http断点续传简单实现（java)

/* ujan2'YT  
**SiteFileFetch.java [iGL~RiXtn  
*/ '8V>:dy>  
package NetFox; -W'T3_  
import java.io.*; cZl/8?dj}  
import java.net.*; linvK.Lf  
} 3JOC!;;  
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public class SiteFileFetch extends Thread { +LB2V3UZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Gzkvj:(V  
long[] nStartPos; //开始位置 cTu"T
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long[] nEndPos; //结束位置 wNQhg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2e|m3  
long nFileLength; //文件长度 X3Yi|dyn T  
boolean bFirst = true; //是否第一次取文件 'wd&O03&  
boolean bStop = false; //停止标志 ~Hb2-V  
File tmpFile; //文件下载的临时信息 t*(buAx  
DataOutputStream output; //输出到文件的输出流 aM!%EaT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BVe c  
public SiteFileFetch(SiteInfoBean bean) throws IOException Pt\GVWi_t  
{ HMl M!Xk?  
siteInfoBean = bean; H}PZJf_E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lqZUU92;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wHE1Jqpo  
if(tmpFile.exists ()) TaNcnAY>9  
{ +Z1y1%a  
bFirst = false; 9*;OHoDh  
read_nPos(); <Oihwr@5<  
} I'e`?H t  
else %shCqS  
{ 4o,G[Cf_  
nStartPos = new long[bean.getNSplitter()]; vTq [Xe"  
nEndPos = new long[bean.getNSplitter()];  kAnK1W>  
} .~7:o.BE`n  
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} 6)[gF1  
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public void run() ?4H>1Wk
b  
{ JN>h:  
//获得文件长度 h)pYV>!d  
//分割文件 RhD
 
//实例FileSplitterFetch ?5<x$YI  
//启动FileSplitterFetch线程 EPd
 
//等待子线程返回 `L7Cf&W\l8  
try{ &h'NC%
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if(bFirst) ,&iZ*6=X?0  
{ $5N\sdyZxg  
nFileLength = getFileSize(); >?|c>HGX  
if(nFileLength == -1) bu,xIT^  
{ Wo7`gf_(  
System.err.println("File Length is not known!"); ;X%8I$Ba,  
} C8AR^FW  
else if(nFileLength == -2) X3R:^ff\  
{ 8T}Dn\f  
System.err.println("File is not access!"); h)h%y)1  
} 4MPR
  
else (o518fmR  
{ ]6@6g>f?  
for(int i=0;i<nStartPos.length;i++) 35n'sVn  
{ ^a?g~G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V@pUU~6R  
} j5MUP&/g3  
for(int i=0;i<nEndPos.length-1;i++) CS\8ej}y  
{ v{pW/Fu~  
nEndPos = nStartPos[i+1]; y,Z2`Zmu  
} Tl L\&n.$  
nEndPos[nEndPos.length-1] = nFileLength; Nn-Et
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} lQ!(lPh  
} OPJ(ub  
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//启动子线程 VYnB&3%DF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z yrjb8  
for(int i=0;i<nStartPos.length;i++) c]A @'{7  
{ tu6<>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xh@;4n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dn:1Mtj-  
nStartPos,nEndPos,i); _71&".A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q=t_m(:0  
fileSplitterFetch.start(); oQK,#>rv  
} (je`sV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j9f[){m`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "GX k;Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N14Q4v-*x  
nEndPos = " + nFileLength); FB2{qG3  
// fileSplitterFetch[nPos.length-1].start(); Wn&9R j  
=kjD ]+l  
3u/ Grs
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//等待子线程结束 N*SUA4bnuM  
//int count = 0; @`XbM7D 5  
//是否结束while循环 EAV6qW\r5]  
boolean breakWhile = false; +Ou<-EQV  
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while(!bStop) @T] G5|\ok  
{ vDC
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write_nPos(); JfRqOEP4Y  
Utility.sleep(500); ufo\p=pGG  
breakWhile = true; &Xi]0\M)  
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%  
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for(int i=0;i<nStartPos.length;i++) BFZ\\rN`  
{ ?I"FmJ;
 
