http断点续传简单实现（java)

/* st36xS  
**SiteFileFetch.java ,)+O.Lf7&.  
*/ gDnG!i+  
package NetFox; n15c1=
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import java.io.*; EAFKf*K=  
import java.net.*; 57+^T}/>  
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public class SiteFileFetch extends Thread { \@4QG.3&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {Z;W|w1t  
long[] nStartPos; //开始位置 Bdm<<<  
long[] nEndPos; //结束位置 u7`<m.\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <2y~7h:  
long nFileLength; //文件长度 >'^l>FPc  
boolean bFirst = true; //是否第一次取文件 I_xJ[ALdm  
boolean bStop = false; //停止标志 /S9Mu )1Y  
File tmpFile; //文件下载的临时信息 N|q:wyS|  
DataOutputStream output; //输出到文件的输出流 |6\ ?"#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h bj^!0m  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZvNXfC3Ia  
{ 
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siteInfoBean = bean; C
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wr*A%:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _?Jm.nT  
if(tmpFile.exists ()) -<&"geJA  
{ oB3>0Pm*a.  
bFirst = false; wlKpHd*  
read_nPos(); txr!3-Ne'!  
} @]*z!>1  
else SVXey?A;CJ  
{ Tjure]wQz  
nStartPos = new long[bean.getNSplitter()]; 21cB_"  
nEndPos = new long[bean.getNSplitter()]; ?vf{v  
} 2~h)'n7Mw  
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} scL7PxJ5  
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public void run()
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{ WF-imI:EK  
//获得文件长度 {LJCY<IGq  
//分割文件 f$V']dOj1q  
//实例FileSplitterFetch ZWf{!L,@Z  
//启动FileSplitterFetch线程 R52q6y:<x  
//等待子线程返回 :g<dwuVO  
try{ >YoK?e6  
if(bFirst) !;CY @=  
{ ?WUE+(oH>  
nFileLength = getFileSize(); >)N,V;j  
if(nFileLength == -1) Y/Y746I  
{ =#%e'\)a  
System.err.println("File Length is not known!"); m/Yi;>I(  
} 8Yq6I>@!  
else if(nFileLength == -2) E pM 4+  
{ [zf9UUc~  
System.err.println("File is not access!"); >47,Hq:2  
} N@)4H2_u \  
else gWgK  
{ <;9vwSH>  
for(int i=0;i<nStartPos.length;i++) +~FH'DsT  
{ wm2Q(l*HH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8n~@Rj5  
} wV56LW  
for(int i=0;i<nEndPos.length-1;i++)  mH?^3T  
{ o'Tqqrr  
nEndPos = nStartPos[i+1]; i-E&Y*\^9H  
} Vp5qul%  
nEndPos[nEndPos.length-1] = nFileLength; fXL>L   
} *QLl jGe  
} $8it&/JP,  
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//启动子线程 ,rX!V=Z5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2?-}(F;Z  
for(int i=0;i<nStartPos.length;i++) miN(a; Q2P  
{ +oQ@E<)H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3v0
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yx/:<^"-$  
nStartPos,nEndPos,i); pM VeUK?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8KoPaq  
fileSplitterFetch.start(); >{GC@Cw  
} nh9K(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RI*Q-n{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m5d;lrk@&/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )XO2DY1/&  
nEndPos = " + nFileLength); $h_@`j  
// fileSplitterFetch[nPos.length-1].start(); Hh!x&;x}  
SZwfYY!ft0  
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//等待子线程结束 Q_uv.\*z_  
//int count = 0; ,hOJe=u46  
//是否结束while循环 VJr?` eY4  
boolean breakWhile = false; PVtQ&m$y  
@&M$`b ^  
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while(!bStop) j@9nX4Z  
{ >J8?n,*  
write_nPos(); !4z"a@$  
Utility.sleep(500); NWNgh/9?  
breakWhile = true; PiH#9XB  
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for(int i=0;i<nStartPos.length;i++) +;>>c`{  
{ $rjv4e}7  
if(!fileSplitterFetch.bDownOver) R`$Odplh>  
{ has5"Bb  
breakWhile = false; s@3!G+ -}  
break; 45-pJf8F  
} +qS$t  
}  d;CD~s  
if(breakWhile) 7CQ48LH]  
break; TUk1h\.q  
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//count++; \<z{@  
//if(count>4) ul% q6=f)  
// siteStop(); +F0M?,  
} ,e,fOL  
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System.err.println("文件下载结束！"); +*|E%pq  
} 6SidH_&C  
catch(Exception e){e.printStackTrace ();} fitm*  
} ?^@;8m  
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//获得文件长度 %OzxR9  
public long getFileSize() S:R%%c
y  
{ b9\=NdyCY  
int nFileLength = -1; *?i~AXJm  
try{ ]AfeaU'>  
URL url = new URL(siteInfoBean.getSSiteURL()); e j`lY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ig9$ PP+3  
httpConnection.setRequestProperty("User-Agent","NetFox"); w\\   
&i!.6M2  

