http断点续传简单实现（java)

/* )9~-^V0A^>  
**SiteFileFetch.java Br}0dha3E  
*/ :&\^r=D  
package NetFox; iT,Ya-9"  
import java.io.*; =&x u"V  
import java.net.*; me
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public class SiteFileFetch extends Thread { 5hg ^K^ZZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <-s5 ;xwtS  
long[] nStartPos; //开始位置 D]*<J"/]d  
long[] nEndPos; //结束位置 gK",D^6T*Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f@aFs]xV  
long nFileLength; //文件长度 GI[XcK^*w  
boolean bFirst = true; //是否第一次取文件 `\M}~  
boolean bStop = false; //停止标志 aC,?FWm  
File tmpFile; //文件下载的临时信息 cM;,nX%/  
DataOutputStream output; //输出到文件的输出流 CMviR<.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bc%N !d  
public SiteFileFetch(SiteInfoBean bean) throws IOException c?7Wjy  
{ OqlP_^Zz7p  
siteInfoBean = bean; BQF7S<O
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "iPX>{'En  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r~Vb*~U"  
if(tmpFile.exists ()) bX'.hHR  
{ "[Hn G(gA  
bFirst = false; x2.YEuSMC  
read_nPos(); z3C@0v=u>  
} }e8u p*#me  
else l<dtc[  
{ JzZ@Z8%a;  
nStartPos = new long[bean.getNSplitter()]; =b/:rSd$NA  
nEndPos = new long[bean.getNSplitter()]; y2
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} -;W`0k^  
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} &p83X  
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public void run() /4%ycr6  
{ @zq]vX-A_  
//获得文件长度  Mcm%G#  
//分割文件 Q%.F Mf  
//实例FileSplitterFetch  mm9xO%  
//启动FileSplitterFetch线程 L/7YI\C2  
//等待子线程返回 zOsk'ZE&  
try{ _6Qb 3tl  
if(bFirst) (\*+HZ`(Uu  
{ hVf;{p &  
nFileLength = getFileSize(); P`]p&:  
if(nFileLength == -1) q-R'5p\C?|  
{ 3Ued>8Gv  
System.err.println("File Length is not known!"); YAJr@v+Ls  
} 6o=Q;Mezl  
else if(nFileLength == -2) _n=,H  
{ =,
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System.err.println("File is not access!"); L1u(\zw  
} &8M^E/#.^;  
else CCp&+LRvR  
{ ql2O%B.6?  
for(int i=0;i<nStartPos.length;i++) *Fu;sR2y%:  
{ wgFAPZr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 29kR7[k  
} w3Z;&sFd  
for(int i=0;i<nEndPos.length-1;i++) m$WN"kV`,9  
{ U?&&yynK  
nEndPos = nStartPos[i+1]; 84jA)  
} .u\xA7X  
nEndPos[nEndPos.length-1] = nFileLength; Q@5v> `  
} /& wA$h  
} /@feY?glc  
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//启动子线程 s8|Fe_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @8"c
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for(int i=0;i<nStartPos.length;i++) (c|Ry[$|  
{ O#3PUuE%d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f0]`TjY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *Y<1KXFU  
nStartPos,nEndPos,i); _>4Qh#6K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @zi_@B  
fileSplitterFetch.start(); HsRQiai*  
} &09g0K66  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C[s='v~}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C*&FApG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S?e*<s9k  
nEndPos = " + nFileLength); k\A[p\  
// fileSplitterFetch[nPos.length-1].start(); M$MFUGS'  

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//等待子线程结束 N={0A  
//int count = 0; ZP;WXB`  
//是否结束while循环 t^SND{[WcM  
boolean breakWhile = false; ]B=2r^fn  
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while(!bStop) ]o2 Z14  
{ W $EAo+V  
write_nPos(); sQgJ`+Y8_  
Utility.sleep(500); LypBS]ru  
breakWhile = true; 6'6,ySo]  
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for(int i=0;i<nStartPos.length;i++) /`VrV{\/!  
