http断点续传简单实现（java)

/* :<G+)hIK  
**SiteFileFetch.java wA+4:CF@  
*/ -PuVI5L<  
package NetFox; "tbBbEj?d  
import java.io.*; ?O]gFn  
import java.net.*; Z?[J_[ZtR3  
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public class SiteFileFetch extends Thread { "[Lp-4A\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *J-jr8&  
long[] nStartPos; //开始位置 q"vT]=Y}:  
long[] nEndPos; //结束位置 @y%qQe/g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {_D'\i(Y_  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 hRiGW_t  
boolean bStop = false; //停止标志 g4932_tC  
File tmpFile; //文件下载的临时信息 :~(^b;yhZ  
DataOutputStream output; //输出到文件的输出流 V3nv5/6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XX+rf  
public SiteFileFetch(SiteInfoBean bean) throws IOException +DDvM;31w  
{ 2^j9m}`  
siteInfoBean = bean; !SNtJi$;v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kn]WXc|("  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /FXfu  
if(tmpFile.exists ()) cE#Y,-f  
{ Lf<9GYNy>`  
bFirst = false; Z ISd0hV  
read_nPos(); aesFv)5DK  
} ~nlY8B(  
else |1x,_uyQ%  
{ "R]K!GUU  
nStartPos = new long[bean.getNSplitter()];  vpMv  
nEndPos = new long[bean.getNSplitter()]; ^u<+tV   
} Mqy`j9FbL  
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} <>GyG-q  
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public void run() MS)bhZ
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{ W>49,A,q  
//获得文件长度 Lr&tpB<  
//分割文件 'LI)6;Yc  
//实例FileSplitterFetch wm4e:&  
//启动FileSplitterFetch线程 K!mgh7Dx  
//等待子线程返回 cPYQ<Y=  
try{ q fe#kF9  
if(bFirst) t$2{U  
{ +cN2 KP  
nFileLength = getFileSize(); `z.#O\@o  
if(nFileLength == -1) |szfup~5es  
{ '`"&RuB  
System.err.println("File Length is not known!"); )}v2Z3:  
} .?TVBbc%5  
else if(nFileLength == -2) !{LwX
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{ `.XU|J*z,  
System.err.println("File is not access!"); ySZ)yT  
} 8'$n|<1X  
else 04TV./uA  
{
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for(int i=0;i<nStartPos.length;i++) `x3c},'@k  
{ $Re %+2c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .#}R$}e+  
} MaM7u:kD#  
for(int i=0;i<nEndPos.length-1;i++) Qp}<8/BM\  
{ :KwYuwYS  
nEndPos = nStartPos[i+1]; 5Ml}m  
} R<U<Y'Y  
nEndPos[nEndPos.length-1] = nFileLength; l0f6Lxfz  
} XR(kR{yo  
} h";sQ'u
s  
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//启动子线程 QQJcvaQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MG|NH0k  
for(int i=0;i<nStartPos.length;i++) v?rN;KY#pK  
{ $= g
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZZUCwczI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I`7[0jA~  
nStartPos,nEndPos,i); *
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9j/B3CjW  
fileSplitterFetch.start(); rQF%;  
} Ru/3>n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a"EXR-+8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JkTL+obu  
nEndPos = " + nFileLength); TSeAC[%pL  
// fileSplitterFetch[nPos.length-1].start(); 3JwmLGj}  
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//等待子线程结束 +-ue={'  
//int count = 0; LYT0 XB)A  
//是否结束while循环 aX!J0
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boolean breakWhile = false; $%/Zm*H  
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while(!bStop) RSy1 wp4W  
{ Z|u_DaSrr|  
write_nPos(); ?U&o
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Utility.sleep(500); 3=z'Ih`  
breakWhile = true; 9,4a?.*4~  
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for(int i=0;i<nStartPos.length;i++) ,ua]h8  
{ H&I0\upd  
if(!fileSplitterFetch.bDownOver) I3$v-OiL  
{ ZC05^  
breakWhile = false; :wMZ&xERDZ  
break; ,^/;!ErR$  
} xi^_C!*J  
} K}6}Opr,Tt  
if(breakWhile) zZkwfF  
break; tP`,Egf"g  
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//count++; *M&~R(TMn  
//if(count>4) ?(F~9V  
// siteStop(); h.PY$W<  
} ${e{#  
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System.err.println("文件下载结束！"); {2-w<t  
} V;.=O}Lr  
catch(Exception e){e.printStackTrace ();} vAX %i(4  
} 7z`)1^M  

