http断点续传简单实现（java)

/* ed!:/+3e/  
**SiteFileFetch.java e/*$^i+S  
*/ |.F  
package NetFox; op"$E1+  
import java.io.*; !" JfOu  
import java.net.*; yMZHUd  
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public class SiteFileFetch extends Thread { b1gaj"]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7_wJpTz  
long[] nStartPos; //开始位置 T"p(]@Ng  
long[] nEndPos; //结束位置 l akp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #Ei,(xiP  
long nFileLength; //文件长度 6oinidB[l  
boolean bFirst = true; //是否第一次取文件 WEa2E?*  
boolean bStop = false; //停止标志 F$Ca;cP"  
File tmpFile; //文件下载的临时信息 2[B4f7  
DataOutputStream output; //输出到文件的输出流 fQ'.8'>T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） aYn8^  
public SiteFileFetch(SiteInfoBean bean) throws IOException x lsqj`=  
{ ewuXpv%vwW  
siteInfoBean = bean; BR v+.(S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N7%TYs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZUp\Ep}  
if(tmpFile.exists ()) 7l."b$U4yv  
{ !Y<oN~<%)  
bFirst = false; :s-o0$PlJ  
read_nPos(); iB1i/l  
} KtB!"yy#  
else yMc:n"-[  
{ $&Kq*m 0g  
nStartPos = new long[bean.getNSplitter()]; G){g  
nEndPos = new long[bean.getNSplitter()]; v8/6wy?  
} *U=]@I}J  
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} p<`+sf}A:  
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public void run() 'R9g7,53R  
{ 6QZ5|T ]  
//获得文件长度 "R9Yb,tIN  
//分割文件 G{x[uE2X&f  
//实例FileSplitterFetch .5> 20\b2  
//启动FileSplitterFetch线程 Y'`"9Db  
//等待子线程返回 TNY4z(r  
try{ :XV} c(+d  
if(bFirst) 7m9"8   
{ (LJ@SeM;  
nFileLength = getFileSize(); 'GJVWpvUU  
if(nFileLength == -1) IeF keE  
{ ,xths3.K  
System.err.println("File Length is not known!"); zzZg$9PT[  
} 5V-jMB  
else if(nFileLength == -2) Eff\Aq{  
{ F9XT lA  
System.err.println("File is not access!"); C:\(~D*GS  
} 7\/5r.  
else :DkAQ-<~  
{ S{p}ux[}=  
for(int i=0;i<nStartPos.length;i++) t7F.[uWD  
{ 0y%L-:/c|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :WXf.+IA  
} #Ogt(5Sd  
for(int i=0;i<nEndPos.length-1;i++) (paf2F
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{ ^uaFg`S  
nEndPos = nStartPos[i+1]; gbOCR1PBg  
} aW{L7N%  
nEndPos[nEndPos.length-1] = nFileLength; gs`^~iD]m  
} qeaA&(|5  
} tfiqr|z  
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S2=%x.  
//启动子线程 Q!CO0w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X<MpN5%|Wo  
for(int i=0;i<nStartPos.length;i++) V2kWiyN  
{ {^&@gkYY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g0#q"v55  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t]m!ee8*X<  
nStartPos,nEndPos,i); vC9@,[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /jrY%C  
fileSplitterFetch.start(); _J"mR]I+  
} V 4qtaHf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fwmLJ5o N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0#|7U_n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Hbr^vYs5  
nEndPos = " + nFileLength); ha'qIT3&  
// fileSplitterFetch[nPos.length-1].start(); \ sf!  
` py}99G  
aR(E7mXQ  
//等待子线程结束 _:,.yRez  
//int count = 0; Pc4R!Tc  
//是否结束while循环 +>E5X4JC  
boolean breakWhile = false; >Pkdu}xP3  
<;KRj85"j  
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while(!bStop) lV7IHX1P  
{ BD1K H;  
write_nPos();
T{ nQjYb?  
Utility.sleep(500); U(A4v0T  
breakWhile = true; Dh8(HiXf:  
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for(int i=0;i<nStartPos.length;i++) m3%
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{ c9|a$^I6  
if(!fileSplitterFetch.bDownOver) W%zmD Hk~  
{ v|y<_Ya  
breakWhile = false; I3ho(Kdi
  
