http断点续传简单实现（java)

/* @U6Iw"@  
**SiteFileFetch.java kP9DCDO`[5  
*/ A4.Q\0  
package NetFox; WJ$D]7  
import java.io.*; jnvi_Rodm  
import java.net.*; YC#N],#  
j 
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public class SiteFileFetch extends Thread { w-?_U7'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V6Kw71'9  
long[] nStartPos; //开始位置 G(F}o]  
long[] nEndPos; //结束位置 q/,>UtRr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 53d8AJ_@X  
long nFileLength; //文件长度 Jrd:6
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boolean bFirst = true; //是否第一次取文件 v*'dA^Q  
boolean bStop = false; //停止标志 5BCHWX*y  
File tmpFile; //文件下载的临时信息 Hc1S:RW  
DataOutputStream output; //输出到文件的输出流 :T(3!}4  
)J4XM(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hjywYd]8  
public SiteFileFetch(SiteInfoBean bean) throws IOException GU'/-6-T  
{ '#REbY5ev  
siteInfoBean = bean; oJJ2y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Fyy)665x/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A+
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if(tmpFile.exists ()) d@~Hp?  
{ d^sS{m\  
bFirst = false; VSa\X~  
read_nPos(); ?sV0T)uk  
} ,$ L>  
else )%lPa|7s  
{ H(U`
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nStartPos = new long[bean.getNSplitter()]; 4(>|f_$  
nEndPos = new long[bean.getNSplitter()]; [k-Q89  
} %EA|2O.D  
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} d 6 t#4!  
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public void run() '{+5+ J  
{ $8gj}0}eH  
//获得文件长度 x5_V5A/@LU  
//分割文件 #?8dInu>
 
//实例FileSplitterFetch _]btsv\)f  
//启动FileSplitterFetch线程 `,|"rn#S  
//等待子线程返回 [%'yHb~<  
try{ Eb66GXF[  
if(bFirst) o.IJ4'}aN  
{ e E:J  
nFileLength = getFileSize(); WPT0=Hqp7  
if(nFileLength == -1) R&Y+x;({  
{ ._j9^Ll  
System.err.println("File Length is not known!"); k@MAi*  
} C&Rv$<qc  
else if(nFileLength == -2) T$[50~  
{ w.w(*5[  
System.err.println("File is not access!"); YCr:nYm<f  
} 7lc -  
else T.\=R  
{
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for(int i=0;i<nStartPos.length;i++) g{wOq{7V  
{ |P!7T.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P%w)*);  
} yClX!
OL  
for(int i=0;i<nEndPos.length-1;i++) -?L~\WJAL  
{ A)"?GK{*  
nEndPos = nStartPos[i+1]; wWjZXsOd  
} #[$^M:X.  
nEndPos[nEndPos.length-1] = nFileLength; 5Fa.X|R~  
} Fq\vFt|m<  
} S"+X+Oxp7?  
jroR2*  
0;9X`z J  
//启动子线程 vz'/]E
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; XFJGL!wWm[  
for(int i=0;i<nStartPos.length;i++) SB"Uu2)wZ  
{ Z
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LbCcOkL/@@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `5da  
nStartPos,nEndPos,i); <r 2$k"*:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); />^sGB  
fileSplitterFetch.start(); GHeucG}?  
} <k59Ni9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )Iu0MN&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !4Q0   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kucH=96  
nEndPos = " + nFileLength); ndW]S7  
// fileSplitterFetch[nPos.length-1].start(); _{$eOwB  
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//等待子线程结束 'x/pV5[hQ  
//int count = 0; KV&4Ep#  
//是否结束while循环 7dxTyn=  
boolean breakWhile = false; PydU.,^7
 
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while(!bStop) z)AZ:^!O  
{ LC8&},iu  
write_nPos(); 4WspPHj  
Utility.sleep(500); 1nGpW$Gx  
breakWhile = true; 2h=QJgpCG  
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for(int i=0;i<nStartPos.length;i++) 'P'f`;'_DC  
{ ":
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if(!fileSplitterFetch.bDownOver) $)or{Z$&  
{ nulLK28q  
breakWhile = false; 3UXaA;  
break; 7LotN6H  
} ^:hI bF4G  
} $W_sIS0\z  
if(breakWhile) OoIs'S-Z#  
break; 4$W}6v  
.|?UqZ(,  
W"3YA+qpI  
//count++; u7>{#]  
//if(count>4) QVT|6znw  
// siteStop(); #E`wqI\'  
} Ec3TY<mVr  
#!yW)RG  
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System.err.println("文件下载结束！"); gXy'@!  
