http断点续传简单实现（java)

/* 8NNs_~+x}  
**SiteFileFetch.java  Bw+?MdS  
*/ :7Uv)@iUk  
package NetFox; '<e$ c  
import java.io.*; {+5Ud#\y  
import java.net.*; 9`^(M^|c  
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public class SiteFileFetch extends Thread { &?xtmg<d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (m2_Eh;  
long[] nStartPos; //开始位置 ?h|DeD!s  
long[] nEndPos; //结束位置 [yc7F0Aw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H_| re  
long nFileLength; //文件长度 M*Q}^<E*  
boolean bFirst = true; //是否第一次取文件 $n47DW&  
boolean bStop = false; //停止标志 +T,A^(&t  
File tmpFile; //文件下载的临时信息 b53s@7/mq  
DataOutputStream output; //输出到文件的输出流 :}#j-ZCC"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7.)_H  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3'0Jn6(  
{ tt6GtYrC 1  
siteInfoBean = bean; +nB0O/m'U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RHbbj}B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x]R0zol  
if(tmpFile.exists ()) ]!jfrj  
{ cc1M9kVi  
bFirst = false; 0$=U\[og  
read_nPos(); ]HXHz(?;F  
} sK/ymEfRv  
else FGm!|iI  
{ TnKOr~@*  
nStartPos = new long[bean.getNSplitter()]; hOFvM&$  
nEndPos = new long[bean.getNSplitter()]; Yu
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} }!|$;3t+c  
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} Fo~q35uB  
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public void run() V|awbff:  
{ Tks1gN^^  
//获得文件长度 nKEw$~F  
//分割文件 YV>&v.x0;  
//实例FileSplitterFetch  b=Ektq  
//启动FileSplitterFetch线程 \CS4aIp  
//等待子线程返回 [T/S/@IT  
try{ <QaUq`,  
if(bFirst) mjk<FXW  
{ FlrYXau  
nFileLength = getFileSize(); #e@[{s7  
if(nFileLength == -1) 5'w&M{{9  
{ OCCC' k  
System.err.println("File Length is not known!"); ^'+#BPo9@  
} %@q2  
else if(nFileLength == -2) 1g$xKe~]4  
{ j>.1RG  
System.err.println("File is not access!"); vI48*&]wTf  
} F/:%YR;  
else ~xws5n}F  
{ 3.ShAL  
for(int i=0;i<nStartPos.length;i++) v5?ct?q  
{ P"@^BQ4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TXs&*\  
} WqCj;Tj|  
for(int i=0;i<nEndPos.length-1;i++) N_+D#Z.g  
{ CEzdH!nP  
nEndPos = nStartPos[i+1]; f^IB:e#j;  
} Q
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nEndPos[nEndPos.length-1] = nFileLength; !u4eI0?R?  
} t.bM]QU!1  
} x[+bLlb  
Ruwp"T}mF  
zh(=kS`  
//启动子线程 {aK
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )}_}D+2  
for(int i=0;i<nStartPos.length;i++) l>(*bb1}b  
{ bhsCeH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4TiH
h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g~9b_PY9  
nStartPos,nEndPos,i); $d.Dk4.ed  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >-w#&T &K  
fileSplitterFetch.start(); B=}QgXg  
} KO"+"1 .  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K&"X7fQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OW!
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Df(+@L5!  
nEndPos = " + nFileLength); SFFJyRCz  
// fileSplitterFetch[nPos.length-1].start(); @2_E9{T  
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//等待子线程结束 M@*Y&(~  
//int count = 0; z|(<Co8#.  
//是否结束while循环 :vaVghN\  
boolean breakWhile = false; N+pCC  
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Jv]$@>#  
while(!bStop) wMCgLh\wi  
{ ;W\?lGOs{  
write_nPos(); 6UqDpL7^U  
Utility.sleep(500); 13Q87i5B  
breakWhile = true; RfCu5Kn  
=
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for(int i=0;i<nStartPos.length;i++) +4[9Eb'k=  
{ hb}QtQ  
if(!fileSplitterFetch.bDownOver) - _%~b  
{ 'jy
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breakWhile = false; :<5jlpV(  
break; <HpUP!q8v  
} Ufor>  
} W!+=`[Ff  
if(breakWhile) ;Uy}(  
break; Z:2%gU&W  
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={o)82LV  
//count++; z;N`jqo   
//if(count>4) rc"8N<D  
// siteStop(); s<3M_mt  
} q; C6ID`  
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System.err.println("文件下载结束！"); \ *g3j  
} z+zEH9.'  
catch(Exception e){e.printStackTrace ();} J*Cf1 D5!  
