http断点续传简单实现（java)

/* i=&]%T6Qk  
**SiteFileFetch.java &UO/p/a
 
*/ 93
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package NetFox; 2b Fr8FUt-  
import java.io.*; VxE;t
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import java.net.*; ,eSpt#M  
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public class SiteFileFetch extends Thread { v^ v \6uEP  
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) )t]5Ys%;  
SiteInfoBean siteInfoBean = null; //文件信息Bean %'VzN3Q5V  
long[] nStartPos; //开始位置 J&B5Ll  
long[] nEndPos; //结束位置 I9xkqj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FI~=A/:  
long nFileLength; //文件长度 +G+1B6S  
boolean bFirst = true; //是否第一次取文件 7Hj7b:3K&!  
boolean bStop = false; //停止标志  bDD29  
File tmpFile; //文件下载的临时信息 E33WT{H&_'  
DataOutputStream output; //输出到文件的输出流 uo(LZUjPbN  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 24wr=5p]Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException QZ[S, c^  
{ KOoV'YSC[(  
siteInfoBean = bean; 8idIJm%y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @LSX@V   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u|k_OUTq  
if(tmpFile.exists ()) y qK*E*  
{ (W}DMcuSd  
bFirst = false; /SyAjZ  
read_nPos(); G<]@nP{P  
} f8G<5_!K_  
else -9Ygn_M  
{ aj=-^iGG  
nStartPos = new long[bean.getNSplitter()]; BkY#wJ'  
nEndPos = new long[bean.getNSplitter()]; ab#z&jg!  
} BB_(!omq[  
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} rq1zvuUx  
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public void run() kq([c r  
{ \tY7Ga%c  
//获得文件长度 L\!Oj5  
//分割文件 `u_k?)lK  
//实例FileSplitterFetch U* uMMb}$  
//启动FileSplitterFetch线程 b *3h}n;  
//等待子线程返回 \HQ.Pwr 6  
try{ Ocn@JOg  
if(bFirst) qEVpkvEq  
{ P+C5 
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nFileLength = getFileSize(); Zv*uUe  
if(nFileLength == -1) AYfe_Dj  
{ s,l*=<  
System.err.println("File Length is not known!"); BuUM~k&SY  
} T0.sL9  
else if(nFileLength == -2) e E(+  
{ 0QxBC7`qp  
System.err.println("File is not access!"); &}K%F)S  
} 8 qZbsZi4  
else O@w_"TJP/z  
{ PWquu`  
for(int i=0;i<nStartPos.length;i++) u9u'5xAO  
{ ] mK{E~Zll  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C5jt(!pi  
} _H-Fm$Q  
for(int i=0;i<nEndPos.length-1;i++) 3#GIZL}!x  
{ Wg<o%6`  
nEndPos = nStartPos[i+1]; P0U&+^W"9  
} 4ElS_u^cP7  
nEndPos[nEndPos.length-1] = nFileLength; C~'.
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} ?^LG>GgV  
} d`%7Pk  
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//启动子线程 7]i6 Gk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B__e*d:)!m  
for(int i=0;i<nStartPos.length;i++) .9Dncsnf,`  
{ N9M",(WTt}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vup|*d2r0E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -KfMKN~  
nStartPos,nEndPos,i); Og8%SnEpMI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JXR]G  
fileSplitterFetch.start(); ~=<uYv?0s  
} Cv4nl7A'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $iA:3DM07  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~PU}==*q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kV8q
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nEndPos = " + nFileLength); _lRIS_^;eE  
// fileSplitterFetch[nPos.length-1].start(); hzpl;Mj  
(]10Z8"fJ  
w'7J`n:{]  
//等待子线程结束 YPO24_B  
//int count = 0; JNP6qM  
//是否结束while循环 ^t$uDQ[hA  
boolean breakWhile = false; ;Cjj_9e,:  
dxH.  
