http断点续传简单实现（java)

/* fw-\|fP  
**SiteFileFetch.java gwB\<rzG  
*/ Zj9c9  
package NetFox; Snw3`|Y~<  
import java.io.*; y*b3&%.ml  
import java.net.*; BzJ;%ywS  
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public class SiteFileFetch extends Thread { |+,[``d>"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "h"NW[R  
long[] nStartPos; //开始位置 <X7\z  
long[] nEndPos; //结束位置 AIijCL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n]Li->1  
long nFileLength; //文件长度 AasZuO_I  
boolean bFirst = true; //是否第一次取文件 $0A~uDbs  
boolean bStop = false; //停止标志 ,Ds.x@p  
File tmpFile; //文件下载的临时信息 1=}qBR#scY  
DataOutputStream output; //输出到文件的输出流 h11.'Eej`  
+/{L#e>  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wEW4gz{s  
public SiteFileFetch(SiteInfoBean bean) throws IOException |`d0^(X  
{ A=5epsB  
siteInfoBean = bean; ;QCrHqRT`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nR;D#"
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c:!zO\P#  
if(tmpFile.exists ()) Mz]:}qmFA  
{
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bFirst = false; Y4.Eq+$gh  
read_nPos(); 0u B'g+MU`  
} Lv[OUW#S  
else &[mZD,  
{ }R4c  
nStartPos = new long[bean.getNSplitter()]; 6.1)IQkO  
nEndPos = new long[bean.getNSplitter()]; >x1p%^cA;=  
} y@V_g'  
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} K5t0L!6<+  
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public void run() m#/_x  
{ gR^>3
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//获得文件长度 HmmS(fU  
//分割文件 hg@}@Wq\)  
//实例FileSplitterFetch T\s)le  
//启动FileSplitterFetch线程 qSCv )S(  
//等待子线程返回 y&[y=0!  
try{ /c2'dJ(H  
if(bFirst) lfsqC};#\  
{ qo6y %[  
nFileLength = getFileSize(); =QJRMF  
if(nFileLength == -1) H5cV5E0  
{ c?2MBtnu  
System.err.println("File Length is not known!"); g?v\!/~(u  
} A=zPLq{Sb  
else if(nFileLength == -2) %#L]]-%  
{ s pLZ2]A  
System.err.println("File is not access!"); |%a4`
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} rx"s!y{!-  
else ;^Sr"v6r>u  
{ ysIh[1E~%:  
for(int i=0;i<nStartPos.length;i++) vR6Bn  
{ Y<"7x#AB!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iTh:N2/-vc  
} }ov&.,vQ  
for(int i=0;i<nEndPos.length-1;i++) 'V+
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{ {yU+)t(.  
nEndPos = nStartPos[i+1]; *1Z5+uVT[  
} {4aWR><  
nEndPos[nEndPos.length-1] = nFileLength; ZPN roCK`  
} ow=UtA-^O  
} 5m:i6,4  
8.=\GV  
8;Fn7k_Uf  
//启动子线程 V(MFna)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s#Jh -+lM  
for(int i=0;i<nStartPos.length;i++) :4S%'d7  
{ 7`IpBm<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t&Os;x?To?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '\fY<Q:!  
nStartPos,nEndPos,i); R2L;bGI*J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {K{EOB_u  
fileSplitterFetch.start(); Cd79 tu|  
} g[>\4B9t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t%zpNd2lk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $uui:wU%Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <WXzh5D2  
nEndPos = " + nFileLength); @pI5lh  
// fileSplitterFetch[nPos.length-1].start(); x6afI<dm  
d8SE,A&  
^ 5VK>  
//等待子线程结束 'evj,zFhW  
//int count = 0; dUgrKDNyA  
//是否结束while循环 wfL-oi'5  
boolean breakWhile = false; /:6Wzj  
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)4?x5#  
while(!bStop) gw`B"c|  
{ 3lLMu B+  
write_nPos(); )yY6rI;:  
Utility.sleep(500); (\"k&O{  
breakWhile = true; Sx:Ur>?hd5  
+(O~]Q-Ez  
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for(int i=0;i<nStartPos.length;i++) p2J|Hl|  
{ f"7M^1)h2%  
if(!fileSplitterFetch.bDownOver) cw&Hgjj2  
{ -S,ln  
breakWhile = false; 6~#Ih)K  
break; N4;7gSc"  
} }pkj:NT  
} 7f<EoSK  
if(breakWhile) cH<q:OYi  
break; lT\a2.E  
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//count++; "M|P+A  
//if(count>4) S1_6C:^k  
// siteStop(); Obw?_@X  
} d_S*#/k  
,U*)2`[  
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System.err.println("文件下载结束！"); iDl;!b&V.  