} H"?Ndl:  
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//获得文件长度 Z=a~0&G  
public long getFileSize() g!cW`B'  
{ T&Z
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int nFileLength = -1; d(KK7SQg  
try{ g{K
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URL url = new URL(siteInfoBean.getSSiteURL()); m)r,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j;-2)ZLm  
httpConnection.setRequestProperty("User-Agent","NetFox"); J L1]auO*  
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|nqN95'u+]  
int responseCode=httpConnection.getResponseCode(); T?tZ?!6  
if(responseCode>=400) la^K|!|  
{ _({wJ$aYC  
processErrorCode(responseCode); # 00?]6`z  
return -2; //-2 represent access is error gplrJaH@  
} i#*lK7  
7[0CVWs,  
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String sHeader; }n"gX>e~  
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for(int i=1;;i++) |M18/{  
{ =hI;5KF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); TS=U%)Ik  
//Utility.log(in.readLine()); 0E{DO<~  
sHeader=httpConnection.getHeaderFieldKey(i); 7E5=Qx  
if(sHeader!=null) \i<7Lk  
{ v(, tu/  
if(sHeader.equals("Content-Length")) Q6N?cQtOT  
{ pA_e{P/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rdAy '38g  
break; 2|NQ5OA0  
} BE54L+$p  
} -*kZ2grLt  
else @,LU!#y(  
break; I\IDt~  
} FiXqypT_(  
} )a%E $`  
catch(IOException e){e.printStackTrace ();} <KE%|6oER  
catch(Exception e){e.printStackTrace ();} K;>9K'n  
6 tB\X^  
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Utility.log(nFileLength); k$kxw_N5d  
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} na@gn  
return nFileLength; S5YEz XG  
} )lJi7 ^,  
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3/]~#y%2  
//保存下载信息（文件指针位置） t5P8?q\  
private void write_nPos() f6PYB&<1  
{ XQtV$Lw  
try{ 6:?mz;oP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j*d+WZm8-g  
output.writeInt(nStartPos.length); tC.etoh  
for(int i=0;i<nStartPos.length;i++) !HeQMz  
{ 2~vvE  
// output.writeLong(nPos); c}H}fyu%n  
output.writeLong(fileSplitterFetch.nStartPos); QC6QqcOX  
output.writeLong(fileSplitterFetch.nEndPos);  D@]/%;  
} u('`.dwkc  
output.close(); en6;I[\  
} :Smyk.B2!  
catch(IOException e){e.printStackTrace ();} BaMF5f+  
catch(Exception e){e.printStackTrace ();} >ZU)bnndA  
} [<d_#(]h'  
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//读取保存的下载信息（文件指针位置） a :cfr*IsK  
private void read_nPos() YtXd>@7  
{ *&V"x=ba,  
try{ cyh;1Q
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z&7Yl(|  
int nCount = input.readInt(); !\'HKk~V  
nStartPos = new long[nCount]; xl,6O!aR  
nEndPos = new long[nCount]; 5'<mfY'B  
for(int i=0;i<nStartPos.length;i++) lAGntYv  
{ +x~p&,w?  
nStartPos = input.readLong(); vN~joQ=d  
nEndPos = input.readLong(); JgV4-B0  
} 9hJ  a K  
input.close(); APCE}%1U  
} 4ti,R'  
catch(IOException e){e.printStackTrace ();} U r8JG&,  
catch(Exception e){e.printStackTrace ();} ,|j\x  
} z.OJ1vY7  
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private void processErrorCode(int nErrorCode) 90ov[|MkM  
{ kv2 H3O  
System.err.println("Error Code : " + nErrorCode); bw!
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} `(6cRT`Wp  
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VZ7E#z+nM#  
//停止文件下载 *?>52 -&b  
public void siteStop() ih|&q  
{ 4H{$zMq8  
bStop = true; &2n5m&  
for(int i=0;i<nStartPos.length;i++) VJ1rU mO~  
fileSplitterFetch.splitterStop(); n;~'W*Ln0  
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} >gl.ILo  
} =Q6JXp  
//负责部分文件的抓取 y I[kaH"J  
**FileSplitterFetch.java 42:,*4t(  
*/ RVF<l?EI4R  
package NetFox;
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import java.io.*; p<y\^a  
import java.net.*;  RcZ&/MY  
g!z &lQnZ  
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public class FileSplitterFetch extends Thread { pIKfTkSqH  
E `V?Io  
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String sURL; //File URL \VypkbE+  
long nStartPos; //File Snippet Start Position $yUPua/-  
long nEndPos; //File Snippet End Position dqi31e{*2\  
int nThreadID; //Thread's ID EOS[MjX+J  
boolean bDownOver = false; //Downing is over G-#rWZ&  
boolean bStop = false; //Stop identical jHV) TBr  
FileAccessI fileAccessI = null; //File Access interface /03?(n= 3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <S12=<c?'  
