http断点续传简单实现（java)

/* :qw:)i  
**SiteFileFetch.java `\#Qr|GC  
*/ 5E~][. d  
package NetFox; 6V!yfps)  
import java.io.*; CYG'WFvZZ  
import java.net.*; 0wxQ,PI1'  
2{ }5WH  
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public class SiteFileFetch extends Thread { qAkx52v6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -08Ys c  
long[] nStartPos; //开始位置 {}vW=  
long[] nEndPos; //结束位置 <9B43  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dqPJ 2j $\  
long nFileLength; //文件长度 @$Z5Ag!  
boolean bFirst = true; //是否第一次取文件 ^8E/I]-  
boolean bStop = false; //停止标志 _MnMT9  
File tmpFile; //文件下载的临时信息 v
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DataOutputStream output; //输出到文件的输出流 3^wJ4=^  
b-%7@j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |jO&qT]{  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1[:?oEI  
{ ;r"YZs&Xd  
siteInfoBean = bean; 9ZeTS~i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^e8~e
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d^!)',`  
if(tmpFile.exists ()) o!gl :izb  
{  (/-2bO  
bFirst = false; <A;R%\V  
read_nPos(); {I&>`?7.  
} Z455g/=ye  
else \|L ~#{a  
{ )k.;.7dXe  
nStartPos = new long[bean.getNSplitter()]; #9F=+
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nEndPos = new long[bean.getNSplitter()]; W}50E.\#  
} 5<0&y3  
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} 2,{m>fF  
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public void run() CE=&ZHt9  
{ y)0r%=  
//获得文件长度 b
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//分割文件 Fo|6 PoSo  
//实例FileSplitterFetch }te\) Yk.N  
//启动FileSplitterFetch线程 "t$c'`  
//等待子线程返回 k1e0kxn  
try{ &^=6W3RD  
if(bFirst) <5%x3e"7u  
{ D(yU:^L  
nFileLength = getFileSize(); *e&Op
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if(nFileLength == -1) l}:&}  
{ 5(W`{{AW  
System.err.println("File Length is not known!"); Rf||(KC<  
} TcPYDAa  
else if(nFileLength == -2) 4D=p#KZ  
{ vq-Tq>  
System.err.println("File is not access!"); kTZ`RW&0  
} P~HzNC  
else klm
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{ e<2?O  
for(int i=0;i<nStartPos.length;i++) FR"yGx#$  
{ $$ma1.t"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dtD)VNkBZ  
} FW~%xUSE5  
for(int i=0;i<nEndPos.length-1;i++) z UN&L7D  
{ XUTI0  
nEndPos = nStartPos[i+1]; iPgewjx  
} `"`/_al^  
nEndPos[nEndPos.length-1] = nFileLength; hfw$820y[  
} Z.TYi~d/9D  
} lMoi5q  
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//启动子线程 GvQKFgO6h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }QrBN:a$(  
for(int i=0;i<nStartPos.length;i++) >1u!(-A  
{ M+4>l\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H <7r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =pSuyM'  
nStartPos,nEndPos,i); r1dP9MT\8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jse;@K5y  
fileSplitterFetch.start(); i8t
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} 8ExEhBX8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c4H5[LPF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5~)m6]-6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cXP*?N4Cf  
nEndPos = " + nFileLength); 9HJrMX  
// fileSplitterFetch[nPos.length-1].start(); a^wGc+  
bn$a7\X-  
D2<(V,h9  
//等待子线程结束 j8gw]V/B:  
//int count = 0; YB?yi( "yL  
//是否结束while循环 "%^T~Z(_j  
boolean breakWhile = false; 'VVEd[  
2L?jp:$;X  
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while(!bStop) 5MU-Eu|*>  
{ |KH981  
write_nPos(); NHI(}Ea|]  
Utility.sleep(500); NmbA~i  
breakWhile = true; [3KP@'52k  
/4K ^-  
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for(int i=0;i<nStartPos.length;i++) uUy~
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{ <<#j?%  
if(!fileSplitterFetch.bDownOver) E(%_aFx>/  
{ J9buf}C[  
breakWhile = false; f&5'1tG  
break; b# v+_7  
} OH+kN/Fd  
} A!x
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if(breakWhile) .eZsKc-@  
break; }wY6^JF  
>s*ZT%TF  
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//count++; RH^!7W*  
//if(count>4) X
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// siteStop(); ph5rS<  
} E![Ye@w  
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System.err.println("文件下载结束！"); ^*-6PV#Z  
} <r`^iR)%  
catch(Exception e){e.printStackTrace ();} o$4xi
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} * |dz.Tr  
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4ju=5D];  
//获得文件长度 B_ x?s  
public long getFileSize() N?Nu'  
{ [v%j?  
int nFileLength = -1; m N&G  
