http断点续传简单实现（java)

/* 2sT\+C&H  
**SiteFileFetch.java S{qsq\X  
*/ 5<|X++y}8)  
package NetFox; w'P!<JaZ  
import java.io.*; THnZbh4#)  
import java.net.*; P64<O5l/  
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public class SiteFileFetch extends Thread { f.Ms3))  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Y/G~P,9  
long[] nStartPos; //开始位置 n7'X.=o7  
long[] nEndPos; //结束位置  76EMS?e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >3y:cPTM5  
long nFileLength; //文件长度 GP=&S|hi  
boolean bFirst = true; //是否第一次取文件 >66v+  
boolean bStop = false; //停止标志 @Yh%.#\i%  
File tmpFile; //文件下载的临时信息 IVSd,AR7yY  
DataOutputStream output; //输出到文件的输出流 YW^sf,zQ  
b`DPf@p^kc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~.8p8\H  
public SiteFileFetch(SiteInfoBean bean) throws IOException R8fB 8 )  
{ LT)G"U~  
siteInfoBean = bean; 9K_p4 mq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Xh"8uJD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |ea}+N  
if(tmpFile.exists ()) ~Z x_"  
{ P:v|JER   
bFirst = false; $oH?7sj  
read_nPos(); of?'FrU  
} @#&y  
else .06[*S  
{ |1^ !rHg  
nStartPos = new long[bean.getNSplitter()]; kY`L[1G$  
nEndPos = new long[bean.getNSplitter()]; K1^x+I7%U[  
} Py-}tFr  
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} lAx^!#
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public void run() ($Ck5`_MK  
{ y4~;H{!  
//获得文件长度 wdTjJfr
 
//分割文件 by0M(h  
//实例FileSplitterFetch $${9 %qPzb  
//启动FileSplitterFetch线程 D$G:#z*  
//等待子线程返回 R(N5K4J  
try{ X2hyxTOp  
if(bFirst) fkK42*U@r  
{ \Dr?}D  
nFileLength = getFileSize(); ".T&nS[z  
if(nFileLength == -1) K,L  
{ (uskVK>L  
System.err.println("File Length is not known!"); NU$?BiB?R  
} 8^6
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else if(nFileLength == -2) ^K n{L  
{ mA>u6Rlc  
System.err.println("File is not access!"); T_b$8GYfCY  
} Q{+N{/tF  
else z\?cazQ  
{ WEFvJ0]  
for(int i=0;i<nStartPos.length;i++) 'J"m`a8no  
{ 7>>6c7e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); dUL3UY3  
} DZ~qk+,I  
for(int i=0;i<nEndPos.length-1;i++) gl~>MasV&  
{ {%Q&CQG_  
nEndPos = nStartPos[i+1]; ;UG]ckV-  
} BX=YS)  
nEndPos[nEndPos.length-1] = nFileLength; F~tT5?+  
} SN/ e41  
} ]Sgc42hk  
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j^'op|l  
//启动子线程 /K<.$B8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UuvI?D  
for(int i=0;i<nStartPos.length;i++) n; fUwon  
{ 9>na3ISh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +Pm yFJH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (r+#}z}  
nStartPos,nEndPos,i); ?Wz rv&E2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |VRzIA4M\  
fileSplitterFetch.start(); O4i5fVy{  
} }+Ne)B E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jLu`DKB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); szx7CP`<8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W4~:3Sk  
nEndPos = " + nFileLength); Ot#O];3  
// fileSplitterFetch[nPos.length-1].start(); iI(7{$y  
G 0;5I_D/  
dy%#E2f  
//等待子线程结束 Ysz&/ry  
//int count = 0; Apx
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//是否结束while循环 i-`n5,  
boolean breakWhile = false; R<jt$--H  
}+4^ZbX+:  
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while(!bStop) 1EvK\  
{ {Ex*8sU%p%  
write_nPos(); %t:pG}A>:C  
Utility.sleep(500); \KJ\>2Y  
breakWhile = true; 3A(sT}  
}+1Y>W7q  
Eu^?e  
for(int i=0;i<nStartPos.length;i++) {Bb:S"7NX  
{ s]z-d!G  
if(!fileSplitterFetch.bDownOver) SsE8;IGH  
{ "Wz#<! .r  
breakWhile = false; . w_oWmD  
break; }+fMYgw  
} R|Lr@k{6+r  
} 05cyWg9a  
if(breakWhile) [spJ%AhV  
break; L| uoFG{  
~:\QC  
#gL$~.1  
//count++; |/R)FT#i  
//if(count>4) W%xg;uzp  
// siteStop(); MWxv\o   
} }bxW@(bs  
0*F{=X~L  
x!08FL)  
System.err.println("文件下载结束！"); F.0
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} Gz9w1[t  
catch(Exception e){e.printStackTrace ();} `N69xAiy  
} Ikn)XZU^  
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//获得文件长度 D~i m1h;>  
public long getFileSize() {{WA=\N8C  
{ (A\p5@ht  
int nFileLength = -1; xA-u%Vf7@  
try{ Wp[R$/uT  
URL url = new URL(siteInfoBean.getSSiteURL()); &Q85Bq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eKq`t.*Ft  
httpConnection.setRequestProperty("User-Agent","NetFox"); _ xAL0 (  
k9ThWo/#u  
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int responseCode=httpConnection.getResponseCode(); T7!"gJ  
if(responseCode>=400) ^\z.E?v%  
{ <{"]&bl  
processErrorCode(responseCode); El}."}l&  
return -2; //-2 represent access is error =D2jJk?AX  
} .9< i  
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String sHeader; cnUYhxE+s  
8$H_:*A?  
