http断点续传简单实现（java)

/* HP[M"u  
**SiteFileFetch.java <io;d$=}  
*/ GFYHt!&[\  
package NetFox; p-2PC{% t|  
import java.io.*; ]4)$dQ59  
import java.net.*; - ]U2G:  
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public class SiteFileFetch extends Thread { y-@{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ::p(ViYG  
long[] nStartPos; //开始位置  <4D.H  
long[] nEndPos; //结束位置 .2QZe8"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L9,O,f  
long nFileLength; //文件长度 PsyXt5Dk  
boolean bFirst = true; //是否第一次取文件 (aSY.#;  
boolean bStop = false; //停止标志 _F tI2G9  
File tmpFile; //文件下载的临时信息 U3M;6j9`  
DataOutputStream output; //输出到文件的输出流 =.t3|5U8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Bx ru7E"  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~)]R  
{ YC =:W  
siteInfoBean = bean; xtX`3=s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yMKVF`D*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t@3y9U$  
if(tmpFile.exists ()) OEXa^M4x   
{ >vfbXnN  
bFirst = false; rHD_sC*  
read_nPos(); fwz-)?   
} !)LVZfQ0  
else eBg:[44V  
{ 71OQ?fc  
nStartPos = new long[bean.getNSplitter()]; .v_-V?7  
nEndPos = new long[bean.getNSplitter()]; 0yBiio  
} }"6 PM)s  
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} ,2Q5'!o  
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public void run() b' fcWp0  
{ 2#xz,RM.  
//获得文件长度 xA]}/*  
//分割文件 O <"\G!y~  
//实例FileSplitterFetch N:&EFfg3  
//启动FileSplitterFetch线程 >\ x!a:}  
//等待子线程返回 a0 8Wt  
try{ ! ^TCe8  
if(bFirst) tY!GJusd  
{ bTW# f$q:4  
nFileLength = getFileSize(); RKO} W#?  
if(nFileLength == -1) _REAzxeS  
{ q?bKh*48  
System.err.println("File Length is not known!"); tIL ]JB  
} th`pf   
else if(nFileLength == -2) }BJR/r  
{ D;+sStZK3  
System.err.println("File is not access!"); +
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} 4LkW`Sbm  
else /=S\v<z  
{ &v g[k#5  
for(int i=0;i<nStartPos.length;i++) 8m 5T  
{ -^&NwLEv=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HAdDr!/`  
} V~"-\@  
for(int i=0;i<nEndPos.length-1;i++) }^zsN`  
{ tu5T^"BqO  
nEndPos = nStartPos[i+1]; 0^>b=a  
} 4-JyK%m,0  
nEndPos[nEndPos.length-1] = nFileLength; W9/HM!  
} !]t5(g_  
} `xF^9;5mi  
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//启动子线程 Y [%<s/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s|9[=JMG  
for(int i=0;i<nStartPos.length;i++) ND\M  
{ 2OsS+6,[x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !6*m<#Qm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W>y&  
nStartPos,nEndPos,i); }5]7lGR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VhLS*YiSY  
fileSplitterFetch.start(); >h{)7Hv  
} }}gtz-w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J)._&O$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0Q!/A5z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qw6i|JM%  
nEndPos = " + nFileLength); _DLELcH Y  
// fileSplitterFetch[nPos.length-1].start(); 0rCQz3gh1  
uG=~kO  
~+CEek  
//等待子线程结束 fRomP-S  
//int count = 0; bO+]1nZ.  
//是否结束while循环 <KBS ;t="1  
boolean breakWhile = false; a9g~(#?a  
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while(!bStop) tx,q=.(  
{ @!p0<&R@x  
write_nPos(); l-?#oy  
Utility.sleep(500); DAf0bh"  
breakWhile = true; jhH&}d9  
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for(int i=0;i<nStartPos.length;i++) A\ r}V-  
{ j]J-#J  
if(!fileSplitterFetch.bDownOver)  EHk$,bM  
{ _@OS,A  
breakWhile = false; KtD XB>  
break; Hb3t|<z  
} __|Y59J%  
} bkFO4OZd  
if(breakWhile) N^f_hL|:9  
break; r-$VPW  
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//count++; {h0T_8L/  
//if(count>4) d9q`IZqee  
// siteStop(); !nL>Ly  
} KpC!C9  
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System.err.println("文件下载结束！"); TGHyBPJb  
} (Rh$0^)A  
catch(Exception e){e.printStackTrace ();} U3~rtc*  
} y 'Ah
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bMB*9<c~  
//获得文件长度 @]7s`?  
