http断点续传简单实现（java)

/* w
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**SiteFileFetch.java Ui`Z>,0sFi  
*/ (AnM_s
 
package NetFox; Xm2p<Xu8h  
import java.io.*; UjU*`}k3  
import java.net.*; tZ]/?+1G  
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public class SiteFileFetch extends Thread { 6-<>P E2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gf8DhiB  
long[] nStartPos; //开始位置 ESl</"<J  
long[] nEndPos; //结束位置 $NtbI:e{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %kJ_o*"  
long nFileLength; //文件长度 JW4~Qwx  
boolean bFirst = true; //是否第一次取文件 MdOQEWJ$|  
boolean bStop = false; //停止标志 fc#zhp5bX  
File tmpFile; //文件下载的临时信息 &u'$q  
DataOutputStream output; //输出到文件的输出流 $fwv'  
2%Y]M%P  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AI&Bv  
public SiteFileFetch(SiteInfoBean bean) throws IOException T~rPpi&  
{ `'{>2d%\g  
siteInfoBean = bean; Q,mmHw.`J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q^_PR|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3i'L5f67  
if(tmpFile.exists ()) Xn'{g  
{ }qf)L.  
bFirst = false; CcZ\QOet&C  
read_nPos(); lklMdsIdj  
} crt )}L8-  
else +JMB98+l  
{ #;32(II  
nStartPos = new long[bean.getNSplitter()]; o7*z@R"  
nEndPos = new long[bean.getNSplitter()]; ]HK|xO(  
} Ty21-0F  
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}
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public void run() <d GGH  
{ XJ|CC.]1u  
//获得文件长度 jQp7TdvLE$  
//分割文件 2?9SM@nAY  
//实例FileSplitterFetch EVW{!\8[  
//启动FileSplitterFetch线程 $Xf gY1S  
//等待子线程返回 9wPc03a  
try{ SG{> t*E  
if(bFirst) ;L5'3+U  
{ u2SnL$A7  
nFileLength = getFileSize(); #l6L7u0~wC  
if(nFileLength == -1) (CRY$+d  
{ S(c,Sinc  
System.err.println("File Length is not known!"); *.UM[Wo  
} ,&;#$ b5  
else if(nFileLength == -2) y
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{ El~x$X*  
System.err.println("File is not access!"); d+_wN2  
} ,{ C  
else @"9^U_Qf1z  
{ n y7
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for(int i=0;i<nStartPos.length;i++) $W46!U3  
{ wr/Z)e =^3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ][|)qQ%V  
} meHAa`  
for(int i=0;i<nEndPos.length-1;i++) ]
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{ 0B^0,d(s  
nEndPos = nStartPos[i+1]; P| o_/BS  
} Lzzf`jN]  
nEndPos[nEndPos.length-1] = nFileLength; ;hz"`{(JY  
} m/)Wn  
} pv.
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//启动子线程 li4rK<O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f-N:  
for(int i=0;i<nStartPos.length;i++) W_NQi  
{ )S
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %t&5o>1C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AR i_m  
nStartPos,nEndPos,i); -'FzH?q:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .u3!%{/v(c  
fileSplitterFetch.start(); wz-9+VN6  
} #:{Bd8PS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OXy>Tlv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S{7*uK3$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4#$~gTc@  
nEndPos = " + nFileLength); qm
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// fileSplitterFetch[nPos.length-1].start(); hKq#i8py  
NGD?.^ (G  
M^\#(0^2@  
//等待子线程结束 Vd2bG4*=  
//int count = 0; .z u0GsU=  
//是否结束while循环 gdupG  
boolean breakWhile = false; / vI sX3v  
JG xuB*}  
3;(6tWWLT  
while(!bStop) +$KUy>  
{ Np4';
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write_nPos(); G3HmLz  
Utility.sleep(500); DBuvbq-  
breakWhile = true; 
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@B;2z_Y!l  
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for(int i=0;i<nStartPos.length;i++) 6b9 oSY-8  
{ / AFn8=9'^  
if(!fileSplitterFetch.bDownOver) 58"Cn ||tF  
{ 5CZii=@  
breakWhile = false; e"u=4nk  
break; wu5]S)?*  
} Pa%;[hbn  
} &?m|PK)I
 
