http断点续传简单实现（java)

/* u{ /gjv  
**SiteFileFetch.java ESI}+  
*/ ^bGi_YC  
package NetFox; e#^by(1@}  
import java.io.*; >sq9c/}X  
import java.net.*; ;k]pq4E  
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public class SiteFileFetch extends Thread { HDOaN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B%/Pn 2  
long[] nStartPos; //开始位置 \Qn8"I83AV  
long[] nEndPos; //结束位置 P
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 huIr*)r&p  
long nFileLength; //文件长度 ~5b %~:  
boolean bFirst = true; //是否第一次取文件 107SXYdhI  
boolean bStop = false; //停止标志 EzaOg|  
File tmpFile; //文件下载的临时信息 uP
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DataOutputStream output; //输出到文件的输出流 gu!A:Q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O
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public SiteFileFetch(SiteInfoBean bean) throws IOException Lif mYn[  
{ I(e
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siteInfoBean = bean; XA68H!I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YX(%jcj*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~S9nLb:O{  
if(tmpFile.exists ()) /e\dsC{uJ  
{ 4w,}1uNEf  
bFirst = false; 5I14"Qf  
read_nPos(); $.kYAsZts  
} Yu=^`I  
else {ig@Iy~DT  
{ |j<'[gB\p  
nStartPos = new long[bean.getNSplitter()]; ]F~5l?4u#  
nEndPos = new long[bean.getNSplitter()]; Gmb57z&:  
} t +_G%tv  
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} 7~&Y"&  
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public void run() @tA.^k0`  
{ S^u!/ =&  
//获得文件长度 v3p..A~XZ.  
//分割文件 iX28+weH  
//实例FileSplitterFetch ':=C2x1d|  
//启动FileSplitterFetch线程 t65!2G"<  
//等待子线程返回 \ gN) GR  
try{ |w5#a_adM  
if(bFirst) <}=
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{ $lQi0*
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nFileLength = getFileSize(); /D q]=P  
if(nFileLength == -1)  >Pu*MD;  
{ (bw;zNW  
System.err.println("File Length is not known!"); P|?z1JUd  
} >Et?7@   
else if(nFileLength == -2) U6Qeode  
{ {2nXItso  
System.err.println("File is not access!"); :A$6Y*s\  
} ^$(|(N[;   
else BC+HP9<]  
{ qhtc?A/0}  
for(int i=0;i<nStartPos.length;i++) )q,}jeM8  
{ :/3`+&T^/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); v#6.VUAw  
} Z6=!}a%  
for(int i=0;i<nEndPos.length-1;i++) /H)g<YA  
{ >@X=E3  
nEndPos = nStartPos[i+1]; cA*%K[9  
} {MS&t09Wh  
nEndPos[nEndPos.length-1] = nFileLength; P+/L,u  
} gSC@uf  
} 8|l Yf%n>j  
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Fri5_rxLl  
//启动子线程 75F&s,4+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3"".kf,O5e  
for(int i=0;i<nStartPos.length;i++) 9#p^Z)[)-  
{ _FV.}%W<u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %/s1ma6q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H\^^p!^)  
nStartPos,nEndPos,i); kahv1s-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?z6C8T~+  
fileSplitterFetch.start(); ]8^2(^3ct  
} XEuv aM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vf@/}=X *  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2#R"#Q!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FR <wp  
nEndPos = " + nFileLength); eZv0"FK X  
// fileSplitterFetch[nPos.length-1].start(); [ /D/  
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//等待子线程结束 Mf *qr9*  
//int count = 0; c]9OP9F  
//是否结束while循环 V*?,r<(  
boolean breakWhile = false;  D;5RcZ  
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while(!bStop) V$@2:@8mo  
{ vD(;VeW[  
write_nPos(); l
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Utility.sleep(500); dug RO[  
breakWhile = true; PyoLk  
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for(int i=0;i<nStartPos.length;i++) Wj3H  y4  
{ A;g[G>J  
if(!fileSplitterFetch.bDownOver) pSAXp#g  
{ *-n$n  
breakWhile = false; <Z5prunov  
break; acH.L_B:  
} w8E,zH  
} 9> |rIw  
if(breakWhile) HG^8&uh]  
break; hk=+t&Y<H  
D&'".N,}  
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//count++; ~5|a9HV:  
//if(count>4) ^mGTZxO  
// siteStop(); =m40{  
} Pg:Nz@CQ  
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System.err.println("文件下载结束！"); i"b*U5k  
} Y8d%L;b[D  
catch(Exception e){e.printStackTrace ();} YONg1.^!(  
} JmBYD[h,  
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//获得文件长度 xS.0u"[  
public long getFileSize() u/MIB`@,  
{ * T-XslI  
int nFileLength = -1; 4uv }6&R  
try{ &O'yhAP] j  
URL url = new URL(siteInfoBean.getSSiteURL()); iCHZ{<k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #*~ (  
httpConnection.setRequestProperty("User-Agent","NetFox"); .1}u0IbJ  
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int responseCode=httpConnection.getResponseCode(); M,9WF)p)V  
if(responseCode>=400) 0t9G
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{ `*slQ}i  
processErrorCode(responseCode); t;*'p  
return -2; //-2 represent access is error
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} T}zi P  
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String sHeader; 0 cQf_o  
1 4|S^UM$  
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for(int i=1;;i++) A(C3kISM  
{ |.,yM|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ghj6&K%b0  
//Utility.log(in.readLine()); L4dbrPE*0  
sHeader=httpConnection.getHeaderFieldKey(i); \UiuJ+  
if(sHeader!=null) H: U_k68  
{ u_uC78`p  
if(sHeader.equals("Content-Length")) )I*V('R6|  
{ 86I".R$d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I[R?j?$}>  
break; E{FNsa  
} 'Hq}h)`  
} gKPV*  
else xNx!