break; %g-0O#8}  
} (.oaMA"B  
} b#}t:yy  
if(breakWhile) 5)x6Q|-u  
break; ~"5C${~{  
l)iv\j  
wjg}[R@!  
//count++; Ix4jof6(  
//if(count>4) P[1m0!,B  
// siteStop(); $OT}`Te~  
} IPkA7VhFF  
\ j x0ZHR  
|#:=\gugh  
System.err.println("文件下载结束！"); !}j,TPpG  
} Flne=ij6g  
catch(Exception e){e.printStackTrace ();} p( HyRCH  
} ,?;sT`Mh)  
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u& AQl.u  
//获得文件长度 Y)5)s0}  
public long getFileSize() 3[iSF5%V*p  
{ `Q+i-y  
int nFileLength = -1; SAQs{M  
try{ mC%%)F'Zf  
URL url = new URL(siteInfoBean.getSSiteURL()); u% r!?-z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); okVp\RC  
httpConnection.setRequestProperty("User-Agent","NetFox"); k>$FT`  
1Q0%7zRirI  
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int responseCode=httpConnection.getResponseCode(); A4}JZi6@  
if(responseCode>=400) v hR twi  
{ u~ VswXc4  
processErrorCode(responseCode); ;K>{_kf  
return -2; //-2 represent access is error 2Ti" s-  
} ;`;G/1]#9  
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`WP@ZSC6  
String sHeader; T-hU+(+hg  
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for(int i=1;;i++) o(?VX`2"  
{ kQqBHA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MT;SRAmUr  
//Utility.log(in.readLine()); W\nHX I  
sHeader=httpConnection.getHeaderFieldKey(i); Mp]yKl  
if(sHeader!=null)
uWJ#+XK.  
{ iMP*]K-O  
if(sHeader.equals("Content-Length")) ;"d?_{>7  
{ CpUI|Rs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^#<:<X6  
break; MLkL.1eGSb  
} e6tH/`Uln  
} ?/o2#iJx  
else "3U{h]  
break; L?Kz P.(t+  
} ccHLL6F{  
} s_S<gR  
catch(IOException e){e.printStackTrace ();} oG4w8+N  
catch(Exception e){e.printStackTrace ();} pDLu+}@  
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Utility.log(nFileLength); GInZ53cQ  
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return nFileLength; <3i4NXnL2  
} 2<46jJYL'  
 VJ~X#Q  
1q}u?7nnSG  
//保存下载信息（文件指针位置） aTL8l.c2  
private void write_nPos() 2uJNc!&  
{ 0)6i~MglY  
try{ NB!'u) lFD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7yqSt)/U  
output.writeInt(nStartPos.length); 'S%} ?#J  
for(int i=0;i<nStartPos.length;i++) 7/p J6>  
{ AHp830\  
// output.writeLong(nPos); F#!@}K8  
output.writeLong(fileSplitterFetch.nStartPos); c&| '3i+  
output.writeLong(fileSplitterFetch.nEndPos); <WQ<<s@#pb  
} +
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output.close(); L5V'Sr  
} /el["l
 