{ KvkU]s_  
if(!fileSplitterFetch.bDownOver) A_}6J,*u  
{ 0S$6j-"  
breakWhile = false; YJMaIFt  
break; R(W}..U0R"  
} 5%;=(Oig  
} N5|wBm>m  
if(breakWhile) XG;Dj<Dm  
break; @@} ]qT*  
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//count++; ,pR.HCR#Y  
//if(count>4) DE!P[$J  
// siteStop(); 4M*!'sG\  
} ql(~3/kA_  
)bR`uV9<  
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System.err.println("文件下载结束！"); u]jvXPE6  
} z-G*:DfgH  
catch(Exception e){e.printStackTrace ();} bPUldkB:  
} Ys+NIV#Q  
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 #[yZP9  
//获得文件长度 =L&dV]'4P  
public long getFileSize() ;$/]6@bqB  
{ mWX{I2  
int nFileLength = -1; 8 GW0w
 
try{ #55_hY#  
URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NZ:KJ8ea"  
httpConnection.setRequestProperty("User-Agent","NetFox"); iNv"!'|  
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int responseCode=httpConnection.getResponseCode(); H rI(uZ]  
if(responseCode>=400) `<IaQY  
{ 5"2pU{xmK  
processErrorCode(responseCode); '-M9v3itC  
return -2; //-2 represent access is error yLEAbd%+  
} Pm==m9  
+!eh\.u|]  
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String sHeader; Da&Brm  
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for(int i=1;;i++) Zx U?d   
{ E<r<ObeRv`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UthM?g^  
//Utility.log(in.readLine()); KU 98"b5  
sHeader=httpConnection.getHeaderFieldKey(i); ZfnJ&H'  
if(sHeader!=null) {q.|UCg[L  
{ J{e`P;ND  
if(sHeader.equals("Content-Length")) {\ ]KYI0  
{ lnv&fu`1P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t 4>\;  
break; %eW2w@8]  
} ^17i98w  
} ~w"e 2a  
else +r$M 9  
break; 2*TPW  
} nZ8jBCh  
} ]7J*(,sp  
catch(IOException e){e.printStackTrace ();} qTI_'q  
catch(Exception e){e.printStackTrace ();} |)+45e  
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Utility.log(nFileLength); !<= ^&\A  
@ GXi{9  
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return nFileLength; UYvdzCUh  
} M=#g_*d  
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//保存下载信息（文件指针位置） &{ZTtK&JF  
private void write_nPos() I;+>@Cn(g<  
{ FC#t}4as  
try{ sPRo=LB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D),hSqJ"  
output.writeInt(nStartPos.length); F`M`c%  
for(int i=0;i<nStartPos.length;i++) =PIarUJ  
{ g [c^7  
// output.writeLong(nPos); {"mb)zr  
output.writeLong(fileSplitterFetch.nStartPos); >N-l2?rE  
output.writeLong(fileSplitterFetch.nEndPos); b/obHB+:  
} DMiB \o  
output.close(); B~47mw&b  
} A+ LX37
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catch(IOException e){e.printStackTrace ();} 8B7~Nq'  
catch(Exception e){e.printStackTrace ();} XU6SYC"t%~  
} Y;#H0v>E  
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//读取保存的下载信息（文件指针位置） M+-1/vR *@  
private void read_nPos() Cp^`-=r+  
{ m(CAXq-t  
try{ 2k+u_tj>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )uC5  
int nCount = input.readInt(); 1-~sj)*k  
nStartPos = new long[nCount]; [ ]42$5eof  
nEndPos = new long[nCount]; UAOH9*9*  
for(int i=0;i<nStartPos.length;i++) %6E:SI4  
{ gp NAM"  
nStartPos = input.readLong(); 5v"Sv  
nEndPos = input.readLong(); Esdw^MGL2  
} %nhE588xf  
input.close(); %:yVjb,Yf  
} CtE <9?  
catch(IOException e){e.printStackTrace ();}  J7p?9  
catch(Exception e){e.printStackTrace ();} Vw+RRi(  
} X][=(l!;w7  
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private void processErrorCode(int nErrorCode) PE<(eIr  
{
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System.err.println("Error Code : " + nErrorCode); zszx~LSvIT  
} h~s h!W8  

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//停止文件下载 [WO>}rGw4  
public void siteStop() pZ5eGA=  
{ _zDf8hy  
bStop = true; Xk}\-&C7  
for(int i=0;i<nStartPos.length;i++) Y@limkN:  
fileSplitterFetch.splitterStop(); Uf#9y182*c  
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} .4XX )f5  
} !#dp[,nk  
//负责部分文件的抓取 ?u~?:a@K  
**FileSplitterFetch.java PGhYkj2  
*/ lS/l iI'Y  
package NetFox; m.ejGm?  