} _|^cudRv  
catch(Exception e){e.printStackTrace ();} a+!r5689  
} LZ'Y3 *  
n^[VN[VC  
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//获得文件长度 %p; 'l  
public long getFileSize() `J l/@bE=  
{ AQ)DiH  
int nFileLength = -1; 1\u{1 V  
try{ q0sdL86  
URL url = new URL(siteInfoBean.getSSiteURL()); ;rj|>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W]B75  
httpConnection.setRequestProperty("User-Agent","NetFox"); =PM6:3aKh  
[\BLb8  
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int responseCode=httpConnection.getResponseCode(); {e]ktj#+{  
if(responseCode>=400) @sPuc.  
{ 7gnrLc$]O  
processErrorCode(responseCode); U*Sjb% Qb  
return -2; //-2 represent access is error r)]8zK4;=  
} #_pQS}$  
F-TDS<[S?  
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String sHeader; Od]B;&F  
+"?O2PX  
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for(int i=1;;i++) BJ*8mKi h  
{ P9yg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n=iL6Yu(  
//Utility.log(in.readLine()); ]tsp}M@  
sHeader=httpConnection.getHeaderFieldKey(i); ,^n5UA`PK  
if(sHeader!=null) -hU1wX%U  
{ 1}/37\  
if(sHeader.equals("Content-Length")) "K)ue@?  
{ JIOeDuw+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E{8-VmY  
break; 7;rf$\-&  
} B;Dl2k^L  
} . Ua
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else '_fj:dy  
break; a<CJ#B2K  
} NK!#K>AO  
} /6@$^paB  
catch(IOException e){e.printStackTrace ();} n4A#T#D!t3  
catch(Exception e){e.printStackTrace ();} s`dwE*~  
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Utility.log(nFileLength); \$Q?  
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return nFileLength; U$m[{r2M  
} {8e4TD9E0  
)YY
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//保存下载信息（文件指针位置） N2.(0 G  
private void write_nPos() spG3"Eodi  
{ MZWicfUy  
try{ M{)|9F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dd'4W  
output.writeInt(nStartPos.length); lU8X{SV!  
for(int i=0;i<nStartPos.length;i++) 2qDyb]9  
{ bH`r=@.:cu  
// output.writeLong(nPos); :=oIvSnh  
output.writeLong(fileSplitterFetch.nStartPos); L)QAI5o:3  
output.writeLong(fileSplitterFetch.nEndPos); IfzW%UL  
} =@*P})w5.  
output.close(); [J\! 2\Oo  
} g!
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catch(IOException e){e.printStackTrace ();} OhiY <  
catch(Exception e){e.printStackTrace ();} 2q}lSa7r  
} QdK PzjA  
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//读取保存的下载信息（文件指针位置） $*qQ/hi  
private void read_nPos() I~T~!^}U  
{ j}aU*p~N  
try{ K06x7W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); As+^6  
int nCount = input.readInt(); @p[ml m  
nStartPos = new long[nCount]; %T,cR>lw  
nEndPos = new long[nCount]; tdOox87YK  
for(int i=0;i<nStartPos.length;i++) COFCa&m9c  
{ r 3FUddF'  
nStartPos = input.readLong(); qk_YFR?R  
nEndPos = input.readLong(); ['_W<  
}  CT[CM+  
input.close(); H
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} /L; c -^  
catch(IOException e){e.printStackTrace ();} V2o1~R~  
catch(Exception e){e.printStackTrace ();} 58[.]f~0  
} F-GrQd:O=  
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\  
1qE*M7_:E>  
private void processErrorCode(int nErrorCode) \:Z8"~G  
{ ~yu\vqN  
System.err.println("Error Code : " + nErrorCode); V
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}
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V*%Lc9<d  
r68d\N`.  
//停止文件下载 cIQe^C  
public void siteStop() 3Bbd2[<W  
{ ?XnKKw\  
bStop = true; #<81`%  
for(int i=0;i<nStartPos.length;i++) LPS]TG\  
fileSplitterFetch.splitterStop(); f"aqg/l  
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} Jk_}y  
} .2x`Fj;o1  
//负责部分文件的抓取 ueLdjASJ  
**FileSplitterFetch.java >vZ^D  
*/ KA{JSi  
package NetFox; c;doxNd6  
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import java.io.*; wvPS0]  
import java.net.*; B j z@X  
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public class FileSplitterFetch extends Thread { J?oEzf;M  
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String sURL; //File URL ,A;wLI  
long nStartPos; //File Snippet Start Position VL8yL`~zc.  
