURL; tn-_3C  
this.nStartPos = nStart; Yx21~:9}  
this.nEndPos = nEnd; :"+/M{qz  
nThreadID = id; 'iM;e K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L lmdydC%  
} W+[XNIg5   
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public void run() EP.nVvuL  
{ ~n:dHK`  
while(nStartPos < nEndPos && !bStop) cqzd9L6=  
{ mE3^5}[>  
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try{ tAfd
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URL url = new URL(sURL); N=J$+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1Ih.?7}
 
httpConnection.setRequestProperty("User-Agent","NetFox"); I\JJ7/S`t  
String sProperty = "bytes="+nStartPos+"-"; SST1vzm!  
httpConnection.setRequestProperty("RANGE",sProperty); /5^"n4/M  
Utility.log(sProperty); k}-@N;zq  
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7\sJ=*  
InputStream input = httpConnection.getInputStream(); <qD/ #$  
//logResponseHead(httpConnection); ITj0u&H:  
?Z-(SC  
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byte[] b = new byte[1024]; Hl"qLrb4  
int nRead; dmHpF\P5f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |oq27*ix~m  
{ 4q"x|}a  
nStartPos += fileAccessI.write(b,0,nRead); ^h+,Kn0@  
//if(nThreadID == 1) YqsN#E3pf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G[4TT#  
} xOCHP|?  
OhmKjY/}  
% AqUVt9}  
Utility.log("Thread " + nThreadID + " is over!"); @5n!t1(  
bDownOver = true; lv_|ws  
//nPos = fileAccessI.write (b,0,nRead); rn^7B-V  
} *I;,|Jjk  
catch(Exception e){e.printStackTrace ();} Sa!r ,l  
} 2}Dd{kC-  
} tlw$/tMa  
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3L$_OXx  
//打印回应的头信息 +0U{CmH  
public void logResponseHead(HttpURLConnection con) QUL^]6$  
{ 1:<=zqh0  
for(int i=1;;i++) y2k'^zE  
{ :'aT4  
String header=con.getHeaderFieldKey(i); ]M
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if(header!=null) ,-PzUR4_Kj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gakmg#ki  
Utility.log(header+" : "+con.getHeaderField(header)); qms+s~oA  
else qbjBN z  
break; Ov1$7 r@  
} /0Q=}:d  
} y,&UST  
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public void splitterStop() _{CMWo"l  
{ |cpBoU  
bStop = true; 2Y_ `&  
} 7.fpGzUM  
*<k8H5z8]  
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} x\t)u
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)(~s-x^\z@  
/* [Nb0&:$ay  
**FileAccess.java `n%uvo}UT  
*//文件访问(定位，写) s(56aE  
package NetFox; tydD~a  
import java.io.*; GOJ*>GpS  
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Y1a[HF^-  
public class FileAccessI implements Serializable{ ,bT|:T@ny  
7%?2>t3~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O+I\Q?  
RandomAccessFile oSavedFile; =}N&c4I[j  
long nPos; [+0rlmB  
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public FileAccessI() throws IOException xU$A/!oK  
{ L><# I  
this("",0); WP,Ll\K)7  
} {awv=s  
.`Ey'T_  
?sQOz[ig;  
public FileAccessI(String sName,long nPos) throws IOException ;,T3C:S?  
