http断点续传简单实现（java)

/* {26/SY  
**SiteFileFetch.java hCS|(8g  
*/ 9ldv*9v  
package NetFox; O`<id+rx  
import java.io.*; Iy%
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import java.net.*; L)p*D(  
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public class SiteFileFetch extends Thread { qbrY5;U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean yhxen  
long[] nStartPos; //开始位置 %5Q5xw]w3  
long[] nEndPos; //结束位置 p=sLKnLmZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +uZ,}J  
long nFileLength; //文件长度 ]?tC+UKb  
boolean bFirst = true; //是否第一次取文件 e=e^;K4  
boolean bStop = false; //停止标志 O/ Yz6VQ  
File tmpFile; //文件下载的临时信息 ^E{M[;sF3y  
DataOutputStream output; //输出到文件的输出流 bk^W]<:z`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5n{J}0C  
public SiteFileFetch(SiteInfoBean bean) throws IOException I6@98w}"  
{ ;;;aM:6\  
siteInfoBean = bean; IYAvO%~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lV924m
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |,#DB  
if(tmpFile.exists ()) _kGJqyYV  
{ }ya@*jH  
bFirst = false; 5G  @  
read_nPos(); $De14  
} P&I%!'<   
else A@M%}h  
{ 4j+FDc`  
nStartPos = new long[bean.getNSplitter()]; ])Rs.Y{Q5  
nEndPos = new long[bean.getNSplitter()]; VAPRI\uM;  
} `
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} :buH\LB*P  
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public void run() K=lm9K  
{ 0oR'"Vo  
//获得文件长度 A)v! {  
//分割文件 _:"PBN9  
//实例FileSplitterFetch 7uy?%5  
//启动FileSplitterFetch线程 2yB)2n#ut  
//等待子线程返回 FVY$A=G  
try{ Z8
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if(bFirst) DNTkv_S  
{ pAK7V;sJ  
nFileLength = getFileSize(); *S _[8L"  
if(nFileLength == -1) d6RO2^  
{ CcDmZ  
System.err.println("File Length is not known!"); %*:X FB  
} tFj[>_d7  
else if(nFileLength == -2) (p6$Vgdt  
{ <;eXbO>Q  
System.err.println("File is not access!"); V/N:Of:\R  
} lSW6\jX  
else F"I{_yleq'  
{ s0D,n1x  
for(int i=0;i<nStartPos.length;i++) [te9ui%JS  
{ CB!5>k+mC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KkD.n#A  
} MZPX
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for(int i=0;i<nEndPos.length-1;i++) EuH[G_5e0  
{ J]h
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nEndPos = nStartPos[i+1]; I|
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} [l`_2{:
 
nEndPos[nEndPos.length-1] = nFileLength; >{/As][  
} 6I8A[  
} ,q_'l?Pn  
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\}:RG^*m  
//启动子线程 O8\>?4)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }8lv
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for(int i=0;i<nStartPos.length;i++) 1&7~.S;km  
{ -=;V*;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _R/^P>Q?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D6Q6yNE
  
nStartPos,nEndPos,i); 5>S=f{ghFw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ng0tNifZ;  
fileSplitterFetch.start(); pYxdE|2j  
} 76'@}wNnw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V?[dg^*0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r:.ydr@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EdH;P\c  
nEndPos = " + nFileLength); xY_<D+OV  
// fileSplitterFetch[nPos.length-1].start(); $4Vpl  
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//等待子线程结束 j:Y1  
//int count = 0; JXhHitUD  
//是否结束while循环 jWUpzf)q=T  
boolean breakWhile = false; }piDg(D  
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while(!bStop) - WEEnwZ  
{ Q`0k=<  
write_nPos(); wO-](3A-8P  
Utility.sleep(500); {p90  
breakWhile = true; 7>
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for(int i=0;i<nStartPos.length;i++) U@'F9UB`  
{ 3oo Tn-`{  
if(!fileSplitterFetch.bDownOver) f+c<|"we  
{ M~!DQ1u  
breakWhile = false; S
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break; s.uw,x  
} 0b3z(x!O  
} 7,v}Ap]Pa  
if(breakWhile) e5z U`R  
break; B* hW  
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//count++; [(81-j1v  
//if(count>4) gK%^}xU+  
// siteStop(); !et[Rdbu  
} Fcp8RBq  
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System.err.println("文件下载结束！"); RZL:k;}5  
} mI4)+8SUu  
catch(Exception e){e.printStackTrace ();} r5s$#,O/&Q  
} l2.Lh<G  
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//获得文件长度 KD(}-zUs  
public long getFileSize() <\6<-x(H5  
{ =Z~nzyaN  
int nFileLength = -1; =7l'3z8  
try{ {E3329t|'  
URL url = new URL(siteInfoBean.getSSiteURL()); lYq/ n&@_1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lk[BS*  
httpConnection.setRequestProperty("User-Agent","NetFox"); iC`mj  
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int responseCode=httpConnection.getResponseCode(); CHGV1X,  
if(responseCode>=400) xlHC?d0}  
{ 97L|IZ s)  
processErrorCode(responseCode); O9/7?"l"  
return -2; //-2 represent access is error ]ysEj3  
} jWE?$r"  
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String sHeader; [m+):q^  
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for(int i=1;;i++) W&'[Xj  
{ Up*.z\|'y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MmL)CT  
//Utility.log(in.readLine()); m.':5  
sHeader=httpConnection.getHeaderFieldKey(i); uB*Y}"Fn  
if(sHeader!=null) ),%(A~\  
{ -0G/a&ss  
if(sHeader.equals("Content-Length")) $KAOJc4<  
{ 0^G5 zQlj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xkPH_+4i8  
break; K:_5#!*^98  
} #y2IHO-  
} <5fb,@YN  
else MzP q(`W  
break; ^:Hx.  
