http断点续传简单实现（java)

/* LIrebz  
**SiteFileFetch.java +&dkJ 4g[  
*/ h?H|)a<^9  
package NetFox; 1rS8+!9C  
import java.io.*; [k0/ZfFwV  
import java.net.*; vvu $8n  
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public class SiteFileFetch extends Thread { &E1m{gB(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~4|Trz2T  
long[] nStartPos; //开始位置 'c_K[p$  
long[] nEndPos; //结束位置 l|{[vZpT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nW} s  
long nFileLength; //文件长度 xQ2:tY#?  
boolean bFirst = true; //是否第一次取文件 a6Joa&`dv  
boolean bStop = false; //停止标志 )\j dF-s  
File tmpFile; //文件下载的临时信息 !!ma]pB,  
DataOutputStream output; //输出到文件的输出流 [9B1%W  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2% /Kf}+  
public SiteFileFetch(SiteInfoBean bean) throws IOException =6+99<G|%M  
{ +xgP&nw[-  
siteInfoBean = bean; 3Fxr=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E NCWOj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AWE ab  
if(tmpFile.exists ()) awI{%u_(nA  
{ CUHT5J*sY  
bFirst = false; bdY:-8!3  
read_nPos(); nt+OaXe5D  
} (,tu7u{  
else m=
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{ 3<xDxj0<  
nStartPos = new long[bean.getNSplitter()]; >x3lA0m  
nEndPos = new long[bean.getNSplitter()]; +jK-k_  
} IibYGF  
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} ]31=8+D  
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public void run() !nvg:$.&  
{ e(xuy'4r  
//获得文件长度 3kk^hvB+f  
//分割文件 FUlhEH  
//实例FileSplitterFetch Ibu9AwPm  
//启动FileSplitterFetch线程 {~uTi>U  
//等待子线程返回 d=n{Wn{C  
try{ b$%Kv
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if(bFirst) M0~%[nX  
{ !_QT{H  
nFileLength = getFileSize(); F>3 o0ke}  
if(nFileLength == -1) k& +gkJm  
{ E1tCY.N{  
System.err.println("File Length is not known!"); dq`{fqGl  
} k].swvIi  
else if(nFileLength == -2) D7T|K :F)  
{ E>f
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System.err.println("File is not access!"); *coUHbP9>  
} AWYlhH4c?t  
else >;'0ymG.`  
{ P"l'? `  
for(int i=0;i<nStartPos.length;i++) Je6w
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{ i>]PW|]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `}KxzD  
} w/(c}%v}=  
for(int i=0;i<nEndPos.length-1;i++) )dqNN tS  
{ fK+ 5  
nEndPos = nStartPos[i+1]; >X eXd{$  
} -egnMc67  
nEndPos[nEndPos.length-1] = nFileLength; DyCzRkH
  
} R y#
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} ,z>-_HOnw  
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//启动子线程 k&%i+5X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IQ~qiFCf  
for(int i=0;i<nStartPos.length;i++) 9#@s(s  
{ Ie!&FQe2q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `=P_ed%&'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Mmu#hb|W  
nStartPos,nEndPos,i); FZ?eX`,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BZHoRd{EH  
fileSplitterFetch.start(); ]W1
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} i9XpP(mf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q,^/Lm|]k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kx?Yin8K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MO0NNVVi%U  
nEndPos = " + nFileLength); `D |/g;  
// fileSplitterFetch[nPos.length-1].start(); 77yYdil^W+  
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//等待子线程结束 nEd "~  
//int count = 0; R"V90bCf  
//是否结束while循环 G^
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boolean breakWhile = false; ?z#*eoPr  
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while(!bStop) l^nvwm`f#:  
{ mV`R'*1UC  
write_nPos(); H~nX!sO  
Utility.sleep(500); uJ -$i  
breakWhile = true; ?%UiW7}j';  
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for(int i=0;i<nStartPos.length;i++)
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{ 4S~kNp$  
if(!fileSplitterFetch.bDownOver) A1-,b.Ni  
{ Y;_F,4H  
breakWhile = false; P.@dB.Ny  
break; @4T
  
} ?x&}ammid  
} ,++HiYOG}e  
if(breakWhile) 8R!-,I"$  
break; 0VtjVz*C7&  
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//count++; *>:phs~r{  
//if(count>4) 8Iw)]}T'  
// siteStop(); GZu12\0nZ  
} |<h}'  
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System.err.println("文件下载结束！"); 452kE@=49  
} LdG?kbJ&y  
catch(Exception e){e.printStackTrace ();} \WFcb\..  