{ DU-dIqi  
this.sURL = sURL; HHOqJb{8S  
this.nStartPos = nStart; AXv-%k};  
this.nEndPos = nEnd; e488}h6#m  
nThreadID = id; WtXf~ :R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |EY1$qItid  
} c<{~j~+  
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public void run() $8Z4jo  
{ S7@/dHN  
while(nStartPos < nEndPos && !bStop) sWi4+PAM0  
{ Sae*VvT6  
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try{ N37CAbw0  
URL url = new URL(sURL); J6@RIia  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rmdg~  
httpConnection.setRequestProperty("User-Agent","NetFox"); fVi[mH0=+  
String sProperty = "bytes="+nStartPos+"-"; MOm+t]vq1  
httpConnection.setRequestProperty("RANGE",sProperty); X9C:AGbp  
Utility.log(sProperty); y!|4]/G]?t  
c2]h.G83  
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InputStream input = httpConnection.getInputStream(); 4y$okn\}i  
//logResponseHead(httpConnection); |lyspD  
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byte[] b = new byte[1024]; /2 qxJvZ  
int nRead; pi/&WMZ<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A[^k
4>  
{ bzZ7L-yD  
nStartPos += fileAccessI.write(b,0,nRead); DW
)X3A(^  
//if(nThreadID == 1) VmZDU(M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OD?y  
} ?Iag-g9#=m  
gOp81)  
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Utility.log("Thread " + nThreadID + " is over!"); HaRx(p0  
bDownOver = true; ~RV9'v4  
//nPos = fileAccessI.write (b,0,nRead); {5+ 39=(  
} Vygh|UEo  
catch(Exception e){e.printStackTrace ();} Gc;-zq  
} /sqfw,h@  
} +Q"XwxL<6  
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-WGlOpg0;  
//打印回应的头信息 h|<;:o?yh  
public void logResponseHead(HttpURLConnection con) `6PBV+]Vm3  
{ 4I.
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for(int i=1;;i++) \@zoM:[sN  
{ \[/}Cy  
String header=con.getHeaderFieldKey(i); Yfy";C7X  
if(header!=null) QHtN_
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); >}d6)s|   
Utility.log(header+" : "+con.getHeaderField(header)); fr8';Jm  
else @[Wf!8_  
break;  vF'IK,  
} GbvbGEG  
} hK3Twzte  
8L`wib2  
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public void splitterStop() xJOp~fKG  
{ |{rhks~  
bStop = true; 9MbF:  
} fS%B/h=  
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} U?Vik  
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/* }$a*XY1  
**FileAccess.java C\ 34R  
*//文件访问(定位，写) 6HH:K0j3'  
package NetFox; u5`b")a  
import java.io.*; T ^/\Rr  
qr~zTBT] E  
VuH}@  
public class FileAccessI implements Serializable{ J@rBrKC  
Ki /j\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eGWwPSIp  
RandomAccessFile oSavedFile; V0_^==Vs  
long nPos; d^"|ESQEU  
drp< f1`l8  
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public FileAccessI() throws IOException tnq ZlS  
{ hl8oE5MU  
this("",0); $4]4G=o  
} xg;F};}5$  
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public FileAccessI(String sName,long nPos) throws IOException WGUd@l
C~  
{ -JclEp  
oSavedFile = new RandomAccessFile(sName,"rw"); )?(_vrc<  
this.nPos = nPos; SN$3cg]z  
oSavedFile.seek(nPos); ,5x9o"N!  
