http断点续传简单实现（java)

/* jCtk3No  
**SiteFileFetch.java _nzq(m1@  
*/ ziO(`"v  
package NetFox; fX,O9d$  
import java.io.*; 9'~qA(=.?  
import java.net.*; &,PA+#  
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public class SiteFileFetch extends Thread { Mi(6HMA.SF  
@VOegf+N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?xMTO  
long[] nStartPos; //开始位置 6ZI7V!k  
long[] nEndPos; //结束位置 91&=UUkK?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MTl @#M  
long nFileLength; //文件长度 gzVZPvTPE  
boolean bFirst = true; //是否第一次取文件 (O09HY:  
boolean bStop = false; //停止标志 kzUj)  
File tmpFile; //文件下载的临时信息 ^9hc`.5N&?  
DataOutputStream output; //输出到文件的输出流 -*w2<DCn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^fd*KM  
public SiteFileFetch(SiteInfoBean bean) throws IOException u&o4?]6  
{ G.XxlI}  
siteInfoBean = bean; X1oR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?RG;q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nSSJl  
if(tmpFile.exists ()) HES$.a  
{ B/lIn'=  
bFirst = false; @%u}|iF|  
read_nPos(); 1#"wfiW  
} &u[F)|  
else 7yg{0a  
{ [D+PDR  
nStartPos = new long[bean.getNSplitter()]; GFbn>dY  
nEndPos = new long[bean.getNSplitter()]; V#b*:E.cA  
} ]x8Y]wAU&{  
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} @(x]+*)  
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public void run() 9%ct   
{ s2N'Ip  
//获得文件长度 q2*)e/}H  
//分割文件 @pv:uON\  
//实例FileSplitterFetch ?Y\WSI?i  
//启动FileSplitterFetch线程 g9g ]X  
//等待子线程返回 !(Y|Vm'  
try{ (?XIhpd  
if(bFirst) !7#*Wdt+P  
{ q |Pebe=  
nFileLength = getFileSize(); p*cyW l  
if(nFileLength == -1) Mx93D   
{  r?0w5I  
System.err.println("File Length is not known!"); dE[X6$H[  
} &l{ctP%q  
else if(nFileLength == -2) ^56D)A=  
{ ~/SLGyu  
System.err.println("File is not access!"); d1^5r 31  
} 0VR,I{<.{  
else 4Vf-D% h>a  
{ 32J/   
for(int i=0;i<nStartPos.length;i++) Fgwe`[  
{ :nnch?J_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (1er?4  
} \KpJIHkBRy  
for(int i=0;i<nEndPos.length-1;i++) O@HD'  
{ w\Q(wH'  
nEndPos = nStartPos[i+1]; l&] %APL  
} R"t2=3K  
nEndPos[nEndPos.length-1] = nFileLength; T72Z<h|<  
} Avljrds+7  
} 5c%Fb:BW=  
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//启动子线程 ,e`n2)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ug gg!zA  
for(int i=0;i<nStartPos.length;i++) /-@F|,O)$n  
{ V~o'L#a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *E|3Vy{4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l!j=em@  
nStartPos,nEndPos,i); 7X$pgNRx/a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <Z]j89wzDZ  
fileSplitterFetch.start(); E){ODyk  
} jgpF+V-n$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MbTmdRf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1)N#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LG("<CU  
nEndPos = " + nFileLength); \Z~@/OVc
  
// fileSplitterFetch[nPos.length-1].start(); tg/!=g  
5?j#  
y?}<SnjP:  
//等待子线程结束 a{ByU%  
//int count = 0; ), VF]  
//是否结束while循环 5X]f}6kT  
boolean breakWhile = false; XL1
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while(!bStop) @2$Uk!  
{ ^\VVx:]  
write_nPos(); ]nxSVKE4p  
Utility.sleep(500); XK0lv8(  
breakWhile = true; [Q8vS;.  