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//获得文件长度 ~Xa >;  
public long getFileSize() :0r@o:H  
{ i9$ -lk  
int nFileLength = -1; lBl`R|Gt  
try{ RxcX\:  
URL url = new URL(siteInfoBean.getSSiteURL()); k |M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tM
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httpConnection.setRequestProperty("User-Agent","NetFox"); )%P!<|s:5  
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int responseCode=httpConnection.getResponseCode(); zGA#7W2?0  
if(responseCode>=400) (FP- K  
{ S9-FKjU  
processErrorCode(responseCode); z" 4$mh  
return -2; //-2 represent access is error PU[] Nw  
} y3kXfSe  
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String sHeader; ?$%#y u#.  
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for(int i=1;;i++) fn;`Vit#  
{ \\xoOA.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [Q6PFdQ_JT  
//Utility.log(in.readLine()); d=yuuS/  
sHeader=httpConnection.getHeaderFieldKey(i); AKu]c-  
if(sHeader!=null) l*^c?lp)  
{ /c6:B5G  
if(sHeader.equals("Content-Length")) w`x4i fZ0q  
{ M*$#j|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J4"?D9T3G  
break; v*U OD'tk  
}  ]?M3X_Mq  
} bW-9YXj%  
else c>mTd{Abi  
break; lp+Uox  
} t}w<xe  
} NU"Ld+gw  
catch(IOException e){e.printStackTrace ();} 5bBY[qp  
catch(Exception e){e.printStackTrace ();} Wa.y7S0(@  
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6 b-'Hui+  
Utility.log(nFileLength); 3qggdi  
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return nFileLength; >>%m,F[  
} @|N{EI  
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//保存下载信息（文件指针位置） #:[^T,YD0  
private void write_nPos()  2:GS(%~  
{ >=O5=\`  
try{ p.)IdbC`B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e>J.r("f  
output.writeInt(nStartPos.length); `"Lk@  
for(int i=0;i<nStartPos.length;i++) U'*~Ju  
{ r?7tI0  
// output.writeLong(nPos); mM(Z8PA9-  
output.writeLong(fileSplitterFetch.nStartPos); a1#",%{I  
output.writeLong(fileSplitterFetch.nEndPos); 6 H{G$[2  
} }-/oL+j  
output.close(); ,)?!p_*@:  
} d RIuA)0s  
catch(IOException e){e.printStackTrace ();} dj-/%MU  
catch(Exception e){e.printStackTrace ();} Q{=DLm`  
} ({$>o]<h  
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//读取保存的下载信息（文件指针位置） .VXadgM  
private void read_nPos() s+0n0C  
{ aE(DNeG-H  
try{ U2G[uDa;
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '+&!;Jj,  
int nCount = input.readInt(); .C|dGE?,  
nStartPos = new long[nCount]; ?+_Y!*J2b  
nEndPos = new long[nCount]; GahIR9_2  
for(int i=0;i<nStartPos.length;i++) k5gvo  
{ VPvQ]}g6k  
nStartPos = input.readLong(); HC!5AJ&+}v  
nEndPos = input.readLong(); W#9A6ir>  
} blx"WVqo  
input.close(); AGhr(\j  
} sq
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catch(IOException e){e.printStackTrace ();} 7hlzuZob+y  
catch(Exception e){e.printStackTrace ();} [hJASX9  
} OE/r0C<&  
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private void processErrorCode(int nErrorCode) |
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{ 8}aS
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System.err.println("Error Code : " + nErrorCode); O:j=L{,d^  
} *#.Ku(C+  
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//停止文件下载 RDxvN:v  
public void siteStop() C]a iu  
{ ;"2(e7ir  
bStop = true; \SooIEl@  
for(int i=0;i<nStartPos.length;i++) byHXRA)39  
fileSplitterFetch.splitterStop(); 'tDV
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} +{\b&q_  
} _^h?JTU^  
//负责部分文件的抓取 &UQP9wS4v  
**FileSplitterFetch.java :M$8<03>F  
*/ #]2,1dJ  
package NetFox; .-:@+=(  
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import java.io.*; ;F:Qz^=.a  
import java.net.*; 7Ga'FT.F  
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public class FileSplitterFetch extends Thread { ,#.9^J  
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String sURL; //File URL s;,ulME  
long nStartPos; //File Snippet Start Position C
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long nEndPos; //File Snippet End Position g7r0U6Y  
int nThreadID; //Thread's ID ^}4ysw  
boolean bDownOver = false; //Downing is over 72sBx3 ;  
boolean bStop = false; //Stop identical 9R N ge;*  
FileAccessI fileAccessI = null; //File Access interface J';XAB }  
&!?qSi~V  
6AKT-r.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GE#LcCa  
{ -O6\!Wo=-  
this.sURL = sURL; eB5<N
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this.nStartPos = nStart; T2}ccnDi  
this.nEndPos = nEnd; 3&
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nThreadID = id; W C3b_ia  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S^  JUQx7  
} *Edr\P
 