long nEndPos; //File Snippet End Position 3)_(t.$D  
int nThreadID; //Thread's ID XpT+xv1`;  
boolean bDownOver = false; //Downing is over R@lA5w  
boolean bStop = false; //Stop identical 2T3b6  
FileAccessI fileAccessI = null; //File Access interface ;bYLQ  
a=AP*adx8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P|rreSv*  
{ *B%ulsm  
this.sURL = sURL; \PM5B"MDZ  
this.nStartPos = nStart; v 0D@`C  
this.nEndPos = nEnd; 0'O6-1Li  
nThreadID = id; U@"f(YL+"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r(p@{L185  
} !d{Ijs'T  
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public void run() RFT`r  
{ N&]_U%#Q  
while(nStartPos < nEndPos && !bStop) ]Nb~-)t%B  
{ 2A(IsUtqO:  
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try{ 3<X*wVi)NN  
URL url = new URL(sURL); O%m>4OdH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3\H0Nkubts  
httpConnection.setRequestProperty("User-Agent","NetFox"); OHK]=DH:M  
String sProperty = "bytes="+nStartPos+"-"; Ry"N_Fb  
httpConnection.setRequestProperty("RANGE",sProperty); 6&[rATU+  
Utility.log(sProperty); 7Lx=VX#]q  
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InputStream input = httpConnection.getInputStream(); :za:gs0  
//logResponseHead(httpConnection); W,|JocDq  
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h
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byte[] b = new byte[1024]; }= (|3\v  
int nRead; \>)#cEX5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1MxO((
k  
{ #GIjU1-  
nStartPos += fileAccessI.write(b,0,nRead); )|IMhB+4  
//if(nThreadID == 1) (x/xqDpmBS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -(l/.yE{X  
} p[:E$#W~;  
7"s8G7  
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Utility.log("Thread " + nThreadID + " is over!"); xF7q9'/F  
bDownOver = true; E2( {[J  
//nPos = fileAccessI.write (b,0,nRead); C~8;2/F7  
} 7|^5E*8/  
catch(Exception e){e.printStackTrace ();} A)641"[  
} f/tJ>^N5  
} J:G~9~V^  
'-vzQd@y  
 :qrCqFl  
//打印回应的头信息 r"x/,!_E  
public void logResponseHead(HttpURLConnection con) q*d@5  
{ ZGC*BP/  
for(int i=1;;i++) 3#~w#Q0%  
{ +JPHQx'W  
String header=con.getHeaderFieldKey(i); f~v@;/HL  
if(header!=null) nW!pOTJq21  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &ngG_y8}&  
Utility.log(header+" : "+con.getHeaderField(header)); (VB-5&b  
else NG\^>.8  
break; ">!<OB  
} o 76QQ+hP  
} OE5JA8/H  
[hXnw'Im/  
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public void splitterStop() K&UTs$_cI  
{ $pfN0/`(  
bStop = true; Z{rD4S@^  
} ,Ep41v;T%`  
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} y4`uU1=  
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/* 7f#r&~=  
**FileAccess.java Wv-nRDNG  
*//文件访问(定位，写) v>E3|w%  
package NetFox; q.
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import java.io.*; -/gAb<=  
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public class FileAccessI implements Serializable{ N!YjMx)P  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (#5TM1/A  
RandomAccessFile oSavedFile; {5J: ]{p  
long nPos; y5$AAas  
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public FileAccessI() throws IOException 0)nY- f0  
{ xI,7ld~  
this("",0); ^K`Vqo  
} %xhA2  
V;%DS)-  
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public FileAccessI(String sName,long nPos) throws IOException J>%uak<  
{ )R5=GHmL  
oSavedFile = new RandomAccessFile(sName,"rw"); {>8u/  
this.nPos = nPos; L__J(6,V2  
oSavedFile.seek(nPos); vu=`s|R  
} O&ZVu>`g  
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public synchronized int write(byte[] b,int nStart,int nLen) /I
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{ }S}9Pm,:  
int n = -1; /Lt Lu  
try{ 1-:{&!  