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for(int i=1;;i++) YtzB/q8I  
{ ptrQ~m-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5jTBPct   
//Utility.log(in.readLine()); Aqwjs 3  
sHeader=httpConnection.getHeaderFieldKey(i); 8%dE$smH  
if(sHeader!=null) ){PL6|5x  
{ BixKK$Lo  
if(sHeader.equals("Content-Length")) &3SQVOW ~T  
{ 8e`'Ox_5a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {PXN$p:'  
break; GtCbzNY  
} ]5+db0  
} lm?1 K:+[  
else L|7F%oR  
break; Q!%4Iq%jr  
} :
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} uz(3ml^S  
catch(IOException e){e.printStackTrace ();} :jol Nl|a  
catch(Exception e){e.printStackTrace ();} /$ -^k[%  
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Utility.log(nFileLength); dc.oK4G}  
:Kl~hzVSOa  
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return nFileLength; |6%B2I&c  
} 'Y ZYRFWXM  
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//保存下载信息（文件指针位置） h@5mVTb}i  
private void write_nPos() TsPx"+>7`  
{ y&HfF~  
try{ fgs){Ng`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .#M'  
output.writeInt(nStartPos.length);
#bqc}h9  
for(int i=0;i<nStartPos.length;i++) l Ikh4T6i  
{ G d".zsn  
// output.writeLong(nPos); 1^*M*>&d<  
output.writeLong(fileSplitterFetch.nStartPos); z%Xz*uu(|  
output.writeLong(fileSplitterFetch.nEndPos); VOkEDH  
} u}eqU%  
output.close(); y5d=r]_S:  
} E|(T(4;  
catch(IOException e){e.printStackTrace ();} s&<6{AU(id  
catch(Exception e){e.printStackTrace ();} X}~5%B(  
} \ 2$nFr?0  
+bG^SH2ke  
s~@4  
//读取保存的下载信息（文件指针位置） ~w&P]L\dB  
private void read_nPos() QEe\1>1"&  
{ /B$9B  
try{ `aj;F
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7X h'VOljB  
int nCount = input.readInt(); Op&i6V}<s  
nStartPos = new long[nCount]; 3;wAm/Z:Q  
nEndPos = new long[nCount]; }r}$8M+1  
for(int i=0;i<nStartPos.length;i++) }tvLe3O  
{ l\PDou@5  
nStartPos = input.readLong(); j4ARGkK5B  
nEndPos = input.readLong(); qUH02"z@9  
} YEL,TU  
input.close(); GOT@  
} (v11;kdJB  
catch(IOException e){e.printStackTrace ();} OJ (ho&((  
catch(Exception e){e.printStackTrace ();} Ow0-}Im~  
} Zc_%hQf2A  
xWwQm'I2}  
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private void processErrorCode(int nErrorCode) Z/#&c  
{ v99gI%TA'  
System.err.println("Error Code : " + nErrorCode); P}] xz Vy  
} HN/ %(y  
v"y0D  
0b)^#+  
//停止文件下载 FT*OF 3  
public void siteStop() ,_STt)  
{ {XT3M{`rWL  
bStop = true; &n_aMZ;  
for(int i=0;i<nStartPos.length;i++) :L~{Q>o  
fileSplitterFetch.splitterStop(); pzX684  
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|v,5s=}7  
} N7S?m@  
} RoV^sbWFt  
//负责部分文件的抓取 n"[VM=YGI  
**FileSplitterFetch.java *Nv!Kuk  
*/ cs'ylGH  
package NetFox; (=hXt=hZ  
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import java.io.*; !H,_*u.  
