http断点续传简单实现（java)

/* ,y+}0q-Ou  
**SiteFileFetch.java /Y>$w$S  
*/ vncak  
package NetFox; cBO.96ZHE  
import java.io.*; ]d}U68$T+  
import java.net.*; ue5C ]  
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public class SiteFileFetch extends Thread { O{^ET:K@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?4kM5NtP  
long[] nStartPos; //开始位置 tR,&|?0  
long[] nEndPos; //结束位置 R*l#[D5A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MrW#~S|ED  
long nFileLength; //文件长度 oM&}akPE  
boolean bFirst = true; //是否第一次取文件 ^11y8[[  
boolean bStop = false; //停止标志 z)RJUmY3B  
File tmpFile; //文件下载的临时信息 0.9%m7.m  
DataOutputStream output; //输出到文件的输出流 _7h:NLd  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _%xe:X+ M  
public SiteFileFetch(SiteInfoBean bean) throws IOException J\kGD  
{ &X^ -|7~N  
siteInfoBean = bean; "h-G=vo,kl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A{HP*x~t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yl>V'  
if(tmpFile.exists ()) +ld]P}  
{ s\)0f_I  
bFirst = false; 'UY
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read_nPos(); (9#$za>  
} gH+s)6  
else yh  
{ m~[4eH,  
nStartPos = new long[bean.getNSplitter()]; pf\ Ybbs  
nEndPos = new long[bean.getNSplitter()]; 8QYP\7}o  
} >tmv3_<=  
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} CNo'qlvF5N  
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public void run()
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{ X 5.%e&`  
//获得文件长度 A5UZUU^  
//分割文件 D%=VhKq  
//实例FileSplitterFetch g[D(]t\#x  
//启动FileSplitterFetch线程 kM0TQX)$m  
//等待子线程返回 >FVBn;1  
try{ pk%%}tP<  
if(bFirst) kB2]Z}  
{ 0tL#-47  
nFileLength = getFileSize(); 88@" +2  
if(nFileLength == -1) v%ldg833l  
{ ?06+"Z  
System.err.println("File Length is not known!"); I@$cw
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} #~_ZG% u  
else if(nFileLength == -2) 9J*M~gKbz  
{ >/r^l)`9_f  
System.err.println("File is not access!"); UABaS(f3  
} qG]G0|f  
else wWVLwp4-  
{ sjZ@}Vk3b  
for(int i=0;i<nStartPos.length;i++) 'ie+/O@G  
{ _d[4EY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w$aiVOjgT  
} (~6D`g`B  
for(int i=0;i<nEndPos.length-1;i++) !Ojf9 6is  
{ Jq5](F!z  
nEndPos = nStartPos[i+1]; ?tA<:.<vtY  
} #OQT@uF!
 
nEndPos[nEndPos.length-1] = nFileLength; q':P9o*N?  
} !kTI@103Wd  
} R_vF$X'Ow  
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//启动子线程 W$>AK_Y}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R0WI s:k2  
for(int i=0;i<nStartPos.length;i++) 8l50@c4UF~  
{ 5x2m]
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [U^@Bkh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !.EDQ1k  
nStartPos,nEndPos,i); nNEIwlj;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +o4W8f=Ga  
fileSplitterFetch.start(); <`f~Z|/-_(  
} f\|R<3 L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C$<['D?8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Dcep^8'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X!AD]sK  
nEndPos = " + nFileLength); k"L?("~   
// fileSplitterFetch[nPos.length-1].start(); &gr)U3w  
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//等待子线程结束 mu>L9Z~(L_  
//int count = 0; )HL[_WfY  
//是否结束while循环 ~Pm[Ud  
boolean breakWhile = false; YQ`m;<  
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while(!bStop) 7rZE7+%]  
{ VGVb3@  
write_nPos(); H wu(}  
Utility.sleep(500); 2," (  
breakWhile = true; w vQ.9  
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for(int i=0;i<nStartPos.length;i++) Lc?q0x^s  
{ =iFI@2  
if(!fileSplitterFetch.bDownOver) P'Gf7sQt7  
{ s6YnNJ,SK  
breakWhile = false; )/Mk\``j  
break; b-"kcl
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} ]iHSUP  
} qJyGr ?  