public long getFileSize() $g_|U:,  
{ .S*VYt%K7  
int nFileLength = -1; <FfmDR  
try{ 0( q:K6zI}  
URL url = new URL(siteInfoBean.getSSiteURL()); )3.=)?XW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [xo-ZDIoG  
httpConnection.setRequestProperty("User-Agent","NetFox"); {Kz!)uaC  
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int responseCode=httpConnection.getResponseCode(); .S[M:<<*  
if(responseCode>=400) ,0f^>3&n>e  
{ W/<Lp+p  
processErrorCode(responseCode); 9D]bCi\  
return -2; //-2 represent access is error S4VM(~,o  
} l'7'G$v  
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String sHeader; X3'd~!a)  
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for(int i=1;;i++) q\xsXM  
{ Zs2;VW4RW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]z8Th5a?o  
//Utility.log(in.readLine()); pgBIYeY,  
sHeader=httpConnection.getHeaderFieldKey(i); YRQ?:a{H  
if(sHeader!=null) z}F^HQ1  
{ 2TgS )  
if(sHeader.equals("Content-Length")) uAu'2M,_  
{ XZT|ID_u"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O Ke 9/._  
break; JqV}$E"M2  
} <[vsGUbc  
} f`YHZ O  
else 49= K]
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break; (t5vBUj  
} EQ]>^VE2B  
} v%7Gh-P  
catch(IOException e){e.printStackTrace ();} W@RD bsc  
catch(Exception e){e.printStackTrace ();} Z-3("%_$/  
}=A+W2D  
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Utility.log(nFileLength); @H}{?-XyA  
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return nFileLength; U/ax`_  
} pnUL+UYeM  
 PZj}]d `  
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//保存下载信息（文件指针位置） 9M-W 1prb  
private void write_nPos() )}u?ftu\  
{ 4U3 `g  
try{ <5zr|BTF]F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zt}b}Bz  
output.writeInt(nStartPos.length); -$I$zo  
for(int i=0;i<nStartPos.length;i++) EAHdt=8W{  
{ OZ/"W)  
// output.writeLong(nPos); H(kxRPH4@]  
output.writeLong(fileSplitterFetch.nStartPos); =.l>Uw!  
output.writeLong(fileSplitterFetch.nEndPos); mR~S$6cc  
} JFq<sY!  
output.close(); >7z(?nQYT^  
} lo-VfKvy  
catch(IOException e){e.printStackTrace ();} 5a4i)I63o  
catch(Exception e){e.printStackTrace ();} %~P3t=r  
} \d3~kq3  
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//读取保存的下载信息（文件指针位置） ,{_56j^d,  
private void read_nPos() -`$J& YU  
{ }!"Cvu  
try{ (
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #)s +I2  
int nCount = input.readInt(); iLNO}EUL  
nStartPos = new long[nCount]; O^8=Xj#}  
nEndPos = new long[nCount]; Zzmo7kFx3  
for(int i=0;i<nStartPos.length;i++) 7!;zkou  
{ V P(JV  
nStartPos = input.readLong(); 7Kpv fyL{  
nEndPos = input.readLong(); 2InM(p7j~K  
} u+c2 m  
input.close(); z\YLO%Mm  
} Mm!;+bM%  
catch(IOException e){e.printStackTrace ();} op3a*KG  
catch(Exception e){e.printStackTrace ();} uQKo2B0  
} QcX&q%*0  
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private void processErrorCode(int nErrorCode) J+wnrGoK  
{ "LH3ZPD  
System.err.println("Error Code : " + nErrorCode); ?xuWha@:  
} :w)9
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GC_c
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//停止文件下载 -j
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public void siteStop() *?A!`JpJn  
{ nZM
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bStop = true; u95D0S  
for(int i=0;i<nStartPos.length;i++) qpzyl~g:C  
fileSplitterFetch.splitterStop(); dF5y' R'  
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-Rx;"J.H  
} ^}`24~|y  
} B~b ='jN  
//负责部分文件的抓取 -Ir>pY\!  
