http断点续传简单实现（java)

/* !-QKh aY  
**SiteFileFetch.java b &JPLUr  
*/ #U1soZ7  
package NetFox; MwuH.# Ez  
import java.io.*; HV sIbQS  
import java.net.*; j.z#fU  
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public class SiteFileFetch extends Thread { 9J?j2!D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rdK.*oT  
long[] nStartPos; //开始位置 {5to;\.  
long[] nEndPos; //结束位置 PH]q#/'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `jV0;sPd;  
long nFileLength; //文件长度 Rl,B !SF  
boolean bFirst = true; //是否第一次取文件 ?XHJCp;f  
boolean bStop = false; //停止标志 }{lOsZA  
File tmpFile; //文件下载的临时信息 YFW+l~[#  
DataOutputStream output; //输出到文件的输出流 t*DM^
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tHGK<rb  
public SiteFileFetch(SiteInfoBean bean) throws IOException 89L-k%R  
{ |6&"r
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siteInfoBean = bean; 'C[gcp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `Q{kiy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^=tyf&"  
if(tmpFile.exists ()) 6sPd")%G  
{ @<};Bo'  
bFirst = false; [iDa6mcth  
read_nPos(); |sI^_RdBv  
} )N}xKw|  
else PKwx)! Rz  
{ `xtN+y F  
nStartPos = new long[bean.getNSplitter()]; c`i
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nEndPos = new long[bean.getNSplitter()]; A1:Fe9q  
} p0@iGyd  
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} i3kI{8h  
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public void run() E&97;VH  
{ !Zs;m`j&9  
//获得文件长度 ?56Zw"89  
//分割文件 \O^= Z{3y  
//实例FileSplitterFetch \,?yj  
//启动FileSplitterFetch线程 o77HRX  
//等待子线程返回 '- Z4GcL  
try{ |5O%@  
if(bFirst) +oyc9PoXF  
{ &AoWT:Ea  
nFileLength = getFileSize(); TzIgEn~  
if(nFileLength == -1) $mpfr#!&3o  
{ Jb0]!*tV  
System.err.println("File Length is not known!"); 02SUyv(Mt  
} ]qXfgc  
else if(nFileLength == -2) @]cpPW-b  
{ V,>#!zUv  
System.err.println("File is not access!"); / {A]('t  
} BkIvoW_  
else "Uyw
7  
{ p<jHUG4?'  
for(int i=0;i<nStartPos.length;i++) :}E*u^v K  
{ '2%hc\P6P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _/KW5  
} vK6bpzI 3  
for(int i=0;i<nEndPos.length-1;i++) OnG!5b  
{ ag] nVE/  
nEndPos = nStartPos[i+1];  R
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} ~M <4HC  
nEndPos[nEndPos.length-1] = nFileLength; 7C&
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} !Dz:6r  
} u'=#~'6  
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//启动子线程 %.Mtn%:I*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1Ce:<.99B  
for(int i=0;i<nStartPos.length;i++) D-[0^  
{ +|o-lb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X.JB&~/rO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {a>)VZw_#  
nStartPos,nEndPos,i); C@KYg/nYw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0}aJCJ9sx=  
fileSplitterFetch.start(); IPJs$PtKok  
} 0V1kZ.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o]jo R3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +[*UC"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dkCSqNFL)  
nEndPos = " + nFileLength); 8fdOV&&D~i  
// fileSplitterFetch[nPos.length-1].start(); .&*Tj}p  
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//等待子线程结束 -"(e*&TJ#  
//int count = 0; 6.ap^9AD  
//是否结束while循环 n+xM))  
boolean breakWhile = false; iPHMyxT+S  
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while(!bStop) OxqP:kM  
{ W}(dhgf  
write_nPos(); dedi6Brl  
Utility.sleep(500); K_RrSI&>  
breakWhile = true; :Z&ipd!yY  
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for(int i=0;i<nStartPos.length;i++) ZW,PZ<  
{ )m6=_q5@o  
if(!fileSplitterFetch.bDownOver) } 1c5#Ym  
{ 1)k))w9  
breakWhile = false; r
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break; k 9s3@S  
} Xst&QKU  
} NbgP,-  
if(breakWhile) i3f/{D/  
break; 6g$+))g  
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{!x-kF
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//count++; v^KJU +  
//if(count>4) kV-a'"W5  
// siteStop(); R$PiF1ffj  
} bv|v9_i  
1no$|n#  
F[9IHT6{  
System.err.println("文件下载结束！"); ab 2V.S  
} ;/ p)vR  
catch(Exception e){e.printStackTrace ();} >a^H7kp  
} Xr':/Qjf  
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Z73 ysn}  
//获得文件长度 y5l4H8{h}  
public long getFileSize() %f?#) 01>  
{ <f:b%Pm7  
int nFileLength = -1; ;9b?[G  
try{ _*&<hAZj  
URL url = new URL(siteInfoBean.getSSiteURL()); qB"y'UW8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i"_JF-IbN  
httpConnection.setRequestProperty("User-Agent","NetFox"); GY0<\-  
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int responseCode=httpConnection.getResponseCode(); =(v/pLLK?  
