http断点续传简单实现（java)

/* .]r[0U  
**SiteFileFetch.java U?#6I-  
*/ 0>Mm |x*5  
package NetFox; QREIr |q'  
import java.io.*; 6K`frt
 
import java.net.*; R#1m_6I  
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public class SiteFileFetch extends Thread { Jb ;el*,K  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =i:?4pIZ  
long[] nStartPos; //开始位置 *:\QD 8^  
long[] nEndPos; //结束位置 Em4TEv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =@3Qsd  
long nFileLength; //文件长度 "Jv&=zJ  
boolean bFirst = true; //是否第一次取文件 AqN(htGvx  
boolean bStop = false; //停止标志 PCw.NJd$  
File tmpFile; //文件下载的临时信息 w?Q@"^IL  
DataOutputStream output; //输出到文件的输出流 IDLA-Vxo  
c (\-7*En  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） OmU.9PDg-  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;yHA.}  
{ CuuHRvU8  
siteInfoBean = bean; <&H.pN1_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :M=!MgD3w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `uzRHbJ`  
if(tmpFile.exists ()) kx'6FkZPIr  
{ .@B\&U7  
bFirst = false; u;=("S{"0  
read_nPos(); [;|g2\  
} pMX7Rl  
else _^SNI~  
{ X-n'?=  
nStartPos = new long[bean.getNSplitter()]; Q8\Ks|u]  
nEndPos = new long[bean.getNSplitter()]; NiWooFPKJ  
} Yq1 ~"he8  
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} VLQfuh;  
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{?5EOp~  
public void run() BJW;A>@Pj  
{ Xc Pn  
//获得文件长度 k)S7SbQ  
//分割文件 +d#ZSNu/  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 C}+(L3Z  
//等待子线程返回 jriliEz;f  
try{ ia?8Z"&lK  
if(bFirst) B'~.>,fg  
{ A;2?!i#f  
nFileLength = getFileSize(); F}sfk}rp  
if(nFileLength == -1) r-'j#|^tz  
{ R \`,Q'3  
System.err.println("File Length is not known!"); {BKI8vy  
} :j9;P7&"?  
else if(nFileLength == -2) qPzgGbmD9  
{ *B3` #t  
System.err.println("File is not access!"); JNMZn/  
} Mb$&~!  
else 0|4XV{\qT$  
{ 6'qs=Ql  
for(int i=0;i<nStartPos.length;i++) B&.XGo)  
{ 2Db[dk( ]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j\Q_NevV  
} 3!*J;Y  
for(int i=0;i<nEndPos.length-1;i++) o ue;$8  
{ lIOLR-:4j  
nEndPos = nStartPos[i+1]; h?$4\^/  
} T_B$  
nEndPos[nEndPos.length-1] = nFileLength; noL<pkks~R  
} bNc=}^  
} lT$A;7
[  
U)c,ZxE  
6oJ~Jdn'  
//启动子线程 ZEApE+m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?[VS0IBS  
for(int i=0;i<nStartPos.length;i++) t,=khZ  
{ u1>|
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E@[`y:P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eb+[=nmP  
nStartPos,nEndPos,i); Jh }3AoD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (wbG0lu  
fileSplitterFetch.start(); O<o_MZN  
} ^Z}INUv]7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V1"+4&R^T_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'f5,%e2#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *K0CUir|  
nEndPos = " + nFileLength); [QL)6Xr  
// fileSplitterFetch[nPos.length-1].start(); %} \@Wk~  
\UN7lDH  
>eJk)q
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//等待子线程结束 KeXQ'.x5O  
//int count = 0; 0!!pNK%(  
//是否结束while循环 U24?+/5D]  
boolean breakWhile = false; %JiA,  
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while(!bStop) B23R9.FK  
{ lm@
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write_nPos(); ^#"!uCq]gM  
Utility.sleep(500); W~DY-;  
breakWhile = true; yNI}=Z  
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for(int i=0;i<nStartPos.length;i++) \_BaV
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{ h4.ZR={E  
if(!fileSplitterFetch.bDownOver) )!M:=}."  
