http断点续传简单实现（java)

/* -m= 8&B  
**SiteFileFetch.java YT/kC'A  
*/ [L$9
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package NetFox; h4pTq[4*  
import java.io.*; zjL.Bhiud  
import java.net.*; ^&/G|  
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public class SiteFileFetch extends Thread { OX:O^ (-r,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {+<P:jbz;  
long[] nStartPos; //开始位置 2g9G{~,@g  
long[] nEndPos; //结束位置 # {fTgq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H=g.34  
long nFileLength; //文件长度 X;F?:Iw\  
boolean bFirst = true; //是否第一次取文件 8;Fn7k_Uf  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 39F Of  
DataOutputStream output; //输出到文件的输出流 ^ta
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） juF{}J2  
public SiteFileFetch(SiteInfoBean bean) throws IOException -F"QEL#  
{ D'l5Zd  
siteInfoBean = bean; I V%VU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )Rat0$6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8n BL\{'B[  
if(tmpFile.exists ()) R2L;bGI*J  
{ vzel#  
bFirst = false; Y!q!5Crfi  
read_nPos(); d%I"/8-J  
} m@`8A  
else ,B&fFis  
{ 0n~Zz  
nStartPos = new long[bean.getNSplitter()]; K-<^$VWh  
nEndPos = new long[bean.getNSplitter()]; kc'pN&]r:  
} H`8``#-|@S  
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} +bK.NcS  
^ 5VK>  
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public void run() `u!l3VZ/4  
{ 5m=I*.qE  
//获得文件长度 MC((M,3L  
//分割文件 K'iIJA*Sn  
//实例FileSplitterFetch b?4/#&z]  
//启动FileSplitterFetch线程 M}_i52  
//等待子线程返回 Kz<@x`0   
try{ 8By,#T".  
if(bFirst) &Lt[WT$  
{ I]Tsz'T!9  
nFileLength = getFileSize(); 5 )2:stT73  
if(nFileLength == -1) 3lLMu B+  
{ BYW^/B Y)  
System.err.println("File Length is not known!"); @''GPL@  
} ]Fvm 7V  
else if(nFileLength == -2) H_!4>G@  
{ O
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System.err.println("File is not access!"); Nfe>3uQK  
} YI-O{U  
else b6t}{_7  
{ Iq+>qX  
for(int i=0;i<nStartPos.length;i++) D47R  
{ #zrTY9m7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e}@)z3Q<l  
} `6y{.$ z  
for(int i=0;i<nEndPos.length-1;i++) .*$
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{ 
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nEndPos = nStartPos[i+1]; ; UiwH  
} MRr</o  
nEndPos[nEndPos.length-1] = nFileLength; \ 6EKgC1  
} !/ y!QXj  
} Sp}D;7  
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vQF vtwd  
//启动子线程 GEjd7s]C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VKm!Ri$  
for(int i=0;i<nStartPos.length;i++) `G1&Z]z  
{ !|2VWI}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kVI#(uO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E$a ?LFa6  
nStartPos,nEndPos,i); (3[z%@I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7@.cOB`y@3  
fileSplitterFetch.start(); P3 c\S[F  
} <]C$xp<2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nf3.\eR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); % |q0-x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G>YAJo  
nEndPos = " + nFileLength); (vR 9H(#  
// fileSplitterFetch[nPos.length-1].start(); <?D[9Mk$  
IfO;S*Qt  
VN4yn| f/  
//等待子线程结束 !@u>A_  
//int count = 0; o!Ev;'D  
//是否结束while循环 e&ANp0|W  
boolean breakWhile = false; RUCPV[{b  

#B'aU#$u  
+ SZYg[  
while(!bStop) 'B83m#HR#  
{ q;5i4|  
write_nPos(); 6b8;}],|  
Utility.sleep(500); EzW)'Zzw~  
breakWhile = true; Md)zEj`\  
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2=-utN@Z  
for(int i=0;i<nStartPos.length;i++) m6eZ_&+u  
{ b1pQ`qt  
if(!fileSplitterFetch.bDownOver) SUWD]k>PH  
{ 6#}93Dgv4  
breakWhile = false; L_Q#(in  
break; d;Hn#2C  
} +^rh[>W  
} W$JebW<z(  