if(breakWhile) qQ/<\6Sl  
break; I&s!}$cD  
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//count++; "/~KB~bB  
//if(count>4) t91z<Y|  
// siteStop(); ndE"v"_H  
} z"PU`v  
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System.err.println("文件下载结束！"); -h`[w:  
} i9O;D*  
catch(Exception e){e.printStackTrace ();} f.{/PL  
} F=9
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//获得文件长度 k "Qr  
public long getFileSize() 0/~20KD{s  
{ 0V!@*Z  
int nFileLength = -1; zAA3bgaa  
try{ loByT p ^  
URL url = new URL(siteInfoBean.getSSiteURL()); 6EY W:o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8oxYgj&~X  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~]S%b3>  
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int responseCode=httpConnection.getResponseCode(); L8.u7(-#  
if(responseCode>=400) C?-_8OA  
{ qQ^bUpk0  
processErrorCode(responseCode); %;-r->  
return -2; //-2 represent access is error e00s*LdC  
} u[b0MNE~  
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String sHeader; wNtPh&  
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for(int i=1;;i++) (|t)MnPfY  
{ NxzRVsNF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {Ip)%uR  
//Utility.log(in.readLine()); 34s>hm=0.  
sHeader=httpConnection.getHeaderFieldKey(i); Fb^f`UI  
if(sHeader!=null) yTpvKCC  
{ nZP%Z=p7  
if(sHeader.equals("Content-Length")) s{@3G8  
{ OtD!@GQ6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); daN#6e4Z+;  
break; *R8qnvE\()  
} whb,2=gIE  
} VU ,tCTXz  
else LvbS")  
break; 6SVh6o@]  
} s3+6Z~g'B  
} ,.-85isco  
catch(IOException e){e.printStackTrace ();} y>iote~  
catch(Exception e){e.printStackTrace ();} 0OF]|hH  
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Utility.log(nFileLength); Zzea  
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return nFileLength; p({)ZU3  
} >#8J@=iuqv  
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//保存下载信息（文件指针位置） 4M3{P  
private void write_nPos() ,W:Bh$%  
{ hJasnY7  
try{ C Y
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 8^)K|+_'m  
output.writeInt(nStartPos.length); F]k$O$)0  
for(int i=0;i<nStartPos.length;i++) A_xUP9g@?  
{ rn"}@5  
// output.writeLong(nPos); y+K21(z.  
output.writeLong(fileSplitterFetch.nStartPos); QJK
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output.writeLong(fileSplitterFetch.nEndPos); gW_^GrKpI  
} XJ9l,:c,  
output.close(); [/Ya4=C@  
} .BqSE  
catch(IOException e){e.printStackTrace ();} 8j%hxAV$  
catch(Exception e){e.printStackTrace ();} w7Y>B`wm?  
} o^b4l'&o  
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//读取保存的下载信息（文件指针位置） xulwn{R s  
private void read_nPos() jm$v0=W9#  
{ 'l`T(_zL\%  
try{ e Zb8x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Bp:i[9w  
int nCount = input.readInt(); &f$[>yg1-  
nStartPos = new long[nCount]; ({l!'>?  
nEndPos = new long[nCount]; $IB>a  
for(int i=0;i<nStartPos.length;i++) j@b18wZ  
{ .f~x*@  
nStartPos = input.readLong(); i~04P  
nEndPos = input.readLong(); ee5QZ,  
} vJE>H4qPmD  
input.close(); 1XvB,DhJ  
} q9`!T4,  
catch(IOException e){e.printStackTrace ();} =|G l  
catch(Exception e){e.printStackTrace ();} |=CV.Su  
} l|onH;g\  
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private void processErrorCode(int nErrorCode) \hcb~>=C  
{ |[]"{Eo"}  
System.err.println("Error Code : " + nErrorCode); g,seqh%  
} T-L;iH~0  
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//停止文件下载 WF{rrU:  
public void siteStop() u  teI[Q  
{ ctg[C$<q|  
bStop = true; .5PcprE/  
for(int i=0;i<nStartPos.length;i++) ;2=H7dq  
fileSplitterFetch.splitterStop(); -{A!zTw1w  
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} 8}0O @ wq  
} <Hq|<^_K  
//负责部分文件的抓取 fGD#|a;,  
**FileSplitterFetch.java +R_w- NI  
*/ L*VO2YI  
package NetFox; !Xbr7:UPN1  
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import java.io.*; b6k'`vLA  
import java.net.*; }FTyRHD|  
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public class FileSplitterFetch extends Thread { ~X/1%  
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String sURL; //File URL uW8LG\Z>D5  
long nStartPos; //File Snippet Start Position 'RlPj0Cg  
long nEndPos; //File Snippet End Position 4ZK8Y[]Lv  
int nThreadID; //Thread's ID xM/B"SG2  
boolean bDownOver = false; //Downing is over YAIDSZ&l[  
boolean bStop = false; //Stop identical TuBl9 p'6  
FileAccessI fileAccessI = null; //File Access interface $Qv+*%c  
9W{=6D86e  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /Wh} ;YTv^  
{ Z5
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this.sURL = sURL; >!
