http断点续传简单实现（java)

/* v$`AN4)}  
**SiteFileFetch.java *<**rY*  
*/ AjQ^ {P  
package NetFox; EPz$`#Sh"  
import java.io.*; /?; 8F  
import java.net.*; _S(]/d(c
 
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public class SiteFileFetch extends Thread { s)e; c<(/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?6bk&"T?  
long[] nStartPos; //开始位置 'CH|w~E  
long[] nEndPos; //结束位置 rX%qWhiEJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j;O{Hvvz  
long nFileLength; //文件长度 ='7n  
boolean bFirst = true; //是否第一次取文件 USnKj_e  
boolean bStop = false; //停止标志 .bm#|X)RO  
File tmpFile; //文件下载的临时信息 <9S?wju4W'  
DataOutputStream output; //输出到文件的输出流 U/B1/96lJ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^;2dZgJ4^  
public SiteFileFetch(SiteInfoBean bean) throws IOException G~{xTpL  
{ X^#.4:>.  
siteInfoBean = bean; $FgpFxz;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .bOueB-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cl;B%5yl  
if(tmpFile.exists ()) dJ#. m  
{ !Cj1:P  
bFirst = false; !P, 9Sg&5)  
read_nPos(); <:u)C;  
} EX[X|"r   
else >a]4}  
{ sBuVm
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nStartPos = new long[bean.getNSplitter()]; g#V3u=I8~  
nEndPos = new long[bean.getNSplitter()]; d0b--v/  
} xw5E!]~D  
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} U4_<  
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public void run() %8kbX  
{ ,>%AEN6N2  
//获得文件长度 hGH{Xp[mW  
//分割文件 <?P UF,  
//实例FileSplitterFetch xXK7i\ny  
//启动FileSplitterFetch线程 HnVUG4yZTD  
//等待子线程返回 5FHpJlFK,  
try{ $2F*p#l(<Z  
if(bFirst) :&dY1.<N+  
{ :y'D] ,_  
nFileLength = getFileSize(); _tQ=ASe0  
if(nFileLength == -1) {Gs&u>>R"^  
{ 4yC{BRbi  
System.err.println("File Length is not known!"); d8g3hyI5\  
} Q=yQEh|Y  
else if(nFileLength == -2) Dd*T5A?  
{ BNg\;2r  
System.err.println("File is not access!"); }0uSm%,"  
} Y}"|J ~  
else `"m"qUd  
{ gv;=Yhw.c  
for(int i=0;i<nStartPos.length;i++) J%xp1/=2  
{ .9WUp>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M6!kn~  
} ~aH*ZA*f  
for(int i=0;i<nEndPos.length-1;i++) 5/mW:G,&  
{ qkv.,z"  
nEndPos = nStartPos[i+1]; J=TbZL4y}4  
} )^)VyI`O  
nEndPos[nEndPos.length-1] = nFileLength; r{kV*^\E  
} tqrvcnQr^  
} 5SX0g(C  
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u *z$I  
//启动子线程 1
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K4xZT+Qb  
for(int i=0;i<nStartPos.length;i++) %yQ-~T@  
{ g4d5G=y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mCtuyGY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w"-bO ~5h  
nStartPos,nEndPos,i); V/|Ln*rm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t9m:E  
fileSplitterFetch.start(); p7!q#o  
} P-No;/!B#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -z0,IYG }  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [j}%&
$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P _Zf(`jJ  
nEndPos = " + nFileLength); &}w,bG$  
// fileSplitterFetch[nPos.length-1].start(); " %|CD"
@  
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//等待子线程结束 \,JRNL&   
//int count = 0; >S{1=N@Ev=  
//是否结束while循环 kOR%<#:J  
boolean breakWhile = false; ,y2ur2  
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while(!bStop) )TyL3Z\>(  
{ D2>EG~xWq  
write_nPos(); %dL|i2+*8  
Utility.sleep(500); 'y}A3RqN  
breakWhile = true; _J   
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for(int i=0;i<nStartPos.length;i++) Qkqn~>  
{ 6!g3Juh  
if(!fileSplitterFetch.bDownOver) &66G  
{ `"(7)T{  
breakWhile = false; fXIeCn  
break; 3Luv$6  
} :":W(O  
} OU9=O>  
if(breakWhile) 0+r/>-3]  
break; HK&F'\'}  
=q[3/'2V$?  