if(breakWhile) 9 7%0;a8  
break; JB</euyV  
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//count++; 3`O?16O  
//if(count>4) }}QTHR  
// siteStop(); >}~#>Ru  
} 53QfTP  
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System.err.println("文件下载结束！"); QU{Ech'  
} r8xyd"Axy  
catch(Exception e){e.printStackTrace ();} 71#I5*8  
} Z'pQ^MO  
)oo~m\`  
e73^#O&Xt  
//获得文件长度 d{et8N  
public long getFileSize() nmlPX7!{$  
{ E{=2\Wkcp  
int nFileLength = -1; O#nR>1h  
try{ _ 7oV<  
URL url = new URL(siteInfoBean.getSSiteURL()); k<w(i k1bi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 89{HJ9}  
httpConnection.setRequestProperty("User-Agent","NetFox"); l=`L7| ^/d  
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int responseCode=httpConnection.getResponseCode(); [MX;,%;;  
if(responseCode>=400) ^/wfXm  
{ [#" =yzR<3  
processErrorCode(responseCode); 3<|`0pt}  
return -2; //-2 represent access is error /|{,sWf2  
} z!=P@b  
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String sHeader; f#%JSV"7  
,!G{5FF8:  
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for(int i=1;;i++) @J[6,$UVu  
{ I3u{zHVwI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]u-SL md  
//Utility.log(in.readLine()); :&}odx!-!C  
sHeader=httpConnection.getHeaderFieldKey(i); ci,+Bjc  
if(sHeader!=null) fkfZ>D^1  
{ +y[@T6_  
if(sHeader.equals("Content-Length")) q<e&0u4  
{ Vi!Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J2GcBzRH  
break; )g| BMmB  
} Q_*_?yf  
} L;_c|\%  
else h*0S$p<[1  
break; {s,+^7  
} f<i7
@%  
} Rg29  
catch(IOException e){e.printStackTrace ();} F9c`({6k  
catch(Exception e){e.printStackTrace ();} XXmE+aI  
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Utility.log(nFileLength); Q^}%c U0  
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return nFileLength; Kj=gm .  
} mOll5O7VW  
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//保存下载信息（文件指针位置） 7k{2Upg;  
private void write_nPos() [}nK"4T"Ri  
{ -y) ,Y |  
try{ /rB{[zk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {TSY|D2  
output.writeInt(nStartPos.length); 
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for(int i=0;i<nStartPos.length;i++) Hyk'c't_O  
{ 5G}6;UY  
// output.writeLong(nPos); !.-tW7  
output.writeLong(fileSplitterFetch.nStartPos); ?9j{V7h  
output.writeLong(fileSplitterFetch.nEndPos); &'|B =7  
} 78#!Q.#
#  
output.close(); ;'T{
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} # jYpVc{]  
catch(IOException e){e.printStackTrace ();} !Gs} tiMH  
catch(Exception e){e.printStackTrace ();}
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} A)nW  
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//读取保存的下载信息（文件指针位置） ]*"s\ix  
private void read_nPos() XY7Qa!>7j  
{ W@L
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try{ 6@;ha=[+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TDK@)mP  
int nCount = input.readInt(); wWW~_zP0  
nStartPos = new long[nCount]; ]rd/;kg.S  
nEndPos = new long[nCount]; 4C_c\;d  
for(int i=0;i<nStartPos.length;i++) _cJ[ FP1  
{ 9~AWng  
nStartPos = input.readLong(); r2*<\ax  
nEndPos = input.readLong(); <T,
A&`/  
} !jX4`/n2  
input.close(); `qpc*enf0  
} MKGS`X]<J  
catch(IOException e){e.printStackTrace ();} ={(j`VSUX0  
catch(Exception e){e.printStackTrace ();} Q}%tt=KD  
} $FM' 3%B[  
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private void processErrorCode(int nErrorCode) E+_&HG}a  
{ 3&&+YX  
System.err.println("Error Code : " + nErrorCode); bPD)D'Hs  
} $j` $[tX6l  
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//停止文件下载 ZwI 1* f  
public void siteStop() #m. AN  
{ eBB:~,C^q.  