try{ ~R+,4  
URL url = new URL(siteInfoBean.getSSiteURL()); dm:2:A8^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CW+]Jv]"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7kT&}`g.  
!:^?GN#~x  
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int responseCode=httpConnection.getResponseCode(); C)z?-f  
if(responseCode>=400) mD"[z}r)  
{ U)sw IisE  
processErrorCode(responseCode); [11D7L%1t  
return -2; //-2 represent access is error cxig<W  
} UgP  
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String sHeader; lK2=[%,~  
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for(int i=1;;i++) UzKB"Q  
{ *~%QXNn`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tso\bxiU  
//Utility.log(in.readLine()); &`LR{7m  
sHeader=httpConnection.getHeaderFieldKey(i); 7W]0bJK+E  
if(sHeader!=null) K @h94Ni6  
{ 12TX_0  
if(sHeader.equals("Content-Length")) W2T-TI,>PC  
{ bQ`|G(g-d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); AcQmY?  
break; Evy_I+l  
} F5s`AjU  
} h~r&7G@[}  
else $a.,;:  
break; LUfo@R  
} d cG)ql4d  
} fpA%
:V  
catch(IOException e){e.printStackTrace ();} T$&vk#qr  
catch(Exception e){e.printStackTrace ();} ? \p,s-CR:  
u+Sj#iZ  
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j  
Utility.log(nFileLength); ypy  
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return nFileLength; +]$c+!khj  
} ,1e\}^  
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//保存下载信息（文件指针位置） ,: Z7P@  
private void write_nPos() r3mmi5   
{ fI"OzIJV  
try{ S '(K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rl[SqmnI)@  
output.writeInt(nStartPos.length); X ApSKJ  
for(int i=0;i<nStartPos.length;i++) ]r@CmwC  
{ 6|B;C  
// output.writeLong(nPos); =`/GBT$  
output.writeLong(fileSplitterFetch.nStartPos); G"|c_qX  
output.writeLong(fileSplitterFetch.nEndPos); a?]~Sw"@  
} y*vg9`$k  
output.close(); ~aL&,
0  
} _M)J{ {?:  
catch(IOException e){e.printStackTrace ();} >)8<d3m  
catch(Exception e){e.printStackTrace ();} ^2-+MWW.  
} z:W|GDD1  
+BgUnu26  
' )~G2Ys  
//读取保存的下载信息（文件指针位置） yGE)EBH  
private void read_nPos() 5fuYva >Ik  
{ ~n{lu'SIX2  
try{ |TRl>1rv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wak`Jte=}m  
int nCount = input.readInt(); Ur,{ZGm  
nStartPos = new long[nCount]; n|Gw?@CU7  
nEndPos = new long[nCount]; Y=(%t:#_  
for(int i=0;i<nStartPos.length;i++) miEf<<L#z  
{ 'da$i  
nStartPos = input.readLong(); !I+F8p   
nEndPos = input.readLong(); l
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} 3fq'<5 ^  
input.close(); CW'<Nh  
} tvR|!N }  
catch(IOException e){e.printStackTrace ();} N51WY7  
catch(Exception e){e.printStackTrace ();} m4 :"c"  
} =0_((eXwf  
CQI\/oaO  
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private void processErrorCode(int nErrorCode) _GsHT\  
{ n~'cKy)m  
System.err.println("Error Code : " + nErrorCode); )(W%Hmi  
} 4$Ud4<  
ea6`%,lF~  
}-%:!*bLj  
//停止文件下载 (F'?c1  
public void siteStop() Mk|*=#e;  
{ cW?~]E'<  
bStop = true; E#/vgm=W;  
for(int i=0;i<nStartPos.length;i++) 3O!TVSo  
fileSplitterFetch.splitterStop(); Rooem dCM  
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1WMwTBHy+  
} FI|@=l;_  
} Q8
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7  
//负责部分文件的抓取 o4g<[X)  
**FileSplitterFetch.java 9QryW\6.@z  
*/ 3U73_=>=&  
package NetFox; m+/-SG  
34P5[j!h  
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import java.io.*; RU^l
R8
;  
import java.net.*; =2=n   
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public class FileSplitterFetch extends Thread { StuDtY  
,lly=OhKb  
4f?Y'+>Z,  
String sURL; //File URL n/3gx4.g  
long nStartPos; //File Snippet Start Position De*Z UN|<  
long nEndPos; //File Snippet End Position boR&'yX  
int nThreadID; //Thread's ID 6:Nz=sw8  
boolean bDownOver = false; //Downing is over  }Rc8\,  
boolean bStop = false; //Stop identical ]'UO]i/  
FileAccessI fileAccessI = null; //File Access interface U-#t&yjh#  
Sr`gQ#b@r}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aQEMCWxZ  
{ %q@eCN  
this.sURL = sURL; ?wR;"  
this.nStartPos = nStart; d&p]O  
this.nEndPos = nEnd; 
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nThreadID = id; rwlV\BU
  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L/w9dk*uv  
} y/m^G=Q6g#  
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public void run() lq$1CI  
{ _ID2yJ  
while(nStartPos < nEndPos && !bStop) *Bt`6u.>e,  
{ WRJ+l_81  
*a@pZI0'  
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try{ b\%=mN
 