catch(IOException e){e.printStackTrace ();} A;kw}!  
catch(Exception e){e.printStackTrace ();}
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} > hDsm;,/  
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//读取保存的下载信息（文件指针位置） Th&Wq  
private void read_nPos() (.@p4q Q-  
{ *D09P%  
try{ m>*A0&??[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8XS{6<  
int nCount = input.readInt(); {LB }v;?l  
nStartPos = new long[nCount]; 1a=9z'8V  
nEndPos = new long[nCount]; 3x(MvW30Lg  
for(int i=0;i<nStartPos.length;i++) @LWxz  
{ xtIehr0{$I  
nStartPos = input.readLong(); gvTOCF  
nEndPos = input.readLong(); 4B3irHs\Q  
} wEHAkc
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input.close(); |=^#d\?]j  
} 53,,%Ue  
catch(IOException e){e.printStackTrace ();} Rvu3Qo+  
catch(Exception e){e.printStackTrace ();} Qa7S'(  
} aG8D%i0  
RaM#@D7  
C#*
*)  
private void processErrorCode(int nErrorCode) |qy"%W@  
{ ExOB P  
System.err.println("Error Code : " + nErrorCode); z:i X]df  
} TOPPa?=vk  
?`l=!>C4s  
rlO%%Qn`  
//停止文件下载 s68_o[[E  
public void siteStop() <Z_wDK/UR  
{ <zDw&s2  
bStop = true; Y?vm%t`K  
for(int i=0;i<nStartPos.length;i++) "{ QHWZ  
fileSplitterFetch.splitterStop(); wD?=u\% &  
0w[0%:R^  
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} CN$A-sjZ  
} @+CSY-g$  
//负责部分文件的抓取 7 NB"oU^h%  
**FileSplitterFetch.java );uZ4PNK/?  
*/ :UhFou_D4l  
package NetFox; @6!y(e8"J]  
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import java.io.*; 6pn@`UK  
import java.net.*; kN9sug^  
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public class FileSplitterFetch extends Thread { ma-Y'  
7SY->-H8  
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String sURL; //File URL \lbiz4^>  
long nStartPos; //File Snippet Start Position 4tTZkJc  
long nEndPos; //File Snippet End Position ][5p.owJse  
int nThreadID; //Thread's ID 6% y)  
boolean bDownOver = false; //Downing is over o&F.mYnqX  
boolean bStop = false; //Stop identical tEX~72v  
FileAccessI fileAccessI = null; //File Access interface W7[S7kd  
j5Wx*~@(  
pnA]@FW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cKYvRe  
{ 0l1]QD+Gc5  
this.sURL = sURL; A-wxf91+:  
this.nStartPos = nStart;
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this.nEndPos = nEnd; yoY)6cn@  
nThreadID = id; So 6cm|{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Okg8Ve2  
} P_lcX;O  
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public void run() .x$T al  
{ v8k^=A:  
while(nStartPos < nEndPos && !bStop) U?^|>cMr  
{ ;)]zv\fC  
lg  
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try{ -*q2Y^A^l  
URL url = new URL(sURL); Qn3
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FC(cXPX}  
httpConnection.setRequestProperty("User-Agent","NetFox"); RMt vEa  
String sProperty = "bytes="+nStartPos+"-"; \fR:+rbQ&|  
httpConnection.setRequestProperty("RANGE",sProperty); h_G7T1;L  
Utility.log(sProperty); :(p rx   
6Vzc:8o>  
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InputStream input = httpConnection.getInputStream(); Odtck9
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//logResponseHead(httpConnection); bNU^tL3QZ  
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byte[] b = new byte[1024]; E=*Q\3G~  
int nRead; &&S4x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4KSN;G  
{ ~wg^>!E  
nStartPos += fileAccessI.write(b,0,nRead); .u;TeP  
//if(nThreadID == 1) B@vH1T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |M>k &p,B-  
} a&VJYAB  
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Utility.log("Thread " + nThreadID + " is over!"); ujqktrhuLb  
bDownOver = true; |+~2sbM  
//nPos = fileAccessI.write (b,0,nRead); 1O7ss_E  
} 3A}8
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catch(Exception e){e.printStackTrace ();} T2; 
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} "FIx^  
} =F[,-B~  
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13kb~'+&r  
//打印回应的头信息 0U*"OSpF  
public void logResponseHead(HttpURLConnection con) GZX!iT  
{ @}!$NI8  
for(int i=1;;i++) )II,HT-LY  
{ !`=?<Fl  
String header=con.getHeaderFieldKey(i); Q^w]Nj(e_  
if(header!=null) oXkhj,{y5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G_mu7w  
Utility.log(header+" : "+con.getHeaderField(header)); =V 7w CW  
else 6l7
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break; += ~}PF  
} s7} )4.vO  
} DP]|}8~L  
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public void splitterStop() :C6rN}_k  
{ 6D(m8  
bStop = true; Oh4WYDyT  
} !P3|T\|]+  
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} 9ksrr{tW  
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/* %TgM-F,8  
**FileAccess.java )D*xOajo+l  
*//文件访问(定位，写) P'~3WL4MKs  
package NetFox; ':$a6f &T  
import java.io.*; uu.N
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c'R|Wyf  
M6!brj\[|  
public class FileAccessI implements Serializable{ rID]!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 L 3@wdC~0  
RandomAccessFile oSavedFile; >.4Sx~VH2  
long nPos; RA/yvr  
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2
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public FileAccessI() throws IOException +Ti@M1A&  
{ Cx~z^YP'  
this("",0); .`XA6e(8KR  
} 5{TF6  
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public FileAccessI(String sName,long nPos) throws IOException kq-RM#Dj:  
{ &KWh5S@w  
oSavedFile = new RandomAccessFile(sName,"rw"); 'QU ?O[CH  
this.nPos = nPos; l/LUwDI{  
oSavedFile.seek(nPos); H1M>60*  
} "o^zOU  
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ppjrm
 
public synchronized int write(byte[] b,int nStart,int nLen) eS
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{ V-3]h ba,  
int n = -1; jXf-+;ZQ  
try{ K<tg+(3  
oSavedFile.write(b,nStart,nLen); u 36;;z  
n = nLen; ,<7f5qg"'  
} \Y$NGB=2[  
catch(IOException e) ZlzFmNe60  
{ /xzL!~g`6<  
e.printStackTrace (); l-rnDl  
} VrK5a9*^  
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return n; XQA2uR4h  
} C#R9Hlb  
+#no$m.bH  
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} g d-fJ._1  