import java.net.*; \+]U1^
 
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public class FileSplitterFetch extends Thread { 2E V M*^A  
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String sURL; //File URL vx:MLmZ.  
long nStartPos; //File Snippet Start Position c4]/{!4 Q  
long nEndPos; //File Snippet End Position "A_,Ga  
int nThreadID; //Thread's ID ]2^tV.^S^  
boolean bDownOver = false; //Downing is over e,Ih7-=Er,  
boolean bStop = false; //Stop identical + 9vd(
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FileAccessI fileAccessI = null; //File Access interface XCQS_'D  
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!1i(6?~#4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9}~WwmC
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{ @x9DV{j)V  
this.sURL = sURL; }(x|  
this.nStartPos = nStart; ']nB_x7  
this.nEndPos = nEnd; ``%uq)G=D  
nThreadID = id; L0v& m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \,:3bY_d  
} ^%)H;  
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public void run() L@ ,-V  
{ fZoV\a6Kj  
while(nStartPos < nEndPos && !bStop) h8IjTd]z{$  
{ "qL4D4  
1!u}~E_  
',
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try{ Q o}&2m  
URL url = new URL(sURL); (C<~:Y?%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aE[>^~Lv}  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1-_op!N  
String sProperty = "bytes="+nStartPos+"-"; 5gZEcJ  
httpConnection.setRequestProperty("RANGE",sProperty); 68m
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Utility.log(sProperty); O]ZP- WG  
' 0iXx   
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InputStream input = httpConnection.getInputStream(); W$&kOdD!$  
//logResponseHead(httpConnection); /u9Md3q*'  
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byte[] b = new byte[1024]; 
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int nRead; ]ne&`uO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
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{ adHZX  
nStartPos += fileAccessI.write(b,0,nRead); OBGA~E;%  
//if(nThreadID == 1) yN*HIN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E,6(/`0H*  
} D`nW9i7  
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Utility.log("Thread " + nThreadID + " is over!"); B{fPj9Y0  
bDownOver = true; 44H#8kV  
//nPos = fileAccessI.write (b,0,nRead); 13oR-Stj|  
} nC^|83  
catch(Exception e){e.printStackTrace ();} U.7;:W}c  
} X~/hv_@  
} EJ
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#;Yn8'a~  
//打印回应的头信息 u{0'"jVJ  
public void logResponseHead(HttpURLConnection con) hkzyI~7  
{ >KjyxJ7  
for(int i=1;;i++) % K$om|]p  
{ w7b?ve3-  
String header=con.getHeaderFieldKey(i); g8 (zvG;Y  
if(header!=null) |_&Tu#er3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e:9CD-  
Utility.log(header+" : "+con.getHeaderField(header)); }}a<!L,{  
else "=l<%em  
break; P;%4Imq3  
} 7aH E:Dnwp  
} liEb(<$a  
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public void splitterStop() SvUC8y  
{ Am~NBQ7  
bStop = true; xrbDqA.b  
} [aM_.[bf  
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} 3nfw:.  
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/* qaBjV6loy  
**FileAccess.java &KfRZ`9H  
*//文件访问(定位，写) #JAU5d  
package NetFox; (bfHxk
R.  
import java.io.*; zV)Ob0M7U  
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/yHM=&Vg]  
public class FileAccessI implements Serializable{ WNkAI9B  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g%z?O[CN  
RandomAccessFile oSavedFile; r>+Hwj0>  
long nPos; H \$04vkR  
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public FileAccessI() throws IOException n7~!klF-  
{ 0mB]*<x8  
this("",0); |RqCw7  
} S5:`fo^5  
ajy.K'B*  
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public FileAccessI(String sName,long nPos) throws IOException &(!Sy?tNe  
{ x{u7#s1|/  
oSavedFile = new RandomAccessFile(sName,"rw"); pm<zw-  
this.nPos = nPos; {r2-^QHF  
oSavedFile.seek(nPos); *#j+,q!X  
} ~8'4/wh+8  
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public synchronized int write(byte[] b,int nStart,int nLen) wI+oG  
{ c1
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int n = -1; Y$3H$F.+  
try{ mq$mB1$3u  
oSavedFile.write(b,nStart,nLen); CFJ F}aW  
n = nLen; z
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} ^6v ob  
catch(IOException e) ^ri?eKy.-g  
{ DJ"O`qNV3  
e.printStackTrace (); t?^C9(;6  