} [YULvWAJ  
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//获得文件长度 1g{}O^ul  
public long getFileSize() SA}Dkt&,  
{ = NZgbl  
int nFileLength = -1; */aQ+%>jf  
try{ $&Vba@v  
URL url = new URL(siteInfoBean.getSSiteURL()); 6[k<&;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TS9<uRO0  
httpConnection.setRequestProperty("User-Agent","NetFox"); (LmU\Pe%  
9;p5z[jI  
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int responseCode=httpConnection.getResponseCode(); /\-}-"dm  
if(responseCode>=400) zgEN2d  
{ 0a{hCx|$J  
processErrorCode(responseCode); 2I_ yUt-  
return -2; //-2 represent access is error 'hU5]}=  
} )~=8Ssu  
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String sHeader; <hCO-r#  
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for(int i=1;;i++) ?8H{AuLB  
{ |{kbc0*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lr~ |=}^  
//Utility.log(in.readLine()); ial{A6X  
sHeader=httpConnection.getHeaderFieldKey(i); 4x[_lsj  
if(sHeader!=null) rIcgf1v70  
{ 
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if(sHeader.equals("Content-Length")) ~:7y!=8#  
{ A)"L+Yu5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0l[52eZ/  
break; dV38-IfGkl  
} OS@uGp=  
} s2S
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else y4h
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break; $rcv@-l  
} "ymR8y'  
} 5s3QN{h8  
catch(IOException e){e.printStackTrace ();} 4%~*}  
catch(Exception e){e.printStackTrace ();} >4luZnWMI  
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Utility.log(nFileLength); -fFtHw:kHh  
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return nFileLength; JH]S'5X8K  
} 07:V[@'  
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//保存下载信息（文件指针位置） WyatHC  
private void write_nPos() E8
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{ N Nk  
try{ G4SA u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G7"(,L` 5  
output.writeInt(nStartPos.length); stajTN*J  
for(int i=0;i<nStartPos.length;i++) N? Jy  
{ 8+|W%}  
// output.writeLong(nPos); s,#We} bv  
output.writeLong(fileSplitterFetch.nStartPos); 9zqo!&  
output.writeLong(fileSplitterFetch.nEndPos); n46!H0mJ  
} H~s8M  
output.close(); <L4$f(2  
} IxuK<Oe:O  
catch(IOException e){e.printStackTrace ();} rIFW1`N}i  
catch(Exception e){e.printStackTrace ();} o!+%|V8Y  
} b-VtQ%Q  
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//读取保存的下载信息（文件指针位置） 2YZ>nqy  
private void read_nPos() |D-[M_T5  
{ RR[zvH} E  
try{ )TiM>{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T}^3Re`i  
int nCount = input.readInt(); ]$L5}pE3  
nStartPos = new long[nCount]; :5CyR3P  
nEndPos = new long[nCount]; o-H?q!  
for(int i=0;i<nStartPos.length;i++) I m I$~q'  
{ q{9 \hEeb  
nStartPos = input.readLong(); I?PqWG!O  
nEndPos = input.readLong(); EB!ne)X  
} nX3?7"v  
input.close(); e,}h^^"  
} `OMX
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catch(IOException e){e.printStackTrace ();} b;jdk w|  
catch(Exception e){e.printStackTrace ();} =AzPAN#e  
} 3A`]Rk   
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private void processErrorCode(int nErrorCode) a-|pSe*rx  
{ rz_W]/G-P  
System.err.println("Error Code : " + nErrorCode); *t| !xO  
} gC2}?nq*  
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8Y`g$2SZ^8  
//停止文件下载 .kU^)H"l  
public void siteStop() ~|S0E:*.  