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import java.io.*; RLbo  
import java.net.*; g)nT]+&  
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public class FileSplitterFetch extends Thread { U 
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String sURL; //File URL K[l5=)G0L  
long nStartPos; //File Snippet Start Position MY l9 &8  
long nEndPos; //File Snippet End Position  I}u&iV`  
int nThreadID; //Thread's ID qkBCI,X_Y  
boolean bDownOver = false; //Downing is over `_!R;f  
boolean bStop = false; //Stop identical U &
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FileAccessI fileAccessI = null; //File Access interface m-lTXA(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zo:NE00  
{ o<Qt<*  
this.sURL = sURL; ="de+S8W  
this.nStartPos = nStart; >*WT[UU  
this.nEndPos = nEnd; Z+2 j(  
nThreadID = id; B!((N{4H+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "mc ]^O  
} o8fY!C)  
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public void run() @bZ,)R  
{ @k)[p+)E  
while(nStartPos < nEndPos && !bStop) YRu#JYti  
{ ,&G!9}EC  
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try{ dgT(]H  
URL url = new URL(sURL); E<\\/Q%w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }70A>JBw  
httpConnection.setRequestProperty("User-Agent","NetFox"); tv%B=E!r  
String sProperty = "bytes="+nStartPos+"-"; #3_ @aq*  
httpConnection.setRequestProperty("RANGE",sProperty); _kdt0Vr,L  
Utility.log(sProperty); F h+g@ u6  
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InputStream input = httpConnection.getInputStream(); qm< mw"]  
//logResponseHead(httpConnection); _ O;R  
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byte[] b = new byte[1024]; rDv`E^\  
int nRead; =b#:j:r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8/R9YiY5*  
{ `o?PLE;)p  
nStartPos += fileAccessI.write(b,0,nRead); s&1
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//if(nThreadID == 1) ~L:H]_8F l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =s&ycc;-5}  
} }J $\<ZT  
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Utility.log("Thread " + nThreadID + " is over!"); RcOfesW o  
bDownOver = true; #U.6HBuQa  
//nPos = fileAccessI.write (b,0,nRead); EkoT U#w5  
} ?X$*8;==6  
catch(Exception e){e.printStackTrace ();} -|I_aOC@  
} h_6c9VI  
} i?f;C_w  
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>Q:h0b_$U  
//打印回应的头信息 K9ek  
public void logResponseHead(HttpURLConnection con) @a,}k<@E  
{ 1NkJs&  
for(int i=1;;i++) [DvQk?,t  
{ o8~<t]Ejw  
String header=con.getHeaderFieldKey(i); $E}N`B7  
if(header!=null) \LM.>vJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >
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Utility.log(header+" : "+con.getHeaderField(header)); ~.CmiG.7  
else N
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break; qWD(rq+9  
} !\!j?z=O8  
} hGR
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public void splitterStop() f$qkb$?]}  
{ s7,D}Zz  
bStop = true; 1rON8=E  
} 51xf.iB  
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} -t: U4r(  
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/* +G)a+r'0Q  
**FileAccess.java ^Hz1z_[X@  
*//文件访问(定位，写) lN x7$z`  
package NetFox; vsJDVJ +=  
import java.io.*; <`WcI`IAb  
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public class FileAccessI implements Serializable{ 0~ o,^AW  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }b]eiPWN  
RandomAccessFile oSavedFile; T3@34}*  
long nPos; hD{ `j
 
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public FileAccessI() throws IOException A9MTAm{  
{ :*s@L2D6  
this("",0); D 9UM8Hxi  
} k 7:Z\RGy  
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public FileAccessI(String sName,long nPos) throws IOException =_CH$F!U  
{ q
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oSavedFile = new RandomAccessFile(sName,"rw"); '4CD }  
this.nPos = nPos; <GF^VT|Ce  
oSavedFile.seek(nPos); k8r1)B4ab  
} !j}L-1*{ l  
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public synchronized int write(byte[] b,int nStart,int nLen) yCN?kHG  
{ ^?*<.rsG  
int n = -1; + )[@  
try{ GWv i  
oSavedFile.write(b,nStart,nLen); LqNyi  
n = nLen; F x^X(!)~]  
} >dgz/n?:v  
catch(IOException e) ]B$J8.{q0  
{ a ,"   
e.printStackTrace (); G#M0 C>n  
} }F"98s W  