{ }{9E~"_[  
breakWhile = false; LI(Wu6*Y  
break; J6::(0HM  
} HfmTk5|/  
} 3QGg;
  
if(breakWhile) yjN|PqtSV  
break; >mh:OJH45  
T
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7eh}Je8  
//count++; QbS w<V  
//if(count>4) S{J$[!F  
// siteStop(); %.<w8ag  
} 3!ulBiMh  
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Ok O;V6`  
System.err.println("文件下载结束！"); HtS:'~DYo  
} :2  
catch(Exception e){e.printStackTrace ();} g^8bY=* .  
} '&s:,o-p  
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//获得文件长度 qTiX;e\W  
public long getFileSize() }U+gJkY2  
{ 8[}MXMRdb  
int nFileLength = -1; ;xwa,1]  
try{ D<Ads  
URL url = new URL(siteInfoBean.getSSiteURL()); ^9"|tWf6O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o-7>^wV%BD  
httpConnection.setRequestProperty("User-Agent","NetFox"); l=bB,7gL  
J;'?(xO3\  
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int responseCode=httpConnection.getResponseCode(); -zMXc"'C^k  
if(responseCode>=400) 1 !OQxY}f  
{ nQg6 j Zf  
processErrorCode(responseCode); &*L:4By)]  
return -2; //-2 represent access is error #p*OLQ3~  
} }GQ8|fg`U  
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String sHeader; ^vo^W:   
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for(int i=1;;i++) --.:eFE/  
{ M
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jlzqa7  
//Utility.log(in.readLine()); Q)HVh[4  
sHeader=httpConnection.getHeaderFieldKey(i); > NK?!!A_  
if(sHeader!=null) g"xLS}Al  
{ $ShL^g@  
if(sHeader.equals("Content-Length")) -\AB!#fh  
{ S1%{/w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (a]'}c$X9`  
break; t'0r4&\  
} U}7$:hO"dX  
} ma?569Z8~0  
else pk(<],0]X  
break; QTK\"  
} >RE&>T^8  
} <k}>eGn  
catch(IOException e){e.printStackTrace ();} D OPOzh  
catch(Exception e){e.printStackTrace ();} kw|bEL9!u  
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Utility.log(nFileLength); (/Z~0hA[Q  
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return nFileLength; d*8 c,x  
} ;z)$wH0xc  
M ~.w:~Jm  
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//保存下载信息（文件指针位置） e+4p__TmZ  
private void write_nPos() ^/mQo`[G  
{ : bT*cgD{  
try{ 8r)eiERv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BalOph4M[  
output.writeInt(nStartPos.length); ?i)-K?4Sb  
for(int i=0;i<nStartPos.length;i++) r/:s2oQ  
{ [$9sr=3:  
// output.writeLong(nPos); ,LWM}L  
output.writeLong(fileSplitterFetch.nStartPos); QR
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output.writeLong(fileSplitterFetch.nEndPos); E9%xSMS8@  
} qmOGsj`#  
output.close(); 8p>%}LX/  
} 6i%LM`8GEk  
catch(IOException e){e.printStackTrace ();} a%Cq?HZ7  
catch(Exception e){e.printStackTrace ();} M1Od%nz3  
} )Qb1$%r.  