} Yg<4}l."  
} mAZfo53  
catch(IOException e){e.printStackTrace ();} P-25]-  
catch(Exception e){e.printStackTrace ();} KJQW))%e  
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Utility.log(nFileLength); d:"#_  
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return nFileLength; 5
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} W_\~CntyZ  
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//保存下载信息（文件指针位置） Q.zE}ZS  
private void write_nPos() \(g/::|  
{ +jifbf-  
try{ 3;t{V$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'G>gN
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output.writeInt(nStartPos.length); (h$[g"8  
for(int i=0;i<nStartPos.length;i++) Z H1UAf  
{ _f1~r^(/T0  
// output.writeLong(nPos); f*tKj.P  
output.writeLong(fileSplitterFetch.nStartPos); qwd7vYBc,  
output.writeLong(fileSplitterFetch.nEndPos); r}%2;!T  
} hP$v,"$  
output.close(); xoQ;fVNp  
} KO''B or  
catch(IOException e){e.printStackTrace ();} J}M_Ka  
catch(Exception e){e.printStackTrace ();} G-#]|)  
} A6faRi703  
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//读取保存的下载信息（文件指针位置） )u67=0s2i+  
private void read_nPos() .r4M]1Of  
{ 5k]xi)%  
try{ eX0ASI9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1v2pPUH\  
int nCount = input.readInt(); K'tck
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nStartPos = new long[nCount]; m_;<7W&p]  
nEndPos = new long[nCount]; qy$1+>f1  
for(int i=0;i<nStartPos.length;i++) |u5Xi5q.f  
{
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nStartPos = input.readLong(); M%S.Z4D (0  
nEndPos = input.readLong(); |Js?@  
} V#-\ 4`c  
input.close(); 3`%U)gCT5  
} M"l<::z  
catch(IOException e){e.printStackTrace ();} wLW[Vur[  
catch(Exception e){e.printStackTrace ();} 6:$+"@ps  
} PS
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private void processErrorCode(int nErrorCode) ;mtv  
{ )o\U4t  
System.err.println("Error Code : " + nErrorCode); ?K>=>bS^h  
} 'v?"TZ  
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|on$)vm  
//停止文件下载 S1&Df%Ra  
public void siteStop() Y[p  
{ o+F]80CH  
bStop = true; )Co&(;zf  
for(int i=0;i<nStartPos.length;i++) ?$Tp|<tx#  
fileSplitterFetch.splitterStop(); bxFDB^  
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"(cMCBVYdA  
} E3`&W8  
} `k.Nphx~%  
//负责部分文件的抓取 Vh o3I[C  
**FileSplitterFetch.java 3`3`iN!8\@  
*/ _G1C5nkDl4  
package NetFox; *\4u:1Cu  
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import java.io.*; @b2JR^  
import java.net.*; -ZKo/N>6}  
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public class FileSplitterFetch extends Thread { ;c;5O@R}3  
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String sURL; //File URL FXd><#U  
long nStartPos; //File Snippet Start Position i<>zN^zn  
long nEndPos; //File Snippet End Position p^/6Rb"e  
int nThreadID; //Thread's ID #lo1GoL\  
boolean bDownOver = false; //Downing is over \&#pJBBG  
boolean bStop = false; //Stop identical 3<vw#]yL  
FileAccessI fileAccessI = null; //File Access interface n |Is&fy  
)cUFb:D*"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8<X,6  
{ !hS~\+E  
this.sURL = sURL; `fm^#Nw  
this.nStartPos = nStart; u?-X07_  
this.nEndPos = nEnd; PY{])z3N  
nThreadID = id; !b:;O +[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8O='Q-&8  
} %g+*.8;"b  
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public void run() v$_YZm{!<  
{ :^H#i:4  
while(nStartPos < nEndPos && !bStop) c(5r  
{ RV{'[8gM  
