http断点续传简单实现（java)

/* (]'4_
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**SiteFileFetch.java 1,BtOzuRo  
*/ QZ%_hvY[%>  
package NetFox; 5h1FvJg  
import java.io.*; o{m$b2BW  
import java.net.*; G`gYwgU;  

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public class SiteFileFetch extends Thread { SC"=M^E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Pqx=j_st  
long[] nStartPos; //开始位置 8%I4jL<  
long[] nEndPos; //结束位置 7S),:Uy[\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Wv$e/N`l  
long nFileLength; //文件长度 Aln\:1MU  
boolean bFirst = true; //是否第一次取文件 T3Qa[>+\  
boolean bStop = false; //停止标志 z_CBOJl#C!  
File tmpFile; //文件下载的临时信息 .
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DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b[VP"KZ?  
public SiteFileFetch(SiteInfoBean bean) throws IOException bZ:w_z[3=  
{ Q{V|{yV^y  
siteInfoBean = bean; ,]1K^UeZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qzsS"=5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jcv3ES^  
if(tmpFile.exists ()) ~{oM&I|d8  
{ ;g7nG{  
bFirst = false; :8jHN_u  
read_nPos(); zEpcJHI%  
} :W8DgL>l  
else Sh}AGNE'  
{ sf@g $  
nStartPos = new long[bean.getNSplitter()]; lRX*\M\`  
nEndPos = new long[bean.getNSplitter()]; UvxJ _  
} qP*$wKY,  
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} \P+lb-~\"  
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public void run() _hM3p  
{ +mYD DlvI  
//获得文件长度 rG}o!I
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//分割文件 zf4@:GM`  
//实例FileSplitterFetch &=xm>;`3  
//启动FileSplitterFetch线程 }`\+_@w  
//等待子线程返回 gNo.&G [  
try{ owJPEx  
if(bFirst) }I9\=jT  
{ O5LB&s  
nFileLength = getFileSize(); ie=tM'fb  
if(nFileLength == -1) (KK9/k  
{ 7P.C~,+D%P  
System.err.println("File Length is not known!"); jx+%X\zokA  
} $:t;WXc.<  
else if(nFileLength == -2) Tr-gdX ;  
{ )1Z*kY?f!  
System.err.println("File is not access!"); Z~9\7QJn  
} w-
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else %, XyhS5[o  
{ [x'xbQLGd  
for(int i=0;i<nStartPos.length;i++) vB#&XK.aW  
{ Ud\Jc:DG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WpWnwQY`#  
} \:'=ccf  
for(int i=0;i<nEndPos.length-1;i++) U;LbP-{B  
{ AJI,>I,}}  
nEndPos = nStartPos[i+1]; Wu,'S;>C  
} bH~ue5q  
nEndPos[nEndPos.length-1] = nFileLength; qR--lvO  
} 7fgA)dU:K  
} BOoLs(p  
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//启动子线程 MrXhVZ"d*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )?:V5UO\  
for(int i=0;i<nStartPos.length;i++) 7eqax33f  
{ +q|2j>k@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W52AX.Nm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mh2t ' O  
nStartPos,nEndPos,i); ?*tb|AL(R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u0Fu_Rtr  
fileSplitterFetch.start(); ?A3pXa  
} eZ(<hE>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ? !MDg_oHd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \8'fy\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e #>wv]V  
nEndPos = " + nFileLength); 6NVf&;laQ  
// fileSplitterFetch[nPos.length-1].start(); {*r*+}@  
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//等待子线程结束 H$9--p  
//int count = 0; NU-({dGK}  
//是否结束while循环 ik=~`3Zp0  
boolean breakWhile = false; S ])Ap'E  
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while(!bStop) L6fc_Mo.EE  
{ ~ou*' w@  
write_nPos(); kQxY"HD  
Utility.sleep(500); !i&^H,  
breakWhile = true; sZ/~pk  
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for(int i=0;i<nStartPos.length;i++) 4=9To|U*  
{ F0t!k>  
if(!fileSplitterFetch.bDownOver) !?`5r)K  
{  yS_,lS  
breakWhile = false; cE '`W7&A  
break; Y4sf
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}  (f,D$mX  
} 0Y,_ DU  
if(breakWhile) 7?:7}xb-  
break; iov55jT~l@  
rZ
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//count++; 0(iTnzx0  
//if(count>4) ,Drd s"H  
// siteStop(); )cNG)F  
} N|EH`eu^i  
"gADHt=MIR  
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System.err.println("文件下载结束！"); _
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} C\Qor3];  
catch(Exception e){e.printStackTrace ();} AB'q!7NR  
} >wS52ng  
~@S5*(&8  
y TfAS.  