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for(int i=0;i<nStartPos.length;i++) E%Ysyk  
{ %|2x7@&s  
if(!fileSplitterFetch.bDownOver) RSjcOQ8&.w  
{ v]q"{c/  
breakWhile = false; !Xq5r8]  
break; +f^|Y
i  
} &"yoJ<L  
} VjiwW%UOM  
if(breakWhile) \)g}  
break; RM25]hx  
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//count++; J]NMqiq  
//if(count>4) 'J0Ea\,if0  
// siteStop(); z=rSb4"W  
} >8`;SEnv  
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System.err.println("文件下载结束！"); lj*=bK  
} [RDY(}P%  
catch(Exception e){e.printStackTrace ();} PP6gU=9[)  
} sa"!ckh  
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//获得文件长度 =AuxM
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public long getFileSize() u$"Ew^C  
{ ^w jMu5f  
int nFileLength = -1; &c= 3BEh  
try{ 4%jQHOZ  
URL url = new URL(siteInfoBean.getSSiteURL()); d&DQ8Gm ^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1HRcEzA  
httpConnection.setRequestProperty("User-Agent","NetFox"); C8 $KVZ  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) 4"+v:t)z6{  
{ D<^K7tJui  
processErrorCode(responseCode); v +?'/Q%  
return -2; //-2 represent access is error SXV f&8  
} .7Itbp6=R  
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String sHeader; )},/=#C0  
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for(int i=1;;i++) )EsFy6K:  
{ _E^ !,Wz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *Y ?&N2@c  
//Utility.log(in.readLine()); x{VUl  
sHeader=httpConnection.getHeaderFieldKey(i); xHn "D@  
if(sHeader!=null) g`H;
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{ uX&Tn1Kg  
if(sHeader.equals("Content-Length")) l]5!$N*  
{ B!1L W4^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vPu{xy  
break; DPlmrN9@=  
} XiyL563gh  
} ENZYrWl  
else XpP}(A@G  
break; F:G Vysy  
} |OBZSk1jp  
} 'R n\CMTH  
catch(IOException e){e.printStackTrace ();} DV~g  
catch(Exception e){e.printStackTrace ();} idZ]d6  
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Utility.log(nFileLength); G>+iisb%  
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return nFileLength; IOH6h=  
} ^ Mq8jw(2  
-lI6!a^  
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//保存下载信息（文件指针位置） a+`;:tX,  
private void write_nPos() BbNl:`  
{ 
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try{ ^cIRP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @9h6D<?  
output.writeInt(nStartPos.length); [F^j(
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for(int i=0;i<nStartPos.length;i++) e:iqv?2t  
{ ~qb-uT\(99  
// output.writeLong(nPos); x/?w1  
output.writeLong(fileSplitterFetch.nStartPos); @Yzb6@g"  
output.writeLong(fileSplitterFetch.nEndPos); esHcE{GNOS  
} TZE;$:1vx>  
output.close(); I!g+K  
} NYF 7Ep; _  
catch(IOException e){e.printStackTrace ();} 4]ETF+   
catch(Exception e){e.printStackTrace ();} 'X1/tB8*  
} qoJ<e`h}
 
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//读取保存的下载信息（文件指针位置） @t,Y<)U  
private void read_nPos() ?~rz'Pu~  
{ '<hgc  
try{ J]$]zD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C +S>;1  
int nCount = input.readInt(); ^$J.l+<hy  
nStartPos = new long[nCount]; 1(m[L=H5>  
nEndPos = new long[nCount]; NvjKB)J  
for(int i=0;i<nStartPos.length;i++) zFO#oW,D  
{ ]*yUb-xY  
nStartPos = input.readLong(); sj%\lq  
nEndPos = input.readLong(); Xwk_QFv3  
} Vg8c}
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input.close(); kntn9G  
} _{0
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catch(IOException e){e.printStackTrace ();} 9rM6kLD  
catch(Exception e){e.printStackTrace ();} \t']Lf  
}

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private void processErrorCode(int nErrorCode) G297)MFF  
{ -jL10~/  
System.err.println("Error Code : " + nErrorCode); PRyzUG&  
} {{e+t8J??  