} sMAc+9G9k  
htbN7B(  
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return n; DKL< "#.7  
} J&~nD(&TY  
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} ocwRU0+j  
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/* YIA}F1:  
**SiteInfoBean.java wC@5[e$  
*/ Z(AI]wk3<  
package NetFox; 11}fPWK  
70!&  
Oqzz9+  
public class SiteInfoBean { }9fH`C/m  
gH-e0134%  
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private String sSiteURL; //Site's URL }Jt( H  
private String sFilePath; //Saved File's Path 4cK6B)X  
private String sFileName; //Saved File's Name UJkg|eu  
private int nSplitter; //Count of Splited Downloading File #3maT*JY  
'j=7'aX>K  
TDg#O!DUF  
public SiteInfoBean() }
~dXz?{p8  
{//nSplitter的缺省值为5 '>[KVvm  
//default value of nSplitter is 5 :bMCmY  
this("","","",5); '2=u<
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} fAWjk&9  
'Omi3LXfDT  
v=?U{{
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MjC;)z  
{ Ky`rf}cI>  
sSiteURL= sURL; +=%13cA*U  
sFilePath = sPath; [wl:"rm  
sFileName = sName; ^z3-$98=A  
this.nSplitter = nSpiltter; Ltpd:c  
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qOz,iR?}  
} $DC*&hqpt  
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")7,ZN;  
public String getSSiteURL() x Yr-,$/  
{ {e[S?1t=l  
return sSiteURL; v'*Q[ ('  
} *!UY;InanX  
}(O/y-  
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public void setSSiteURL(String value) hNUAwTH6  
{ dz.]5R  
sSiteURL = value; iC&=-$vu  
} O z%K*  
.z+?b8Q\  
1&c>v3 $2  
public String getSFilePath() 8Q^yh6z  
{ %JDG aG'  
return sFilePath; CFqoD l  
} -yeQQ4b  
:7p0JGd  
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public void setSFilePath(String value) Pgg6(O9}B^  
{ c"t1E-Nsk  
sFilePath = value; 4vTO  #F  
} k
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c\U
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}gyJaMA  
public String getSFileName() VB*N;bM^  
{ z h0m3|9O  
return sFileName; ?GU/Rf!H#  
} 4NbX!"0  
S5d:?^PGg  
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public void setSFileName(String value) 3tI=?E#  
{ sj2v*tFb  
sFileName = value; l.1)%q&@^  
} B?-RzWB\3  
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public int getNSplitter() qf+jfc(Iby  
{ ]4\^>  
return nSplitter; `LH!"M  
} -2|D( sO  
>yUThhJRn  
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public void setNSplitter(int nCount) ];6c/#2x  
{ rwFR5  
nSplitter = nCount; wRb%-s  
} 7CUu:6%  
} *103  
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/* jpyV52  
**Utility.java }p}i_'%  
*/ KSVIX!EsX  
package NetFox; (}O)pqZ>  
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>h<eEv/  
public class Utility { f2_LfbvH  
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k
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public Utility() u1`8f]qt  
{ KpC)A5u6  
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w>; :mf  
} +@]1!|@(  
n<8$_?-
 
//线程睡眠 mLk@&WxG  
public static void sleep(int nSecond) H#k"[eZ  
{ 9 f-T>}  
try{ [ar:zlV8  
Thread.sleep(nSecond); 4DEsB)%X  
} cGkl=-oQ'  
catch(Exception e) R%aH{UhE`  
{ b@^M|h.Va  
e.printStackTrace (); lZ0+:DaP2  
} T;GBZR%  
} V-A^9AAPm  
qh0)~JL4  
//日志 &o^wgmS  
public static void log(String sMsg) /`\-.S9  
{ vPmP<c)cb  
System.err.println(sMsg); h@Ea$1'e,  
}
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b-]E-$Uz  
oHI~-{m3)  
public static void log(int sMsg) XZcsx  
{ uA C:&  
System.err.println(sMsg); #1hT#YN  
} ,9|%  
} :m5& i&  
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/* FvG9PPd  
**TestMethod.java -_uL;9r  
*/ B_hob  
package NetFox; T_Z@uZom.  
_I~TpH^1K  
;07!^#:L=Q  
public class TestMethod { ;DC0LJ  
au"HIyi?k  
"c!s\iuBU  
public TestMethod() dtA- 4Ndm  
{ ///xx/weblogic60b2_win.exe ^Q!:0D*  
try{ +n,8o:fU:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \2_>$:UoV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); edGV[=]F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P(
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fileFetch.start(); PC\Xm,,  
} IS&`O=7  
catch(Exception e){e.printStackTrace ();} 0
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} mI9h| n  
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public static void main(String[] args) QIi*'21a+  
{ ,z1# |Y  
new TestMethod(); n/$BdFH  
} C^nL{ZP,  
} v^@L?{"}8  
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