wC=IN  
//count++; K N0S$nW+  
//if(count>4) ;=)CjC8)  
// siteStop(); xvp{F9~qT  
} #JuO  
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System.err.println("文件下载结束！"); [rPW@|^5  
} TmX~vZ  
catch(Exception e){e.printStackTrace ();} K~,,xsy,G&  
} o?p) V^7  
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//获得文件长度 *TE6p  
public long getFileSize() 7GK| A{r  
{ LUo3y'  
int nFileLength = -1; .Ji r<"*<  
try{ Di-"y,[  
URL url = new URL(siteInfoBean.getSSiteURL()); &R*d/~SU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]X?+]9Fr  
httpConnection.setRequestProperty("User-Agent","NetFox"); s o~p+]  
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{,s:vPoiA  
int responseCode=httpConnection.getResponseCode(); 'Q(A5zfN]Y  
if(responseCode>=400) eIof{#  
{ zq4mT;rqz  
processErrorCode(responseCode); mW8CqW\Q5  
return -2; //-2 represent access is error RNX}Wlo-s  
} :?RK>}4|F  
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String sHeader; =/dW5qy;*+  
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for(int i=1;;i++) &,$A7:  
{ Z"!C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M"p$9t  
//Utility.log(in.readLine()); OIewG5O  
sHeader=httpConnection.getHeaderFieldKey(i); /~ V"v"7E  
if(sHeader!=null) rKJ%/7m  
{ 1uXtBk6  
if(sHeader.equals("Content-Length")) TF=S \ Q  
{ JxD@y}ZYE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'Fc&"(!||  
break; $AsM 9D<BE  
} 3\D jV2t  
} 5>A3;P  
else 7ky(g'  
break; ix!u#7  
} S~6<'N&[  
} HHEFX9u  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} h Qu9ux  
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Utility.log(nFileLength); aL=VNZ!Pqc  
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return nFileLength; Rut6m5>  
} u5R^++  
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//保存下载信息（文件指针位置） SxH}/I|W  
private void write_nPos() 9m6w.:S  
{ /pb7  
try{ 4&|9304<H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "lmiGR*u  
output.writeInt(nStartPos.length); 5utj$ha2  
for(int i=0;i<nStartPos.length;i++) gWWy!H  
{ z6{0\#'K  
// output.writeLong(nPos); Yhlk#>I  
output.writeLong(fileSplitterFetch.nStartPos); Rf%ver  
output.writeLong(fileSplitterFetch.nEndPos); >eUAHmXQ|  
} ~^5uOeTZ~  
output.close(); z
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}  K8ThZY%  
catch(IOException e){e.printStackTrace ();} Ak}l6{ ..  
catch(Exception e){e.printStackTrace ();} /+IR^WG#C}  
} n$=n:$`q  
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//读取保存的下载信息（文件指针位置） 1m![;Pg3  
private void read_nPos() 'GW@P  
{ }y[o[>  
try{ {O^1WgGc[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?_tOqh@in  
int nCount = input.readInt(); #bdJ]v.n  
nStartPos = new long[nCount]; )m)>k` 0  
nEndPos = new long[nCount]; ~RMOEH.o  
for(int i=0;i<nStartPos.length;i++) ;G\rhk  
{ U`8)rtYw  
nStartPos = input.readLong(); ,5L&$Q6  
nEndPos = input.readLong(); oFIs,[Go  
} G&n_vwZ%  
input.close(); 2qn~A0r  
} foJ|Q\Z,T  
catch(IOException e){e.printStackTrace ();} <B``/EX^  
catch(Exception e){e.printStackTrace ();}  u?'X%'K*  
} bpU^|r^W  
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private void processErrorCode(int nErrorCode) {u5)zVYC,U  
{ 49kY]z|"w  
System.err.println("Error Code : " + nErrorCode); $@#nn5^IX  
} gXfAz,  
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A!^,QRkRN  
//停止文件下载 YInW)My.h  
public void siteStop() OVivJx  
{ bC@b9opD  
bStop = true; {9=U6m^R2  
for(int i=0;i<nStartPos.length;i++) "3>#
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fileSplitterFetch.splitterStop(); 5VPuHY2  