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this.nStartPos = nStart; 'wd-!aZAd  
this.nEndPos = nEnd; A&2)iQ  
nThreadID = id; 62&(+'$n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R18jju>Zr  
} _d'x6$Jg
 
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public void run() T'cahkSw'O  
{ m q`EMOH  
while(nStartPos < nEndPos && !bStop) `o6Hm  
{ pr8eRV!x  
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try{ u6AReL'f  
URL url = new URL(sURL); d7y`AS@q6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?q(7avS9  
httpConnection.setRequestProperty("User-Agent","NetFox"); *v[WJ"8@  
String sProperty = "bytes="+nStartPos+"-"; %pNK ?M+  
httpConnection.setRequestProperty("RANGE",sProperty); Lt+ Cm$3  
Utility.log(sProperty); ,%#FK|  
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InputStream input = httpConnection.getInputStream(); }&)X4=  
//logResponseHead(httpConnection);  u%<Je  
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byte[] b = new byte[1024]; IcMfZ{H1  
int nRead; ab!,)^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 31\l0Jg  
{ Y]aVa2!Wb  
nStartPos += fileAccessI.write(b,0,nRead); D.zEE-cGyb  
//if(nThreadID == 1) k/A8|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _jOu`1w  
} GsG.9nd  
79|=y7i#  
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Utility.log("Thread " + nThreadID + " is over!"); >NWrT^rk
 
bDownOver = true; M=$ qus  
//nPos = fileAccessI.write (b,0,nRead); V9*Z  
} ?IR]y-r  
catch(Exception e){e.printStackTrace ();} @:\Iw"P  
} Tf/j
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} ~0"(C#l9  
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 #nV F.  
//打印回应的头信息 YqhZndktX  
public void logResponseHead(HttpURLConnection con) kR2kV"-l  
{ We&~]-b AW  
for(int i=1;;i++) u;f${Wn'3  
{ Y;$wD9W  
String header=con.getHeaderFieldKey(i); -FRMal4Pg0  
if(header!=null) \$GM4:R D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '4-J0S<<_  
Utility.log(header+" : "+con.getHeaderField(header)); H9}z0VI  
else +XV7W=  
break; VfWU-lJ  
} 1t&LNIc|^  
} WWf#
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public void splitterStop() SU>2M
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{ (QS4<J"  
bStop = true; []^fb,5a  
} O5X@'.#rU  
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} -|F(qf  
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/* 7 ) Q>R  
**FileAccess.java % YgGw:wZ  
*//文件访问(定位，写) s=KK
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package NetFox; tW$Di*
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import java.io.*; wE*o1.
 
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public class FileAccessI implements Serializable{ W20qn>{z  
9:\#GOg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vZ6_/ew8  
RandomAccessFile oSavedFile; ~)fd+~4L  
long nPos; ,F;<Y9]  
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public FileAccessI() throws IOException rjaG{ i  
{ Zqi;by%  
this("",0); r &.g
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} aG*Mj;J  
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public FileAccessI(String sName,long nPos) throws IOException =NNA7E7c  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); ]
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this.nPos = nPos; 5f}GV0=n  
oSavedFile.seek(nPos); GZx?vSoHh  
} IKs2.sj"o  
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public synchronized int write(byte[] b,int nStart,int nLen) E|9'{3$  
{ =5kTzH.  
