http断点续传简单实现（java)

/* pH*L8tT  
**SiteFileFetch.java  c\x?k<=  
*/ Y

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package NetFox; d)0%|yX6  
import java.io.*; \{&55>  
import java.net.*; i 9b^\&&  
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public class SiteFileFetch extends Thread { L8$7^muad  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :J<S-d=  
long[] nStartPos; //开始位置 \e=@h!p  
long[] nEndPos; //结束位置 P_?1Rwm-45  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [lnN~#(Y  
long nFileLength; //文件长度 PCU6E9~t2  
boolean bFirst = true; //是否第一次取文件 *".7O*jjV  
boolean bStop = false; //停止标志 QHQj6]
 
File tmpFile; //文件下载的临时信息 % ,X(GwX  
DataOutputStream output; //输出到文件的输出流 "TxXrt%>A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 62zlO{ >rJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException kO5KZ;+N-  
{ lS,Hr3Lz  
siteInfoBean = bean; c'(]n]a%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J L Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \Js9U|lY  
if(tmpFile.exists ()) =X1$K_cN  
{ t=pG6U  
bFirst = false; #uH1!UQb  
read_nPos(); i@p?.%K{  
} hyBSS,I  
else i'57|;?  
{ F^w0TD8  
nStartPos = new long[bean.getNSplitter()]; j`#|z9`(pB  
nEndPos = new long[bean.getNSplitter()]; MJD4#G  
} 
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} F>}).qx  
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public void run() +&t{IP(?  
{ ?ph"|LyL  
//获得文件长度 JhD8.@} b~  
//分割文件 x7/2e{p uu  
//实例FileSplitterFetch p\,lbrv  
//启动FileSplitterFetch线程 Bq_<v)M*  
//等待子线程返回 H`".L^  
try{ 2.x3^/  
if(bFirst) 1'd "O @  
{ )GR^V=o7,Y  
nFileLength = getFileSize(); i&l$G55F  
if(nFileLength == -1) ZNx{7]=a  
{ CHLMY}O0  
System.err.println("File Length is not known!"); Kc(_?`  
} c"QI`;D_c  
else if(nFileLength == -2) 16]O^R;r  
{ s$]I@;_  
System.err.println("File is not access!"); YnNei 7R  
} xqG` _S l  
else Oa7W&wi  
{ g%+nMjif  
for(int i=0;i<nStartPos.length;i++)  (0k0gq;  
{ 'LX=yL]I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P@Qo2zTh%  
} zL_X?UmV  
for(int i=0;i<nEndPos.length-1;i++) SGbo|Xe7:  
{ 6\]-J*e>  
nEndPos = nStartPos[i+1]; Pjx9@i  
} Gis'IX(  
nEndPos[nEndPos.length-1] = nFileLength; 4RzG3CJdS  
} sC}/?^
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} -OziUM1qs  
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//启动子线程 L72GF5+!!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kQ:2@SOm  
for(int i=0;i<nStartPos.length;i++) 5=
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{ u}$U|Cw-;T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p;B +g X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {b+IDq`)=  
nStartPos,nEndPos,i); g_}@/5?y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G3e%~  
fileSplitterFetch.start(); X!"y>J  
} :q= XE$%H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KYeA=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A7sej  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EdU3k'z$  
nEndPos = " + nFileLength); 7/~"\nN:/  
// fileSplitterFetch[nPos.length-1].start(); N*z<VZ  
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-Z
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//等待子线程结束 N[mOJa:  
//int count = 0; F4PD3E_#  
//是否结束while循环 z=u4&x|xA  
boolean breakWhile = false; @hv9=v+  
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while(!bStop) H37Z\x
S  
{ ?Jma^ S  
write_nPos(); sS0psw1  
Utility.sleep(500); X`vDhfh>N  
breakWhile = true; c1z5t]d  
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/ )EB~|4']  
for(int i=0;i<nStartPos.length;i++) v<-D>iJ  
{ |UBJu `
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if(!fileSplitterFetch.bDownOver) A+dY~@*a  
{ )dvOg'it  
breakWhile = false; x~mXtqg  
break; g-]td8}#  
} kiECJ@5p  
} v(0vP}[Q7E  
if(breakWhile) pLIBNo?  