} =5D nR  
catch(Exception e){e.printStackTrace ();} E6Rz@"^XV  
} 7z\m; 1  
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d1!i(MaV!  
//获得文件长度 C ]Si|D
  
public long getFileSize() D3Jr3 %>  
{ 1%M&CX  
int nFileLength = -1; o01kYBD  
try{ $(s\{(Wn  
URL url = new URL(siteInfoBean.getSSiteURL()); VZ>On$hp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *O:r7_ Y0  
httpConnection.setRequestProperty("User-Agent","NetFox"); yix'rA-T  
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int responseCode=httpConnection.getResponseCode(); =k}SD96  
if(responseCode>=400) M)?dEgU}M  
{ `=#01YX[0  
processErrorCode(responseCode); ?EMK8;  
return -2; //-2 represent access is error @L84>3O  
} _!xD8Di#  
4 (?MUc  
,#u\l>&$  
String sHeader; my^ak*N  
Q ~|R Z7G  
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for(int i=1;;i++) @_'OyRd8  
{ JV"NZvjN7d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *3{J#Q6fk3  
//Utility.log(in.readLine()); ^%bBW6eZ  
sHeader=httpConnection.getHeaderFieldKey(i); H>7dND2;  
if(sHeader!=null) 54p tP  
{ ND]S(C"?  
if(sHeader.equals("Content-Length")) g#^|oYuH6  
{ 7|YrdK<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e29y7:)c=  
break; DQ!J!ltQ  
} "X1vZwK8N  
} zok D:c  
else 6XUuGxQV/  
break; Rq)BssdF  
} a<Uqyilm  
} 2wpjU&8W!  
catch(IOException e){e.printStackTrace ();} [$\>~nj=  
catch(Exception e){e.printStackTrace ();} =G>(~+EA  
|"k&fkS$  
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Utility.log(nFileLength); )^;DGzG  
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return nFileLength; Lyoor1   
} 1p\Ak  
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+$pJ5+v  
//保存下载信息（文件指针位置） av'*u  
private void write_nPos() 3]}'TA`v  
{ 9U<Hf32  
try{ #}o<v|;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D1"7s,Hmu  
output.writeInt(nStartPos.length); X , ZeD  
for(int i=0;i<nStartPos.length;i++) I-:`cON=G  
{ =HE m)  
// output.writeLong(nPos); m6n hC  
output.writeLong(fileSplitterFetch.nStartPos); moO_-@i  
output.writeLong(fileSplitterFetch.nEndPos); lizTRVBE  
} m^tNqJs8  
output.close(); ~mH+DV3  
} {+=i?  
catch(IOException e){e.printStackTrace ();} S<oQ}+4[~  
catch(Exception e){e.printStackTrace ();} ,IjdO(?TC  
} v]bAWo  
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//读取保存的下载信息（文件指针位置） \Hum}0[  
private void read_nPos() a$+#V=bA  
{ 9~Xg#{  
try{ L>nO:`>h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ju
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int nCount = input.readInt(); `pYE[y+  
nStartPos = new long[nCount]; eTZ`q_LfI1  
nEndPos = new long[nCount]; ay[+2"  
for(int i=0;i<nStartPos.length;i++)
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{ D8/sz`N7Q  
nStartPos = input.readLong(); I7Zq}Pxa  
nEndPos = input.readLong(); f[@#7,2~M  
} d| \#?W&  
input.close(); F*<Ws;j  
} +{ab1))/  
catch(IOException e){e.printStackTrace ();} 6D^%'[4t  
catch(Exception e){e.printStackTrace ();} c~oe,9  
} Qa?QbHc  
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private void processErrorCode(int nErrorCode) }}
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{ 6QptKXu7  
System.err.println("Error Code : " + nErrorCode); APuu_!ez1  
} *2:Yf7rvI+  
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//停止文件下载 Ap,q `S  
public void siteStop() },3R%?89%  
{ HjPH  
bStop = true; 0C7"3l  
for(int i=0;i<nStartPos.length;i++) /2'c>  
fileSplitterFetch.splitterStop(); "2K|#,%N  
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} {lKEZirO  
} iy9VruT<x  
//负责部分文件的抓取 /K&wr6  
**FileSplitterFetch.java Es,0'\m&  
*/ +{bh  
package NetFox; <v-92?  