if(responseCode>=400) vUj7rDT|  
{ hydn" 9;  
processErrorCode(responseCode); Jb_/c``  
return -2; //-2 represent access is error JCE364$$"  
} =g?r.;OO  
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String sHeader; 7dxY07yu  
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for(int i=1;;i++)  #]n[  
{ TS@EE&Wq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NcqE)"yObo  
//Utility.log(in.readLine()); ca$D|3  
sHeader=httpConnection.getHeaderFieldKey(i); {:fyz#>>^  
if(sHeader!=null) -cJ(iz9!  
{ V@T G"YF  
if(sHeader.equals("Content-Length")) IHf A;&b  
{ Ho*S>Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }|Cw]GW  
break; +X.iJ$)  
} .viA+V  
} `[Kh[|  
else %!LrC!6P4  
break; iZ)7%R?5  
} #& Rx(  
} L"#Tas\5  
catch(IOException e){e.printStackTrace ();} *$uKg zv3  
catch(Exception e){e.printStackTrace ();} ^8E/I]-  
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Utility.log(nFileLength); mrk Q20D  
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return nFileLength; )Z"7^i  
} k' pu%nWN  
(#7pGGp*E  
w QwY_ _  
//保存下载信息（文件指针位置） %k1*&2"1#  
private void write_nPos() Zb8i
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{ mqwN<:  
try{ nM\Wa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u=k\]W-  
output.writeInt(nStartPos.length); a]$KI$)e  
for(int i=0;i<nStartPos.length;i++) d.2   
{ Hq6VwQu?  
// output.writeLong(nPos); Wf>UI)^n  
output.writeLong(fileSplitterFetch.nStartPos); Hm%[d;Z7  
output.writeLong(fileSplitterFetch.nEndPos); V<n
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}
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output.close(); :cIE8<\%  
} v"y e\ZG  
catch(IOException e){e.printStackTrace ();} ml\7JW6Rx  
catch(Exception e){e.printStackTrace ();} Je+L8TB  
} !|,=rM9x  
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//读取保存的下载信息（文件指针位置） Iu%/~FgPj{  
private void read_nPos() 2 R1S>X  
{ }MuXN<DDb  
try{ u;1#eP\;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '^lrGO6 z7  
int nCount = input.readInt(); d<fS52~l  
nStartPos = new long[nCount]; hW _NARA  
nEndPos = new long[nCount]; z[] AH#h  
for(int i=0;i<nStartPos.length;i++) es&+5  
{ cidS/OH  
nStartPos = input.readLong(); -&@[]/  
nEndPos = input.readLong(); 29x "E$e  
} CA[k$Sw*  
input.close(); !(l,+@j  
} ojtcKw  
catch(IOException e){e.printStackTrace ();} P@ 1D  
catch(Exception e){e.printStackTrace ();} g 9>p?XY  
} nolTvqMT  
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private void processErrorCode(int nErrorCode) N~Ax78TX  
{ /.7x[Yc  
System.err.println("Error Code : " + nErrorCode); *!'00fv  
} +~8/7V22  
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//停止文件下载 At+on9&=  
public void siteStop() r(J7&vR}h  
{ ' G)Wy|*  
bStop = true; \#G`$JD  
for(int i=0;i<nStartPos.length;i++) L$lo5  
fileSplitterFetch.splitterStop(); zVkHDT[  
|) THuE(  
|I85]'K9a  
} $N:m 9R  
} LvhF@%(9J  
//负责部分文件的抓取 Eu
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**FileSplitterFetch.java nb(#;3DQ  
*/ D-~
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package NetFox; ;(VJZ_
 
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import java.io.*; ctH`71Y  
import java.net.*; tv\P$|LV`8  
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public class FileSplitterFetch extends Thread { |hOqz2|  
|F9/7 z\5+  
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String sURL; //File URL [rE,fR   
long nStartPos; //File Snippet Start Position TX*s T  
long nEndPos; //File Snippet End Position z}u  
int nThreadID; //Thread's ID c>=[|F{{e  
boolean bDownOver = false; //Downing is over 4)Z78H%>  
boolean bStop = false; //Stop identical 6i=m1Yk  
FileAccessI fileAccessI = null; //File Access interface ?%*Zgk!l7  
+!.=M8[  
{#Mz4s`M  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
5x4(5c5^  
{ ;h0?o*i_  
this.sURL = sURL; V"T;3@N/4  
this.nStartPos = nStart; "1h|1'S50?  