if(!fileSplitterFetch.bDownOver) ?KG4Z
  
{ ~(]'ah,  
breakWhile = false; 5?*Iaw  
break; 4@=[rZb9  
} P5__[aTD  
} 00pe4^U  
if(breakWhile) x\8gb
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break; zQoJ8i>  
R~BFZF>:  
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//count++; 5MK.>3fE  
//if(count>4) )}@Z*.HZL  
// siteStop(); +>Pq]{Uf1j  
} j-zWckT{  
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System.err.println("文件下载结束！"); #rQT)n  
} vHN/~k#  
catch(Exception e){e.printStackTrace ();} .F3~eas  
} [nLd>2P  
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g ,yB^^%  
//获得文件长度 GW2v&Ul7(  
public long getFileSize() %'ea
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{ jvhD_L/  
int nFileLength = -1; Tsocc5gWZ*  
try{ h9QQ8}g  
URL url = new URL(siteInfoBean.getSSiteURL()); :=\`P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h<i.Z7F;tj  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5hfx2O)  
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int responseCode=httpConnection.getResponseCode(); 
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if(responseCode>=400) 0aGAF ]  
{ Y#FSU#a$<  
processErrorCode(responseCode); 64D4*GQ  
return -2; //-2 represent access is error TIxlLOs
 
} S"/gZfxer  
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String sHeader; JC9OL.Ob  
:<uCi\9(  
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for(int i=1;;i++) 1~vv<`-  
{ 5"w%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); Z|j\_VKhl  
sHeader=httpConnection.getHeaderFieldKey(i); D!D}mPi[  
if(sHeader!=null) >Sm#-4B-  
{ Pz-=Eq  
if(sHeader.equals("Content-Length")) M] W5%3do  
{ ;V^I>-fnm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MT<3OKo?:  
break;
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} 2>im'x 5  
} EC?U#!kv  
else 4}Hf"L[ l  
break; n yNHjn |W  
} ;h#CT#R2  
} Q#Xa]A-  
catch(IOException e){e.printStackTrace ();} IXsOTBM  
catch(Exception e){e.printStackTrace ();} a2H_8iQ!  
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Utility.log(nFileLength); E /V`NqC  
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return nFileLength; K_V$ktL  
} 6/Z 8/PL  
;MjOs&1f0K  
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//保存下载信息（文件指针位置） #4!6pMW(&7  
private void write_nPos() %`:+A?zL  
{ rE\.[mFI  
try{ vo2TP:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 66cP
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output.writeInt(nStartPos.length); 92L{be;SY  
for(int i=0;i<nStartPos.length;i++) j,#R?Ig  
{ ]BBjFs4#  
// output.writeLong(nPos); )F:UkS  
output.writeLong(fileSplitterFetch.nStartPos); H$]FUv8  
output.writeLong(fileSplitterFetch.nEndPos); [RHji47  
} S;S_<GX  
output.close(); cin3)lm  
} ow,=M%x"0  
catch(IOException e){e.printStackTrace ();} SL>0_
 