break; eygyVhJ  
}cf-r>WaR  
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//count++; :@p`E}1r{  
//if(count>4) nd?m+C&W  
// siteStop(); Sj*H4ZHD<&  
} <^&'r5H  
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System.err.println("文件下载结束！"); SHaZ-d  
} y}3V3uqK  
catch(Exception e){e.printStackTrace ();} QO%LSRw  
} 7X.1QSuE  
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//获得文件长度
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public long getFileSize() i<T`]g  
{ H
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int nFileLength = -1; FJD*A`a  
try{ E8503  
URL url = new URL(siteInfoBean.getSSiteURL()); aCTVY1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $~2Ao[  
httpConnection.setRequestProperty("User-Agent","NetFox"); E>[~"~x"pV  
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int responseCode=httpConnection.getResponseCode(); m1cyCD  
if(responseCode>=400) nQgn^z#  
{ 7z$+ *]9-  
processErrorCode(responseCode); v:+se6HY?p  
return -2; //-2 represent access is error 4SOj>(a#  
} ]F_u  
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String sHeader; o 1b#q/  
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for(int i=1;;i++) ;P{ *'@  
{ 4bKZ@r%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c=K M[s.  
//Utility.log(in.readLine()); 4Pt0^;H&jn  
sHeader=httpConnection.getHeaderFieldKey(i); D`gY6wX  
if(sHeader!=null) ~:0h o  
{ .=NK^  
if(sHeader.equals("Content-Length")) dzcPSbbpt  
{ '3xSzsDn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kn<[v;+  
break; ~jPe9  
} =*'`\}];"  
} F8k1fmM]Y  
else isN"7y|r:X  
break; 8=?I/9Xh  
} #a0 (Wh7  
} |ST&,a$(  
catch(IOException e){e.printStackTrace ();} =]"PSY7
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catch(Exception e){e.printStackTrace ();} .d*vfE$  
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Utility.log(nFileLength);
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return nFileLength; ;^xku%u  
} =EG[_i{r  
*s/F4?*  
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//保存下载信息（文件指针位置） xo*a9H?@  
private void write_nPos() *L!R4;ubE  
{ n.T [a  
try{ Lh0<A%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5=$D~>-#  
output.writeInt(nStartPos.length); /
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for(int i=0;i<nStartPos.length;i++) [`:\(( 8  
{ <vAg\Tv:S  
// output.writeLong(nPos); p'R}z|d)  
output.writeLong(fileSplitterFetch.nStartPos); Q[k}_1sWs$  
output.writeLong(fileSplitterFetch.nEndPos); r+U-l#Q  
} KUp lN1Sy  
output.close(); :xA'X+d/'  
} X-%*`XG'  
catch(IOException e){e.printStackTrace ();} PeG8_X}u9  
catch(Exception e){e.printStackTrace ();} >97V2W  
} {:"bX~<^  
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//读取保存的下载信息（文件指针位置） _ '}UNIL  
private void read_nPos() ~+1t17  
{ J4JKAv~3  
try{ Ltu
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -PX {W)Aw  
int nCount = input.readInt(); EBn7waBS  
nStartPos = new long[nCount]; =A,i9Z&  
nEndPos = new long[nCount]; _E1:3N|  
for(int i=0;i<nStartPos.length;i++) .|rpj&>g  
{ LsLsSV  
nStartPos = input.readLong(); jKtbGVZ7r  
nEndPos = input.readLong(); VfQSfNsi  
} 5ecqJ  
input.close(); uh GL1{  
} Vdjca:`  
catch(IOException e){e.printStackTrace ();} f6z[k_lLN  
catch(Exception e){e.printStackTrace ();} O/FQ'o1F  
} sqkPC_;A  
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private void processErrorCode(int nErrorCode) zIlQqyOQ8  
{ m7d? SU  
System.err.println("Error Code : " + nErrorCode); (l$bA_F\  
} VbZZ=q=Kd  
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//停止文件下载 ('>!dXA$  
public void siteStop() 1c\$ziB  
{ DSQ2z3s2  
bStop = true; ,Z3.Le"  
for(int i=0;i<nStartPos.length;i++) Y(-+>>j_  
fileSplitterFetch.splitterStop(); >`t |a  
/Jo*O=Lpo  
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} ;ASlsUE\)  
} uRp-yu[nt%  
//负责部分文件的抓取 7H=/FT?e]  
**FileSplitterFetch.java z;Kyg}  
*/ uv Z!3UH.  