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return n; nLCaik_,m  
} )j\_*SoH  
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} lQEsa45  
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/* @_W13@|  
**SiteInfoBean.java a&UzIFdB  
*/ +(y8q  
package NetFox; g@T}h[  
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public class SiteInfoBean { K$w;|UJc  
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private String sSiteURL; //Site's URL H8g%h}6h  
private String sFilePath; //Saved File's Path bwj{5-FU  
private String sFileName; //Saved File's Name (.X)=  
private int nSplitter; //Count of Splited Downloading File 1b86@f  
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public SiteInfoBean() [ D.%v~j  
{//nSplitter的缺省值为5 C!ch !E#  
//default value of nSplitter is 5 lQBEq"7$  
this("","","",5); 7?{y&sf  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #<Lv&-U<KT  
{ -/V(Z+dj  
sSiteURL= sURL; E AZX  
sFilePath = sPath; e<*qaUI  
sFileName = sName; F-oe49p5e  
this.nSplitter = nSpiltter; >\w]i*%  
vB}c6A4'U  
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} 1z-A3a/-  
5+;Mc[V3-  
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public String getSSiteURL() f*xr0l  
{ s]|tKQGl,  
return sSiteURL; 79D~Mau#  
} t 7o4 aBl"  
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public void setSSiteURL(String value) %ek0NBE7  
{ nO!&;E&  
sSiteURL = value; &1R#!|h1W  
} &pjj
 
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public String getSFilePath() {L~dER  
{ "|[9 Q?  
return sFilePath; P/.<sr=2  
} 5bAdF'~  
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public void setSFilePath(String value) ^L)TfI_n  
{ G"OP`OMDc  
sFilePath = value; b9m`y*My  
} GqR|hg  
sZT~5c8  
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public String getSFileName() goA=U  
{ elQjPvb  
return sFileName; Z\x
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} *OznZIn  
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public void setSFileName(String value) ydo9 P5E  
{ rq4g~e!S  
sFileName = value; _#NibW  
} iC
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public int getNSplitter() #v<`|_  
{ "YY<T&n  
return nSplitter; v_Sa0
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} ",D!8>=s  
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public void setNSplitter(int nCount) EJ#I7_  
{ q,O_y<uw  
nSplitter = nCount; 4\u`MR  
} yn_f%^!G  
} -0#"
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/* `bfUP s  
**Utility.java wjwCs`  
*/ U4fv$gV  
package NetFox; !p!Qg1O6o  
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public class Utility { $rmxwxz&W:  
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public Utility() ]vvA]e  
{ Sx'oa$J  
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} L"vrX  
Q=Mv"~2>B  
//线程睡眠 O- QT+]  
public static void sleep(int nSecond) ^tGAJ_b79  
{ o>C,Db~L/  
try{ 2HmK['(  
Thread.sleep(nSecond); ch]Q
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} T`":Q1n  
catch(Exception e) <O0tg[ub  
{ T` h%=u|D  
e.printStackTrace ();
&)tiO>B^6  
} G=|?aK{p  
} 1F,U^O  
Ig}hap]G  
//日志 5=I({=/>  
public static void log(String sMsg) AXHY
$f|  
{ tjwf;g}$  
System.err.println(sMsg); py:L-5  
} cM'MgX9  
3 0[Xkz  
oSD=3DQ;  
public static void log(int sMsg) iL);bv W  
{ 1>rQ).eT  
System.err.println(sMsg); !DFTg4xb  
} P"^Yx8L#  
} <q!HY~"V  
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/* <Y7j'n  
**TestMethod.java fc@<'-VA  
*/ XjN=UhC  
package NetFox; klnNBo!  
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public class TestMethod { v)_c*+6u  
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public TestMethod() Hq 5#.rZ#  
{ ///xx/weblogic60b2_win.exe ejZ-A?f-K  
try{ y,`n9[$K\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =K}Pfh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fYy w2"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pJ}U'*Z2  
fileFetch.start(); gi,7X\`KQ  
} 3-hcKE  
catch(Exception e){e.printStackTrace ();} >y#MEN>?  
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} !AE;s}v)0{  
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public static void main(String[] args) Jw}t~m3  
{ [;,E cw^  
new TestMethod(); fVgK6?<8^  
} }Y.YJXum  
} D
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