6>vj({,1Y*  
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} }3i@5ctQ  
} ER|5_  
//负责部分文件的抓取 *yX_dgC>[  
**FileSplitterFetch.java RE7[bM3a  
*/ $L`7J$'^  
package NetFox; @'U4-x  
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import java.io.*; f~U|flL^  
import java.net.*; #Gg^fm  
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public class FileSplitterFetch extends Thread { \Lc]6?,R  
}0!\%7-Q  
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String sURL; //File URL 9GGBJTk-  
long nStartPos; //File Snippet Start Position &#)3v8  
long nEndPos; //File Snippet End Position c,-< 4e  
int nThreadID; //Thread's ID nh8h?&q|  
boolean bDownOver = false; //Downing is over P$oa6`%l  
boolean bStop = false; //Stop identical >AfJxdd1  
FileAccessI fileAccessI = null; //File Access interface +0a',`yc  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z?@07Y[|K  
{ Q^F-8  
this.sURL = sURL; UU !I@  
this.nStartPos = nStart; !#?tA/t@  
this.nEndPos = nEnd; +tA rH C]  
nThreadID = id; 9wwvh'T&NK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0FW=8hFp,  
} JBg>E3*N  
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public void run() [n^___7  
{ npe*A  
while(nStartPos < nEndPos && !bStop) cCeD3CuRA%  
{ WFdS#XfV  
\:#b9t{B-  
tDwXb>  
try{ '-~86Q  
URL url = new URL(sURL);  KA<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H_2hr[  
httpConnection.setRequestProperty("User-Agent","NetFox"); <zUmcZ  
String sProperty = "bytes="+nStartPos+"-"; *X>rvAd3  
httpConnection.setRequestProperty("RANGE",sProperty); [v&_MQ  
Utility.log(sProperty); vSyN_AB?$  
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InputStream input = httpConnection.getInputStream(); W"0#  
//logResponseHead(httpConnection);  OkQSqL  
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byte[] b = new byte[1024]; ~Ch`A@=5  
int nRead; JxWHrsh[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Jv?e?U  
{ I2Us!W>6-  
nStartPos += fileAccessI.write(b,0,nRead); }s|v-gRM{  
//if(nThreadID == 1) ;L)}blN.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [WK_Vh{  
} xv ja  
w_Ls.K5"  
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Utility.log("Thread " + nThreadID + " is over!"); urN&."c  
bDownOver = true; Vy?w,E0^:  
//nPos = fileAccessI.write (b,0,nRead); BkJcT  
} ;F:(5GBi  
catch(Exception e){e.printStackTrace ();} y>o#Hq&qM  
} *oPSkEA{  
} eu4x{NmQ  
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//打印回应的头信息 wx1uduT)  
public void logResponseHead(HttpURLConnection con) v#X? KqD  
{ sM4wh
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for(int i=1;;i++) 9}\T?6?8pX  
{ 6lhVwgy3A  
String header=con.getHeaderFieldKey(i); "-Ns1A8  
if(header!=null) J>'o,"D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HOw][}M_w  
Utility.log(header+" : "+con.getHeaderField(header)); [Cs2H8=#  
else #8RQ7|7b|  
break; &@Q3CCDS  
} f+1]#"9i|  
} Nhf!;>  
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#"Zr#P{P  
public void splitterStop() l^vq'<kI  
{ wVPq1? 9  
bStop = true; LY|h*a6Ym  
} J^W.TM&q$,  
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} S*]IR"YL  
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/* 'Hg(N?1"  
**FileAccess.java }l/md/C0  
*//文件访问(定位，写) qV}zV\Nz  
package NetFox; _3E7|drIX  
import java.io.*; $""[( d?0  
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public class FileAccessI implements Serializable{ D"o>\Q  
]EK"AuEz`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '[HFIJ0K!  