{ (CIcM3|9C  
bStop = true; G-)e(u   
for(int i=0;i<nStartPos.length;i++) K0( S%v|,}  
fileSplitterFetch.splitterStop(); _-({MX[3k<  
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} Ed u(dZbKg  
} %k4Qx5`?d  
//负责部分文件的抓取 sPZwA0%  
**FileSplitterFetch.java hJ ^+asr  
*/ b]z_2h~`  
package NetFox; >D!R)W`  
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import java.io.*; 50Gr\  
import java.net.*; '(B -{}l  
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public class FileSplitterFetch extends Thread { +^(_S9CO  
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String sURL; //File URL 9#U]?^DJ@  
long nStartPos; //File Snippet Start Position FhUi{`  
long nEndPos; //File Snippet End Position (K=0c6M3=  
int nThreadID; //Thread's ID ?SgFD4<~P  
boolean bDownOver = false; //Downing is over aXj UDu7  
boolean bStop = false; //Stop identical #d$zW4ur2  
FileAccessI fileAccessI = null; //File Access interface Ty
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ben-<3r  
{ |OCiq|#  
this.sURL = sURL; <e BmCrJ  
this.nStartPos = nStart; {7m2vv?Z  
this.nEndPos = nEnd; &2u |7U.  
nThreadID = id; 
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 69r%b7#  
} =5Db^  
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public void run() UAXp;W`  
{ *B!Ox}CI.L  
while(nStartPos < nEndPos && !bStop) w>f.@luO4  
{ 0=HB!{@  
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try{ 8[J%TWq%9  
URL url = new URL(sURL); ]dGH i \  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `Z,WKus  
httpConnection.setRequestProperty("User-Agent","NetFox"); ek<B=F  
String sProperty = "bytes="+nStartPos+"-"; (Z$7;OAI  
httpConnection.setRequestProperty("RANGE",sProperty); ]2f-oz*hU  
Utility.log(sProperty); H6`k%O*  
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InputStream input = httpConnection.getInputStream(); @>46.V{P}B  
//logResponseHead(httpConnection); 6w &<j&V  
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byte[] b = new byte[1024]; MV$E_@pg  
int nRead; ,H6P%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
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{ @Ik5BT  
nStartPos += fileAccessI.write(b,0,nRead); o`Z3}  
//if(nThreadID == 1) aMe&4Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IQ\!wWKmY  
} &_Cc  
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Utility.log("Thread " + nThreadID + " is over!"); 'Iw`+=iVz  
bDownOver = true; p]S'pzh  
//nPos = fileAccessI.write (b,0,nRead); A<c<!N  
} ktqFgU#rT  
catch(Exception e){e.printStackTrace ();} JmCHwyUK?  
} &cyB}Gv  
} d>F7i~W  
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//打印回应的头信息 zu?112-v2  
public void logResponseHead(HttpURLConnection con) -x6_HibbD  
{ LI}e_=E  
for(int i=1;;i++) )2y [#Blo  
{ !
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String header=con.getHeaderFieldKey(i); NqF*hat  
if(header!=null) U3Gg:onuE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [\Wl~ a l  
Utility.log(header+" : "+con.getHeaderField(header)); moFrNcso  
else Jk}3c>^D  
break; cG0)F%?X?  
} ^NU_Tp:2^  
} \,NT5>  
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public void splitterStop() gHp4q!SJ7  
{ yx?oxDJg  
bStop = true; 
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} R-pON4D"*  
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} zZ-/S~l  
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/* }!fIY7gv  
**FileAccess.java Oi|cTZ@A-  
*//文件访问(定位，写) 5w>TCx  
package NetFox; h
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import java.io.*; AUF[hzA  
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public class FileAccessI implements Serializable{ DmgDhNXKq  
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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 $Xo_8SX,  
RandomAccessFile oSavedFile; FP{=b/  
long nPos; MbYgGE,LA  
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public FileAccessI() throws IOException + rB3\R"d  
{ p Cx_[#DrP  
this("",0); EK>x\]O%T  
} >N! Xey  
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public FileAccessI(String sName,long nPos) throws IOException FB?V<x  
{ uh9b!8  
oSavedFile = new RandomAccessFile(sName,"rw"); V 7~9z\lW  
this.nPos = nPos; y /8iEs  
oSavedFile.seek(nPos); NlhC7  
} D3g5#.$,}>  
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public synchronized int write(byte[] b,int nStart,int nLen) Da! fwth  
{ p79QEIbk=  
int n = -1; (@T{
[\  
try{ 5R.jhYAj  
oSavedFile.write(b,nStart,nLen); #%GBopv  
n = nLen; kQ\l7xd  
} yAGQD[ih  
catch(IOException e) =?Co<972Z  
{ Q!-"5PX  
e.printStackTrace (); yWc%z6dXC  
} Pt-mLINvG  
}<
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return n; 4Z{R36 {  
} b[&ri
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} A Ef@o+A  
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/* n~>b}DY  
**SiteInfoBean.java -H\j-k  
*/ 9nO&d(r g  
package NetFox; ^|U5
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public class SiteInfoBean { hn6'
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private String sSiteURL; //Site's URL 9-A@2&J1  
private String sFilePath; //Saved File's Path /HqD4GDoug  
private String sFileName; //Saved File's Name .d#Hh&jj  
private int nSplitter; //Count of Splited Downloading File 92,@tNQQ}  
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public SiteInfoBean() ~h+B&F+5  
{//nSplitter的缺省值为5 =fy.'+  
//default value of nSplitter is 5 ]t17= Lr?  