catch(Exception e){e.printStackTrace ();} Y--Uo|
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} 3/2G~$C  
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//读取保存的下载信息（文件指针位置） WK6|e[iP  
private void read_nPos() )rv<"  
{ I`EgR?5 `  
try{ `<d{(9:+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pJ]i)$M  
int nCount = input.readInt(); 1fb!sbGD.k  
nStartPos = new long[nCount]; FcZ)_m6m  
nEndPos = new long[nCount]; ~UV$(5&-  
for(int i=0;i<nStartPos.length;i++) )F4P-u  
{ yn-TN_/Y,  
nStartPos = input.readLong(); < 5#}EiT5  
nEndPos = input.readLong(); V .VV:`S  
} x$aFJCL  
input.close(); 7 {#^zr  
} J2~oIe2!+  
catch(IOException e){e.printStackTrace ();} 4';(\42  
catch(Exception e){e.printStackTrace ();} pwO U6A!  
} Qz/1^xy  
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private void processErrorCode(int nErrorCode) .[4Dvt|>6  
{ *^P$^lm?S  
System.err.println("Error Code : " + nErrorCode); E`>u*D$un~  
} H:M;H=0  
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q%A.)1<'_  
//停止文件下载 knJoVo]  
public void siteStop() |cUBS)
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{ |v%xOl  
bStop = true; 5Mq7l$]h$  
for(int i=0;i<nStartPos.length;i++) &%4*~;o  
fileSplitterFetch.splitterStop(); uKocEWB=/F  
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} csay\Q{  
} 1#<KZN =$  
//负责部分文件的抓取 4w5mn6MxR  
**FileSplitterFetch.java Fz4g:8qdA  
*/ bR}{xHe  
package NetFox; 5?n@.hcL  
,HE +|y#  
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import java.io.*; +Tw]u`  
import java.net.*; &.}Zj*BD  
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public class FileSplitterFetch extends Thread { \E<t'\>@X  
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String sURL; //File URL uY6|LTK&x  
long nStartPos; //File Snippet Start Position 3bW(VvgcL4  
long nEndPos; //File Snippet End Position ;<=B I!  
int nThreadID; //Thread's ID R2[-Q"|Ra  
boolean bDownOver = false; //Downing is over u\
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boolean bStop = false; //Stop identical hqKftk)+  
FileAccessI fileAccessI = null; //File Access interface {)8!>K%G  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1k8zAtuj  
{ (;@\gRL  
this.sURL = sURL; ]wQ#8}zO  
this.nStartPos = nStart; <x|P}  
this.nEndPos = nEnd; /{9"O y7E  
nThreadID = id; Dqw?3 KB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?$#,h30  
} #,KjJ  
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public void run() d;$<K  
{ _26<}&]b*  
while(nStartPos < nEndPos && !bStop) *N;# _0)/  
{ /M1 /  
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try{ oe
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URL url = new URL(sURL); 1eZ759PoO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /b)V=mcR  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~j`;$o  
String sProperty = "bytes="+nStartPos+"-"; 9y~5@/32R  
httpConnection.setRequestProperty("RANGE",sProperty); Yc,qXK-  
Utility.log(sProperty); azxGUS_i<  
#Wz7ju;  
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InputStream input = httpConnection.getInputStream(); 8"zFTP*;u  
//logResponseHead(httpConnection); d,_Ky#K5b  
n!r<\4I  
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byte[] b = new byte[1024]; Whd2mKwiO  
int nRead; H7xyK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $#k8xb  
{ ]d}U68$T+  
nStartPos += fileAccessI.write(b,0,nRead); %`cP|k  
//if(nThreadID == 1) B3lP#ckh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m;S!E-W  
} h}k/okG  
!`rR;5&sT  
a}Dx"zl;  
Utility.log("Thread " + nThreadID + " is over!"); FSs<A@  
bDownOver = true; D[7+xAwS  
//nPos = fileAccessI.write (b,0,nRead); |Mj2lZS  
} 8<Y*@1*j  
catch(Exception e){e.printStackTrace ();} BJ0P1vh6M  
} %V+hm5Q  
} W_%
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//打印回应的头信息 I,*zZNvRi  
public void logResponseHead(HttpURLConnection con) xb2xl.2x!  
{ ,[ UqUEO  
for(int i=1;;i++) OM]d}}=Y  
{ zT\nj&7  
String header=con.getHeaderFieldKey(i); 6`tc]a"#Zb  
if(header!=null) DHUK_#!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |#_F  
Utility.log(header+" : "+con.getHeaderField(header)); s+@+<QE  
else m0I)_R#X[  
break; |L@&plyB-  
} &DX&*Xq2  
} /Ria"lLv  
% Rv;e  
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public void splitterStop() 8QYP\7}o  
{
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bStop = true; )(?,1>k`Z  
} j
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;.O#|Z[  
} xnuu#@f  
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/* Z
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**FileAccess.java _(U|Kpi  
*//文件访问(定位，写) ^V1.Y  
package NetFox; \iBEyr]  
import java.io.*; K@JGGgrE`!  
S,ENbP%0r  
~o_zV'^f@o  
public class FileAccessI implements Serializable{ mW/6FC  
[MQU~+]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 kB2]Z}  
RandomAccessFile oSavedFile; P}2i[m.*,  
long nPos; ~rUcko8  
6.!aJJLN  