package NetFox; =WHdy;  
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import java.io.*; |J8c|h<  
import java.net.*; 5I@< 6S&X  
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public class FileSplitterFetch extends Thread { 2o6%P}C  
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String sURL; //File URL x|1OGbBK  
long nStartPos; //File Snippet Start Position &,bJ]J)8O  
long nEndPos; //File Snippet End Position !x&/M*nBE  
int nThreadID; //Thread's ID B1\}'g8%f  
boolean bDownOver = false; //Downing is over Yz[^?M%(D  
boolean bStop = false; //Stop identical IY+P Yad  
FileAccessI fileAccessI = null; //File Access interface +$P0&YaQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N U\B  
{ rZ *}jD[  
this.sURL = sURL; !hEtUF  
this.nStartPos = nStart; ^ @sg{_.~l  
this.nEndPos = nEnd; kWF, *@.B  
nThreadID = id; T
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 )88z=5.  
} 3g)pLW  
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public void run() Fq9AO~z  
{ PjDYdT[  
while(nStartPos < nEndPos && !bStop) h>q&X4-  
{ C#+Gkzq  
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try{ &pV'/  
URL url = new URL(sURL); RlC|xj"l%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +AO(e  
httpConnection.setRequestProperty("User-Agent","NetFox"); A-qdTJP  
String sProperty = "bytes="+nStartPos+"-"; 6gNsh  
httpConnection.setRequestProperty("RANGE",sProperty); 3N[t2Y1r  
Utility.log(sProperty); FG:(H0  
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InputStream input = httpConnection.getInputStream(); 1d"g$i4e  
//logResponseHead(httpConnection); 7gNJ}pLDx  
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byte[] b = new byte[1024]; 1 VcZg%I  
int nRead; 0p)#!$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Etj@wy/E  
{ 2ntL7F<ow  
nStartPos += fileAccessI.write(b,0,nRead); +7.\>Ucq`  
//if(nThreadID == 1) 4v_<<l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FxW~Co  
} 3)3?/y)_  
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Utility.log("Thread " + nThreadID + " is over!"); !g'kWE[  
bDownOver = true; a~>+I~^K5q  
//nPos = fileAccessI.write (b,0,nRead); 9'Le}`Gf  
} N8#wQ*MM>  
catch(Exception e){e.printStackTrace ();} -c{O!z6sX  
} 'S;INs2|->  
}  At@H  
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//打印回应的头信息 EyO=M~nsS  
public void logResponseHead(HttpURLConnection con) 5bKM}?=L  
{ .nl!KzO6g  
for(int i=1;;i++) [
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{ F0(P2j  
String header=con.getHeaderFieldKey(i); db -h=L|  
if(header!=null) >g+yw1nC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~4fUaMT  
Utility.log(header+" : "+con.getHeaderField(header)); 4YX/=  
else /H3z~PBa  
break; 1DLAf
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} 6V-u<FJ  
} *t=8^q(K[  
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public void splitterStop() C>wOoXjt  
{ 4z%::?  
bStop = true; iI.pxo s  
} |qm_ESzl  
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} &6wD  
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/* 1 etl:gcEC  
**FileAccess.java +-2o b90_m  
*//文件访问(定位，写) :8h\x  
package NetFox; B8.a#@R  
import java.io.*; &YpViC4K.  
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public class FileAccessI implements Serializable{ E.LD1Pm0  
aG_@--=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pW5ch"HE  
RandomAccessFile oSavedFile; #!?jxfsFa  
long nPos; H?oBax:  
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public FileAccessI() throws IOException )SU\s+"M  
{ hQ7-m.UZw  
this("",0); 4*Uzomb?q  
} 4|U$ON?x  
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public FileAccessI(String sName,long nPos) throws IOException qtrN=c3
x  
{ yM}~]aQ y  
oSavedFile = new RandomAccessFile(sName,"rw"); G.")Bg  
this.nPos = nPos; Z=Z
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oSavedFile.seek(nPos); pmwVVUEQ  
} =-bGH   
)_C+\K*  
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public synchronized int write(byte[] b,int nStart,int nLen) (/gv U80  
{ cV$an  
int n = -1; $Z|
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try{ b!p
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oSavedFile.write(b,nStart,nLen); qPQ6`rD\  
n = nLen; Nwwn #+  
} )fy-]Ky *  
catch(IOException e) r{>`"  
{ f`<elWgc"  
e.printStackTrace (); 2x5^kN7  
} (n{x"rLy/  
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return n; &zR\Rmpt  
} _sqj~|K  
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} Bo,>blspw  
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/* r1axC%  
**SiteInfoBean.java tgyW:<iv  
*/ fZ aTckbE  
package NetFox; Ko|m<;LX  
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public class SiteInfoBean { )-\C{>  
]-j.\+(*  
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private String sSiteURL; //Site's URL 57wHo[CJ  
private String sFilePath; //Saved File's Path 'aWqj+Wbh  
private String sFileName; //Saved File's Name **V8a-@  
private int nSplitter; //Count of Splited Downloading File n!dXjInV  
yJK:4af;.  