RandomAccessFile oSavedFile; saV3<zgx  
long nPos; >WpPYUbH  
*n*OVI8L  
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public FileAccessI() throws IOException *yf+5q4t  
{ kY|_wDBSb\  
this("",0); +-oXW>`&  
} Mz06cw&  
!98s[)B:  
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public FileAccessI(String sName,long nPos) throws IOException ^GbyAYEp  
{ HU'd/5fun  
oSavedFile = new RandomAccessFile(sName,"rw"); +<iw
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this.nPos = nPos; hcBfau;r  
oSavedFile.seek(nPos); 0VbZBLe  
} qvt~wJf<  
#mj+|/0  
:4WwCpgz,  
public synchronized int write(byte[] b,int nStart,int nLen) Y3-P*  
{ x,>=X`T  
int n = -1; 3!d|K%J  
try{ uM\~*@
  
oSavedFile.write(b,nStart,nLen); x=H*"L=  
n = nLen; c)lK{DC  
} 1{,WY(,c  
catch(IOException e) Mpj3<vj   
{ ~@-Az([H  
e.printStackTrace (); A$ S9 `  
} 7' 6m;b~F  
Yd,*LYd2EL  
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return n; 9 ROKueP  
} L7KHs'c*  
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} ;hg]5r_  
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/* "ex? #qD&  
**SiteInfoBean.java w,l1&=d  
*/ "'PDreS  
package NetFox; xLGAP-mx]  
nyMA%9,B  
>#kzPYsp  
public class SiteInfoBean { eAl&[_o|S  
#fFEo)YG  
LA
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private String sSiteURL; //Site's URL YY.;J3C  
private String sFilePath; //Saved File's Path 2=#O4k.@  
private String sFileName; //Saved File's Name `R; ct4-  
private int nSplitter; //Count of Splited Downloading File {g);HnmPN  
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j$Kubg(I5  
public SiteInfoBean() ~gV
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{//nSplitter的缺省值为5 2{ptV\f]D  
//default value of nSplitter is 5 Xu'u"amt  
this("","","",5); PM_q"}-  
} ypml22)kz  
v&?Bqj  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N),Zb^~nw  
{ Z|j8:Ohz  
sSiteURL= sURL; \V&ly/\ )  
sFilePath = sPath; L$jRg  
sFileName = sName; 
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this.nSplitter = nSpiltter; pY:xxnE  
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} Gd'^vqo<  
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public String getSSiteURL() mB!81%f%|  
{ yP"_j&ef7  
return sSiteURL; XL"e<P;t  
} }we"IqLb  
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2x`# f0[  
public void setSSiteURL(String value) m=n V$H  
{ l,d8%\  
sSiteURL = value; ZkK +?:9  
} Ru sa &#[  
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public String getSFilePath() Xe%n.DW m  
{ 8HWY]:|oh  
return sFilePath; Ds-%\@p  
} 9J1&g(?>-  
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public void setSFilePath(String value) myXp]=Sb?  
{ )\s:.<?EQ  
sFilePath = value; 9t)t-t#P;  
} @4&sL](q  
.Oim7JQ8  
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public String getSFileName() s~TYzfA  
{ KRz\ct|  
return sFileName; i1scoxX3\  
} O,DA{> *m  
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*FqNzly  
public void setSFileName(String value) yJgnw6>r2  
{ ^91k@MC  
sFileName = value; L6',s4  
} z?cRsqf  
}]f)Fz  
.&L#%
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public int getNSplitter() 0tl  
{ *ZY{^f  
return nSplitter; 3<Cd>o.  
} M.t5,NJ  
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O[-wm;_(=*  
public void setNSplitter(int nCount) ZL@7Mr!e  
{ )ll}hGS  
nSplitter = nCount; R(hqBa/V  
} M>'-P  
} } #$Y^ +UN  
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^%C.S :  
/* []u!p
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**Utility.java ,.E:mm  
*/ 3J@#V '  
package NetFox; IoA"e@~t  
) I@gy  
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public class Utility { &;,w})  
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<iL+/^#  
public Utility() m-;u]X=a  
{ fOrqY,P'  
n /rQ*hr  
mWO=(}Fb\  
} w8>p[F5`O  
-BB5bsjA  
//线程睡眠 JSO>rpO  
public static void sleep(int nSecond) dmf~w_(7  
{ N=|w]t0*yc  
try{ whv
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Thread.sleep(nSecond); agt7b@-5=  
} 8;+t.{  
catch(Exception e) -B@jQg@ >  
{ ]1gt|M^  
e.printStackTrace (); :vc[ iZ  
} <m9IZIY<  
} PN<Y&/fB  
DGp'Xx_8  
//日志 7+?  
public static void log(String sMsg) A*@!tz<  
{ lK}F>6^\  
System.err.println(sMsg); eZf-i1lJ  
} z07!i@ue~  
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.w&{2,a3  
public static void log(int sMsg) /eZAA
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{ N7
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System.err.println(sMsg); '9i:b]Hru  
} C[&Lh_F\  
} I:='LH,  
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/* P3(u+UI3  
**TestMethod.java +dR$;!WB3  
*/ '0w'||#1  
package NetFox; $] w&`F-  
6nxf<1  
Rqu;;VI[  
public class TestMethod { =@B9I<GKf  
()XL}~I{!A  
b8T'DY;~  
public TestMethod() #&&^5r-b-  
{ ///xx/weblogic60b2_win.exe
r?V\X7` +  
try{ U9kt7#@FDK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fz,8 <  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H@OYtPHGR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~I2IgEj>]  
fileFetch.start(); l6a,:*_  
} QNn$`Qz.  
catch(Exception e){e.printStackTrace ();} S1zV.]  

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} <gJ|Wee  
m<r.sq&;  
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public static void main(String[] args) RM QlciG  
{ [b
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new TestMethod(); zn@tLLX  
} F5&4x"c  
} Ma wio5  
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