this("","","",5); 1G(wESe  
} 2,|@a\H  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5M8   
{ /f. ,xs!  
sSiteURL= sURL; f~jdN~  
sFilePath = sPath; )=N.z6?  
sFileName = sName; h_Er$ZT64  
this.nSplitter = nSpiltter; >9g^-~X;v  
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} Ra~:O\Z  
/3"S_KE1@+  
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public String getSSiteURL() M-!#-l  
{ Z +<Y.*6  
return sSiteURL; FNl^ lj`Y  
} ,:8
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public void setSSiteURL(String value) LM.#~7jC  
{ jNIz:_c-~  
sSiteURL = value; !P6y_Frpe  
} ri9n.-xs  
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public String getSFilePath() ov>`MCS,v  
{ zlh\P`  
return sFilePath; a ?wg~|g  
} jd+HIR  
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public void setSFilePath(String value) KA`)dMWL  
{ wp/x|AV  
sFilePath = value; P}PMRAek  
} )fT0FLl|1  
"bjbJC&T  
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public String getSFileName() P_@ty~u  
{ +A_jm!tJS(  
return sFileName; 1@<>GDB9  
} B7'2@+(  
/hyCR___  
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public void setSFileName(String value) URTJA<r8D  
{ 61TL]S8  
sFileName = value; S7hfwu&7F  
} jm|zn  
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public int getNSplitter() k#@)gL  
{ %bnjK
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return nSplitter; ;u%4K$   
} 3'`X_C|d53  
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public void setNSplitter(int nCount) klj.\wg/p{  
{ Au?(_*/0  
nSplitter = nCount; ewinG-hX_  
} t2%gS" [  
} #+3
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/* }% ?WS  
**Utility.java 9**u\H)P6  
*/ D_cd l^  
package NetFox; OoAZ t  
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public class Utility { 1]jUiX=T  
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public Utility()  M Xl!  
{ ]jJ4\O`  
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} o Bp.|8-  
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//线程睡眠 i>rsq[l  
public static void sleep(int nSecond) ; >>/}Jw\  
{ P,Rqv)}X  
try{ mZ t:  
Thread.sleep(nSecond); KT
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} a<V* )  
catch(Exception e) V-9z{  
{ 3_k3U  
e.printStackTrace (); N_8L8ds5  
} [$GQ]Y  
} 2$QuR~  
t!vlZNc  
//日志 o)6udRzBv  
public static void log(String sMsg) 8"S? Toqq  
{ ;%aWA  
System.err.println(sMsg); ol8uV{:"  
} 6NqLo^ "g  
GUK3`}!%  
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public static void log(int sMsg) S{ !m})1?  
{ &28n1  
System.err.println(sMsg); Sst`*PX:  
} 3H
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} [
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\8X8NCM  
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/* 1]XIF?_Dm  
**TestMethod.java j2|!h%{nI  
*/ lf9_!`DGV  
package NetFox; *C?x\.\C  
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public class TestMethod {  =!Y{Mz  
/%GMbO_  
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public TestMethod() _.Bite^  
{ ///xx/weblogic60b2_win.exe 4
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try{ C(*)7| m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A,s .<TG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tlFc+3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dQL! >6a  
fileFetch.start(); S$I:rbc  
} ETVT.R8  
catch(Exception e){e.printStackTrace ();} >taZ
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} W(tXq  
aw:0R=S,>  
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public static void main(String[] args) p
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{  goT:\2  
new TestMethod(); JZ=a3)x"  
} H{T)?J~  
} dfq5P!'  
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