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int responseCode=httpConnection.getResponseCode(); l5@k8tnz  
if(responseCode>=400) 5B@&]-'~  
{ Zo&U3b{Dy  
processErrorCode(responseCode); l[h??C`  
return -2; //-2 represent access is error sa*hoL18  
} LL:B H,[  
jNB-FVaT  
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String sHeader; Z?^AX&F  
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for(int i=1;;i++) aFl(K\  
{ :KW   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~>qcV=F^d,  
//Utility.log(in.readLine()); G2em>W_n  
sHeader=httpConnection.getHeaderFieldKey(i); Y%Saz+  
if(sHeader!=null) 3 i>uKU1  
{ tF=96u_X  
if(sHeader.equals("Content-Length")) _\u'~wWl  
{ aA\v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T@f$w/15  
break; X\flx~  
} [Si`pPvl  
} 7@06x+!  
else <.:B .k  
break; jg2>=}  
}  H'2pmwk  
} `qUmOFl  
catch(IOException e){e.printStackTrace ();} /y NU0/  
catch(Exception e){e.printStackTrace ();} k2O==IG]
6  
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Utility.log(nFileLength); G0<m3 Up  
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return nFileLength; a N_M  
} C'hZNFsF;  
ky[FNgQ3n  
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//保存下载信息（文件指针位置） z+Y0Zh";/#  
private void write_nPos() ve'hz{W  
{ \ocJJc9  
try{ .`iOWCS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3rOv j&2  
output.writeInt(nStartPos.length); OBu$T&  
for(int i=0;i<nStartPos.length;i++) 4R}2H>VV%  
{ -R|v&h%T  
// output.writeLong(nPos); (i&:=Bfn)  
output.writeLong(fileSplitterFetch.nStartPos); 5Vf#
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output.writeLong(fileSplitterFetch.nEndPos); = q;ACW,z  
} 1[mX_ }K  
output.close(); ~ M@8O  
} .y|*  
catch(IOException e){e.printStackTrace ();} o5A@U0c_  
catch(Exception e){e.printStackTrace ();} rr9N(AoxW  
} C+jlIT+  
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//读取保存的下载信息（文件指针位置） qK,rT*5=  
private void read_nPos() X`#vH8  
{ '\=aSZVO  
try{ AvH^9zEE(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >pUR>?t"  
int nCount = input.readInt(); :[,-wZiT~6  
nStartPos = new long[nCount]; 8FU8E2zo  
nEndPos = new long[nCount]; XeJn,=  
for(int i=0;i<nStartPos.length;i++) MBp%TX!  
{ <Y9e n!3\  
nStartPos = input.readLong(); RMDzPda.  
nEndPos = input.readLong(); G[@RZ~o4  
} yIA-+# r[  
input.close(); sA#}0>`3S  
} <D%.'=%pZ  
catch(IOException e){e.printStackTrace ();} ? 0
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catch(Exception e){e.printStackTrace ();} &M&*3  
} k`_sKr]9  
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private void processErrorCode(int nErrorCode) O,x[6P5
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{ W2&o'(P\  
System.err.println("Error Code : " + nErrorCode); F}wy7s2i  
} _h6SW2:z!E  
e ^2n58  
whxTCI
V  
//停止文件下载 g1Ed:V]_  
public void siteStop() TD!--l*gL  
{ F2QFQX(j  
bStop = true; )[+82~F  
for(int i=0;i<nStartPos.length;i++) J;|a)Nw  
fileSplitterFetch.splitterStop(); GRM6H|.
  