//获得文件长度 "45O!AjP  
public long getFileSize() gQ%'2m+  
{ I2hX;pk,  
int nFileLength = -1; "Sz pFw  
try{ ()6)|A<^U  
URL url = new URL(siteInfoBean.getSSiteURL()); D^W6Cq5\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !([Q1r{u  
httpConnection.setRequestProperty("User-Agent","NetFox"); br*L|s\P\9  
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int responseCode=httpConnection.getResponseCode(); oM/(&"  
if(responseCode>=400) #"&h'V  
{ 8;mn7XX  
processErrorCode(responseCode); Fy3&Emu  
return -2; //-2 represent access is error /Y_F"
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} L']EYK5  
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String sHeader; $=uyZTYF)}  
}A3(g$8KR  
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for(int i=1;;i++) +/y 3]}  
{ #80DM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D_ybgX?0:  
//Utility.log(in.readLine()); r+-KrO'  
sHeader=httpConnection.getHeaderFieldKey(i); xWWfts1t  
if(sHeader!=null) -K hXb  
{ h~)oiT2v  
if(sHeader.equals("Content-Length")) 4vq,W_n.hQ  
{ xwhH_[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w'oP{=y[  
break; 1H`T=:
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} 6*u#^">,<  
} ^UHt1[  
else
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break; Wly-z$\  
} mO;X>~K  
} %wn|H>  
catch(IOException e){e.printStackTrace ();} v_?0|Ei[  
catch(Exception e){e.printStackTrace ();} TkXD#%nFY  
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Utility.log(nFileLength); 0{#c  
"
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return nFileLength; Oaf!\z}  
} ]S4TX  
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//保存下载信息（文件指针位置） [ R1S+i  
private void write_nPos() -fIX6  
{ *jM~VTXw
t  
try{ z6 2gF|Uj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yb*P&si5bY  
output.writeInt(nStartPos.length); ?3~]H 
 
for(int i=0;i<nStartPos.length;i++) Mk9'  
{ pt.0%3  
// output.writeLong(nPos); 8gwJ%"-K  
output.writeLong(fileSplitterFetch.nStartPos); 5 fY\0  
output.writeLong(fileSplitterFetch.nEndPos); ,6:ya8vB  
} n=!]!'h\:  
output.close(); V1 T?T9m  
} E:/G!1  
catch(IOException e){e.printStackTrace ();} ]vj=M-:+  
catch(Exception e){e.printStackTrace ();}  F* "  
} 6KC.l}Y*  
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//读取保存的下载信息（文件指针位置） HTiqErD2_  
private void read_nPos() rlTCVmE8[  
{ 1Y!"
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try{ m|
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &m2FEQLj  
int nCount = input.readInt(); }mQ7N&cC  
nStartPos = new long[nCount]; P6V_cw$  
nEndPos = new long[nCount]; 8wz%e(  
for(int i=0;i<nStartPos.length;i++) |fnP@k  
{ >ly`1t1  
nStartPos = input.readLong(); M&o@~z0  
nEndPos = input.readLong(); a
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} MUsF/1  
input.close(); ka? |_(  
} d7s? c  
catch(IOException e){e.printStackTrace ();} WtOpxAq  
catch(Exception e){e.printStackTrace ();}
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} dYV'<  
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private void processErrorCode(int nErrorCode) t"Ok-!c|  
{ `_Iy8rv:P  
System.err.println("Error Code : " + nErrorCode); 'X&sH/>r  
} ov&4&v  
cr
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o&}!bq]  
//停止文件下载 q8%T)$!  
public void siteStop() )HbsUm#  
{ $/^DY&  
bStop = true; ~?i;~S  
for(int i=0;i<nStartPos.length;i++) Si#I^aF`%  
fileSplitterFetch.splitterStop(); KPO?eeT.WZ  
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} R&}"En`$s  
} A*#.7Np!"  