URL url = new URL(sURL); KZL5>
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?'K}bmdt}.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'r%`(Z{~  
String sProperty = "bytes="+nStartPos+"-"; PiZt?r?5w|  
httpConnection.setRequestProperty("RANGE",sProperty); Lrr^ob
c  
Utility.log(sProperty); :XMw="u=  
*_$%Tv.]  
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InputStream input = httpConnection.getInputStream(); vL13~q*F  
//logResponseHead(httpConnection); 9jiZtwRpk  
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byte[] b = new byte[1024]; 2C%{A  
int nRead; I<.3"F1}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +7o3TA]-  
{ bG>pm|/  
nStartPos += fileAccessI.write(b,0,nRead); HB\y [:E  
//if(nThreadID == 1) ASAz<H$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9c806>]U^  
} o:#MP(h,N  
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Utility.log("Thread " + nThreadID + " is over!"); q+t*3;X.  
bDownOver = true; K2L+tw  
//nPos = fileAccessI.write (b,0,nRead); QQ97BP7W  
} F5.V
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catch(Exception e){e.printStackTrace ();} !O)Ruwy  
} d>NElug  
} Og%qv Bj 6  
%Md;=,a:6  
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//打印回应的头信息 @6ZQkX/  
public void logResponseHead(HttpURLConnection con) c3!d4mC:  
{ Hbx=vLQ6  
for(int i=1;;i++) 9wC q  
{ bR49(K$~  
String header=con.getHeaderFieldKey(i); A;w,m{9<  
if(header!=null) >t?;*K\x"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tp_*U,  
Utility.log(header+" : "+con.getHeaderField(header)); uFb&WIo1  
else Az6f I*yP  
break; Q9X_aB0  
} `>'E4z]-_  
} qJVW :$1q  
+D`IcR-x  
# o)a`,f  
public void splitterStop() e0+N1kY  
{ k%/Z.4vQG  
bStop = true; +Ld4e]  
} ed2QGTgR  
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} yFshV\  
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RXb+"/  
/* 3F[z]B  
**FileAccess.java U8?QyG 2A  
*//文件访问(定位，写) 5)2lZ(5.A#  
package NetFox; |9jeOV}/  
import java.io.*; 4rc4}Yu,JI  
y!."FoQ  
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public class FileAccessI implements Serializable{ BE:HO^-.1  
/^i7^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C\j|+s  
RandomAccessFile oSavedFile; My76]\Psh  
long nPos; g03I<<|@  
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public FileAccessI() throws IOException vkOCyi?c  
{ 6OF&Q`*4  
this("",0); s6lo11  
} B5~S&HQ?B6  
,H2[["1DH
 
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public FileAccessI(String sName,long nPos) throws IOException ow!utAF  
{ H? Z5ex  
oSavedFile = new RandomAccessFile(sName,"rw"); '0[D-jEr  
this.nPos = nPos; ;x$,x-  
oSavedFile.seek(nPos); f6j;Y<}' g  
} (Gp/^[.%&  
B?`Gs^Y{z  
s%2w&Us*  
public synchronized int write(byte[] b,int nStart,int nLen) uK6R+a  
{ a"EX<6"  
int n = -1; 3'}(:X(  
try{ 2
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oSavedFile.write(b,nStart,nLen); / Of*II&  
n = nLen; 3vfm$sx@  
} ?{NP3  
catch(IOException e) R?b3G4~  
{ >\y|}|?  
e.printStackTrace (); pwtB{6)VH{  
}  s!X@ l  
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return n; dlmF?N|EC  
} fb
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}:<`L\8q\  
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} Q1yMI8  
8[\F*H  
}^U7NZn<"  
/* ebK/cPa8  
**SiteInfoBean.java s!(O7Ub  
*/ F7P?*!dx  
package NetFox; ?~X*\  
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%Hx8%G!  
public class SiteInfoBean { &YC Z L  
%Xc50n2Z  
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private String sSiteURL; //Site's URL FcVQ_6  
private String sFilePath; //Saved File's Path A#;6~f  
private String sFileName; //Saved File's Name 2[!#Xf  
private int nSplitter; //Count of Splited Downloading File U4)x"s[CP  
$/*19e~  
}MQNzaXY^  
public SiteInfoBean() ^/@Z4(E  
{//nSplitter的缺省值为5 p+M#hF5o  
//default value of nSplitter is 5 Q+@/.qJ  
this("","","",5); r9MS,KG8  
} Q^13KWvuV  
&!i'Q;q  
sNB*S{   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _G3L+
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{ Q1f)uwh  
sSiteURL= sURL; K^32nQX  
sFilePath = sPath; s/Ne,v  
sFileName = sName; QguRU|y  
this.nSplitter = nSpiltter; )/4eT\=  
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?{=&Ro  
} RJ}%pA4I  