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} ,)@njC?J  
} E2K{9@i  
//负责部分文件的抓取 ]l>LU2 sx  
**FileSplitterFetch.java ~t^ Umx"Ew  
*/ dhv?36uE  
package NetFox; ' Dcj\=8
 
ti'B}bH>'  
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import java.io.*; EMQGP<[  
import java.net.*; 0Q?)?8_  
4PjC[A*  
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public class FileSplitterFetch extends Thread { 0v+-yEkw  
' Dp;fEU$  
}C4wED.  
String sURL; //File URL U}@xMt8@l  
long nStartPos; //File Snippet Start Position txE=AOY5  
long nEndPos; //File Snippet End Position _NefzZWUJ  
int nThreadID; //Thread's ID 6S`0<Z;;/  
boolean bDownOver = false; //Downing is over jaw&[f 7  
boolean bStop = false; //Stop identical ~=va<%
{ U  
FileAccessI fileAccessI = null; //File Access interface 7-:R{&3Lm:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;3x*pjLG:Q  
{ {Y-~7@  
this.sURL = sURL; NNt n  
this.nStartPos = nStart; J0V`sK  
this.nEndPos = nEnd; v5>A1\  
nThreadID = id; vAp<Muj(a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z_W
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} m8@&-,T   
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public void run() jr,N+K(@T  
{ b9-IrR4h  
while(nStartPos < nEndPos && !bStop) E\|nP~;~F9  
{ I4W@t4bZ  
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try{  ^M{,{bG  
URL url = new URL(sURL); #x;,RPw5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >H^#!eaqw  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~)^'5^  
String sProperty = "bytes="+nStartPos+"-"; ,AmwsXN"F  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); Z
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InputStream input = httpConnection.getInputStream(); 
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//logResponseHead(httpConnection); @/F61Ut  
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byte[] b = new byte[1024]; 4qdoF_  
int nRead; H
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T]ls&cW5  
{ baBBn%_V  
nStartPos += fileAccessI.write(b,0,nRead); 2 /FQ;<L  
//if(nThreadID == 1)  V\o7KF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zw['
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} T]\c2U  
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Utility.log("Thread " + nThreadID + " is over!"); <XIIT-b[  
bDownOver = true; @(Y!$><Is  
//nPos = fileAccessI.write (b,0,nRead); #0>xa]S  
} VGmvfhf#"  
catch(Exception e){e.printStackTrace ();} nq)F$@  
} K#YQB3rX  
} )P$|9<_q7x  
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&)Xc'RQ.C  
//打印回应的头信息 MF8-q'upyT  
public void logResponseHead(HttpURLConnection con) EHk\Q\  
{ ;$QC_l''b  
for(int i=1;;i++) f<NR6],}  
{ |M7cB$y  
String header=con.getHeaderFieldKey(i); ]3rVULU"K-  
if(header!=null) j-":>}oW2.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q0iJy@?A  
Utility.log(header+" : "+con.getHeaderField(header)); 1@DC#2hPr  
else fbNzRXw  
break; e
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} 64<;6*
 
} <eoie6@3  
(k?HT'3)  
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public void splitterStop() ){*+s RBW  
{ z3Q&O$5\  
bStop = true; wT4@X[5$  
} :OG I|[  
)th[fUC(  
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} <h/%jM>9/  
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>Icr4?zq  
/* xG9Sk  
**FileAccess.java i"WYcF|  
*//文件访问(定位，写) ~SnUnNDm`  
package NetFox; /ad9Q~nJ  
import java.io.*; =l/6-j^  
pk :P;\  
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public class FileAccessI implements Serializable{ g8W,Xq+  
;2p+i/sVj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j3gDGw;  
RandomAccessFile oSavedFile; qN $t_  
long nPos; #c^V%  
Y;"k5+ q  
9}(w*>_L  
public FileAccessI() throws IOException 'X^auyL  
{ aD^$v  
this("",0); eU[g@Pq:Y  
} b:m+I  
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public FileAccessI(String sName,long nPos) throws IOException ]~({;;3o-  
{ ,NSf  
oSavedFile = new RandomAccessFile(sName,"rw"); UB/> Ro  
this.nPos = nPos; ?sf<cFF  
oSavedFile.seek(nPos); KdkA@>L!;  
} Gv:~P_vBH[  
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g7\=  
public synchronized int write(byte[] b,int nStart,int nLen) |$RNY``J  
{ lQn" 6o1  
int n = -1; {.p.?  
try{ " kDiK`i  
oSavedFile.write(b,nStart,nLen); YX\vk/[|  
n = nLen; &Y]'
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} r|Ui1f5  
catch(IOException e) 0MG>77  
{ w;z7vN~/O  
e.printStackTrace (); (|gQ i{8  
} ag-A}k>v  
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return n; dftBD  
} Shm> r@C?  
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} 6Sr]<I +:  
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/* ,,H"?VO  
**SiteInfoBean.java g^AQBF  
*/ ~zVxprEf_  
package NetFox; I6>J.6luF9  
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JK k0f9)  
public class SiteInfoBean { bc)>h!'Y  
$[gN#QW%  
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private String sSiteURL; //Site's URL )!T~l(g  
private String sFilePath; //Saved File's Path |Splbsk  
private String sFileName; //Saved File's Name $ghZ<Y2}9  
private int nSplitter; //Count of Splited Downloading File g3R(,IH  
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public SiteInfoBean() I \:WD"  
{//nSplitter的缺省值为5 :^;c(>u{  
//default value of nSplitter is 5 }z3j7I  
this("","","",5); V%Uj\cv  
}  bGRt  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F3tps jQ  
{ %)ho<z:7U  
sSiteURL= sURL; dG\wW@}J  
sFilePath = sPath; -yqsJGY
 