//负责部分文件的抓取 1sp>UBG  
**FileSplitterFetch.java 6vp\~J  
*/ G?$|aQ0j  
package NetFox; "]h4L  
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import java.io.*; [r,a0s  
import java.net.*; *y +T(73  
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public class FileSplitterFetch extends Thread { [iVCorU  
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String sURL; //File URL xL8r'gV@  
long nStartPos; //File Snippet Start Position 6[fpe  
long nEndPos; //File Snippet End Position xG:eS:iT  
int nThreadID; //Thread's ID  eX7dyM  
boolean bDownOver = false; //Downing is over ~/Gx~P]  
boolean bStop = false; //Stop identical /Y$UJt  
FileAccessI fileAccessI = null; //File Access interface eF+:w:\h  
A;~lG3j4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GPBp.$q+B  
{ QHOA__?  
this.sURL = sURL; S9/oBxGN  
this.nStartPos = nStart; ~\_aT2j0  
this.nEndPos = nEnd; cojtQD
6  
nThreadID = id; 7PQ03dtfg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9gP-//L@  
} 4CA(` _i~  
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public void run() -6lsR  
{ sb"z=4  
while(nStartPos < nEndPos && !bStop) '<! b}1w0  
{ uYjE)"  
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try{ X"_,#3Ko!  
URL url = new URL(sURL); gc``z9@Xg
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `o~dQb/k+  
httpConnection.setRequestProperty("User-Agent","NetFox"); iSDE6  
String sProperty = "bytes="+nStartPos+"-"; *Ju$A  
httpConnection.setRequestProperty("RANGE",sProperty); K.3)m]dCl  
Utility.log(sProperty); WJH-~,u  
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InputStream input = httpConnection.getInputStream(); )I7~<$w  
//logResponseHead(httpConnection); 4C@ .X[r  
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byte[] b = new byte[1024]; MmUtBT  
int nRead; 05= $Dnv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /{Ff)<Q.Z  
{ :)f/>-   
nStartPos += fileAccessI.write(b,0,nRead); 8!8 yA  
//if(nThreadID == 1) *sNZ.Y:.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yB][ 3?lv  
} 1Rrp#E}
 
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Utility.log("Thread " + nThreadID + " is over!"); >6fc`3*!  
bDownOver = true; 'a]4]d  
//nPos = fileAccessI.write (b,0,nRead); f#4,2Xf  
} M"cB6{st[  
catch(Exception e){e.printStackTrace ();} JjBG9Rp{  
} QwF\s13  
} 5f5bhBZ<  
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+?"N5%a%F  
//打印回应的头信息 .Up\ 0|b  
public void logResponseHead(HttpURLConnection con) u,h,;'J  
{ Ns?qLSN  
for(int i=1;;i++) Xvy3D@o  
{ pkWJb!  
String header=con.getHeaderFieldKey(i); l!r2[T]I@7  
if(header!=null) 5:3%RTLG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SvR:tyF  
Utility.log(header+" : "+con.getHeaderField(header)); 3FWl_d~uD  
else sEBZ-qql  
break; /u hA\m(  
} uu08q<B5b)  
} TL^af
-  
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public void splitterStop() S b0p?  
{ ,'=Tf=wq  
bStop = true; #<_gY  
} sK1YmB :~a  
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} D,cGW,2Nv  
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Af*e:}}  
/* rByC6HV"  
**FileAccess.java -e#~CE
-  
*//文件访问(定位，写) pwj?  
package NetFox; w5j6RQml  
import java.io.*; #&Xr2?E@  
Y&vn`#   
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public class FileAccessI implements Serializable{ 2'R;z<_  
?-'m#5i"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <i~O0f]  
RandomAccessFile oSavedFile; OnD!*jy  
long nPos; (_:k s  
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public FileAccessI() throws IOException %BdQ.\4DS  
{ DV={bcQ  
this("",0); Eqx2.S  
} n-HQk7=mQ  
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public FileAccessI(String sName,long nPos) throws IOException I``S%`h  
{ YH_m
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oSavedFile = new RandomAccessFile(sName,"rw"); |r5e#3w  
this.nPos = nPos; kNC.^8ryz[  
oSavedFile.seek(nPos); {VBn@^'s  
} ,`4chD  
F0yvV6;  
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public synchronized int write(byte[] b,int nStart,int nLen) ,tt .oF|  
{ r>!$eqX_  
int n = -1; _G$SA-W(  
try{ pN\YAc*@:  
oSavedFile.write(b,nStart,nLen); hLs<g!*O  
n = nLen; x2q6y  
} 9\yGv  
catch(IOException e) "c0I2wq  
{ Uavr>-  
e.printStackTrace (); yH\3*#+  
} 'VgdQp$L$  
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return n; uL\b*rI  
} [#+yL  
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} =rw60B  
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|2i=oX(r|  