hA=.${uIO  
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public String getSSiteURL() eBT+|  
{ .X1xpi%  
return sSiteURL; ohEIr2  
} ,4W~CkLD  
r?9D/|`  
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public void setSSiteURL(String value) n[[2<s*YJ  
{ 9}-;OJe  
sSiteURL = value; Sb QM!Q  
} >o/+z18x
 
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public String getSFilePath() r..&6-%:N  
{ P~}Yj@2  
return sFilePath; fEJF3<UF&  
} E;1QD/E$  
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public void setSFilePath(String value) R6m6bsZ`  
{ (e"\%p`  
sFilePath = value; "J(T?|t  
} 8*x/NaH /\  
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public String getSFileName() D[p_uDIz  
{ -3GlpC22  
return sFileName; qV{iUtYt  
} +b sc3  
MV.&GUez{  
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public void setSFileName(String value) 0_&5S`tj  
{ A)9F_;BY  
sFileName = value; >PS`;S!(  
} 'w"hG$".  
jp+s[rRc\{  
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public int getNSplitter() 'ZFbyt Q2  
{ P. Kfoos  
return nSplitter; /{R>o0oW  
} k0bDEz.X  
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2{|mL`$04<  
public void setNSplitter(int nCount) 8}{W.np_  
{ C]NL9Gq`  
nSplitter = nCount; a$]i8AeG  
} []hC*  
} 4(TR'_X(  
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/* ^'Qe.DW[  
**Utility.java XG01g3  
*/ !EB[L
utm  
package NetFox; d< b,].  
L(DDyA{bA  
MT{ovDA].  
public class Utility { hv#|dI=kZR  
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;CLOZ{  
public Utility() <L+y 6B  
{ OtZc;
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><H*T{
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} DgODTxiX  
Yqb3g(0
 
//线程睡眠 Qgxpq{y  
public static void sleep(int nSecond) `w EAU7m:  
{ cc{^0JT  
try{ G1G*TSf  
Thread.sleep(nSecond); Xsd+5="{N  
} 1)hO!%  
catch(Exception e) N^%7  
{ kn&>4/')  
e.printStackTrace (); lB*HLC  
} DLd1Cl:"~:  
} Xhp={p;  
IM=3n%6  
//日志 &%r<_1  
public static void log(String sMsg) "g:1br?X,9  
{ >8.o  
System.err.println(sMsg); LGq T$ O|  
} Z
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1fqJtP6  
public static void log(int sMsg) &*#Obv  
{ IIO-Jr  
System.err.println(sMsg); odhcU5  
} #D-Ttla  
} F}c}I8Ao
  
/&+*X)#v  
:
N64FR#  
/* vJ{aBx`VS  
**TestMethod.java SaFNPnk=  
*/ >>%E?'9A  
package NetFox; OCE
hwB0  
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Cq[<CPAS  
public class TestMethod { Zmz $ hr  
_&e$?hY  
cf,^7,-`"  
public TestMethod() Iad&Z8E  
{ ///xx/weblogic60b2_win.exe _B7+n"t\r  
try{ 7mA:~-.u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); odKdpa Zc[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =[LUOOR*]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S!
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fileFetch.start(); <+_WMSf;4  
} J*4T|#0  
catch(Exception e){e.printStackTrace ();} e[Jh7r>'  
22@w:  
Ud)2Mq1#M  
} g17 fge6%  
(?1
/\r  
',]^Qu`a  
public static void main(String[] args) [F+*e=wjN>  
{ GDYFhH7H  
new TestMethod(); +}iuTqu5  
} &]O^d4/  
} v]y=+* A  
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