**FileSplitterFetch.java 5W=Jn?y2  
*/ m -0EcA/  
package NetFox; #99=wn  
rC_saHo>#R  
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import java.io.*; \7IT[<Se  
import java.net.*; (iIzoEpb8W  
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public class FileSplitterFetch extends Thread { !#W3Q  
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String sURL; //File URL ?}= $zN  
long nStartPos; //File Snippet Start Position ~_IQ:]k  
long nEndPos; //File Snippet End Position riRG9c |  
int nThreadID; //Thread's ID 7r2p+LP[  
boolean bDownOver = false; //Downing is over #w8.aNU+]  
boolean bStop = false; //Stop identical 50a';!H  
FileAccessI fileAccessI = null; //File Access interface &VcO,7 A|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b5ul|p  
{ J*m7 d4^  
this.sURL = sURL; &wN}<Ge6  
this.nStartPos = nStart; r%NzKPW'  
this.nEndPos = nEnd; M#
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nThreadID = id; wWSE[S$V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G[u{! 2RS  
} : %uaaFl  
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public void run() 1&vR7z]*  
{ `wr*@/P  
while(nStartPos < nEndPos && !bStop) #%L_wJB-  
{ o/[Ks;l  
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try{ 7xR:\FBa^  
URL url = new URL(sURL); ` k(Q:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sbFIKq]  
httpConnection.setRequestProperty("User-Agent","NetFox");  t~BWN  
String sProperty = "bytes="+nStartPos+"-"; vsQvJDna~  
httpConnection.setRequestProperty("RANGE",sProperty); _>r(T4}]  
Utility.log(sProperty); jhBfy|Ftu  
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Z`|\%D%  
InputStream input = httpConnection.getInputStream(); InRcIQT  
//logResponseHead(httpConnection); L3 KJ~LI  
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byte[] b = new byte[1024]; t<RPDQ>  
int nRead; Kaaz,C.$^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A PrrUo  
{ M 9NT%7Il  
nStartPos += fileAccessI.write(b,0,nRead);  *I}_g4  
//if(nThreadID == 1) oel?we6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F+j"bhe  
} B~J63Os/  
ed`7GZB  
L$@+'Qn@:  
Utility.log("Thread " + nThreadID + " is over!"); )@!T_#  
bDownOver = true; J3B+WD]  
//nPos = fileAccessI.write (b,0,nRead); Z&=
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} }mI0D>n  
catch(Exception e){e.printStackTrace ();} >6IUle>z  
} 51*[Ibx  
} t2|0no  
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O
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//打印回应的头信息 r=p^~tuyxr  
public void logResponseHead(HttpURLConnection con) AJ3Byb=.  
{ cIK4sOTJ&  
for(int i=1;;i++) _1WA:7$C  
{ kf#S"[/E  
String header=con.getHeaderFieldKey(i); NzN"_ojM  
if(header!=null) Zv?"1Y< L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y{~tMpo<  
Utility.log(header+" : "+con.getHeaderField(header)); I|;C}lfp  
else W7{^/s5r  
break; B|{E[]
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} 5KIhk`S  
} yS3or(K  

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public void splitterStop() i [Wxu M  
{ {XD':2E  
bStop = true; D=Yr/qc?  
} "v0SvV<7  
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} 77wod}h!:  
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/* KuL+~  
**FileAccess.java "|R75m,Id  
*//文件访问(定位，写) OI3j!L2f  
package NetFox; OKk"S_`  
import java.io.*; `DM)tm3&m  
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@RL'pKab9  
public class FileAccessI implements Serializable{ s?4nR:ZC}  
LvZ',u}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $@L2zl1  
RandomAccessFile oSavedFile; +oHbAPs8  
long nPos; ou`KkY||  
=)*ZrD  
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public FileAccessI() throws IOException z\?<j%e!t  
{
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this("",0); 02,.UqCz  
} hF`<I.z}  
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| h+vdE8  
public FileAccessI(String sName,long nPos) throws IOException c\O2|'JzE  
{ !|- U,  
oSavedFile = new RandomAccessFile(sName,"rw"); zJ:%iL@  
this.nPos = nPos; xuVc1jJH  
oSavedFile.seek(nPos); ]\k& l ['  
} <'7s3  
x"cB8bZ!$  
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public synchronized int write(byte[] b,int nStart,int nLen) 5g$>J)Ry  
{ 1'8-+?r  
int n = -1; mgM"u94-]
 
try{ xO,;4uE  
oSavedFile.write(b,nStart,nLen); ]KG.-o30  
n = nLen; h~z}N
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} u0g"x_3  
catch(IOException e) L{&=SR.  
{  Vo%Z|  
e.printStackTrace (); {z;4t&5  
} " SP6o  
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!,]c}Y{i  
return n; =^_a2_BBl  
} G2+ gEg  
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} (hIo0.  