2MW7nIEs  
while(!bStop) MmFtG-  
{ #&?}h)Jr'  
write_nPos(); 4r86@^c*  
Utility.sleep(500); _'^_9u G  
breakWhile = true; g_?Q3  
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for(int i=0;i<nStartPos.length;i++) 6\.LG4@LO  
{ \'|t>|zhp  
if(!fileSplitterFetch.bDownOver) n-,mC/4  
{ &qIdT;^=I  
breakWhile = false; fKtlfQG  
break; txQr|\4k  
} B(O6qWsL  
} x5rLGt  
if(breakWhile) 4Y4zBD=<  
break; @RL'pKab9  
u:B=lZ[  
&5[+p{2  
//count++; E]S:F3  
//if(count>4) K$r)^K=s  
// siteStop(); .YP&E1lNi  
} 73SH[
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System.err.println("文件下载结束！"); `tXd?E/e  
} %|>D{q6C  
catch(Exception e){e.printStackTrace ();} Q ;5A~n  
}
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//获得文件长度 2uV5hSHYe  
public long getFileSize() ]v?jfy  
{ AS[j)x!  
int nFileLength = -1; 9E0x\%2K  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); F[W0gjUc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z+CX$
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httpConnection.setRequestProperty("User-Agent","NetFox"); <:mK&quf  
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int responseCode=httpConnection.getResponseCode(); `O;4b#!g  
if(responseCode>=400) @Pi]kWW})  
{ 2^w{Hcf  
processErrorCode(responseCode); .[3C  
return -2; //-2 represent access is error Ttp%U8-LJR  
}
/-WmOn*  
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"/2kf)l{4  
String sHeader; 2iO{*cB
 
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for(int i=1;;i++) ]1W]  
{ )r)ZmS5O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8#o2qQ2+  
//Utility.log(in.readLine()); \w(0k^<7  
sHeader=httpConnection.getHeaderFieldKey(i); 1?.NJ<)F  
if(sHeader!=null) {vZAOz7#  
{ u`Y~r<?P(  
if(sHeader.equals("Content-Length")) d\tY-X3  
{ FV,aQ#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dca,IaT'  
break; H0.A;`  
} %Z,n3iND  
} bD|VT  
else Pf?15POg&B  
break; 4?[1JN>  
} %Y5F@=>&  
} f&RjvVP?s  
catch(IOException e){e.printStackTrace ();} ^62I 5k/u  
catch(Exception e){e.printStackTrace ();} <U\
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Utility.log(nFileLength); ra_v+HR7  
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return nFileLength; e#k)F.TZ:%  
} >l=^3B,j  
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//保存下载信息（文件指针位置） bw+IH-b  
private void write_nPos() "pH;0
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{ ?1] \3nj  
try{ U}5]Vm$]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D0TFC3.k}  
output.writeInt(nStartPos.length); dxtG3  
for(int i=0;i<nStartPos.length;i++) _sy]k A  
{ up0=Y o@  
// output.writeLong(nPos); >g@@ yR,  
output.writeLong(fileSplitterFetch.nStartPos); 8s-X H  
output.writeLong(fileSplitterFetch.nEndPos); `0!%jz=  
} 4T v=sP  
output.close(); rq}xuSFI  
} oEj$xm_}  
catch(IOException e){e.printStackTrace ();} BW`;QF<  
catch(Exception e){e.printStackTrace ();} U)Tl<l<  
} { 9\/aXPS  
2t45/:,  
^uVPN1}b^@  
//读取保存的下载信息（文件指针位置） b^P\Q s*m  
private void read_nPos() H\9ePo\b~  
{ P_75-0G  
try{ i*A_Po  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); raU_Z[  
nStartPos = new long[nCount]; "QD>:G;u  
nEndPos = new long[nCount]; S;%k?O7v  
for(int i=0;i<nStartPos.length;i++) `9P`f4x  
{ b@K1;A! S  
nStartPos = input.readLong(); }qZ^S9  
nEndPos = input.readLong(); tAujm*|&  
} aH8]$e8_,\  
input.close(); ;W FiMM\  
} ez5>V7Y  
catch(IOException e){e.printStackTrace ();} yMD0Tj5ZQ  
catch(Exception e){e.printStackTrace ();} /V#?d  
} +V[;DOlll  
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private void processErrorCode(int nErrorCode) 4%JJ}{Ff  
{ UQ@szE  
System.err.println("Error Code : " + nErrorCode); &0J8ICd=  
} 3v`@**  
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//停止文件下载 U%;E:|  
public void siteStop() A* Pz-z>z  
{ D*sL&Rt][Y  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) 5 [4{1v  
fileSplitterFetch.splitterStop(); 7+hc?H[&'  
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} ^<   
} 2d  YU  
//负责部分文件的抓取 E]^n\bE
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**FileSplitterFetch.java LZE9]Gd  
*/ jJ,y+o  
package NetFox; ,wv>
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import java.io.*; 8+32hg@^F  
import java.net.*; we@*;k@_  
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public class FileSplitterFetch extends Thread { :lm
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String sURL; //File URL '0&HkM{ D  
long nStartPos; //File Snippet Start Position HsT6 #K  
long nEndPos; //File Snippet End Position %kgT=<E'  
int nThreadID; //Thread's ID wub7w#  
boolean bDownOver = false; //Downing is over +OtD@lD`!  
boolean bStop = false; //Stop identical HIfi18  
FileAccessI fileAccessI = null; //File Access interface T eu.i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Kq+vAp
).  