sFileName = sName; @u~S!(7.Wi  
this.nSplitter = nSpiltter; 2*#|t: (c  
8|u
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} aZfMeW  
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public String getSSiteURL() n3^(y"q  
{ Z8$}Rpo  
return sSiteURL; 5
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} d,<ni"  
%,>z`D,Hg  
P4zo[R%4  
public void setSSiteURL(String value) lu8G$EQI  
{ u9lZHh#V-  
sSiteURL = value; kfy!T rf  
} 4S_ -9&z  
1{}p_"s>  
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public String getSFilePath() \Mf>X\}  
{ #&3,T1i`  
return sFilePath; @[GV0*yz$  
} uuzV,q  
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public void setSFilePath(String value) \pmS*Dt  
{ NOb`)qb  
sFilePath = value; TBlSZZ-55]  
} rhv~H"qzW  
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public String getSFileName() @]\fO)\f  
{ Fs+tcr/\[  
return sFileName; $d?+\r:I{,  
} oXPA<ef o  
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'Zx5+rM${}  
public void setSFileName(String value) [4)Oi-_Y>  
{ t
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sFileName = value; Q>niJ'7WF  
} c*USA eP  
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public int getNSplitter() pR0[qsQM  
{ STKL
 
return nSplitter; bcIae0LZ  
} 7ZcF0h  
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public void setNSplitter(int nCount) %nA})nA7=  
{ l#)X/(?;  
nSplitter = nCount; 2y[Q  
} *TOdIq&z  
}  hfB$4s9  
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"ra$x2|=}  
/* >e]g T  
**Utility.java R2bqhSlF  
*/ jNZ.Fb  
package NetFox; :e1h!G  
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public class Utility { zzmC[,u}  
{v={q1  
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public Utility() \Ne`9k  
{ DE13x*2  
# :+Nr  
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} CEfqFn3^  
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//线程睡眠 xC76jE4  
public static void sleep(int nSecond) S ?Zh#`(*  
{ <JPN< Kv  
try{ .1QGNW  
Thread.sleep(nSecond); pn"!wqg  
} 8}%F`=Y0  
catch(Exception e) <,vIN,Kl8/  
{ )"x6V""Rb  
e.printStackTrace (); 5Ds[?  
} I| TNo-!$  
} r[9m-#)>  
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//日志 2mY!gVi  
public static void log(String sMsg) HZrA}|:h  
{ y6 (L=$+B  
System.err.println(sMsg); 
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} U1\EwBK8*T  
q` S ~w  
hY}Q|-|  
public static void log(int sMsg) EKc<|e,F  
{ '1u?-2  
System.err.println(sMsg); KGt:  
} 74e=zW?  
} XQ1]F{?/H  
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Lg4|6.Ez|P  
/* *F$@!ByV  
**TestMethod.java VuLb9Kn  
*/ B>{%$@4  
package NetFox; qI'pjTMDY  
=By@%ioIGG  
-jQ*r$iRE  
public class TestMethod { {lK2yi  
gUiO66#x  
a\sK{`|X*  
public TestMethod() PRfq_:xy  
{ ///xx/weblogic60b2_win.exe YS3~sA  
try{ :.PA(97xb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RO3LZBL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .AN1Yt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); MqJTRBs%  
fileFetch.start(); ^y,h0?Z9  
} ^f[6NYS?  
catch(Exception e){e.printStackTrace ();} eKLvBa-{@  
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} $(}rTm  
m.++nF  
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public static void main(String[] args) $f@YQN=  
{ %9YY \a {  
new TestMethod(); XPhP1 ^>\  
} }u#3hYa  
} f y2vAwl  
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