\PgMMc4'  
U jB5Xks  
//停止文件下载 U
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public void siteStop() 0^z
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{ G}gmkp]
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bStop = true; H!uq5`j0K  
for(int i=0;i<nStartPos.length;i++) kZHIzU  
fileSplitterFetch.splitterStop(); Nmu=p~f}3`  
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} g7<u eF  
} 3v:c'R0  
//负责部分文件的抓取 oh^QW`#(  
**FileSplitterFetch.java 1A;f[Rze  
*/ cR/z;*wr7  
package NetFox; OE_A$8L  
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import java.io.*; .V\:)\<|  
import java.net.*; Tq!.M1{&  
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public class FileSplitterFetch extends Thread { hYU4%"X  
2W vf[2Xw  
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String sURL; //File URL p& +w  
long nStartPos; //File Snippet Start Position 2sNV09id  
long nEndPos; //File Snippet End Position ($*R>*6<x  
int nThreadID; //Thread's ID tk,Vp3p  
boolean bDownOver = false; //Downing is over \TTt!"aK  
boolean bStop = false; //Stop identical 04QY x}a  
FileAccessI fileAccessI = null; //File Access interface &{H LYxh  
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7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @}iY(-V  
{ B>,&{ah/5J  
this.sURL = sURL; ,l
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this.nStartPos = nStart; EZg$mp1  
this.nEndPos = nEnd; b0!ZA/YC-  
nThreadID = id; 'AJlkLqm#>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .z&,d&E  
} CWS&f g%o{  
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public void run() )MU)'1jc,  
{ o<nkK+=Afm  
while(nStartPos < nEndPos && !bStop) QPT%CW61M  
{ yOXL19d@p_  
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try{ xO2CgqEb  
URL url = new URL(sURL); g|PRk9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x^P~+(g  
httpConnection.setRequestProperty("User-Agent","NetFox"); S 0L"5B@  
String sProperty = "bytes="+nStartPos+"-"; 0dKi25J  
httpConnection.setRequestProperty("RANGE",sProperty); xRPUGGv  
Utility.log(sProperty); Hlye:.$  
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InputStream input = httpConnection.getInputStream(); a>XlkkX  
//logResponseHead(httpConnection); $3Srr*  
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byte[] b = new byte[1024]; ^=V b'g3P~  
int nRead; P gK> Z,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 76rRF   
{ mj9r#v3.  
nStartPos += fileAccessI.write(b,0,nRead); NoG`J$D  
//if(nThreadID == 1) z;d]=PT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h,%b>JFo  
} r&?i>.Kz8  
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Utility.log("Thread " + nThreadID + " is over!"); |B/A)(c yV  
bDownOver = true; AEr8^6  
//nPos = fileAccessI.write (b,0,nRead); I-?Dil3  
} Jt}0%C3d  
catch(Exception e){e.printStackTrace ();} >@wyiBU  
} hAv.rjhw_  
} _k2*2db   
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//打印回应的头信息 /WWD;keP5  
public void logResponseHead(HttpURLConnection con) :Mq-4U.e  
{ A,'JmF$d  
for(int i=1;;i++) OD\F*Ry~  
{ SBynu  
String header=con.getHeaderFieldKey(i); +X&b  
if(header!=null) Zr U9oy&!C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?*h2:a$  
Utility.log(header+" : "+con.getHeaderField(header)); ~i ImM|*0  
else g8^YDrH  
break; qS{E+
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} BqA  
} 2AK]x`GY  
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public void splitterStop() pk,]yi,ZF  
{ ,]UCq?YW)T  
bStop = true; 3Sb'){.MT+  
} ,
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//_aIp  
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} ?rG>SA>o  
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/* ?6=u[))M&  
**FileAccess.java rbw5.NU  
*//文件访问(定位，写) JL1z8Nu  
package NetFox; eub2[,  
import java.io.*; bm:"&U*tu'  
jx7b$x]  
:s5wFumD  
public class FileAccessI implements Serializable{ tUPdq0%t[  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +>uiI
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RandomAccessFile oSavedFile; -lNq.pp3-$  
long nPos; tB i
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public FileAccessI() throws IOException wxx3']:  
{ _'"whZ)2  
this("",0); zj9)vr`7  
} /\0rRT  
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public FileAccessI(String sName,long nPos) throws IOException }KZt7)  
{ |)vC^=N{+  
oSavedFile = new RandomAccessFile(sName,"rw"); 2sryhS'(H  
this.nPos = nPos; iE;D_m.>`O  
oSavedFile.seek(nPos); !8V  
} yK3b^  
 ~;#OQ[  
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public synchronized int write(byte[] b,int nStart,int nLen) )=vQrMyB  
{ 'q_^28rK  
int n = -1; D%+
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try{ R rtr\a  