if(breakWhile) 1$Rua  
break; @!0@f'}e  
=W(mZ#*vdY  
bce>DLF  
//count++; $;1#gq%  
//if(count>4) [:
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// siteStop(); H]V@Q~?e  
} {VBx;A3*I  
?{W@TY@S  
29DYL  
System.err.println("文件下载结束！"); zc&>RM  
} -lr)z=})  
catch(Exception e){e.printStackTrace ();} eMk?#&a)  
} 6eSc
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8_8r{a<xW  
8OoKP4,;  
//获得文件长度 `mTpL^f  
public long getFileSize() g9> 0N#<  
{ V)M+dhl  
int nFileLength = -1; YPQ&hEu0  
try{ tMxa:h;/x  
URL url = new URL(siteInfoBean.getSSiteURL()); vT)(#0>z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3n;UXYJ%  
httpConnection.setRequestProperty("User-Agent","NetFox"); hj@
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gs)wQgJ[  
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int responseCode=httpConnection.getResponseCode(); Y4cIYUSc  
if(responseCode>=400) x8I=I"Sp  
{ okfGd= &  
processErrorCode(responseCode); }J27Y;Zp9  
return -2; //-2 represent access is error >U\,(VB  
} :_;9&[H9ha  
+cQGX5 K  
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String sHeader; tsdkpt  
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for(int i=1;;i++) +uMOT#KjR  
{ p=m)lR9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %n-:mSus  
//Utility.log(in.readLine()); ]-d:wEj  
sHeader=httpConnection.getHeaderFieldKey(i); ?N2/;u>  
if(sHeader!=null) %~uMa  
{ U4]>8L  
if(sHeader.equals("Content-Length")) _=9o:F  
{ EoM}Co  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vL"U=Q+/eY  
break; }oHA@o5  
} +L_!$"I  
} %?K1X^52d  
else qdo
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break; lhsd39NM  
} iM;7V*u  
} ?I{pv4G:  
catch(IOException e){e.printStackTrace ();} ?;!d5Xuu  
catch(Exception e){e.printStackTrace ();} H^cB?i  
<rd7<@>5D  
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Utility.log(nFileLength); 9 p6QNDp  
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return nFileLength; et|QW;*L  
} '<"eG!O  
#g,JNJ}  
xQV5-VoFC  
//保存下载信息（文件指针位置） 40cgsRa|  
private void write_nPos() t]?u<KD<  
{ dn0?#=  
try{ ]m}<0-0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SE=3`rVJ  
output.writeInt(nStartPos.length); j+0=)Q%I=  
for(int i=0;i<nStartPos.length;i++) dIiQ^M  
{ o:E+c_^q`  
// output.writeLong(nPos); smEKQHB  
output.writeLong(fileSplitterFetch.nStartPos); `$j"nP F_  
output.writeLong(fileSplitterFetch.nEndPos); u^H:z0  
} JBa( O-T  
output.close(); \DsP'-t  
} .]+Z<5Fo  
catch(IOException e){e.printStackTrace ();} :#8#tLv  
catch(Exception e){e.printStackTrace ();} ~~eR,HYk  
} ,c#IxB/0  
T_ifDQX;  
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//读取保存的下载信息（文件指针位置） ,H!E :k  
private void read_nPos() L'k)  
{ )rJ{}U:S  
try{ q]F2
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T1TKwU8l  
int nCount = input.readInt(); 4%wP}Zj#  
nStartPos = new long[nCount]; My'u('Q%  
nEndPos = new long[nCount]; ?c712a ?  
for(int i=0;i<nStartPos.length;i++) S#+Dfa`8X  
{ O>e2MT|#k  
nStartPos = input.readLong(); e(7F| G*  
nEndPos = input.readLong(); p%) 1(R8qM  
} rjzRZ  
input.close(); GKf,1kns  
} k(|D0%#b7  
catch(IOException e){e.printStackTrace ();} 69{^Vfd;Y  
catch(Exception e){e.printStackTrace ();} JjarMJr|D  
} nb}*IExd  
+*"u(7AV  
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private void processErrorCode(int nErrorCode) E!.>*`)?.  
{ nO^aZmSu  
System.err.println("Error Code : " + nErrorCode); FoY_5/  
} {qO[93yg)/  
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H^ _[IkuA%  
//停止文件下载 4QbDDvRQ^  
public void siteStop() l}-JtZ?[?  
{ p/jC}[
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bStop = true; @]r,cPx0Y  
for(int i=0;i<nStartPos.length;i++) H8d%_jCr  
fileSplitterFetch.splitterStop(); *FoH'\=  
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} G+Ft2/+\  
} A:$Qt%c  
//负责部分文件的抓取 TR:V7d  
**FileSplitterFetch.java df_hmkyj  
*/ wc7gOrPpm  
package NetFox; 7J@iJW],,  
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import java.io.*; nNNs3h(Ss  
import java.net.*; <SeK3@Gi  
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8,\toT7  
public class FileSplitterFetch extends Thread { k}T#-Gb
 