/* wiwAdYEQ\  
**SiteInfoBean.java dC&OjBQ  
*/ qh|t}#DrR  
package NetFox; 6Kl%|VrJs  
\a_75^2  
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public class SiteInfoBean { x.5!F2$  
LB(I^  
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private String sSiteURL; //Site's URL M
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private String sFilePath; //Saved File's Path >9WJa5{  
private String sFileName; //Saved File's Name UN FQ`L  
private int nSplitter; //Count of Splited Downloading File Q9i&]V[`  
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public SiteInfoBean() L|?$F*bs  
{//nSplitter的缺省值为5 I_/E0qSJI  
//default value of nSplitter is 5 Yk;-]qi7  
this("","","",5); jOkc'  
} ,A$#gLyk<  
{7'Evfn)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~CtLSyB  
{ >)Udb//  
sSiteURL= sURL; 6KvoHo  
sFilePath = sPath; wjq;9%eXk  
sFileName = sName; Fjs:rZ#{  
this.nSplitter = nSpiltter; KF4D)NM|  
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} %9q]  
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public String getSSiteURL() 4
# L}
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{ d@0p<at>~  
return sSiteURL; L:.z FW,  
} Bf21u9  
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public void setSSiteURL(String value) %Tv2op  
{ Q[vQT?J7  
sSiteURL = value; bpr  
} vvTQ!Aa  
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!J6;F}Pd/  
public String getSFilePath() rexNsKRK_  
{ 483/ZgzT`  
return sFilePath; Nf]h8d~  
} $_ BoG  
~6Xr^An/Z  
V 6*ohC:  
public void setSFilePath(String value) >=6 j:  
{ h7P<3m}  
sFilePath = value; n@JZ2K4  
} s3/iG37K  
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public String getSFileName() f`gs/R  
{ qk{+Y  
return sFileName; @W1F4HYds  
} 2
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n9%&HDl4  
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public void setSFileName(String value) *QGyF`Go{  
{ HM]mOmL90N  
sFileName = value; RPB%6z$  
} t:O"t G  
.eHOG]H  
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public int getNSplitter() lEYAq'=  
{ L25v7U  
return nSplitter; {@&%Bq*&  
} ~Z>!SMXp<  
6Mj
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Z1y=L$t8  
public void setNSplitter(int nCount) Mb^E  
{ ,J4rKGG  
nSplitter = nCount; W\pO`FL  
} WAUgbImc{  
} Xl %ax!/  
)ppIO"\  
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/* PB(q9gf"1}  
**Utility.java BY5ODc$  
*/ {8pN]=SaJ~  
package NetFox; cuoZ:
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public class Utility { KNG7$icG  
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public Utility() Fl}{"eCF8  
{ :V
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} V^%P}RFMc  
9SQcChG~j  
//线程睡眠 5Ly
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public static void sleep(int nSecond) f 0r?cZ  
{ xO{$6M3-~  
try{ HZ[
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Thread.sleep(nSecond); sW&5Mu-  
} x(+H1D\W  
catch(Exception e) >e^^YR^  
{ e|d~&Bk0  
e.printStackTrace ();  =$-+~  
} e X{#FgFc  
} 2_GbK-  
WNS
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//日志 gVI{eoJ  
public static void log(String sMsg) Q*ixg$
>  
{ *TgD{>s  
System.err.println(sMsg); [ 0z-X7=e  
} )?;+<,  
[?55vYt  
)m$M
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public static void log(int sMsg) ;-^8lWt  
{ dCA! R"HD  
System.err.println(sMsg); X#k:J  
} 5ENEx  
} ~X<?&;6  
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d]K
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/* `t#9 yN  
**TestMethod.java 9UCA&n  
*/ %W^Zob  
package NetFox; uQYenCNXS  
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b

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public class TestMethod { ML.|\:r*  
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9~{,Hj1xE  
public TestMethod() oTg 'N  
{ ///xx/weblogic60b2_win.exe k] A(nr  
try{ ,Bs/.htQj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >o1,Y&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); abw5Gz@Ag  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T|-llhJ8  
fileFetch.start(); )fl+3!tq  
} P
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catch(Exception e){e.printStackTrace ();} }`y%*--  
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_9y!,ST  
} DMA`Jx  
7$mB.\|  
6x;!E&<  
public static void main(String[] args) [P`<y#J3F  
{ zvn3i5z  
new TestMethod(); l:~/%=  
} jAdZS\?w  
} ~;}uYJ  
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