int n = -1; )4O* D92  
try{ A5q%ytI  
oSavedFile.write(b,nStart,nLen); |M$ESj4@  
n = nLen; HUWCCVn&  
} <8sy*A?0z  
catch(IOException e) d>bS)  
{ ,!I'0x1OR  
e.printStackTrace (); /9k}Ip  
} 
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return n; I]jK]]@  
} qJ5gdID1_  
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} a"pejW`m  
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/* 'boAv%1_sa  
**SiteInfoBean.java +jrMvk"  
*/ L\/YS;Y  
package NetFox; {z0PB] U  
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public class SiteInfoBean { ;=oGg%@aP  
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private String sSiteURL; //Site's URL vo3[)BDbT  
private String sFilePath; //Saved File's Path ;DN:AgXP  
private String sFileName; //Saved File's Name B'` jdyaE9  
private int nSplitter; //Count of Splited Downloading File u*C"d1v=  
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public SiteInfoBean() MI<XLn!*  
{//nSplitter的缺省值为5 nbM7 >tnsk  
//default value of nSplitter is 5 4}t&AW4  
this("","","",5); #&jr9RB  
} 9e xHR&>{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zcTY"w\b  
{ H%:u9DlEK/  
sSiteURL= sURL; H@R2mw  
sFilePath = sPath; uY5Gn.Y  
sFileName = sName; FII>6c  
this.nSplitter = nSpiltter; 0XNj!^&  
.
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} Gr a(DGX  
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public String getSSiteURL() Hx]{'?  
{ }ST0?_0F*  
return sSiteURL; &_!g|-  
}  8/|~E  
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public void setSSiteURL(String value) Y}C~&Ph  
{ q;kN+NK64  
sSiteURL = value; vG<JOxP  
} o5N];Nj  
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public String getSFilePath() I2!0,1Q  
{ 1/bu}?a  
return sFilePath; 3-Q*umh  
} E&/D%}Wl  
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public void setSFilePath(String value) BHwQB2t gc  
{ !8|]R  
sFilePath = value; X`ifjZ9}d  
} *6)u5  
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public String getSFileName() / 4K*iq  
{ N.q4Ar[x#p  
return sFileName; 3986;>v  
} }0#cdw#gH  
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public void setSFileName(String value) -#b-@sD  
{ T[=XGAJ  
sFileName = value; hGH{Xp[mW  
} $}S5&  
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[&rW+/  
public int getNSplitter() l%"eQ  
{ twx8TQ9  
return nSplitter; Q=yQEh|Y  
} HPAg1bV:-  
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public void setNSplitter(int nCount) M~7?m/Wj  
{ {!B0&x  
nSplitter = nCount; -(>x@];r0  
} b]mRn{r?  
} ,u(g#T  
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h GS";
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/* 7(~^6Ql!  
**Utility.java 3O
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*/ v>g1\yIw  
package NetFox; W #qM$  
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public class Utility { 6%ID*  
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public Utility() -H.;73Kb[  
{ 'y}A3RqN  
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} `M4;aN  
vD1jxk'fd  
//线程睡眠 DfV_0
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public static void sleep(int nSecond) ffm19B=  
{ MkJL9eG  
try{ I U4[}x  
Thread.sleep(nSecond); 15U=2j*.b  
} uVu`TgbZ  
catch(Exception e) 66)@4 3V  
{ _V:D7\Gs  
e.printStackTrace (); 1Q
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} ^n]tf9{I  
} {%S1x{U}W-  
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//日志 &R*d/~SU  
public static void log(String sMsg) }(M<sEK~  
{ `2S{.s  
System.err.println(sMsg); !k<+-Lf:2  
} L?9Vz&8]  
#0xvxg%{  
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public static void log(int sMsg) {b/AOR o  
{ M"p$9t  
System.err.println(sMsg); SC|cCK hqi  
} v S%+  
} },i?3dSvl  
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/* )-jvp8%BK  
**TestMethod.java %&gx@ \v  
*/ oY.JK  
package NetFox; a-QHm;_S  
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public class TestMethod { {5%<@<?)  
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public TestMethod() sgB3i`_M  
{ ///xx/weblogic60b2_win.exe &F.lo9JJ  
try{ Nz:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Vq<|DM3z<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ORHC bw9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wk5a &  
fileFetch.start(); <M\Z}2d  
} {O^1WgGc[  
catch(Exception e){e.printStackTrace ();} 41C=O@9m  
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} R/^ rh  
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public static void main(String[] args) T%]: tDa  
{ (wA|lK3  
new TestMethod(); ?ke C  
} U9k}y  
} 6"=e+V@  
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