{ tpe:]T/xh  
oSavedFile = new RandomAccessFile(sName,"rw"); *,$cW,LN  
this.nPos = nPos; 9(?9yFbj5  
oSavedFile.seek(nPos); N3?hyR<T  
} E$5)]<p! <  
dQ6:c7hp>D  
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[  
public synchronized int write(byte[] b,int nStart,int nLen) M@$}Og  
{ ~hi\*W6jg  
int n = -1; AR9D;YfR~  
try{ tL0<xGI5^  
oSavedFile.write(b,nStart,nLen); ,ra!O=d~0  
n = nLen; Sa5+_TW  
} -dXlGOD+C  
catch(IOException e) ? b;_T,S[  
{ (_S`9Z8=  
e.printStackTrace (); x] [/9e  
} u6o:~=WwM  
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return n; \]Nlka  
} V
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} I&9_F%rX  
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/* j#^EZ/  
**SiteInfoBean.java H;('h#=cD  
*/ kev|AU (WX  
package NetFox; *1FDK{  
^%(HZ'$wC  
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public class SiteInfoBean { cM&5SyxiuE  
~JjL411pG  
2'O2n]{  
private String sSiteURL; //Site's URL EfxW^zm)  
private String sFilePath; //Saved File's Path C:S*juK  
private String sFileName; //Saved File's Name Ore>j+  
private int nSplitter; //Count of Splited Downloading File +ZH-'l  
cj ?aCVa  
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public SiteInfoBean() y %R-Oc  
{//nSplitter的缺省值为5 T: zO9C/  
//default value of nSplitter is 5 a!UQ]prT  
this("","","",5); Z(Styn/x  
} y|r+<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aYTVY
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{ ^L}ICm_#  
sSiteURL= sURL; "R8:s  
sFilePath = sPath; Ul"9zTH  
sFileName = sName; 50
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this.nSplitter = nSpiltter; 5^kLNNum  
5%H(AaG*q  
&72 ( <  
} ZJL8"(/R  
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public String getSSiteURL() xBba&A]=  
{ L`sg60z  
return sSiteURL; Po(Y',xI[  
} ug?gVK  
M::  
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public void setSSiteURL(String value) X`-7: !+  
{ p~(+4uA  
sSiteURL = value; m Acny$u  
} UZcsMMKH  
w'Y(doY,  
hw2'.}B"(  
public String getSFilePath()  :P,g,  
{ 5ynBVrYf  
return sFilePath; }~W:3A{7;  
} k2bjBAT  
6JrwPZB  
dO?zLc0f  
public void setSFilePath(String value) &%@e6..Ex  
{ E6 g]EE  
sFilePath = value; ;_$Q~X  
} m1pge4*  
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public String getSFileName() r4YiXss  
{ &Hz{  
return sFileName; dh9Qo4-{  
} VtP^fM^{  
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"0*yD[2  
public void setSFileName(String value) w!/\dqjv  
{ ,=_)tX^  
sFileName = value; BE0Ov{'  
} RB\ Hl  
ppm=o4`s[  
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public int getNSplitter() Oy}^|MFfA  
{ d
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return nSplitter; xL&evG#  
} }l>\D
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lpq)vKM}^  
`Wl_yC_*G;  
public void setNSplitter(int nCount) /EIQMZuYp  
{ Ob~7w[n3  
nSplitter = nCount; ]QU 9|1  
} saRYd{%+  
} MV{\:l}y  
[Xa,|  
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/* -R]Iu\  
**Utility.java vU,V[1^a  
*/ GyC/39<P  
package NetFox; '2S/FO
b  
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public class Utility { "|Ke/0rGB  
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public Utility() =:M/hM)#  
{ QGCg~TV;  
o&t*[#  
~|lEi1|  
} @3w6!Sgh  
*b}/fG)XZ  
//线程睡眠 H|Y*TI2vf8  
public static void sleep(int nSecond) U#iGR5&^3  
{ a1>Tz  
try{ sSLVR^  
Thread.sleep(nSecond); P5JE = &M  
} }ed{8"bj  
catch(Exception e) kOE\.}~4  
{ `@<~VWe5  
e.printStackTrace (); <e?1&56  
} Y|
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} en_W4\7^  
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//日志 q)l1tC72  
public static void log(String sMsg) d[\$a4G+  
{ <Fi*
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System.err.println(sMsg); tCR#TW+IY-  
} MpVZL29)  
b$
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_,<@II  
public static void log(int sMsg) [Ot<8)Jm  
{ &s(mbpV  
System.err.println(sMsg); c(kYCVc   
} 4Uk\hgT0  
} z',f'3+  
+h)1NX;o1  
dw-o71(1d  
/* h3[x ZJO  
**TestMethod.java FvJkb!5*e_  
*/ KY%LqcC  
package NetFox; n%ypxY0  
]PlLy:(  
dC/@OV)0#  
public class TestMethod { S-[S?&c`  
;0
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arc{:u.K  
public TestMethod() w.(?
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{ ///xx/weblogic60b2_win.exe |\U5m6q  
try{ r h c&#JS  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V/+D]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =3Ohy,5L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -uNM_|MO  
fileFetch.start(); ja4zLf(<  
} ?sW}<8\  
catch(Exception e){e.printStackTrace ();} [VE>{4]W  
(@Kc(>(: Y  
1=_Qj}!1  
} 3>6rO4,  
48,uO!  
#l 6QE=:  
public static void main(String[] args) n#5S-z1KNw  
{ -Rwx`=6tV  
new TestMethod(); Db*&'32W  
} A!v:W6yiz  
} A[`2Mnj  
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