oSavedFile.write(b,nStart,nLen); AsOkOS3  
n = nLen; 5UgxuuP4  
} 8o SNnT  
catch(IOException e) \(db1zmS~  
{ xR`W9Z5  
e.printStackTrace (); v3ky;
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} OdrnPo{  
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return n; \=yWJ  
} [7btoo|P]  
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} v,VCbmc  
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/* BM,]W
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**SiteInfoBean.java %]m/fo4b  
*/ h'tb  
package NetFox; &O:IRR7p  
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,L.*95,  
public class SiteInfoBean { @> ]O6P2  
;;zQVD )X  
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private String sSiteURL; //Site's URL m);0sb  
private String sFilePath; //Saved File's Path iW #|N^
 
private String sFileName; //Saved File's Name +'lj\_n
 
private int nSplitter; //Count of Splited Downloading File rEF0A&5  
a^ __Z3g,  
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public SiteInfoBean() lzE{e6  
{//nSplitter的缺省值为5 D
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//default value of nSplitter is 5 ZgzjRa++  
this("","","",5); /qd5{%:  
} xRI7_8Jpyn  
>OLKaghV.5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YcaomPo  
{ 3hi0  
sSiteURL= sURL; j+9;Cp]NV  
sFilePath = sPath; `Nnaw+<]  
sFileName = sName; =1vl-*uYh  
this.nSplitter = nSpiltter; WEnI[JGe  
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} ,Hzz:ce  
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public String getSSiteURL() q9h3/uTv  
{ AVnH|31dC~  
return sSiteURL; C+m%_6<  
} zFba("E Z  
%2;Nj; J$  
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public void setSSiteURL(String value) 4!</JZX~$  
{ ]VkM)< +  
sSiteURL = value; dKk#j@[n"  
} N*w6D:  
nr{#Krkb  
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public String getSFilePath() u{'|/g&  
{ ].Sz2vI  
return sFilePath; Z0'&@P$  
} lA/.4"nN  
0aRHXc2<  
\`:nmFO(9  
public void setSFilePath(String value) AbExJ~JV\g  
{ F4*ssx  
sFilePath = value; 4x)etH^o  
} g!\H^d4  
@BmI1  
!S3^{l-  
public String getSFileName() ixY[ HDPq  
{ f'oO/0lx  
return sFileName; s
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} ^cnTZzT#Q  
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public void setSFileName(String value) 2bnYYQ14:  
{ z%Eok  
sFileName = value;  CK"OHjR  
} M/mm2?4  
7@1GSO:Yf  
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public int getNSplitter() [2P6XoI#  
{ Q;xJ/4 Z"  
return nSplitter; H,3WdSL`K  
} K0usBA  
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public void setNSplitter(int nCount) Due@'  
{ {z
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nSplitter = nCount; z}a9%Fb  
} XkhGU?={  
} =G9I7Y@  
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/* :OFs"bC  
**Utility.java FTQNS8  
*/ mz|p=[lR|  
package NetFox; j>`-BN_  
~Jh1$O,9o  
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public class Utility { G`Df'Yy  
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public Utility() TYKs2+S6  
{ 9Wv}g"KY0  
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} 3oOr*N3R  
-.OZ  
//线程睡眠 dSI<s^n  
public static void sleep(int nSecond) we/sv9v}n  
{ cSTF$62E  
try{ (6*  
Thread.sleep(nSecond); yu>o7ie+;Y  
} .%EYof  
catch(Exception e) \2^o,1r/  
{ Rc vp@  
e.printStackTrace (); ni85Ne$  
} IG Ax+3V  
} }a%1$>sj  
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//日志 $Jo4n>/  
public static void log(String sMsg) ph$vP;}  
{ b
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System.err.println(sMsg); @h9QfJ_f  
}  i
}_"  
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public static void log(int sMsg) akFT 0@9  
{ 7^7Jh&b)/  
System.err.println(sMsg); #U(kK(uO  
} `&9iC 4P  
} 63i&<  
3$_JNF`  
dmWCNeja.  
/* T#<Q[h=  
**TestMethod.java (6Ciqf8  
*/ I^Dm 3yz  
package NetFox; N8iLI`  
"~mY4WVG  
2?{'(iay  
public class TestMethod { nTl2F1(sV7  
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=4$ErwI_dm  
public TestMethod() %
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{ ///xx/weblogic60b2_win.exe >6R3KJe  
try{ r
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pm=m~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .8->n aj|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J&iSS9c  
fileFetch.start(); #aQQd8  
} 2EOx],(|  
catch(Exception e){e.printStackTrace ();} s"XwO8yhM  
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Eq%f`Qg+1E  
} ^ L]e]<h(  
/J(vqYK"  
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public static void main(String[] args) 2M*i'K;;)P  
{ 58d[>0Xa[g  
new TestMethod(); \wDL oR  
} zW\s{  
} fTso[r:F.  
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