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import java.io.*; lZ+/\s,]|  
import java.net.*; ^f"&}%"M  
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public class FileSplitterFetch extends Thread { XAGiu;<,=  
/iTH0@Kw;  
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String sURL; //File URL 6q!7i%fK?  
long nStartPos; //File Snippet Start Position 5vl2yN  
long nEndPos; //File Snippet End Position U
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int nThreadID; //Thread's ID ob)D{4B'  
boolean bDownOver = false; //Downing is over u^^jt(j  
boolean bStop = false; //Stop identical | ~>7_:  
FileAccessI fileAccessI = null; //File Access interface ) d'H&c3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VFnxj52<  
{ $K\e Pfk  
this.sURL = sURL; M e:l)8+  
this.nStartPos = nStart; :iE`=( o  
this.nEndPos = nEnd; 3rN}iSF^  
nThreadID = id; @Ss W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 97}l`z;Z  
} [F,s=,S'M  
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public void run() 4%SA%]a L1  
{ Z/e[$xT <  
while(nStartPos < nEndPos && !bStop) lO1]P&@  
{ |1+mHp  
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try{ (~#-J7
 
URL url = new URL(sURL); CG
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #BI Z|  
httpConnection.setRequestProperty("User-Agent","NetFox"); YE-}1&8  
String sProperty = "bytes="+nStartPos+"-"; !~}@Eoii4  
httpConnection.setRequestProperty("RANGE",sProperty); OI^qX;#Kd  
Utility.log(sProperty); 9_%??@^>  
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InputStream input = httpConnection.getInputStream(); 6eK7Jv\K  
//logResponseHead(httpConnection); 9u_D@A"aC`  
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byte[] b = new byte[1024]; A4TW`g_zm  
int nRead; U~8, N[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >\s+A2P  
{ p!`S]\XEB  
nStartPos += fileAccessI.write(b,0,nRead); FMqes5\ 3  
//if(nThreadID == 1) :LTjV"f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R9~c: A4G  
} +!-U+W  
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Utility.log("Thread " + nThreadID + " is over!"); e,@5`aYHM@  
bDownOver = true; 34aSRFsk*  
//nPos = fileAccessI.write (b,0,nRead); " 8g\UR"[  
} >q1rdq  
catch(Exception e){e.printStackTrace ();} %VO>6iVn  
} VO7&<Y}{x  
} Z`y%#B6x.  
;*>Y8^K&Q  
 G`8i{3:  
//打印回应的头信息 >Vc;s!R  
public void logResponseHead(HttpURLConnection con) *WdnP.'Y  
{ Y` t-Bg!~  
for(int i=1;;i++) @px2/x  
{ =$xxkc.~G  
String header=con.getHeaderFieldKey(i); BQ!v\1'C  
if(header!=null) cc`+rD5I-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }TE4)vXs  
Utility.log(header+" : "+con.getHeaderField(header)); p?F%a;V3  
else g:<2yT  
break; :'p+Ql~c  
} ;%wQ
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} ;U$Fz~rJ  
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public void splitterStop() 0 ~K4vSa  
{ ip.aM#  
bStop = true;  {}x{OP  
} y/{&mo1\  
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} %49^S&  
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/* f-]5Z
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**FileAccess.java Ujb7uho  
*//文件访问(定位，写) >Vp#  
package NetFox; '1rHvz`B/"  
import java.io.*; Ek#?B6s  
R/5@*mv{  
;<^t)8E  
public class FileAccessI implements Serializable{ XNZW J  
d^-sxl3}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [OTZ"XQLI  
RandomAccessFile oSavedFile; P[q`{TdV  
long nPos; L`"B;a
&  
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w&U>w@H^  
public FileAccessI() throws IOException $K-od3h4=  
{ C{gY*+  
this("",0); JIJ79HB  
} \9FWH}|  
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<OR f{  
public FileAccessI(String sName,long nPos) throws IOException LA\)B"{J  
{ FEoH$.4  
oSavedFile = new RandomAccessFile(sName,"rw"); @)h
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this.nPos = nPos; H6fR6Kr4j  
oSavedFile.seek(nPos); \7l%@  
} Wu:@+~J.h  
=A yDVWpE  
Z#Q
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public synchronized int write(byte[] b,int nStart,int nLen) IJnh@?BC  
{ iD/
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int n = -1; Adyv>T9  
try{ ]E8S`[Vn  
oSavedFile.write(b,nStart,nLen); +WGL`RP  
n = nLen; BkO)hze  
} +[2X@J  
catch(IOException e) Po+tk5}''5  
{ W5#5RK"uX  
e.printStackTrace (); !"dn!X  
} c"<bq}L7S  
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return n; ohy?l  
} JsA9Xdk`  
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} Ku W$  