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break; *BF1Sso  
} f[z#
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} 3U}z?gP[  
catch(IOException e){e.printStackTrace ();} >s{[d$  
catch(Exception e){e.printStackTrace ();} lUp 7#q  
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Utility.log(nFileLength); zRKg>GG`  
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return nFileLength; yXkgGY5  
} X`22Hf4ct  
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#)\KV7f!;  
//保存下载信息（文件指针位置） *z(.D\{%  
private void write_nPos() 3Y=S^*ztd  
{ Obw uyhjQ  
try{ =]D##R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5Po.&eS  
output.writeInt(nStartPos.length); ZGS=;jM  
for(int i=0;i<nStartPos.length;i++) \zKVgywR  
{ s*S@}l  
// output.writeLong(nPos); \Q#F&q0  
output.writeLong(fileSplitterFetch.nStartPos); \^_F>M  
output.writeLong(fileSplitterFetch.nEndPos); NSxDCTw  
} F<I-^BY)  
output.close(); 7igrRU#1%  
} {yJ{DU?%Y  
catch(IOException e){e.printStackTrace ();} o`&idn|,  
catch(Exception e){e.printStackTrace ();} j6Vuj/+}  
} "=qdBG9  
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> sUk6Z~  
//读取保存的下载信息（文件指针位置） al^ yCoB  
private void read_nPos() 
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{ f'}23\>  
try{ {Xl 5F.q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lD{9o2  
int nCount = input.readInt(); k1]?d7g$w  
nStartPos = new long[nCount]; h'N,oDB)  
nEndPos = new long[nCount]; ]o_ Ps|  
for(int i=0;i<nStartPos.length;i++) haY.rH]z  
{ D L$P  
nStartPos = input.readLong(); ."MBKyg6  
nEndPos = input.readLong(); ]qrO"X=  
} )[/+j"F   
input.close(); ov?>ALRg  
} 7=JiL=  
catch(IOException e){e.printStackTrace ();} :FK(*BUh  
catch(Exception e){e.printStackTrace ();} V+E2nJ  
} ost~<4~  
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private void processErrorCode(int nErrorCode) 2#sE\D  
{ p[W8XX  
System.err.println("Error Code : " + nErrorCode); ] Li(E:  
} N<?RN;M  
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//停止文件下载 {lqnn n3  
public void siteStop() \b' <q  
{ }J:~}?^%n  
bStop = true; y\ouIsI77  
for(int i=0;i<nStartPos.length;i++) 96 C|R  
fileSplitterFetch.splitterStop(); n#m )]YQC  
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} cA_v*`YL  
} lS}5bcjR=k  
//负责部分文件的抓取 cz.-cuD[iD  
**FileSplitterFetch.java @1rF9< 4g  
*/ {Rbc  
package NetFox; Ll&Y_Ry  
}"_S;[{d  
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import java.io.*; GT*\gZ  
import java.net.*; B<+}_3.  