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public void run() :s
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{ l`vr({A  
while(nStartPos < nEndPos && !bStop) &$.x1$%  
{ l]mn4cn3  
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try{ &:Sb$+z  
URL url = new URL(sURL); \?NT,t=3J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &>z}u&oF
 
httpConnection.setRequestProperty("User-Agent","NetFox"); 3bMUsyJ2  
String sProperty = "bytes="+nStartPos+"-"; Zq>}SR  
httpConnection.setRequestProperty("RANGE",sProperty); i ,g<y  
Utility.log(sProperty); R,ddH[3  
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InputStream input = httpConnection.getInputStream(); fn'N^  
//logResponseHead(httpConnection); ZUUfn~ORc  
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byte[] b = new byte[1024]; My\  
int nRead; `-)Fx<e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JulxFjC  
{ pd X"M>  
nStartPos += fileAccessI.write(b,0,nRead); LdYaJh~h  
//if(nThreadID == 1) N>_d {=P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^9I^A!w=  
} }lt]]094,  
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Utility.log("Thread " + nThreadID + " is over!"); <jRs/?1R  
bDownOver = true;  LYX\#  
//nPos = fileAccessI.write (b,0,nRead); h\^> s$  
} r.;(Kx/M  
catch(Exception e){e.printStackTrace ();} 1MzOHE
 
} #]5|Qhrr+  
} ;j/-
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//打印回应的头信息 T4{&@b 0*  
public void logResponseHead(HttpURLConnection con) $MG. I[h  
{ }qOC*k:  
for(int i=1;;i++) q3E_.{t  
{ 3fJwj}wL  
String header=con.getHeaderFieldKey(i); ^y"$k  
if(header!=null) c=p@l<)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q>q@ztt  
Utility.log(header+" : "+con.getHeaderField(header));  <XxFR  
else =pS\gLQu  
break; S Yvifgp  
} :B'}#;8_  
} RKP->@Gs  
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public void splitterStop() ;pNHT*>u,  
{ :
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bStop = true; 5!*5mtI  
} 5i$~1ZC  
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} 3EcmNwr
 
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/* #7U,kTj9  
**FileAccess.java '.@R_sj
  
