http断点续传简单实现（java)

/* 4b3F9  
**SiteFileFetch.java /(hP7_]`2  
*/ CX&yjT6`  
package NetFox; eZN3H
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import java.io.*; < "L){$  
import java.net.*; ?)Czl4J  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean (n":]8}  
long[] nStartPos; //开始位置 WuP([8  
long[] nEndPos; //结束位置 X/`#5<x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :/yr(V{  
long nFileLength; //文件长度 [6,]9|~  
boolean bFirst = true; //是否第一次取文件 J'G`=m"-'  
boolean bStop = false; //停止标志 .R$+#_  
File tmpFile; //文件下载的临时信息 s0XRL1kWr  
DataOutputStream output; //输出到文件的输出流 _e:5XQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ]v^`+s}3  
public SiteFileFetch(SiteInfoBean bean) throws IOException bMqu5G_q  
{ v GR \GFm  
siteInfoBean = bean; 6mI_Q2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wZ]BY;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O]Ry3j  
if(tmpFile.exists ())
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{ uhC=  
bFirst = false; F$6])F  
read_nPos(); dPH! V6r  
} VQNYQqu`[  
else ~`G;=ITo  
{ I |<+'G  
nStartPos = new long[bean.getNSplitter()]; 9z|>roNe  
nEndPos = new long[bean.getNSplitter()]; L6[rvM|9_  
} PxP
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} fncwe ';?  
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public void run() 2vh!pez_  
{ X>6~{3  
//获得文件长度 U<gUX07  
//分割文件 Ew?/@KAV\  
//实例FileSplitterFetch |L.~Amd  
//启动FileSplitterFetch线程 9h3~;Q  
//等待子线程返回 P[#WHbn  
try{ qOcG|UgF  
if(bFirst) 86^ZY
h  
{ ]df9'\  
nFileLength = getFileSize(); N
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if(nFileLength == -1) p(x1D]#Z[  
{ O)U$Ef  
System.err.println("File Length is not known!"); {0)WS}&  
} VHgF#6'  
else if(nFileLength == -2) K)h"G#NZM  
{ I7
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System.err.println("File is not access!"); 7uv/@(J"$  
} 8JtI&aH-L  
else =|6^)lt$
 
{ Z+``/Q]>+  
for(int i=0;i<nStartPos.length;i++) FQ9csUjpB  
{ U7*VIRibv+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3h D2C'KD  
} (1elF
)  
for(int i=0;i<nEndPos.length-1;i++) XftJ=  *  
{ i"sYf9,  
nEndPos = nStartPos[i+1]; N}l]Ilm$34  
} S,"ChR  
nEndPos[nEndPos.length-1] = nFileLength; OO !S w  
} S\v&{  
} St3(1mApl  
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//启动子线程 6t7;}t]t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >+; b>  
for(int i=0;i<nStartPos.length;i++) 4M0
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{ ZB^4(F')H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :E>n)_^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7>2j=Y_Kp  
nStartPos,nEndPos,i); JIY ^N9_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XJxs4a1[t  
fileSplitterFetch.start();  jC/JiI  
} 3U9+l0mBa  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), od5w9E.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :LIKp;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l6`d48U
 