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/* fL]jk1.Xv-  
**SiteInfoBean.java ?,%PemN  
*/ whrDw1>(  
package NetFox; BNFYUcVP  
S_RP&+!7  
|Q";a:&$  
public class SiteInfoBean { ,e'"SVQc  
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private String sSiteURL; //Site's URL {))Cb9'  
private String sFilePath; //Saved File's Path |YfJ#Agm+  
private String sFileName; //Saved File's Name ?[Ma" l>  
private int nSplitter; //Count of Splited Downloading File Q~P|=*  
GhjqStjS&l  
{K?e6-N(z  
public SiteInfoBean() >J)4e~9EJ2  
{//nSplitter的缺省值为5 eV}H  
//default value of nSplitter is 5 6\-u:dvGI?  
this("","","",5); Dk8@x8  
} Kxz|0l  
~ tN/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {y%@1q%"  
{ 5@I/+D  
sSiteURL= sURL; "}H2dn2n  
sFilePath = sPath; gFfKK`)}D'  
sFileName = sName; \ Z5160  
this.nSplitter = nSpiltter; peOoZdJd  
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cR*~JwC:  
} *~b~y7C  
{MDM=;WP_  
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public String getSSiteURL() 0[N1SY\lj  
{ LB}J7yEQvj  
return sSiteURL; [ q[2\F?CE  
} ,Tk53"  
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public void setSSiteURL(String value) 2 &_>2"=<@  
{ &fU48n1Uh  
sSiteURL = value; NS*Lv  
} |+>U91!  
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public String getSFilePath() 9jNh%raG|  
{ R|wS*xd,  
return sFilePath; xj3{Ke`6  
} FT J{  
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&& PZ;  
public void setSFilePath(String value) 7 `c!  
{ ]v]:8>N  
sFilePath = value; W
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} wqJl[~O$  
iWW >]3
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public String getSFileName() P.1Z@HC  
{ V-X Ty iv  
return sFileName; 3v`@**  
} \YF07L]qs-  
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public void setSFileName(String value) A* Pz-z>z  
{ >*n4j:  
sFileName = value; EV
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} Bqb`WX[<`  
4nh0bIN1  
dNov= w  
public int getNSplitter() [6/8O
 
{ NZFUCD)  
return nSplitter; :()K2<E  
} :/t_5QN  
8|5+\1!#/)  
6Lg#co}9  
public void setNSplitter(int nCount) 3 +`,'Q9  
{ fRkx ^u P  
nSplitter = nCount; 6k<3,`VV|  
} x;LO{S4Z  
} B7oUS}M  
2=1qmQE  
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/* s
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**Utility.java gi)C5J4  
*/ h,b_8g{!  
package NetFox; $Q,]2/o6n  
m#RMd,'X  
+OtD@lD`!  
public class Utility { ((^vsKT  
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public Utility() L6ypn)l  
{ cFuQ>xR1  
?MFXZ/3(ba  
mS0;2xU  
} ;<xPzf  
7_rDNK@e  
//线程睡眠 u bZ`Y$  
public static void sleep(int nSecond) e:_[0#  
{ mmCGIX  
try{ lTtc#  
Thread.sleep(nSecond); C+mPl+}w  
}
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catch(Exception e) P4c}@Mq3  
{ !FB2\hiM  
e.printStackTrace (); 1CV?  
} 9[`\ZGWD  
} f2v~
: u  
(#>Q#Izr  
//日志 x`'s  
public static void log(String sMsg) v3kT~uv  
{ 47A[-&y*X  
System.err.println(sMsg); j)juvat  
} fWF!%|L  
s!Iinc^p  
h///
 
public static void log(int sMsg) Mt%Q5^  
{ h96<9L  
System.err.println(sMsg); Qk
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} _p9 _Pg8  
}   &._Mh  
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<xH! Yskc  
/* s9fEx-!y  
**TestMethod.java v`:!$U* H=  
*/ pJ H@v &a  
package NetFox; ^ lM.lS>)  
ETtoY<`#  
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public class TestMethod { 2qfKDZ9f^  
v!%VH?cA8  
#kPsg9Y  
public TestMethod() @w@ `-1  
{ ///xx/weblogic60b2_win.exe $z'_Hr'  
try{ :,Ad1(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VfJdCg_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JzuP AI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T,fDH!a  
fileFetch.start(); U~YjTjbd  
} H4JwgQ  
catch(Exception e){e.printStackTrace ();} yDXW#q  
pJPP6Be<  
W,sPg\G 3  
} UWg+7RL  
l. 0|>gj`0  
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public static void main(String[] args) L<H6AzR+  
{ EGJrnz8  
new TestMethod(); m005*>IY  
} /faP@Q3kR  
} y`p(}X`>  
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