bStop = true; :1fagaPg  
for(int i=0;i<nStartPos.length;i++) oT+(W,G  
fileSplitterFetch.splitterStop(); }F1s tDx  
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}Ag|gF!_  
} AMlV%U#  
} N$aZ== $5  
//负责部分文件的抓取 uF(k[[qaiN  
**FileSplitterFetch.java [5ethM  
*/ 9G+f/k,P  
package NetFox; =Z0t :{  
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import java.io.*; .CV _\  
import java.net.*; ^tAO_~4  
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public class FileSplitterFetch extends Thread { q|#MB7e/  
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String sURL; //File URL pu;3nUH  
long nStartPos; //File Snippet Start Position 9Ld9N;rWm#  
long nEndPos; //File Snippet End Position cf8-]G?tK  
int nThreadID; //Thread's ID h* .w"JO  
boolean bDownOver = false; //Downing is over GG-[`!>.pw  
boolean bStop = false; //Stop identical O
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FileAccessI fileAccessI = null; //File Access interface W|c.l{A5Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |"k&fkS$  
{ `7Ug/R<  
this.sURL = sURL; x!{   
this.nStartPos = nStart; crmUrF#  
this.nEndPos = nEnd; CmC0k-%w  
nThreadID = id; >q( 5ir  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D!FaEN  
} ," R>}kPli  
Df=q-iq<{/  
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public void run() Ek
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{ rg&+  
while(nStartPos < nEndPos && !bStop) uDG+SdyN@  
{ )s")y  
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try{ rY70^<z  
URL url = new URL(sURL); vZjZb(jlN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =Sxol>?t  
httpConnection.setRequestProperty("User-Agent","NetFox"); #s"B-sWE  
String sProperty = "bytes="+nStartPos+"-"; F>Jg~ FD*  
httpConnection.setRequestProperty("RANGE",sProperty); iBb
br,  
Utility.log(sProperty); !oMt_k X  
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InputStream input = httpConnection.getInputStream(); I6dm@{/:>  
//logResponseHead(httpConnection); d79N-O-  
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byte[] b = new byte[1024]; R2^iSl%pj  
int nRead; U</+.$b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &hN,xpC  
{ (([I]q  
nStartPos += fileAccessI.write(b,0,nRead); !WKk
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//if(nThreadID == 1)  (K #A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U"5q;9#q  
} ])$S\fFm  
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Utility.log("Thread " + nThreadID + " is over!"); nR'#s%Kj  
bDownOver = true; *SZ>upg  
//nPos = fileAccessI.write (b,0,nRead); -V=arm\#z  
} M\UWWb&%\  
catch(Exception e){e.printStackTrace ();} c4|so=  
} :C%47qv  
} h~ha  
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//打印回应的头信息 3?ba 1F0Nw  
public void logResponseHead(HttpURLConnection con) G[6=u|(M  
{ tA qs2  
for(int i=1;;i++) *Mi6  
{ %0v*n8  
String header=con.getHeaderFieldKey(i); ;BTJ%F.  
if(header!=null) )73DT3-0$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lG]GlgSs  
Utility.log(header+" : "+con.getHeaderField(header)); O,9X8$5H-a  
else >eo8  
break; jOl1_  
} NgxO&Zp  
} I7Zq}Pxa  
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public void splitterStop() Yq;&F0paK  
{ MVAc8dS  
bStop = true; OK\]*r  
} M(S{1|,V  
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}#YQg0(  
} r5)f82pQ  
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@Z2/9K%1'  
/* XI g|G}i.  
**FileAccess.java 4~WlP,,M  
*//文件访问(定位，写) jr1Se9u D  
package NetFox; b-b;7a\N  
import java.io.*; }}
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public class FileAccessI implements Serializable{ m/N(%oMWB=  
6SAQDE
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [NR1d-Wg  
RandomAccessFile oSavedFile; }2xb&6g~o  
long nPos; ~y%7w5%Un  
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*
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public FileAccessI() throws IOException Ib(,P3  
{ -9Xw]I#QR  
this("",0); p,^>*/O>  
} dh,7iQ s  
9oD#t~+F4  
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public FileAccessI(String sName,long nPos) throws IOException _^3@PM>  
{ KqY>4tb  
oSavedFile = new RandomAccessFile(sName,"rw"); |Kn^w4mN  
this.nPos = nPos; cFxSDTR  
oSavedFile.seek(nPos); G[B*TM6$  
} Faw. GU  
:\T_'Shq  
/K&wr6  
public synchronized int write(byte[] b,int nStart,int nLen) 2c*2\93>  
{ >,w P!;dh  
int n = -1; x k#*=  
try{ ?/L1tX)  
oSavedFile.write(b,nStart,nLen); T/3;NXe6E  
n = nLen; 'Sk6U]E~  
} #|D:f~"d3  
catch(IOException e) "p2u+ 8?  
{ l?N`V2SuR  
e.printStackTrace (); o}W7.7^2  
} L/%xbm~  
;WPI+`-  
1 pYsjo~  
return n; th;]Vo  
} F6h/0i  
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} c{ZqQtfM  
t"
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}8X:?S %  
/* +0)5H>h  
**SiteInfoBean.java {S# 5g2  
*/ ; vhnA$'a  
package NetFox; ob)D{4B'  
7{8)ykBU^  
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public class SiteInfoBean { m.