nEndPos = " + nFileLength); L"[wa.<  
// fileSplitterFetch[nPos.length-1].start(); 1&@wb'MBs.  
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//等待子线程结束 X,!OWz:[  
//int count = 0; B'gk/^6$eg  
//是否结束while循环 $MJDB  
boolean breakWhile = false; [
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while(!bStop) SG|i/K|7  
{ yz2oS|0'  
write_nPos(); [q>i  
Utility.sleep(500); 2$i 0yPv  
breakWhile = true; l LD)i J1  
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for(int i=0;i<nStartPos.length;i++) cdtzf:#q  
{ HyX4ob[X  
if(!fileSplitterFetch.bDownOver) eR* ]<0=  
{ #`#aSqGmc  
breakWhile = false; dW^_tzfF7  
break; oIL+@}u7  
} qiKtR  
} 5.K$ X$+7}  
if(breakWhile) ETWmeMN  
break; #PLB$
$  
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//count++; :{N3o:  
//if(count>4) DHumBnQ  
// siteStop(); g2 {?EP  
} i;'X}KW  
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,  
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System.err.println("文件下载结束！"); -TU{r_!Z(  
} mKFHT  
catch(Exception e){e.printStackTrace ();} 7E75s)KH  
} !qGx(D{\  
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//获得文件长度 Z=t#*"J  
public long getFileSize() #&2N,M!Q  
{ sv{0XVn+^  
int nFileLength = -1; ^L
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try{ %J ( }D7-,  
URL url = new URL(siteInfoBean.getSSiteURL()); b}U&bFl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Or4`JOO  
httpConnection.setRequestProperty("User-Agent","NetFox"); GwpBDMk  
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int responseCode=httpConnection.getResponseCode(); Hv7D+j8M  
if(responseCode>=400) }Keon.N?   
{ >RqT7n8h  
processErrorCode(responseCode); y:[VRLo  
return -2; //-2 represent access is error ZNC?Ntw  
} /2\=sTd  
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String sHeader; -^xKG'uth  
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for(int i=1;;i++) 'SD|ObBY  
{ Y <i}"eI*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -MW(={#  
//Utility.log(in.readLine()); Y./}zCT  
sHeader=httpConnection.getHeaderFieldKey(i); RdVis|7o  
if(sHeader!=null) K\E]X\:  
{ 4C9"Q,o%&  
if(sHeader.equals("Content-Length")) R6@~   
{ a~eLkWnh<k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @?cXa: tX  
break; b= ec?n #7  
} :2Rci`lp  
} 7 }MJK)  
else -0IFPL8  
break; V45Udwp^  
} yY-t4WeXP  
} =qR7-Q8B  
catch(IOException e){e.printStackTrace ();} DHNii_w4v  
catch(Exception e){e.printStackTrace ();} lGHu@(n<  
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Utility.log(nFileLength); 7(USp#"  
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return nFileLength; I;.E}k   
} )qP{X,Uf  
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#\S$$gP  
//保存下载信息（文件指针位置） Q;,3W+(  
private void write_nPos() 70*iJ^|  
{ U <$xp  
try{ nV xMo_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^8*SCM_A  
output.writeInt(nStartPos.length); s!fY^3  
for(int i=0;i<nStartPos.length;i++) S9#N%{8P  
{ [W;dguh  
// output.writeLong(nPos); Csm!\I  
output.writeLong(fileSplitterFetch.nStartPos); F`V[G(f+r  
output.writeLong(fileSplitterFetch.nEndPos); qg:I+"u  
} Rf0\CEc  
output.close(); JEF7hJz~  
} YM*6W?  
catch(IOException e){e.printStackTrace ();} '2J6%Gg  
catch(Exception e){e.printStackTrace ();} QV7c9)<]'}  
} o@`E.4
 
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//读取保存的下载信息（文件指针位置） /F}\V ^  
private void read_nPos() ~ 2oP,  
{ :ItW|  
try{ 2bxMIr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H;Qn?^  
int nCount = input.readInt(); uW'4 Kt  
nStartPos = new long[nCount]; QuRg(K%:  
nEndPos = new long[nCount]; ^(JbJ@m/  
for(int i=0;i<nStartPos.length;i++) Fj('l  
{ jz7
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nStartPos = input.readLong(); lR2;g:&H  
nEndPos = input.readLong(); W
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} U5$DJ5>8  
input.close(); sP8&p*TJF  
} yrNc[kS/  
catch(IOException e){e.printStackTrace ();} f\r4[gU@  
catch(Exception e){e.printStackTrace ();} Zt0%E<C{  
} :;Rt#!  
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private void processErrorCode(int nErrorCode) tskODM0Zf  
{ 2
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System.err.println("Error Code : " + nErrorCode); VEKITBs  
} :k/U7 2  
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;/3/R/^g  
//停止文件下载 gOmyFHv.  
public void siteStop() I>o; %}  
{ TZyQOjUu  
bStop = true; 0F'UFn>{  
for(int i=0;i<nStartPos.length;i++) aDv/kFfn  
fileSplitterFetch.splitterStop();
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} oYErG],  
} Xq!tXJ)  
//负责部分文件的抓取 Cwf$`?|W  
**FileSplitterFetch.java Rj;e82%%N
 