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try{ U5!T-o;3}  
URL url = new URL(sURL); `:&jbd4H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s4uYp  
httpConnection.setRequestProperty("User-Agent","NetFox"); >56I`[)  
String sProperty = "bytes="+nStartPos+"-"; }US^GEs(  
httpConnection.setRequestProperty("RANGE",sProperty); "PhP1;A9,  
Utility.log(sProperty); xfsf  
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InputStream input = httpConnection.getInputStream(); O>)Fl42IeD  
//logResponseHead(httpConnection); p.50BcDg  
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byte[] b = new byte[1024]; `L#`WC@[o  
int nRead; !`$xN~_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [ _Nw5_  
{ gdKn!; ,w#  
nStartPos += fileAccessI.write(b,0,nRead); }63Qh}_Y  
//if(nThreadID == 1) QW[ gDc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I&lb5'6D  
} ^w1&A3=6  
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Utility.log("Thread " + nThreadID + " is over!"); m(6SiV=D9  
bDownOver = true; ?9I=XTR  
//nPos = fileAccessI.write (b,0,nRead); c"H59 j
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} 8a}et8df:  
catch(Exception e){e.printStackTrace ();} )CAEqP  
} THcK,`lX@  
} |'?./  
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//打印回应的头信息 <[W41{  
public void logResponseHead(HttpURLConnection con) -<MA\iSP  
{ LLlt9(^d  
for(int i=1;;i++) }>T$2"pf  
{ R_
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String header=con.getHeaderFieldKey(i); ~0 5p+F)  
if(header!=null) TcjTF|q>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); piv/QP-X  
Utility.log(header+" : "+con.getHeaderField(header)); `$hna{e^n  
else 40ZHDtIu<  
break; C[0*>W8o  
} byrK``f  
} M`jqUg  
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public void splitterStop() gp`H>Sn.|  
{ fVJsVZ"6v`  
bStop = true; zVL"$ )  
} 9f/RD?(1O  
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} I]dt1iXu_{  
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/* d@u)'AY%/  
**FileAccess.java +dB/SC-^U  
*//文件访问(定位，写) Kx[u9MD  
package NetFox; 93+p~?  
import java.io.*; gs?=yNL  
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public class FileAccessI implements Serializable{ (Z
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*pMu,?uE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <XAW-m9SC  
RandomAccessFile oSavedFile; :p6.v>s8  
long nPos; bm Hl\?  
;WG6|QgV?-  
6.|Qyk*  
public FileAccessI() throws IOException wy)I6`v  
{ ?oKY"C8/  
this("",0); h
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} PX%Y$`  
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public FileAccessI(String sName,long nPos) throws IOException gXzp$#  
{ :fW\!o8Z2  
oSavedFile = new RandomAccessFile(sName,"rw"); c/bIt  
this.nPos = nPos; d 6$,N|  
oSavedFile.seek(nPos); $: %U`46%s  
} Ln2dD>{2  
O5;$cP:  
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public synchronized int write(byte[] b,int nStart,int nLen) LBs:O*;  
{ afJ`1l  
int n = -1; rElbzL"&<  
try{ @mbR I0  
oSavedFile.write(b,nStart,nLen); 2:>|zmh_  
n = nLen; E@%X  
} 9N?BWv}  
catch(IOException e) JC[G5$E  
{ n,.ZLuBEX  
e.printStackTrace (); 4Em$L]7  
} 
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/!//i^  
return n; 7j <:hF~  
} k'hJ@6eKS  
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} mV58&SZT  
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/* k8~/lE.Wy  
**SiteInfoBean.java H$j`75#u?-  
*/ lN<,<'&^.  