oSavedFile.write(b,nStart,nLen); ZDt|g^  
n = nLen; o}VW%G"  
} Ct\n1T }  
catch(IOException e) O.^1r  
{ NI33lp$V  
e.printStackTrace (); VVVw\|JB>  
} PDtLJt$  
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return n; fd/?x^Z  
} xYl ScM_~  
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} mmx;Vt$i  
.Q$/\E  
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/* ylVBK{w9  
**SiteInfoBean.java 8zWKKcf7t  
*/ GjGt' m*  
package NetFox; l>iE1`iL<  
}`*DMI;-  
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public class SiteInfoBean { 9&7$oI$!J  
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J sc`^a%`'  
private String sSiteURL; //Site's URL -]e@FN
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private String sFilePath; //Saved File's Path [lbe_G;  
private String sFileName; //Saved File's Name g@][h_? {  
private int nSplitter; //Count of Splited Downloading File M<VZISu)dy  
(J,^)!g7  
%X>P+6<=  
public SiteInfoBean()  1@p'><\  
{//nSplitter的缺省值为5 M@?,nzs K  
//default value of nSplitter is 5 ?K/N{GK%{  
this("","","",5); ITf, )?|]Y  
} \Czuf   
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P K9BowlW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ki{]5Rz  
{ <QZ X""  
sSiteURL= sURL; PS3%V_2  
sFilePath = sPath; ?84B0K2Ns  
sFileName = sName; $TR#-q  
this.nSplitter = nSpiltter; V-.Nc#  
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} wrmbOT  
1Z| {3W  
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public String getSSiteURL() nD/; Gq  
{ (TQhO$,  
return sSiteURL; C#Y_La  
} ]v6s](CE  
[H&Z /.{F  
];VJ54  
public void setSSiteURL(String value) u{dI[?@  
{ 3El5g0'G  
sSiteURL = value; JC}oc M j0  
} QXg9ah~  
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whdoG{/
  
public String getSFilePath() U9:w^t[Pp  
{ vh">Z4  
return sFilePath; :L'U>)k  
} Y,;$RV@g  
#k*P/I~  
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public void setSFilePath(String value) ZuIw4u(9  
{ R;2q=%  
sFilePath = value; /ig'p53jL  
} 1j":j%9M  
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public String getSFileName() w +~,Mv\  
{ x8q3 Njr

 
return sFileName; |
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} xHo iu$i6  
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public void setSFileName(String value) u^NZsuak  
{ dOfEEqPI  
sFileName = value; &Y/Myh[P  
} ="=Aac#n`  
v
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@& vtY._  
public int getNSplitter() 2^.qKY@g@  
{ ZN]LJ4|xu  
return nSplitter; {:m%n-  
} e6JT|>9A7  
n0*a.  
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public void setNSplitter(int nCount) Pk6l*+"r<  
{ B[Gl}(E  
nSplitter = nCount; lmjoSINy  
} @4%
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} 3+` <2TP  
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\  
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/* JDA:)[;  
**Utility.java p[Yja y+  
*/ Nt^9N #+N  
package NetFox; Y Cbt(nmr  
%/r}_V(UN  
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public class Utility { alB[/.1  
vsU1Lzna6@  
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public Utility() +>,4d  
{ _Uxt9 X  
FBCi,_ \4  
,b/qcu_|-  
} O^W.5SaR  
D3BNA]P\2@  
//线程睡眠 f6d:5 X_  
public static void sleep(int nSecond) n,+/%IZ  
{ 4?3*%_bDJ,  
try{ N-g=_86C"  
Thread.sleep(nSecond); $%ts#56*  
} I8RPW:B;B  
catch(Exception e) .2V`sg.!  
{ !qjIhZi  
e.printStackTrace (); M],}.l  
} >,V~-Tp  
} | ]DJz  
^3B&E^R  
//日志
1dgy-$H~  
public static void log(String sMsg) 6zfi\(fop  
{ t"]+}
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System.err.println(sMsg); t
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} _3lci  
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:"pA0oB  
public static void log(int sMsg) @},25"x)  
{ p[zKc2TPk  
System.err.println(sMsg); ?k*%r;e>  
}  3~mi  
} 9Un3La8PX  
86BY032H  
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/* j m]d:=4_  
**TestMethod.java )zR(e>VX  
*/ \UF/_'=K  
package NetFox; 2{sx"/k\A  
^=lh|C\#  
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public class TestMethod { R2 I 7d'|v  
yi*2^??` 1  
nX|f?5 O  
public TestMethod() U^n71m>]%T  
{ ///xx/weblogic60b2_win.exe XIAHUT5~J  
try{ _8f? H#&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H:d@@/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gC+PpY#2h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %rmn+L),;  
fileFetch.start(); \.`;p  
} Pr%Y
!|  
catch(Exception e){e.printStackTrace ();} m@z.H;  
YA:7^-Bv  
c8^M::NI  
} $@[`v0y*  
c89+}]mGq  
ds*N1[ *  
public static void main(String[] args) R.FC3<TTv  
{ }KBz8M5  
new TestMethod(); `}Of'i   
} QQnpy.`:/  
} ^Pq4 n%x  
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