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public class FileSplitterFetch extends Thread { m,Os$>{Ok  
.(3B}}gB>  
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String sURL; //File URL I2D<~xP~2+  
long nStartPos; //File Snippet Start Position '|Cs!Zl  
long nEndPos; //File Snippet End Position 0gxbo  
int nThreadID; //Thread's ID w!tQU9+*  
boolean bDownOver = false; //Downing is over 5q" ;R$+j  
boolean bStop = false; //Stop identical 17J|g.]m-&  
FileAccessI fileAccessI = null; //File Access interface o^gqpQv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HZ]'?&0  
{ ,p0R4gi  
this.sURL = sURL; /G\-v2iD  
this.nStartPos = nStart; % &{>oEQ  
this.nEndPos = nEnd; :Iw)xd1d}\  
nThreadID = id; YQ2ie>C8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m &s0Ub  
} =XyK/$  
[O9(sWL'  
)7:2v1Xr]  
public void run() nB"q   
{ "o%N`Xlx  
while(nStartPos < nEndPos && !bStop) 7@MV
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{ oO!@s`  
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try{ HuCH`|v-  
URL url = new URL(sURL); _! \X>rfz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rAk
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httpConnection.setRequestProperty("User-Agent","NetFox"); '^n2
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String sProperty = "bytes="+nStartPos+"-"; EcFYP"{
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httpConnection.setRequestProperty("RANGE",sProperty); J*qepq`_  
Utility.log(sProperty); [\eUCt F  
}kGJ)zh  
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InputStream input = httpConnection.getInputStream(); zN*/G6>A  
//logResponseHead(httpConnection); NhXTt!S6C  
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byte[] b = new byte[1024]; ,??xW{*|  
int nRead; r(0I>|u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?}lgwKBHl;  
{ PUF"^9v  
nStartPos += fileAccessI.write(b,0,nRead); G23Mr9m5O  
//if(nThreadID == 1) (\>_{"*=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j=M_>  
} 0g~WM  
^=}~  
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Utility.log("Thread " + nThreadID + " is over!"); :>;-uve8'  
bDownOver = true; WSKG8JT^|  
//nPos = fileAccessI.write (b,0,nRead); ,r+=>vre  
} kjJ\7x6M  
catch(Exception e){e.printStackTrace ();} rN8 ZQiJC  
} G{$9e}#  
} t&eY+3y,T  
zH}u9IR3`  
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//打印回应的头信息 ,m9Nd "6\  
public void logResponseHead(HttpURLConnection con) A:0  
{ ~`u?|+*BO  
for(int i=1;;i++) c-n
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{ ^s_E|~U  
String header=con.getHeaderFieldKey(i); _|x%M}O},  
if(header!=null) 5d<-y2!M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m>jX4D7KZ  
Utility.log(header+" : "+con.getHeaderField(header)); j"yL6Q9P  
else Xo;J
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break; [P`Q_L,+  
} #c./<<P5}  
} _T<ney}Y<  
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public void splitterStop() kT[]^Jtc  
{ Y6W3WPs(  
bStop = true; rM/*_0[`d  
} MuO7_*q'n  
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} #$e~o}(r  
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/* TJ ;4QL  
**FileAccess.java k;#$Oxa>t=  
*//文件访问(定位，写) AW!|xA6'`:  
package NetFox; L_=J(H|  
import java.io.*; 2<qq[2  
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 QSmE:Y  
public class FileAccessI implements Serializable{ *B#<5<T  
5MO:hE5sm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BAx)R6kS;  
RandomAccessFile oSavedFile; JOx75}  
long nPos; ^Qs-@]E-  
{uDL"~^\  
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public FileAccessI() throws IOException ;yx+BaG~?  