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private String sSiteURL; //Site's URL O/'f$Zj36  
private String sFilePath; //Saved File's Path Zr~"\llk  
private String sFileName; //Saved File's Name M|aQ)ivh3  
private int nSplitter; //Count of Splited Downloading File `jt(DKB+J  
iNMLYYq]l  
*GB$sXF  
public SiteInfoBean() +._f.BRmX.  
{//nSplitter的缺省值为5 $::51#^Wg  
//default value of nSplitter is 5 -1dIZy  
this("","","",5); aj+zmk~-  
} I%C]>ZZh  
y;*My#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C5d/)aC  
{ Gf!t< =T   
sSiteURL= sURL; %Gnd"SGs  
sFilePath = sPath; nT(!HD
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sFileName = sName; d;IJ0xB+by  
this.nSplitter = nSpiltter; F12S(5Z0%  
/<Gyg7o0  
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} UEk|8yq  
7UY('Q[  
^!XU+e+:0  
public String getSSiteURL() HE4`9$kVLr  
{ qLU15cOM  
return sSiteURL; Ul7,k\q@  
} YeR7*[l  
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public void setSSiteURL(String value) 8kKRx  
{ t>fA!K%{  
sSiteURL = value; aA!@;rR<yU  
} 8JFnB(3xU  
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$,!dan<eA  
public String getSFilePath() |YMzp8Da(  
{ n/,rn>k7:  
return sFilePath; :cIu?7A  
} ?^F*"+qI  
'lSnyW{  
%>oT7|x  
public void setSFilePath(String value) OpbszSl"y  
{ Jc9@VxWY  
sFilePath = value; iGpK\oH  
} W` 6"!V  
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:K a^  
public String getSFileName() `"-`D!U?$  
{ qhv4R|)  
return sFileName; il 8A&`%  
} vU
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public void setSFileName(String value) Phk`=:xh  
{ bs4fyb  
sFileName = value; woC FN1W  
} mRix0XBI~  
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public int getNSplitter() x(T!I&i={  
{ 'npT+p$V  
return nSplitter; F5om-tzy  
} 6jQ&dN{=qB  
;+#za?w  
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public void setNSplitter(int nCount) 4OB~h]Vc  
{ I{Y {
  
nSplitter = nCount; kM}ic(K  
} ]-+.lR%vd9  
}
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C
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/* GhchfI.  
**Utility.java pfT`WT  
*/ .jrR4@  
package NetFox; A$$R_3ne  
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public class Utility { Q:Nwy(,I  
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public Utility() J_((o  
{ qJAv=D  
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} !Sr0Im0  
, L AJ  
//线程睡眠 &d &oP  
public static void sleep(int nSecond) {O3oUE+  
{ yScov)dp(  
try{ Lbm
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Thread.sleep(nSecond); (Mire%$h  
} '"G %0y  
catch(Exception e) +h9l%Pz  
{ +X|m>9  
e.printStackTrace (); Wvzzjcr(j  
} N4JqW  
} `mHOgS>|  
3R$CxRc:  
//日志 AcfkY m~  
public static void log(String sMsg) X?k V1  
{ 4q2=:"z4  
System.err.println(sMsg); M}KM]<  
} <^X'f  
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\Z7([Gh  
public static void log(int sMsg) o\:f9JL  
{ 7! A%6  
System.err.println(sMsg); 8BoT%kVeJv  
} 6XxG1]84  
} h1UlLy8  
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3I{ta/(  
/* )su
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**TestMethod.java IP4b[|ef  
*/ H2pXJ/XF  
package NetFox; ba)YbP[  
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&4Iqm(  
public class TestMethod { ,mBKy
a)  
h/+I-],RF  
9'*ZEl^?D  
public TestMethod() ^xkppN2  
{ ///xx/weblogic60b2_win.exe -GkK[KCH  
try{ #SLxNAH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S&)) 0d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E(4lu%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^*UfCoj9Z  
fileFetch.start();  W$VCST  
} GO GXM4I  
catch(Exception e){e.printStackTrace ();} G]NtX4'4  
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} 36A.h,~  
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public static void main(String[] args) #* /W!UOu  
{ V]PhXVJ  
new TestMethod(); LkZo/K~  
} He_(JXTP  
} ';CuJXAj  
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