{ lE8_Q*ev  
this.sURL = sURL; Vf=,@7  
this.nStartPos = nStart; l\d[S]  
this.nEndPos = nEnd; E33x)CP  
nThreadID = id; ng6E&<Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yC4%z)t&R  
} frV_5yK'  
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public void run() t~!ag#3['.  
{ Y|W#VyM-  
while(nStartPos < nEndPos && !bStop) Ln/*lLIOb  
{ /sPa$D  
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w]
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try{ [=u@6Y  
URL url = new URL(sURL); 0}T56aD=!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k ,r*xt  
httpConnection.setRequestProperty("User-Agent","NetFox"); st#^pWL  
String sProperty = "bytes="+nStartPos+"-"; wOrj-Smx  
httpConnection.setRequestProperty("RANGE",sProperty); %?8.UW\m  
Utility.log(sProperty); XjxI@VXzUV  
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InputStream input = httpConnection.getInputStream(); -OKXfN]  
//logResponseHead(httpConnection); U<'z,P
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byte[] b = new byte[1024]; 3Gw*K-.  
int nRead; C/ ]Bx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;$qc@)Uwp  
{ AU9:Gu@M/  
nStartPos += fileAccessI.write(b,0,nRead);
'[HU!8F  
//if(nThreadID == 1) n:H |=SF{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %z"$?Iv  
} *)HVK&'  
F`+S(APT8  
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Utility.log("Thread " + nThreadID + " is over!"); F#qc#s  
bDownOver = true; Vgy12dE  
//nPos = fileAccessI.write (b,0,nRead); 7~QAprwVS  
} ]2|KG3t  
catch(Exception e){e.printStackTrace ();} 4]Gm4zO  
} -;i:bE  
} F>%,}Y~B:  

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//打印回应的头信息 ^a!oq~ZSy  
public void logResponseHead(HttpURLConnection con) ?3v-ppw%  
{ QPvWdjf#mM  
for(int i=1;;i++) )[y
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{ UM0#S}  
String header=con.getHeaderFieldKey(i); Kf$6D 79#  
if(header!=null) \fYPz }wt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X[?E{[@Z  
Utility.log(header+" : "+con.getHeaderField(header)); zNEN[  
else t!>0^['g4  
break; 8Kn}o@Yd  
} ICTjUQP  
} `1FNs?j  
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public void splitterStop() Q H>g-@  
{ ";n%^I}  
bStop = true; l[nf"'  
} 5\}QOL  
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} jd`]]FAww  
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/* c5[~2e  
**FileAccess.java R F;u1vEQ8  
*//文件访问(定位，写) Y&i&H=U  
package NetFox; CKU)wJ5t  
import java.io.*; S@4bpnhK  
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PK_2  
public class FileAccessI implements Serializable{ 1Va@w  
li}>xDSQ4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *r6v9  
RandomAccessFile oSavedFile; ZalL}?E ?  
long nPos; J%E0Wd  
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public FileAccessI() throws IOException Lk-h AN{[  
{ P1`YbLER5  
this("",0); z qd1G(tO  
} 4@M
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public FileAccessI(String sName,long nPos) throws IOException q+lCA#Sx  
{ =Q!V6+}nY^  
oSavedFile = new RandomAccessFile(sName,"rw"); Jp~[Dm  
this.nPos = nPos; ,^@/I:  
oSavedFile.seek(nPos); XKT[8o<L  
} \@_?mL@=  
SMQC/t]HT  
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public synchronized int write(byte[] b,int nStart,int nLen) _IvqZ/6Y(  
{ cZw_^@!  