*//文件访问(定位，写) 5b[:B~J  
package NetFox; 6Bp{FOj:Ss  
import java.io.*; OR^Wd  
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public class FileAccessI implements Serializable{ %1]2+_6  
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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 T}[W')[s  
RandomAccessFile oSavedFile; |b/J$.R  
long nPos; @X/S h:  
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public FileAccessI() throws IOException jl2nRo  
{ KX)xCR~  
this("",0); ]+':=&+:  
} C)z[Blt  
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public FileAccessI(String sName,long nPos) throws IOException =,[46 ;q  
{ "\BP+AF  
oSavedFile = new RandomAccessFile(sName,"rw"); :<&}/r  
this.nPos = nPos; _|TE )h  
oSavedFile.seek(nPos); MQY1he2M  
} Lx?bO`=qg7  
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public synchronized int write(byte[] b,int nStart,int nLen) .3|9 ~]  
{ ;*W]]4fy  
int n = -1; X_'.@q<!CV  
try{ ;$&-c/]F#  
oSavedFile.write(b,nStart,nLen); BQS9q'u_  
n = nLen; qqzQKN  
} EkSTN  
catch(IOException e) ;wQWt_OtuJ  
{ -'PpY302  
e.printStackTrace (); U-FA^c;  
} N0vd>b  
N^ D/}n  
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return n; U*&ZQw  
} dWqFP  
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} ^Nsl5  
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/* "ZyHt HAK  
**SiteInfoBean.java 9)l_(*F  
*/ AVyZ#`,  
package NetFox; ooZ-T>$  
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public class SiteInfoBean { Q?a"uei[  
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private String sSiteURL; //Site's URL 9wq%Fnt  
private String sFilePath; //Saved File's Path bf74 "  
private String sFileName; //Saved File's Name 4*+EUJ|  
private int nSplitter; //Count of Splited Downloading File Q"Ec7C5eM  
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I }/Oi]jA6  
public SiteInfoBean() _"sRL}-Z  
{//nSplitter的缺省值为5 i9xv`Ev=R  
//default value of nSplitter is 5 \W}EyA  
this("","","",5); m_(hCY=Q$  
} tH'VV-!MZ  
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+ kF[Oh#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KvD$`"L/CT  
{ q9 ;\B&  
sSiteURL= sURL; wi9|  
sFilePath = sPath; 'u3+k.  
sFileName = sName; $1?X%8V  
this.nSplitter = nSpiltter; !X8UP{J)L  
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} xI<dBg|]+  
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public String getSSiteURL() v$i%>tQ\  
{ od}x7RI%m  
return sSiteURL; O0{  
} YW{V4yW  
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public void setSSiteURL(String value) Yy)a,clZ*$  
{ +lT]s#Fif  
sSiteURL = value; S1zw'!O5  
} c_q+
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public String getSFilePath() z{g<y^Im+E  
{ GzXP  
return sFilePath; _;q-+"6L;  
} M0zD)@  
\z`d}\3(R  
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public void setSFilePath(String value) Kk98FI0]  
{ \r%Vgne-g  
sFilePath = value; W{+0iAYnp  
} 6h_k`z  
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public String getSFileName() T+nC>}*jgJ  
{ >ij4z N  
return sFileName; otVyuh  
} dO4#BDn"=  
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public void setSFileName(String value) ~9 WJrRWB  
{ _O;~ }N4u  
sFileName = value; gqD^Bs'VF  
} /eRtj:9M  
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!(_xu{(DL  
public int getNSplitter() "$IwQ  
{ =P;;&j3Z  
return nSplitter; -mHhB(Td'  
} '}`hY1v  
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public void setNSplitter(int nCount) sHTePEJ_h  
{ Eb[H3v48,  
nSplitter = nCount; <SM&VOiaOz  
} _Q}RElA  
} ,q@(L  
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/* KO]?>>5S6  
**Utility.java y]pN=<*h5  
*/ u4#~ i0@  
package NetFox; eN<pU%7  
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public class Utility { %M)oHX1p  
7YXXkdgbd  
ul=a\;3x#|  
public Utility() Fma`Cm.  
{ h GA0F9.U  
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8 1KG1i)  
} @2~O^5[>  
^z%o];  
//线程睡眠 n|mJE,N  
public static void sleep(int nSecond) 4=F]`Lql  
{ (LT\ IJSM  
try{ BtpjQNN  
Thread.sleep(nSecond); Xk&F4BJQk<  
} Fy_<Ui  
catch(Exception e) ok>P [ &!  
{ J<($L}T*$  
e.printStackTrace (); q:-]d0B+  
} %$Jqt  
} _5U%'\5s  
Ef_F#X0#  
//日志 S1az3VJI\  
public static void log(String sMsg) _Xk03\n6  
{ <(bCz>o|  
System.err.println(sMsg); dp UdFuU"  
} FU(}=5n  
2iR:*}5  
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public static void log(int sMsg) uzVG q!'H  
{ #GY&$8.u*  
System.err.println(sMsg); hP4)8>  
} "%}Gy>;  
} (N*<\6kr  
0V>ESyae5  
s}[A4`EWH  
/* ~E<PtDab  
**TestMethod.java (DG@<K,6  
*/ /jjW/lr  
package NetFox; #7-kL7 MK]  
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7z/(V\9B  
public class TestMethod { `'[7~Ew[  
[xZ/ZWb/  
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public TestMethod() t?]\M&i&  
{ ///xx/weblogic60b2_win.exe |8DH4*y!  
try{ J$6-c'8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r 1l/) ;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xZ.~:V03\t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e(OwS?K  
fileFetch.start(); v+!y;N;Q  
} /-
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catch(Exception e){e.printStackTrace ();} z`emKFbv  
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} O8K@&V
p  
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public static void main(String[] args) >\|kJ?h  
{ w+Z--@\  
new TestMethod(); 8iMF8\  
} Vl5SL{+D  
} ~w Zl2I  
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