{ cJGA5m/{I  
this("",0); \"<&8  
} P (_:8|E  
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public FileAccessI(String sName,long nPos) throws IOException k'xnl"q  
{ 1e _V@Vy  
oSavedFile = new RandomAccessFile(sName,"rw"); +d2+w1o^V  
this.nPos = nPos; 3Yp_k  
oSavedFile.seek(nPos); OHR9u  
} GmcxN<  
ZL+{?1&-  
F C2oP,  
public synchronized int write(byte[] b,int nStart,int nLen) J<H$B +;qR  
{ m Wsegq4  
int n = -1; 1x V~EX  
try{ B@63=a*kG  
oSavedFile.write(b,nStart,nLen); :2 n5;fp  
n = nLen; ;#G>qo  
} rM
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catch(IOException e) Go^W\y  
{ vpMNulXb,  
e.printStackTrace (); d9R0P2  
} yaa+j8s]  
=9LC"eI&|  
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return n; 3`5?Zgp  
} 3BKW  
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} U-Fr[1I6p  
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tPDV"Md#m<  
/* 'N,x=1R5  
**SiteInfoBean.java )tz8(S  
*/ Y~,[9:SR  
package NetFox; XqyfeY5t  
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public class SiteInfoBean { ;TEZD70r  
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private String sSiteURL; //Site's URL c_kxjzA#  
private String sFilePath; //Saved File's Path Yn'XSV|g  
private String sFileName; //Saved File's Name 1;?b-FEq:  
private int nSplitter; //Count of Splited Downloading File dWg$yH  
2j=3i
@  
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public SiteInfoBean()  &j2L-)  
{//nSplitter的缺省值为5 V<\:iNXX{  
//default value of nSplitter is 5 b0rC\^x  
this("","","",5); A:cc @ku  
} z }R-J/xr2  
q^n6"&;*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ceH7Rq:4W  
{ pE^LQi  
sSiteURL= sURL; s%H5Qa+Uh  
sFilePath = sPath; 1mFc]1W  
sFileName = sName; $gJMF(  
this.nSplitter = nSpiltter; YxGIv8O]  
!MTm4Ls  
AZI%KM[  
} pn{.oXomf  
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.^,fw=T|1  
public String getSSiteURL() 6$%]p1"!K  
{ jQ%}e"  
return sSiteURL; !r.X.C  
} .: 87B=  
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public void setSSiteURL(String value) |b'tf:l  
{ e&<#8;2X  
sSiteURL = value; IW$&V``v  
} oT\B-lx  
;}.jRmnJ  
/+JCi6{sHS  
public String getSFilePath() ag:#82C  
{ VB
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return sFilePath; BXZ( %tnY  
} !D7\$ g6g  
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qVZ=:D{  
public void setSFilePath(String value) wrK$ZO]  
{ H1s{JJAM>i  
sFilePath = value; )WwysGkqol  
} eq(|%]a=  
e4khReF;  
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public String getSFileName() No=f&GVg  
{ '?_I-="Mr  
return sFileName; \^|ncu:T  
} t{F6+dp  
L6r&Y~+/  
;Zw!  
public void setSFileName(String value) *q|.H9 K(  
{ %
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sFileName = value; gS4K](KH |  
} 0b?9LFd  
31w?bx !Pp  
&{Uaa  
public int getNSplitter() dQ/Xs.8  
{ K4,VSy1byI  
return nSplitter; i:qc2#O:J  
} z*zLK[t+  
u'yePJTE  
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public void setNSplitter(int nCount) |pq z(j7  
{ _^#PV}  
nSplitter = nCount; T_5 E  
} K 2LLuS!  
} o1GWcxu*\  
}{=%j~V;&  
S4~^HvMG[Y  
/* oYlq1MB?  
**Utility.java XLEA|#  
*/ o~mY,7@a  
package NetFox; >Q[]i4*A  
;#~rd8Z52  
P:ys--$"  
public class Utility { b]hRmW  
=1VY/sv  
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public Utility() k(u W( 6  
{ %Q
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}..}]J;To  
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} 0kmVP~K  
<%qbU-  
//线程睡眠 AGLzA+6M
 
public static void sleep(int nSecond) NawnC!~ $  
{ ^R>&^"oI  
try{ e] **Z,Z  
Thread.sleep(nSecond); s8.oS);`  
} YH
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catch(Exception e) B quyPG"  
{ B:^5W{  
e.printStackTrace (); {BJ[h  
} W5J"#^kdF8  
} axXAy5  
SV6Np?U  
//日志 +qzsC/y  
public static void log(String sMsg)  M"X/([G  
{ "=P@x|I  
System.err.println(sMsg); N{|N_}X`Y  
} dgX0\lKpf  
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^hY<avi6s  
public static void log(int sMsg) u'Mq^8  
{ +]5JXt^  
System.err.println(sMsg); )JeiTh^  
} AHn^^'&
x[  
} s)~Q@ze2  
_F,@mQ$!  
7F)HAbIS  
/* h %MPppCEa  
**TestMethod.java l~F,i n.  
*/ 0fi+tc30  
package NetFox; !. q*bY  
s7a\L=#p(  
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public class TestMethod { =
1`  
k9yA#
 
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public TestMethod() }{j[  
{ ///xx/weblogic60b2_win.exe 47ir QK*  
try{ eR8h4M~O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )7c^@I;7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?w3f;v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z'fGHiX7.0  
fileFetch.start(); XK(<N<Z@|e  
} ew}C*4qH  
catch(Exception e){e.printStackTrace ();} }1X,~y]  
A g
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9FJU'$FN  
} h+N75  
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T][\wyLx1  
public static void main(String[] args) Q\ro )r  
{ 33"{"2==`  
new TestMethod(); 2&Wc4,O!i  
} qI5/ME(}  
} -!w
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