package NetFox; VXpbmg!{S  
P%-@AmO^_  
)w.\xA~|  
public class SiteInfoBean { k~<b~VcU  
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private String sSiteURL; //Site's URL K:i{us`  
private String sFilePath; //Saved File's Path mROXwzL
 
private String sFileName; //Saved File's Name _Coh11  
private int nSplitter; //Count of Splited Downloading File T<\!7RnLc  
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C6-71`C0  
public SiteInfoBean() z 5T_  
{//nSplitter的缺省值为5 x-Cy,d:YX  
//default value of nSplitter is 5 l_Ffbs_6t  
this("","","",5); qBkI9H  
} tmCm54  
~|7jz;$V  
99<0xN(25  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "gR W91 T  
{ 3*DwXH+  
sSiteURL= sURL; D m|_;iO,  
sFilePath = sPath; ylEQeN  
sFileName = sName; %Q0J$eC  
this.nSplitter = nSpiltter; #DL( %=:  
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:n4X>YL)  
} `?X=
@  
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public String getSSiteURL() eTV%+  
{ Mk*&CNo3  
return sSiteURL; Zv`j+b  
} +&w=*IAKZ  
q $Hg\ {c  
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public void setSSiteURL(String value) ZW]Q|vPh4U  
{ 7,\Uk|  
sSiteURL = value; m}x&]">9  
} |CC(`<\R  
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public String getSFilePath() UHtxzp =[  
{ \Lz2"JI  
return sFilePath; Q}?yj,DD  
} :oH~{EQ  
.Q,IOCHk  
"]jGCo>9  
public void setSFilePath(String value) gZ5E%']sT  
{ "iCR68e  
sFilePath = value; ]m#.MZe  
} 4)o_gm~6c4  
:?Xd&u0){  
5 W<\J  
public String getSFileName() x<0-'EF/S  
{ G%a8'3d,  
return sFileName; kH!I&4d&  
} hLVS}HE2  
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public void setSFileName(String value) x4PH-f-7  
{ n\nC.|_G@  
sFileName = value; "%c\i-&t  
} k~(j    
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6AZJ,Q\E@  
public int getNSplitter() ]7QRelMiz+  
{ He)<S?X-6  
return nSplitter; Wdt9k.hzN  
} "d a%@Zy  
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public void setNSplitter(int nCount) N0@&eX|$i4  
{
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nSplitter = nCount; >H@ zP8  
} 'L*nC T;  
} OIF0X!  
&&0,;r,-)  
|(gq:O  
/* t'uZho~^F  
**Utility.java 05(lh<C  
*/ \#(cI  
package NetFox; ;&2J9  
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public class Utility { Y$%/H"1bk  
*E<%db C2  
4:\s.Z{!3  
public Utility() r( _9_%[  
{ [sC]<2
r  
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EDR;" G(N  
} wVvk{tS  
h[D"O6 y  
//线程睡眠 8>Xyz`$kH  
public static void sleep(int nSecond) ~jab/cR  
{ _y}]j;e8>{  
try{ Azx4+`!-  
Thread.sleep(nSecond); q$EicH}k8  
} IqK??KSC  
catch(Exception e) aU]A#g   
{ pYo]lO  
e.printStackTrace (); ^|@t2Rp@  
} h+k:G9;sS  
} UV%Al)3  
k+>-?S,  
//日志 <|~8Ezd  
public static void log(String sMsg) huu:z3{=J  
{ 5Sd+Cc  
System.err.println(sMsg); qp*C%U  
} y4aSf2   
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I_mnXd;n  
public static void log(int sMsg) j]EeL=H<P  
{ a3i4eGT-  
System.err.println(sMsg); Cf`s:A5<J  
} (W3~r  
} ]KfjZ
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 ?[Od.  
$m`?x5rL8  
/* O/^7TBTn<r  
**TestMethod.java 75~>[JM  
*/ ffK A  
package NetFox; x^kV;^ I  
5V&3m@d0aq  
<syMrXk)R(  
public class TestMethod { SwV{t}I  
'qS&7 W(  
3]BK*OqJ  
public TestMethod() X cmR/+  
{ ///xx/weblogic60b2_win.exe gF;i3OJg  
try{ n7`R+4/s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `_C4L=q"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q=lQy  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w,dDA2,  
fileFetch.start(); xJ>U_Gd  
} rvZXK<@#+  
catch(Exception e){e.printStackTrace ();} Zr,:i MPZ  
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59:Xu%Hp  
} 'Z#8]YP`  
~"89NVk"  
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public static void main(String[] args) g+o
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{ 4S>A}rWz  
new TestMethod(); _p/ _t76s  
} V|3}~(5=  
} !6hUTjhW7z  
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