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public SiteInfoBean() a,|Hn  
{//nSplitter的缺省值为5 Iq?n*P$  
//default value of nSplitter is 5 9])Id;+91  
this("","","",5); ,<=gPs;x  
} )2lB  
r.q*S4IS.m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^sKdN-{  
{ (_%l[:o6  
sSiteURL= sURL; 1Q_Q-Z  
sFilePath = sPath; KpBOmXE  
sFileName = sName; !,+<?o y  
this.nSplitter = nSpiltter; `w&?SXFO8  
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} Kf-XL),3l  
o|$r;<o3R  
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public String getSSiteURL() &S=Qu?H  
{ (%c&Km7K  
return sSiteURL; Gf +>AjU'  
} 4bCA"QM[[  
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public void setSSiteURL(String value) 3$?nzKTW\  
{ 0bpGPG's&  
sSiteURL = value; #<~oR5ddlb  
} *>/w,E]  
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public String getSFilePath() <0VC`+p<)  
{ xw}rFY$  
return sFilePath; bl
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} H&8~"h6n  
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public void setSFilePath(String value) Egz6rRCvg  
{ 1Ys)b[:  
sFilePath = value; q*Oj5;  
} ?S;z!) H)P  
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public String getSFileName() g:O/~L0Xb  
{ r$v\\^?2  
return sFileName; Wks zNh  
} ]x).C[^  
ce;$)Ff\  
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public void setSFileName(String value) %K+hG=3O  
{ CIui9XNU  
sFileName = value; \K9.]PfbI  
} fWPa1E@  
*s#6e}  
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public int getNSplitter() );T&pm:C>  
{ TMD\=8Na  
return nSplitter; <"K2t Tg.  
} n=)LB& m  
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public void setNSplitter(int nCount) /Xj{]i3{  
{ k( I
k+=u  
nSplitter = nCount; h oO847  
} Ml9m#c  
} QW'*^^  
Pl!E$   
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/* ^62z\Y  
**Utility.java E7i/gY  
*/ l-cBN^^  
package NetFox; pHx$  
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public class Utility { @{UUB=}9  
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public Utility() TV0sxod6  
{ JhjH_)  
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} ps?su`  
$IS!GS&:  
//线程睡眠 C~ A
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public static void sleep(int nSecond) ?hAO-*);  
{ YcV^Fqi!  
try{ w >%^pO~}`  
Thread.sleep(nSecond); BQ<\[H;  
} VxS3lR=  
catch(Exception e) l]~9BPsR  
{ n!AW9]  
e.printStackTrace (); q6*i/"mN*  
} $UdBZT-  
} Tt9cX}&&  
k q]E@tE*3  
//日志 {]U \HE1w  
public static void log(String sMsg) GqNOWK2O  
{ "+4Jmf9  
System.err.println(sMsg); 00'SceL=`  
} ~(^pGL3<  
p;'.7_1  
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public static void log(int sMsg) $m~&|s  
{ qou\4YZ  
System.err.println(sMsg); ]'?Ue7  
} #AP;GoIf"j  
} Z m%,L$F*L  
$=,pQ q  

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/* 7QnWw0  
**TestMethod.java mA$86X_  
*/ 1=5HQ~|[TO  
package NetFox; Z9NN
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\2=I//YF  
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public class TestMethod { &;pM<h  
?%8%1d  
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public TestMethod() 5M~+F"Hl  
{ ///xx/weblogic60b2_win.exe
,?Ie!r$6  
try{ Z*f%R\u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wkPjMmW+!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CbW[_\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [&4+ <Nl'  
fileFetch.start(); 
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} ]" e'z  
catch(Exception e){e.printStackTrace ();} KQb&7k.  
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} T iL.py,  
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public static void main(String[] args) %.u*nM7sos  
{ h~]e~u V  
new TestMethod(); -BI!ZsC'  
} $Zo|ta^  
} P7zUf  
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