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//读取保存的下载信息（文件指针位置） Y5cUOfYT  
private void read_nPos() DV*8Mkzg  
{ Nr3td`;  
try{ 7:{4'Wr@6|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :14O=C  
int nCount = input.readInt();  U7tT  
nStartPos = new long[nCount]; w&`gx6?-na  
nEndPos = new long[nCount]; f9&D0x?  
for(int i=0;i<nStartPos.length;i++) Mwp#.du(  
{ xgsD<3  
nStartPos = input.readLong(); (. 1<.PZp)  
nEndPos = input.readLong(); .l !:|Fd  
} D\N-ye1LE  
input.close(); SECL(@0(^  
} BAdHGwomh  
catch(IOException e){e.printStackTrace ();} f(?>z!n0  
catch(Exception e){e.printStackTrace ();} z`>a,X
 
} p^ 9QYR  
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private void processErrorCode(int nErrorCode) ~e,  
{ 0ydAdgD  
System.err.println("Error Code : " + nErrorCode); eey <:n/Z  
} yTkYPx  
+7N6]pK|"  
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//停止文件下载 !+9H=u  
public void siteStop() Qj[4gN?}=  
{ 3`IDm5  
bStop = true; !ssE >bDa  
for(int i=0;i<nStartPos.length;i++) RyIr_:&-~  
fileSplitterFetch.splitterStop(); h_*=_2|}  
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} b(;"p-^  
}
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//负责部分文件的抓取 hLYSYMUb  
**FileSplitterFetch.java Uu>YE0/)  
*/ e%(zjCA  
package NetFox; ~9h6"0K!  
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import java.io.*; |>jlY|  
import java.net.*; D:8-f3  
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public class FileSplitterFetch extends Thread { zdU<]ge  
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String sURL; //File URL tvf"w`H  
long nStartPos; //File Snippet Start Position "&Q-'L!M'/  
long nEndPos; //File Snippet End Position Dn<2.!ZKQ  
int nThreadID; //Thread's ID ^dYFFKQ  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical |K aXek  
FileAccessI fileAccessI = null; //File Access interface C&zgt :q6}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (gl CTF9v  
{ C.%iQx`
 
this.sURL = sURL; j05ahquI  
this.nStartPos = nStart; im*QaO%a4  
this.nEndPos = nEnd; hKt AvTg  
nThreadID = id; \dbpCZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L4 x  
} /uW6P3M  
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public void run() Ibd7[A\  
{ Y]&HU) u  
while(nStartPos < nEndPos && !bStop) 7.8ukAu
d  
{ Xb)XV$0  
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try{ K&D -1u  
URL url = new URL(sURL); P.&,nFIg3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !COaPrg  
httpConnection.setRequestProperty("User-Agent","NetFox"); s/`4]B;2U  
String sProperty = "bytes="+nStartPos+"-"; q fadsVp  
httpConnection.setRequestProperty("RANGE",sProperty); at6f(+  
Utility.log(sProperty); }1N)3~  
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InputStream input = httpConnection.getInputStream(); `(W V pP?  
//logResponseHead(httpConnection); Fm*n>^P@Y  
7:mM`0g!  
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byte[] b = new byte[1024]; Gv?3}8Wp  
int nRead; d3 fE[/oU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E88_15'3D  
{ e_\4(4x  
nStartPos += fileAccessI.write(b,0,nRead); |~8iNcIS  
//if(nThreadID == 1) Ga N4In[d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rQj.W6w=  
} lv&<kYWY  
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Utility.log("Thread " + nThreadID + " is over!"); p
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bDownOver = true; 6.KR(V  
//nPos = fileAccessI.write (b,0,nRead); /D 2v1  
} YOP=gvZq  
catch(Exception e){e.printStackTrace ();} i. `S0  
} + 5sTGNG  
} 8l+\Qyj  
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UMx>n18;f9  
//打印回应的头信息 'n)M0e  
public void logResponseHead(HttpURLConnection con) <3Co/.VQd  
{ Uu }ai."iB  
for(int i=1;;i++) w/h?, L|  
{ } Yjic4?  