int n = -1; 2d&HSW  
try{ >R\!Qk  
oSavedFile.write(b,nStart,nLen); 6%&w\<(SG  
n = nLen; ]v$2JgF]@  
} #Jfmt~ks'  
catch(IOException e) A5G@u}YS5  
{ )/bv@Am  
e.printStackTrace (); Ek '%%%  
} \6/!{D,  
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return n; m
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} }O6E5YCm  
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} 3C#Sr6  
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/* (%{!TJgZR  
**SiteInfoBean.java >5Sm.7}R  
*/ Q1DiEg  
package NetFox; IXR%IggJA  
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public class SiteInfoBean { Oc/ i'  
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private String sSiteURL; //Site's URL SCq3Kh  
private String sFilePath; //Saved File's Path YUlH5rO3  
private String sFileName; //Saved File's Name v=YI%{tx)  
private int nSplitter; //Count of Splited Downloading File Gn%k#  
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public SiteInfoBean() Ys@\~?ym+  
{//nSplitter的缺省值为5 e~$aJO@B.R  
//default value of nSplitter is 5 ban;HGGNG{  
this("","","",5); R!:F
}*  
} YA8ZB&]En/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j|
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{ Kr%O}<"  
sSiteURL= sURL; %lGg}9k'  
sFilePath = sPath; TnPx.mwK\  
sFileName = sName; 4'L.I%#tZ  
this.nSplitter = nSpiltter; <!~NG3KW[>  
&3YXDNm  
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} ZV~9{E8  
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public String getSSiteURL() q&: t$tSS  
{ FW"gj\  
return sSiteURL; ? UBE0C  
} 5Yx 7Q:D  
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public void setSSiteURL(String value) '\Uy;,tu /  
{ 2L7ogyrU/A  
sSiteURL = value; -qDL':  
} W_|7hwr  
k FE<M6a9@  
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public String getSFilePath() h.aXW]]}(P  
{ r59BBW)M  
return sFilePath; /#e-x|L  
} bbFzmS1  
j`k:)  
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public void setSFilePath(String value) j4eq.{$  
{ \l/<[ZZ  
sFilePath = value; +Pb@@C&  
} l gTw>r   
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public String getSFileName() K%NgZ(x(  
{ Dmn{ppfyb  
return sFileName; ^e1mK4`  
} *Q,9 [
k  
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public void setSFileName(String value) :74G5U8%  
{ >W=
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sFileName = value; 0|`iop%(n  
} +(##B pC  
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public int getNSplitter() 3qwSm<  
{ _S6SCSFc  
return nSplitter; L7$1rO<  
} 2<^eVpNJR  
-|/*S]6kK  
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public void setNSplitter(int nCount) Hc-Ke1+  
{ &^])iG,Ew  
nSplitter = nCount; p`oHF 5  
} OG2&=~hOz-  
} wXUgxa  
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#:}mi;{  
/* (Z at|R.F  
**Utility.java ;%$wA5"2M  
*/ )W3kBDD  
package NetFox; 
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public class Utility { QhmOO
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public Utility() c$R<j'7  
{ [knwp$  
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} <~35tOpv  
)r:gDd#/X  
//线程睡眠 ?F@X>zR2  
public static void sleep(int nSecond) +We=- e7  
{ hquN+eIDH  
try{ M0"}>`1lJ  
Thread.sleep(nSecond); SI/p8 ^  
} T+)#Du  
catch(Exception e) 9l:vVp7Uk  
{ K{]\}7+   
e.printStackTrace (); 17B`  
} gYvT'7

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} N1espc@j  
NIxtT>[+3  
//日志 #%SF2P
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public static void log(String sMsg) $O^U"  
{ 6ragRS/'x  
System.err.println(sMsg); G0pqiU6  
} A=pyaU`aE  
g9:V00^<  
.0#{?R,  
public static void log(int sMsg) Yjp*T:6  
{ F}=O Mo:.  
System.err.println(sMsg); ;v>+D {s  
} K&/!3vc  
} !yf7y/qY  
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F]`_akE  
/* Gque@u  
**TestMethod.java +{"w5o<CO  
*/ ]`_eaW?Ua  
package NetFox; RWINdJZ  
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public class TestMethod { L QA6iZBP  
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r
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public TestMethod() be:=-B7!  
{ ///xx/weblogic60b2_win.exe )dZ1$MC[  
try{ 3C(V<R?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BZAF;j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }tUr V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n3JSEu;J  
fileFetch.start(); u1_NC;  
} DjQgF=;  
catch(Exception e){e.printStackTrace ();} RS /*Dp^  
=!P$[pN2  
@1iH4RE*  
} glgXSOj  
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public static void main(String[] args) spv'r!*\ed  
{ +]jJ:V  
new TestMethod(); 4+4C0/$Y  
} 7DCu#Y[  
} WS1$cAD2N  
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