this.nEndPos = nEnd; EQu M|4$ix  
nThreadID = id;  1=W>zC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :+!hR4Z~\;  
} 6Dw[n   
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public void run() *gVRMSrx4  
{ ]U'KYrh  
while(nStartPos < nEndPos && !bStop) vF1]L]z:?  
{ LD]XN'?"W  
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j2  
tw\/1wa.  
try{ H }</a%y  
URL url = new URL(sURL); YuLW]Q?v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %UgyGQeo  
httpConnection.setRequestProperty("User-Agent","NetFox"); LxsB.jb-  
String sProperty = "bytes="+nStartPos+"-"; Ed_A#@V  
httpConnection.setRequestProperty("RANGE",sProperty); #{i\t E  
Utility.log(sProperty); J"I{0>@  
/1o~x~g(b  
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InputStream input = httpConnection.getInputStream(); ^ 8egn|  
//logResponseHead(httpConnection); GZ*cV3Y`&  
}$81FSKh  
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byte[] b = new byte[1024]; f>l}y->-Ug  
int nRead; 8[2^`g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;`s/|v  
{ [ V/*{Z  
nStartPos += fileAccessI.write(b,0,nRead); CbI[K|  
//if(nThreadID == 1) dM#\h*:=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~hYG%  
} /R 2:Js  
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Utility.log("Thread " + nThreadID + " is over!"); o}Dy\UfU  
bDownOver = true; umSbxEZU@  
//nPos = fileAccessI.write (b,0,nRead); NC@OmSR\0  
} Fag%#jxI  
catch(Exception e){e.printStackTrace ();} O62H4oT  
} *%\z#Bje@  
} Xxp<qIEm  
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//打印回应的头信息 BWfsk/lej  
public void logResponseHead(HttpURLConnection con) iI&J_Y{1a_  
{ EcBSi995dj  
for(int i=1;;i++) wM_k D  
{ I>b!4?h  
String header=con.getHeaderFieldKey(i); MU%C_d%.  
if(header!=null) X0Xs"--}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Da)9s %_4  
Utility.log(header+" : "+con.getHeaderField(header)); 2c_#q1/Z/  
else *d?,i-Q.+  
break; OUS@)Tyh  
} GC~Tfrf=r  
} ;r"YZs&Xd  
-:AknQq  
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public void splitterStop() _{C:aIl[2  
{ e>z3\4  
bStop = true; 3-Xum*)Y  
} /\_0daUx  
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$ R,7#7bG  
} AQQeLdTq  
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/* WENPS*0oS]  
**FileAccess.java XGbtmmQG  
*//文件访问(定位，写) K p~x  
package NetFox; pg [F{T<  
import java.io.*; |!aMj8i2  
{: T'2+OH>  
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public class FileAccessI implements Serializable{ .FtW$Y~y  
#Bj.#5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z)~.OqRw]  
RandomAccessFile oSavedFile; {I&>`?7.  