*/ "UnSZ[;t  
package NetFox; .ehvhMuG|  
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#$C]0]|  
import java.io.*; q=i<vcw  
import java.net.*; LK/V]YG  
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public class FileSplitterFetch extends Thread { W2Z]?l;vQQ  
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~  
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String sURL; //File URL 2Lgvy/uN  
long nStartPos; //File Snippet Start Position arL&^]JnZ,  
long nEndPos; //File Snippet End Position G6VHl:e7z  
int nThreadID; //Thread's ID (w B[ ]O$@  
boolean bDownOver = false; //Downing is over ^uElQI  
boolean bStop = false; //Stop identical lG#&1  
FileAccessI fileAccessI = null; //File Access interface lA 0_I"b2Y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;-^9j)31+F  
{ qk1D#1vl  
this.sURL = sURL; 6mpUk.M"  
this.nStartPos = nStart; geSo#mV  
this.nEndPos = nEnd; Q.$h![`6  
nThreadID = id; U2nRgd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3g:+p  
} x99 Oq!  
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public void run() TFPq(i  
{ %k)I=|  
while(nStartPos < nEndPos && !bStop) XQ;dew+  
{ pT$AdvI]  
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try{ )!-'SH  
URL url = new URL(sURL); e91d~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &B7KWvAy  
httpConnection.setRequestProperty("User-Agent","NetFox"); Utp\}0GZY  
String sProperty = "bytes="+nStartPos+"-"; YKd?)$J  
httpConnection.setRequestProperty("RANGE",sProperty); Mg/2w  
Utility.log(sProperty); bA,D]  
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InputStream input = httpConnection.getInputStream(); #eyx  
//logResponseHead(httpConnection); *OcptmY<  
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) <~7<.0  
byte[] b = new byte[1024]; W78-'c  
int nRead; !,uw./8@Ku  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .6#2i <oPW  
{ M4\Io]}-M  
nStartPos += fileAccessI.write(b,0,nRead); Zotv]P2k  
//if(nThreadID == 1) wuQkeWxJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YWFHiB7x
 
} f+AIxSw  
2GS2,  
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Utility.log("Thread " + nThreadID + " is over!"); )\G#[Pc7  
bDownOver = true; y-k-E/V}  
//nPos = fileAccessI.write (b,0,nRead); vb!KuI!:p  
}
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catch(Exception e){e.printStackTrace ();} -v@^6bQVp  
} k"zHrn"$  
} YaNVpLA  
x#j_}L!V;  
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//打印回应的头信息 a9Rh  
public void logResponseHead(HttpURLConnection con) M!'tD!NWc  
{ 42LV
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for(int i=1;;i++) kk#d-! $[  
{ ,1L^#?Q~  
String header=con.getHeaderFieldKey(i); tjt#VFq?  
if(header!=null) m#'9)%t!J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A79SAheX#  
Utility.log(header+" : "+con.getHeaderField(header)); 6V/mR~F1r  
else c[q3O**  
break; WLH2B1_):  
} R8*4E0\br  
} e~dU "  
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public void splitterStop() '9XwUQx  
{ 4HAfTQ 1G  
bStop = true; "H@AT$Ny(  
} 4R6 .G
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j)Gr@F>  
} ccAEN  
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7lu;lAAP  
/* H;`@SJBf  
**FileAccess.java GvY8O|a  
*//文件访问(定位，写) _`58G#z  
package NetFox; zV#k #/$  
import java.io.*; St<\qC  
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9'M({/7y  
public class FileAccessI implements Serializable{ ;d:7\  
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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 isqW?$s  
RandomAccessFile oSavedFile; |kD?^Nx  
long nPos; @P/{x@J  
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public FileAccessI() throws IOException u#QQCgrs  
{ 'WoX-y  
this("",0); Sob+l'U$  
} 2J$Uz,@  
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public FileAccessI(String sName,long nPos) throws IOException Ff30%  
{ '_8Vay~  
oSavedFile = new RandomAccessFile(sName,"rw"); "]% L{aP  
this.nPos = nPos; 89l}6p/L  
oSavedFile.seek(nPos); klKt^h-  
} m6}"g[nN  
NH/H+7,o  
XUWza=BR"  
public synchronized int write(byte[] b,int nStart,int nLen) @EvnV.  
{ h fNBWN  
int n = -1; -.y3:^){^  
try{ IiL?@pIq  
oSavedFile.write(b,nStart,nLen); <JlKtR&nSo  
n = nLen; fO+;%B  
} bbnAmZ   
catch(IOException e) ~2H)#`\ac8  
{ Cv3H%g+as  
e.printStackTrace (); SU^/qF%8  
} 4Y
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@: NrC76  
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return n; rB\UNXy  
} @eul~%B{X  
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} KW)yTE<  
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) Ez=#dIq  
/* +VfJ:[q  
**SiteInfoBean.java 7~ 2X/  
*/ &c'unKH  
package NetFox; -$*YN{D+  
}x+{=%~N  
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public class SiteInfoBean { 9r!%PjNvE  
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private String sSiteURL; //Site's URL r\yj$Gu>(  
private String sFilePath; //Saved File's Path (jXgJ" m  
private String sFileName; //Saved File's Name ?tOzhrv  
private int nSplitter; //Count of Splited Downloading File ;2$^=:8  
ky*-_  
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public SiteInfoBean() ][9M_.  
{//nSplitter的缺省值为5 nt4>9;  
//default value of nSplitter is 5 +IU]=qS  
this("","","",5); (mycUU%  
} RNPqW,B!0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y8sI @y6  
{ <I}k%q'  
sSiteURL= sURL; mu*wX'.'  
sFilePath = sPath; jjs-[g'}  
sFileName = sName; 5(,
WN  
this.nSplitter = nSpiltter; sUA)I%Q!  
om(#P5cSM;  
1m&(3%#{  
} 45#`R%3
 