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String sURL; //File URL ,B|~V 3)(  
long nStartPos; //File Snippet Start Position 7x8/Vz@\  
long nEndPos; //File Snippet End Position !d Ns3d  
int nThreadID; //Thread's ID Cf@~W)K  
boolean bDownOver = false; //Downing is over V8`o71p  
boolean bStop = false; //Stop identical eZes) &4  
FileAccessI fileAccessI = null; //File Access interface m
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AD_RU_a9  
{ +"1@6,M  
this.sURL = sURL;
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this.nStartPos = nStart; $ M?VJ\8
 
this.nEndPos = nEnd; 3^m0 k E
 
nThreadID = id; Ny_d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &h1.9AO  
} cMxuG'{=.  
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public void run() W Z'UVUi8  
{ \\P
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while(nStartPos < nEndPos && !bStop) D@9adwQb  
{ )+;Xfftz  
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try{ s~N WJ*i  
URL url = new URL(sURL); e}%~S9\UL5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #{-l(016y  
httpConnection.setRequestProperty("User-Agent","NetFox"); Nl~'W  
String sProperty = "bytes="+nStartPos+"-"; Ph@hk0dgr/  
httpConnection.setRequestProperty("RANGE",sProperty); ~>8yJLZ.7  
Utility.log(sProperty); ZDHm@,d  
NP }b  
Mr/;$O{  
InputStream input = httpConnection.getInputStream(); YN.[KQ(!  
//logResponseHead(httpConnection); ~mAv)JK  
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|~)!8N.{  
byte[] b = new byte[1024]; WI@l2`X  
int nRead; R_?Q`+X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]w7wwU^^*U  
{ {O24:'K&  
nStartPos += fileAccessI.write(b,0,nRead); nPlg5&E  
//if(nThreadID == 1) Mn`);[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TVy\%FP^L  
} .|ZO2MCd  
1 Hw%DJ  
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Utility.log("Thread " + nThreadID + " is over!"); Sv&_LZ-"P  
bDownOver = true;
=$kSvCjP  
//nPos = fileAccessI.write (b,0,nRead); D==C"}J  
} 6ZvGD}/  
catch(Exception e){e.printStackTrace ();} o$PY0~#  
} |HT5G=dw
 
} 6uNWL `v  
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L!/Zw~  
//打印回应的头信息 c, IAz  
public void logResponseHead(HttpURLConnection con) @\ udaZc  
{ _JEe]  
for(int i=1;;i++) -@=As00Bg  
{ ~m`j=ot  
String header=con.getHeaderFieldKey(i); 4MM
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if(header!=null) =r1-M.*a.M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L_@P fI
 