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/* .%@=,+nqz  
**SiteInfoBean.java <IF\;,.c  
*/ cZ" Ut  
package NetFox; GC3:ZpV`  
0shNwV1zF  
6$'6x2,  
public class SiteInfoBean { }/Wd9x  
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J-W,^%  
private String sSiteURL; //Site's URL -9S.G  
private String sFilePath; //Saved File's Path jH*+\:UP-  
private String sFileName; //Saved File's Name !(!BW9Zt+  
private int nSplitter; //Count of Splited Downloading File $E^#DjhRQ3  
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public SiteInfoBean() ?-FSDNQ  
{//nSplitter的缺省值为5 NLJD}{8Ot  
//default value of nSplitter is 5 y>S.B/d  
this("","","",5); 3I_
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} tPS.r.0#^  
J! 4l-.-  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -=E/_c;  
{ ?=<vC  
sSiteURL= sURL; .P=uR8  
sFilePath = sPath; ? OBe!NDf  
sFileName = sName; eiZv|?^0  
this.nSplitter = nSpiltter; @o+T<}kWX  
F<?e79},`  
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} 1K'0ajl1A  
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b`n+[UCPtn  
public String getSSiteURL() s)HbBt-  
{ 9p!V?cH#8  
return sSiteURL; 'f`~"@  
} SVp]}!jI  
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qEE3x>&T]  
public void setSSiteURL(String value) Y#
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{ O0"i>}g4  
sSiteURL = value; _Z6/r^c  
} {e2 (  
1){1 HK  
3V`K^X3  
public String getSFilePath() q*A2>0O  
{ 5;V#Z@S  
return sFilePath; ;T6^cS{Gj  
} (0W%YZ!&  
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8'*z>1ZS5  
public void setSFilePath(String value) .jr1<LE  
{ bF'~&<c  
sFilePath = value; t1B0M4x9  
} "yc/8{U  
~`hI|i<]  
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public String getSFileName() h^>kjMM  
{ Xr M[8a  
return sFileName; %>i7A?L  
} PZpwi?N  
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public void setSFileName(String value) 8Mg4y1)RU  
{ ^V_acAuS^  
sFileName = value; @D"#B@j  
} D5T\X-+]O  
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jXi
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public int getNSplitter() w}NgFrL  
{ ]02 l!"  
return nSplitter; "MC&!AMv  
} 4,s: G.g  
4g\a$7r  
#TW$J/Jb  
public void setNSplitter(int nCount) l,*Q?q  
{ B[4y(Im  
nSplitter = nCount; _gC<%6#V`r  
} (:+IS W  
} ~8pf.^,fi  
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/* gyCb\y+\a  
**Utility.java GeHDc[7  
*/ W]
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package NetFox; 2z0HB+Y}x  
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$Q{1^  
public class Utility { ?783LBe  
]; ^OY\,  
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public Utility() \|62E):i1  
{ sWavxh8A  
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w,}}mC)\*  
} BLaXp0  
P< WD_W  
//线程睡眠 HENCQ_Wra  
public static void sleep(int nSecond) _a<PUdP  
{ r]HLO'<]  
try{ &-b=gnT   
Thread.sleep(nSecond); 3gabk/  
} e/Q[%y.X  
catch(Exception e) \o % ES  
{ akCl05YW  
e.printStackTrace (); &PgdCijGq;  
} iL,3g[g  
} t9`NCng 5  

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//日志 wj'iU&aca  
public static void log(String sMsg) %BG5[XQ7  
{ 1|. 0]~0  
System.err.println(sMsg); }F{C= l2  
} W(2+z5z  
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U=F-]lD  
public static void log(int sMsg) -@SOo"P  
{ mQJ4;BJw  
System.err.println(sMsg); 9fP) Fwih  
} `RL,ZoYuu  
} Gefnk!;;  
w%3Fg~Up  
)W8L91-  
/* Z 7s;F}=  
**TestMethod.java (Qk&g"I  
*/ -`!_h[   
package NetFox;
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+{xMIl_  
|N:MZ#};  
public class TestMethod {
$ViojW>  
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%Kh2E2Pe  
public TestMethod() `'p`PyMt`  
{ ///xx/weblogic60b2_win.exe 7E$eN8H  
try{ &/](HLdF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h?0F-6z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3`58ah  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ia=_78MgZ  
fileFetch.start(); i2$*}Cu  
} gyi)T?uS)  
catch(Exception e){e.printStackTrace ();} v9%nau4  
LthGZ|>  
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} =~J
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Rl_.;?v"!  
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public static void main(String[] args) Hqvc7-c6  
{ Z'Kd^`mt 9  
new TestMethod(); ^vpIZjN  
} 4P|$LkI  
} )ZHc$+fU  
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