w>#~_x,`  
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public String getSSiteURL()
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{ ,Ti#g8j  
return sSiteURL; .NabK  
} U7Ps2~x3  
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public void setSSiteURL(String value) \2T@]!n  
{ X(/W|RY{@  
sSiteURL = value; >kd2GZe^_J  
} FG'1;x!  
i~4:]r22  
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public String getSFilePath() >XA#/K  
{  N3E=t#n  
return sFilePath; o zv><e#  
} .L8S_Mz  
H -`7T;t~  
DS^PHk39  
public void setSFilePath(String value) hD;[}8qN{  
{ |d8/ZD  
sFilePath = value; 2/I^:*e  
} P
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Zl]\sJ1"  
public String getSFileName() cU+/I>V  
{ 2mI=V.X[&  
return sFileName; ;]|Z8#s
 
} )t=Cj?5  
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op[5]tjL  
public void setSFileName(String value) R}*e%EG/  
{ %3Y&
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sFileName = value; 6kHAoE
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} iN_G|w[d  
Riw#+#r]/  
o XA*K.X<  
public int getNSplitter() U$qSMkj6RK  
{ 7kHEY5s "  
return nSplitter; B;L~hM  
} Qb6s]QZEV  
,xNuc$8Jd  
'a*tee ^RS  
public void setNSplitter(int nCount) &c0U\G|j  
{ ZY=x$($f  
nSplitter = nCount; UT+B*?,h  
}
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}  |G{TA  

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.  
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/* C;M.dd  
**Utility.java nxCwg>  
*/ rk{DrbRx  
package NetFox; <1>\?$)D  
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public class Utility { GAV|x]R  
/`3<@{D  
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public Utility() Ar N*9  
{ a6fMx~  
+U% = w8b  
{!@Pho)Q  
} \2@OS6LUe  
s7#w5fe  
//线程睡眠 @u#Tx%  
public static void sleep(int nSecond) EJ"[{AV  
{ # KK>D?.:  
try{ 8" XbW7^o  
Thread.sleep(nSecond); _m#M^<0n  
} Yu`b[]W  
catch(Exception e) t L}i%7  
{ Y&'Bl$`  
e.printStackTrace (); yuWoz*:t  
}  5k{a(I  
} ANZD7v6a  
TIYI\/a\;  
//日志 YD 1u  
public static void log(String sMsg) x/ lW=EQ  
{ XzIhFX6  
System.err.println(sMsg); G
BV]7.  
} \E5%.KR  
TeSF  
|/5j0  
public static void log(int sMsg) MPhO#;v  
{ FT!|YJz<K  
System.err.println(sMsg); !inonR  
} :Em[>XA  
} [RTB|0Q  
AtGk _tpVZ  
JL=MlZ  
/* k.NgE/;3  
**TestMethod.java |9$K'+'  
*/ t 5g@t0$  
package NetFox; wK!4:]rhG  
18jI6$DY  
Y1vl,Yi  
public class TestMethod { 9l5l"Wj&  
^(r?k_i/  
Yh\} i  
public TestMethod() 0.Pd,L(  
{ ///xx/weblogic60b2_win.exe OB FG!.)  
try{ *W~+Nho.A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <E[X-S%&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s~W:N.}*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CA, &R<]  
fileFetch.start(); pn<M`,F~q  
} x >hnH{~w  
catch(Exception e){e.printStackTrace ();} ep* (  
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h(*!s`1  
} { AdPC?R`  
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public static void main(String[] args) PBc.}TSGj  
{ l6IpyIex  
new TestMethod(); maW,YOyRN  
} R]L|&{  
} ~ x- R78'  
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