Utility.log(header+" : "+con.getHeaderField(header)); mbSG  
else '!\t!@I$  
break; tk]>\}%  
} r Uau??  
} x-E@[=  
4$~A%JN3  
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public void splitterStop() TwdY6E3`  
{ Hl"^E*9x  
bStop = true; )4O>V?B  
} $U*b;'o  
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} \mp2LICQg  
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/* zCz"[9k  
**FileAccess.java gUa-6@  
*//文件访问(定位，写) 2!
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package NetFox; h^ o@=%b  
import java.io.*; h#:_GNu
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public class FileAccessI implements Serializable{ rS|nO_9f  
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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 5MX7V4ist  
RandomAccessFile oSavedFile; x->H~/  
long nPos; $^K12Wcp-  
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public FileAccessI() throws IOException Xtk3~@  
{ h/s8".\  
this("",0); td!Y
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} 0bz':M#k &  
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public FileAccessI(String sName,long nPos) throws IOException k-jlYHsA  
{ &P pb2  
oSavedFile = new RandomAccessFile(sName,"rw"); "=Xky,k  
this.nPos = nPos; ^1w<wB\B  
oSavedFile.seek(nPos); )x&4 Q=  
} xofxE4.  
2G&H[`  
8-5g6qAS  
public synchronized int write(byte[] b,int nStart,int nLen) # A#,]XP  
{ /ka "YU  
int n = -1; r?%,#1|$$  
try{ rds4eUxe  
oSavedFile.write(b,nStart,nLen); 4R}$P1 E  
n = nLen; k*
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} M+l~^E0Wj  
catch(IOException e) P[K42mm  
{ y F;KyY{  
e.printStackTrace (); =WEWs4V5A  
} %|(Cb!ySX  
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p!/ *(TT  
return n; a/Ik^:>m  
} Nm{J=`  
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} &=[N{N?(  
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/* SO+J5,)HA  
**SiteInfoBean.java JWsOze8#  
*/ dUc?>#TU  
package NetFox; 3kJ7aBiR<  
lz:+y/+1  
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public class SiteInfoBean { YgLHp/  
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private String sSiteURL; //Site's URL =<.h.n  
private String sFilePath; //Saved File's Path j"Z9}F@  
private String sFileName; //Saved File's Name 5E!Wp[^  
private int nSplitter; //Count of Splited Downloading File ?WBA:?=$58  
9jJ:T$}  
 K)P].htw  
public SiteInfoBean() F7&Oc)f"B  
{//nSplitter的缺省值为5 7<zI'^l  
//default value of nSplitter is 5 Ksb55cp`  
this("","","",5); ;\54(x}|K  
} z)f
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) seS)`@n  
{ MT^krv(G  
sSiteURL= sURL; ?'mi6jFFh  
sFilePath = sPath; }kF*I@:g  
sFileName = sName; Y;1J`oT  
this.nSplitter = nSpiltter; nV_[40KP_  
^$;5ZkQy  
evE$$# 6R  
} D.,~I^W  
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public String getSSiteURL() l~#%j( Yo  
{
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return sSiteURL; uu
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} _xdFQ  
dk.VH!uVb  
+8 }p-<a  
public void setSSiteURL(String value) aMO+y91Y(  
{ - -ZSl  
sSiteURL = value; %&&;06GU}  
}
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]-8yZWal  
7b hJt_`Q  
public String getSFilePath() Lb0BmR%0  
{ F2C v,&'  
return sFilePath; )(DX]Tr`  
} 5@`DS-7h  
3.V-r59  
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public void setSFilePath(String value) 4^{~MgQWK+  
{ GcHZ&m4  
sFilePath = value; WXX08"  
} *6QmYq6c<  
c n^z=?  
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public String getSFileName() Wu U_RE  
{ ='vkd=`Si  
return sFileName; ,H:{twc   
} 822jZ sb  
*K=Yrisz  
OO-b*\QW  
public void setSFileName(String value) -n]E
\"  
{ _-nIy*',=  
sFileName = value; ?gl[=NV  
} 1'YksuYx6f  
l3;MjNB^V  
ky{-NrK  
public int getNSplitter() DtOL=m]s  
{ w<G'gi]  
return nSplitter; 3vRBK?Q.y  
} 4qmaL+Q  
)/4U]c{-  
wf/DLAC  
public void setNSplitter(int nCount) g/jlG%kI}  
{ '/Ag3R  
nSplitter = nCount; ~/1
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} j[&C6l+wH  
} yUlYf#`H  
{+x;J4  
tjt#2i8/  
/* {aYCrk1  
**Utility.java ca?;!~%zA  
*/ O K2|/y  
package NetFox; +
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\"AzT{l!;  
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public class Utility { %#-'|~  
6),VN>j  
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public Utility() X.hVMX2B  
{ YMIX|bj6Y  
mFeoeI,Jv  
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} V0a)9\x(\  
*pKj6x  
//线程睡眠 d ~3GEK  
public static void sleep(int nSecond) c(!8L\69V}  
{ EP}NT)z,{  
try{ F<|x_6a\  
Thread.sleep(nSecond); 'qnnZE  
} -40OS=wpA  
catch(Exception e) -8D$[@y(  
{ z!/ MBM  
e.printStackTrace (); iVqa0Gl+}  
} P4.snRQ  
} O/bpm-h`8c  
]Q*eCt;l"K  
//日志 h;`]rK;g  
public static void log(String sMsg) ZX03FJL7u  
{ }5a$Ka-  
System.err.println(sMsg); u|uPvbM  
} `6`oLu\l  
>2@ a\  
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public static void log(int sMsg) /%5X:*:H  
{ $][$ e  
System.err.println(sMsg); QP0[  
} n 2m!a0;
 
} +Rb0:r>kU  
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P},d`4Ty@  
/* {fAj*,pzl  
**TestMethod.java fY{&W@#g  
*/ Ceco^Mw  
package NetFox; (b4;c=<[{  
@gHWU>k,A  
- |j4u#z  
public class TestMethod { Ss c3uo0  
2$%E:J+2:$  
@N,I}_9-  
public TestMethod() okv`v ({  
{ ///xx/weblogic60b2_win.exe sCwX|  
try{ EABy<i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  cnwpd%]o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >djTJ>dl_u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kEpCF:@A  
fileFetch.start(); ;^Y]nsd  
} ?f ]!~  
catch(Exception e){e.printStackTrace ();} N>'|fNx]  
t ]yD95|  
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} o6~9.~_e  
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public static void main(String[] args) -L)b;0%  
{ -)2sR>`A%  
new TestMethod(); sU}.2k  
} @Nk]f  
} XP'7+/A  
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