long nPos; R%"wf   
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public FileAccessI() throws IOException V<ziJ7H/  
{ KtG|m'\D  
this("",0); FrIguk1  
} <=W;z=$!Bb  
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public FileAccessI(String sName,long nPos) throws IOException BlF>TI%2  
{ E=_M=5]  
oSavedFile = new RandomAccessFile(sName,"rw"); uosFpa  
this.nPos = nPos; /U4F\pZl  
oSavedFile.seek(nPos); )+'FTz` c  
} NldeD2~H  
$-Lk,}s.*  
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public synchronized int write(byte[] b,int nStart,int nLen) rwWs\~.H  
{ ODyK/Q3  
int n = -1; H~Xi;[{7  
try{ UA>UW!I  
oSavedFile.write(b,nStart,nLen); ,_,Z<X/
 
n = nLen; #2<.0@@ TI  
} <7NY.zvwk]  
catch(IOException e) 56Z 1jN^U  
{ 2MS1<VKZ@  
e.printStackTrace (); C_mPw  
} 6 9_etv  
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return n; Q
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} 4
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} rtd&WkU rD  
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];P$w.0  
/* $lz\te  
**SiteInfoBean.java mxt fKPb  
*/ 'id]<<F  
package NetFox; E&ou(Q={  
*{5p/}p  
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public class SiteInfoBean { \wwY?lOe  
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private String sSiteURL; //Site's URL 5$9g4  
private String sFilePath; //Saved File's Path T
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private String sFileName; //Saved File's Name 0/z=G!z\  
private int nSplitter; //Count of Splited Downloading File 8@y@}  
KKB&)R  
X!#rw= Q  
public SiteInfoBean() tl5}#uJ  
{//nSplitter的缺省值为5 fl%X>\i/7  
//default value of nSplitter is 5 !ZlBM{C  
this("","","",5); ,v(K|P@  
} /E8{:>2  
AT*J '37  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0*G =~:  
{ $3.hZx>  
sSiteURL= sURL; u By[x 0  
sFilePath = sPath; kYMKVR  
sFileName = sName; t6m&+N  
this.nSplitter = nSpiltter; K`}8fU  
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} )*6]m1  
Nmu;+{19M  
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public String getSSiteURL() v',%   
{ C(/{53G(  
return sSiteURL; /~=W3lhY  
} $646"1S  
a@+n  
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public void setSSiteURL(String value) >|[ l?`  
{ 9*`(*>S  
sSiteURL = value; )g;*u,C  
} +q*Cw>t /  
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V!^5#A<  
public String getSFilePath() 6yU#;|6d  
{ ,e]|[,r#5  
return sFilePath;  Y7q=]  
} f&5'1tG  
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public void setSFilePath(String value) A!x
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{ .eZsKc-@  
sFilePath = value; `
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} ?7?hDw_Nk  
yxz)32B?  
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public String getSFileName() )7`2FLG  
{ 0 rge]w.X  
return sFileName; 98Dg[O  
} [9c|!w^F  
108cf~2&  
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public void setSFileName(String value) 9?x
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{ Ad%3 fvn  
sFileName = value; JSf \ApX  
} L'A>IBrz  
%]U'   
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public int getNSplitter() +Y|1 7n  
{ 7~f"8\  
return nSplitter;
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} \x(ILk|'c  
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public void setNSplitter(int nCount) IH2V.>h  
{ r9\7I7z  
nSplitter = nCount; _`Lv@T.  
} *PF}L%K(?  
} v-utDQT3  
D# Gf.c  
iCZuE:I1K,  
/* PKxI09B  
**Utility.java @Q%9b)\\  
*/ AP:(/@K|  
package NetFox; a7~%( L@r  
e]!`Cl-f80  
9P7^*f:E  
public class Utility { AJJa<c+j  
P #PRzt  
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public Utility() ;1[a*z<l&s  
{ $yoIz.?V  
&%=]lP]  
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} s^vw]D  
y' r I1eF  
//线程睡眠 [t}@>@W|  
public static void sleep(int nSecond) Quts~Q  
{ pRez${f.(s  
try{ .@`5>_  
Thread.sleep(nSecond); <Na .6P  
} z&Kh$ $)[  
catch(Exception e) y$Rh$eK  
{ N"zg)MsX  
e.printStackTrace (); EvJ<X,Bo  
} 0e,U&B<W  
} l'Kx#y$  
x)0''}E~  
//日志 j7>a^W  
public static void log(String sMsg) X{BS]   
{ \r5L7y$9 h  
System.err.println(sMsg); UzKB"Q  
} &W
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public static void log(int sMsg) #*~3gMI{=  
{ =3
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System.err.println(sMsg); $p)e.ZMgE  
} \;FE@  
} hf1h*x^J  
es
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/* _7bQR7s  
**TestMethod.java Gp
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*/ h2_A'  
package NetFox; jiGXFM2  
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J
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public class TestMethod { }xb?C""q^q  
14S_HwX  
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public TestMethod() x T{s%wE  
{ ///xx/weblogic60b2_win.exe z0-[ RGg  
try{ !;U;5e=0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 87ptab@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )TtYm3,  
SiteFileFetch fileFetch = new SiteFileFetch(bean);   B'QcD  
fileFetch.start(); PZYVLUw `  
} i$jzn ga  
catch(Exception e){e.printStackTrace ();} 6BY(Y(z  
9.^2CM6l  
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} Dwa.ZY}-  
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public static void main(String[] args) ["~T)d'  
{ 8}.V[,]6  
new TestMethod(); (/e[n.T  
} 4%"Df1U  
} + :;6kyM6X  
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