} yEVnG` 1  
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v}@Uc-(  
public synchronized int write(byte[] b,int nStart,int nLen) HYNpvK  
{ C~M,N|m+^  
int n = -1; qI[AsM+  
try{ Io('kCOR;  
oSavedFile.write(b,nStart,nLen); unr`.}A2>  
n = nLen; mlz|KI~\F;  
} HrRw  
catch(IOException e) V\AF%=6}  
{ }3-`e3  
e.printStackTrace (); WHRBYq_  
} 02^Nf
7DMR  
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return n; tHFUV\D;,  
} EIOP+9zP  
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} ) Loh
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/* ];QX&";Z  
**SiteInfoBean.java +t(Gt0+  
*/ {$C"yksr  
package NetFox; l4^MYwFR{O  
:6Gf@Z&+  
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public class SiteInfoBean { W QeQ`pM  
[] R8VC>Ah  
Gw
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private String sSiteURL; //Site's URL u>V~:q\X  
private String sFilePath; //Saved File's Path YIHGXi<"n  
private String sFileName; //Saved File's Name bq{eu#rQJ  
private int nSplitter; //Count of Splited Downloading File z/pxZB~"  
0 R>!jw  
O#)YbaE  
public SiteInfoBean() .gCun_td#  
{//nSplitter的缺省值为5 hh-sm8  
//default value of nSplitter is 5 'Ojxzz*tT  
this("","","",5); |
  
} Q%0 N\  
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9]|C$;kw@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y!~ }7=  
{ (^~~&/U_U$  
sSiteURL= sURL; +y 48.5  
sFilePath = sPath; mS+sh'VH  
sFileName = sName; ~{t<g;F  
this.nSplitter = nSpiltter; .nei9Y*  
y`pgJO  
tjcsT>  
} 4^ZbT  
+_
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public String getSSiteURL() Hr*xAx  
{ .Z@iz5  
return sSiteURL; @ b}-<~  
} gdg "g6b  
 >Xxi2Vy  
\ns} M3  
public void setSSiteURL(String value) _*wlK;`  
{ )J 8mn*  
sSiteURL = value; 4?c0rC<  
} /LG}nY
 

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public String getSFilePath() H^jcWwy:  
{ Lv>OBHD  
return sFilePath; Dt'bbX'edw  
} t* =i8`8  
L^Fb;sJYI  
Gf-GDy\{  
public void setSFilePath(String value) z#6(PZC}  
{ c7]0>nU;  
sFilePath = value; 9x#Tj/5%  
} ZSLvr-
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*EFuK8 ;  
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public String getSFileName() ./
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{ bj@f<f`  
return sFileName; vJ>o9:(6  
} #`%V/#YK  
JHJ]BMm  
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public void setSFileName(String value) m~gcc  
{ ?BU?c:"f  
sFileName = value; oKPG0iM:  
} @u:
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&pHXSU  
 8(}cbW  
public int getNSplitter() b.cBg.a  
{ -v9x tNg  
return nSplitter; H?;@r1ZAn  
} u0%bv\$m  
9T<k|b[6  
"71Y{WQ   
public void setNSplitter(int nCount) EnEa
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{ <=%G%V_s  
nSplitter = nCount; LKg9{0Y:  
} tYx>?~   
} )Dyyb1\)  
;b
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/* ,hCbx#h  
**Utility.java )4n]n:FjN  
*/ )!'7!" $  
package NetFox; yp<)v(8|'  
dlwOmO'Bm)  
:DFtH13qO  
public class Utility { SOluTFxUw  
vtRz;~,Z  
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public Utility() XLlJ|xhY-K  
{ P8 R^46  
VYQ]?XF3i  
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} .+~9 vH  
5IbCE.>iU  
//线程睡眠 C-/+n5J  
public static void sleep(int nSecond) Sre:l'
.  
{ )O>M~  
try{ )00jRuF  
Thread.sleep(nSecond); b[MKo7  
} B8>@q!G8P  
catch(Exception e) 5oo6d4[  
{ [2r
i=lf,  
e.printStackTrace (); ;VbB]aUg  
} 8L*#zaSAf  
} ~31-)*tJ]  
4\ny]A:~  
//日志 DK|/|C}6  
public static void log(String sMsg) G#6O'G N  
{ 8Y;2.Z`Rz  
System.err.println(sMsg); g>{t>B%v^K  
} |wuN`;gc"  
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Q;kl-upn~8  
public static void log(int sMsg) qKs"L^b  
{ n.1$p  
System.err.println(sMsg); uIR   
} _$KkSMA~_  
} ;.7]zn.X]2  
DO~~  
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/* ;ih;8  
**TestMethod.java ~$YasFEz
 
*/ 5Z13s  
package NetFox; R[H#av  
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B XO,  
public class TestMethod { |lh&l<=(f  
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l;h5Y<A%?  
public TestMethod() *7),v+ET  
{ ///xx/weblogic60b2_win.exe GZ.KL!,R!  
try{ cp
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U \jFB*U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X&!($*/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _FN#Vq2  
fileFetch.start(); cgR8+o  
} ;z~j%L%b  
catch(Exception e){e.printStackTrace ();} D+7[2$:z  
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} + ,rl\|J%  
,+FiP{`  
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public static void main(String[] args) K pmq C$  
{ *++}ll6  
new TestMethod(); 8>(/:u_x  
} /Y| <0tq  
} 8aW<lu  
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