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public FileAccessI() throws IOException ,P%a0\  
{ 5f~49(v]  
this("",0); UABaS(f3  
} %`4\ 8H`  
sjZ@}Vk3b  
'`)r<lYN,  
public FileAccessI(String sName,long nPos) throws IOException w$aiVOjgT  
{ }nsxo5WP  
oSavedFile = new RandomAccessFile(sName,"rw"); :t7M'BSm2z  
this.nPos = nPos; ?tA<:.<vtY  
oSavedFile.seek(nPos); ujLz<5gKuO  
} ul-A'  
z]twh&^1L  
33M10 1X{6  
public synchronized int write(byte[] b,int nStart,int nLen) z0jF.ub  
{ tL#]G?0d  
int n = -1; @VzD>?)  
try{ NwISf  
oSavedFile.write(b,nStart,nLen); *_ U=KpZ
F  
n = nLen; pX/42W  
} !4/s|b
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catch(IOException e) ~jpdDV&u\  
{ ru#CywK{{;  
e.printStackTrace (); 7 {n>0@_  
} %>mB"Y,  
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return n; Pf,lZU?f  
} ]\.3<^  
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} O$K?2-  
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/* J;|i6q q  
**SiteInfoBean.java 67{3/(`x  
*/ -s!cZ3  
package NetFox; ng-rvr  
uto E}U7]  
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public class SiteInfoBean { 4#fgUlV  
}vXf}2C  
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private String sSiteURL; //Site's URL %8]~+#]p  
private String sFilePath; //Saved File's Path (nUSgZz5  
private String sFileName; //Saved File's Name =iFI@2  
private int nSplitter; //Count of Splited Downloading File 8wX|hK!Gz  
M
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public SiteInfoBean() YM`I&!n  
{//nSplitter的缺省值为5 5ieF8F%  
//default value of nSplitter is 5 v6#i>n~x,  
this("","","",5); qJyGr ?  
} "?f_U/+D<  
<`P7^ 'z!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) # VAL\Z  
{ iuGly~  
sSiteURL= sURL; 4r-CF#o  
sFilePath = sPath; .1@8rVp7  
sFileName = sName; TEEt]R-y  
this.nSplitter = nSpiltter; \:pd+8  
+W}dO#  
dSkx*#FEE  
} 9N*!C{VW  
a?NoNv)&  
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public String getSSiteURL() 7FYq6wi  
{ Tz<@k  
return sSiteURL; _]"uq/UWp  
} q Xj]O3 mm  
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public void setSSiteURL(String value) 8_h:_7e  
{ !gX(Vh*k  
sSiteURL = value; bH1MDBb2  
} v9K=\ j  
f$I$A(0P  
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public String getSFilePath() -q")qNt.  
{ hha!uD~(  
return sFilePath; dZ;rn!dg>  
} s^lm 81;  
9'I$8Su  
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public void setSFilePath(String value) MWHzrqCA  
{ 7c>{og6  
sFilePath = value; $>6Kn`UX  
} ll#_v^  
h#?)H7ft  
G$7!/O%#_  
public String getSFileName() hG!|
ts  
{ dxk~  
return sFileName; o7^u@*"F  
} 
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public void setSFileName(String value) f`Wces=5  
{ YLkdT%  
sFileName = value; y|h:{<  
} vIpitbFC  
f J$>VN  
=+>^:3cCQ  
public int getNSplitter() E7AYK&  
{ -s,guW |  
return nSplitter; yTpvKCC  
} 5 cz6\A&  
2y` :#e`x1  
je`w$ ^w  
public void setNSplitter(int nCount) &br_opNi  
{ r6:c<p[c  
nSplitter = nCount; ]<<+#Rg  
} > a"4aYj  
} VU ,tCTXz  
("T8mt[w>  
6,j&u7  
/* NWt5)xl  
**Utility.java Ou,Eu05jt'  
*/ &8'QD~  
package NetFox; aX,ux9#  
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public class Utility { Y>a2w zr  
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{q
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public Utility() J]mq|vE  
{ n.tJ-l5[  
r>.^4Z@  
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} ~h@<14c{X  
~ s# !\Ye  
//线程睡眠 e,rCutA)  
public static void sleep(int nSecond) &Rxy]kBA  
{ * u{CnH  
try{ Yt#e[CYnu  
Thread.sleep(nSecond); Zg2F%f$Y  
} <h<4R Rj  
catch(Exception e) ^Z
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{ ?KF.v1w7  
e.printStackTrace (); 6z>Zm1
h  
} #M5[TN!  
} .pd_SQ~  
:"e,& %  
//日志 F2k)hG*|{  
public static void log(String sMsg) N,Ys}qP  
{ q[T='!Z\  
System.err.println(sMsg); :.%Hu9=GL  
} Kl)PF),  
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public static void log(int sMsg) ' *x?8-KP  
{ ee5QZ,  
System.err.println(sMsg); jhmWwT/O8^  
} "Ca?liy  
}
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@vc
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7<?~A6  
/* )s';m$  
**TestMethod.java %}%vey  
*/ %`Q<_LTU  
package NetFox; #Kp/AN5YC  
!Qd4Y=  
B U^3Ux$  
public class TestMethod { Z*Qra4GBl]  
(&x#VmDL  
]/y&5X  
public TestMethod() &%/kPF~<  
{ ///xx/weblogic60b2_win.exe {Noa4i  
try{ HBc^[fJ^-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y"U -Rc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zg@NMT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '[h|f  
fileFetch.start(); /o19/Pvwm  
} tE: m& ;I  
catch(Exception e){e.printStackTrace ();} %kg%ttu7  
,&\uuD&.
@  
>/DyR+?>4  
} >|[74#}7  
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uK`T1*_  
public static void main(String[] args) 27t23@{YL  
{ HZ1e~IIw  
new TestMethod(); wM;9plYlw0  
} `.FvuwP  
} TuBl9 p'6  
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