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/* Lnzhs;7L  
**SiteInfoBean.java `*a,8M%  
*/ *QX$Mo^E  
package NetFox; "`k[4C  
z$NLFJvy_-  
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public class SiteInfoBean { _u0dt) $  
K5$ y  
w#XJ!f6*_9  
private String sSiteURL; //Site's URL -]e@cevy  
private String sFilePath; //Saved File's Path {~S
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private String sFileName; //Saved File's Name 1X5\VY>S`h  
private int nSplitter; //Count of Splited Downloading File `6/7},"9t  
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public SiteInfoBean() ":Q^/;D}U  
{//nSplitter的缺省值为5 [o~w>,a  
//default value of nSplitter is 5 3-05y!vbcE  
this("","","",5); [,dsVd  
} ?2M15Q  
]WG\+1x9  
2+enRR~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,RZktWW_  
{ :X^B1z3X4  
sSiteURL= sURL; o|+tRl  
sFilePath = sPath; &Wba2fD  
sFileName = sName; jHd~yCq  
this.nSplitter = nSpiltter; #ua#$&p  
w3*JVIQC  
>QyMeH  
} 0V^?~ex  
*M="k 1P1  
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public String getSSiteURL() ,FTF@h-Cs  
{ Na=q(OKN  
return sSiteURL; _]\mh,}  
} 4avM:h  
"x{S3v4Rb5  
Zy'bX* s|  
public void setSSiteURL(String value) ]?kf;A@  
{ .Ee8s]h5W  
sSiteURL = value; R\<^A~(Gl  
} P=h2Z,2  
fROhn}<**[  

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public String getSFilePath() xzy9~))o  
{ FOZqN K  
return sFilePath; ]`MRH[{  
} 6)TFb,  
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k8h$#@^  
public void setSFilePath(String value) ?Z;knX\?J  
{ .G^.kg ,  
sFilePath = value; '?-GZ0oM  
} UZ<!(g.  

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public String getSFileName() jtZ@`io  
{ 7_JK2  
return sFileName; %3q@\:s  
} Tj.;\a|d  
~oOOCB  
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public void setSFileName(String value) %DiZ&}^Ck  
{ N&=,)d~M
 
sFileName = value; Jk`A}  
} 50CU|  

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public int getNSplitter() N 4Dyec\  
{ ecr pv+  
return nSplitter; cP(/+ /9  
} GXsHc
,  
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public void setNSplitter(int nCount) Ua(!:5q?  
{ NC0x!tJ#7  
nSplitter = nCount; iA=
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} #A?U_32z/2  
} Y,?rykRj  
4j/8Otn  
_pW\F(+8  
/* G:f]z;Xdp  
**Utility.java W<kJ%42^j  
*/ (/c9v8Pr(7  
package NetFox; BjJ+~R  
DUa`8cE}  
7Sr7a{  
public class Utility { J5I
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U2!9Tl9".  

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public Utility() YwEXTy>0  
{ DaaLRMQ=  
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@TsOc0?-  
} %YA=W=Yd  
H/YZwDx,i  
//线程睡眠 Il>!C\hU  
public static void sleep(int nSecond) }5FdX3YR  
{ \A Y7%>  
try{ C4]vq+  
Thread.sleep(nSecond); 6O!&!  
} 8E ^yHd4Y  
catch(Exception e) p'ukV(B  
{ gVl%:Ra%  
e.printStackTrace (); D?;$:D"  
} Jah~h44&  
} S2h?Q$e3  
D`2Iy.|!  
//日志 Mq8jPjL  
public static void log(String sMsg) NAlYfbp  
{ +t})tDPXw  
System.err.println(sMsg); a3sXl+$D@  
} a>G|t5w  
s-~Tf|  
-!k"*P  
public static void log(int sMsg) vn9_tL&  
{ he;&KzEu  
System.err.println(sMsg); MkF:1-=L  
} YFL9Q<  
} Ir}r98lz  
,?P@ :S<8  
%70sS].@  
/* )E'iC
  
**TestMethod.java g,@0 ;uVq  
*/ +x\b- '  
package NetFox; 2r^|  
hqmKUlo  
^?VYE26  
public class TestMethod { |Qo;=~7  
HE,# pj(D  
TG~:Cmc  
public TestMethod() d:|X|0#\uH  
{ ///xx/weblogic60b2_win.exe CfNHv-jDL  
try{ rfpeX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _ko16wfg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p
'fU}B1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DP6M4  
fileFetch.start(); 8A~5@  
} b7^VWX%  
catch(Exception e){e.printStackTrace ();} |<t"O  
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} h/j+b.|  
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VPx"l5\  
public static void main(String[] args) M}kt q)  
{ u_[s+J/  
new TestMethod(); {L$]NQdz  
} Kz:g9  
} 5zWxI]4d\  
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