String header=con.getHeaderFieldKey(i); xJ^Gtq Um  
if(header!=null) .~ZNlI {K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aR*z5p2-w  
Utility.log(header+" : "+con.getHeaderField(header)); Kdik7jL/J  
else Ax=Rb B"  
break; !Lk|eGd*  
} ,Z&"@g  
} j= ]WAjT  
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public void splitterStop() ~iEH?J%i1r  
{ SZK~<@q5  
bStop = true; @"'1"$  
} y?CEV-3+  
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} i,<TaW*I  
o
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/* w<-CKM3qe  
**FileAccess.java BU<A+Pe>  
*//文件访问(定位，写) wKXKc\r  
package NetFox; KosAc'/ M  
import java.io.*; Z3~$"V*ZB{  
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public class FileAccessI implements Serializable{ gqyQ Zew  
%I&Hx<Hj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0)yvyQ5  
RandomAccessFile oSavedFile; nd'zO#"m?  
long nPos; P]j{JL/g&  
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public FileAccessI() throws IOException pR
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{ Y.[
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this("",0); $-jj%x\}  
} <M7@JgC &  
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public FileAccessI(String sName,long nPos) throws IOException T$0//7$')  
{ bkLm]n3  
oSavedFile = new RandomAccessFile(sName,"rw"); [fxAj]  
this.nPos = nPos; T AwA)Zg  
oSavedFile.seek(nPos); y9pQ1H<F;  
} /".+OpL  
k8 ,.~HkU  
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public synchronized int write(byte[] b,int nStart,int nLen) R`!x<J  
{ ^
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int n = -1; ~ NKw}6  
try{ 2\CFt;fk  
oSavedFile.write(b,nStart,nLen); b H?dyS6Bx  
n = nLen;  #RbPNVs  
} $X9-0-  
catch(IOException e) 4g$mz:vo  
{ =HQH;c"  
e.printStackTrace (); 0p*(<8D}  
} ;jo,&C  
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return n; M_Z*F!al<  
} 7'J}|m{7  
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} LXJ"ct  
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/* f+Put  
**SiteInfoBean.java UF|v=|*{#  
*/ Jc-0.^]E}  
package NetFox; (C!u3ke2D  
uG${`4  
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public class SiteInfoBean { IgG@v9'  
[3]!*Cd  
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private String sSiteURL; //Site's URL w`CGDF\Oo  
private String sFilePath; //Saved File's Path e7{3:y|]d3  
private String sFileName; //Saved File's Name neoT\HV  
private int nSplitter; //Count of Splited Downloading File 4u"V52  
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public SiteInfoBean() U~s&}M\n  
{//nSplitter的缺省值为5 V`l.F"<L  
//default value of nSplitter is 5 v,KH2 (N  
this("","","",5); `Ft.Rwj2:m  
} BYqDC<Fq  
qCc'w8A  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <DvpqlT  
{ <q~&g &&+  
sSiteURL= sURL; )67Kd]  
sFilePath = sPath; BBnj}XP*4  
sFileName = sName; /IxMRi=  
this.nSplitter = nSpiltter; 7M<7^)9  
di "rvw;R  
z%hB=V!~91  
} V+nqQ~pJ&  
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public String getSSiteURL() pV=X  
{ :eo2t>zF-<  
return sSiteURL; Om\?<aul  
} 0N;Pb(%7UU  
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public void setSSiteURL(String value) #]_S{sO  
{ Qx>S>f  
sSiteURL = value; ";J1$a  
} 7;dV]N  
{[m %1O1  
>dUnk)7  
public String getSFilePath() |z<E%`u%  
{ _W@q%L>  
return sFilePath; 0mF3Vs`-Q  
} LrX7WI  
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public void setSFilePath(String value) |p4F^!9  
{ 4hg#7#?boW  
sFilePath = value; ]>b.oI/  
} :K#'?tH  
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public String getSFileName() ^+Ie   
{ u `1cXL['  
return sFileName; y"<nx3  
} CSN]k)\N(  
[;7&E{,C  
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public void setSFileName(String value) GO.mT/rB  
{ O'Lgb9  
sFileName = value; Q0Y0Zt,h  
} V)mRG`L  
(%rO'X  
qSlC@@.>  
public int getNSplitter() ]S[M]-I  
{ 7M=LyrO  
return nSplitter; /[#<@o  
} 7{ (t_N>  
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public void setNSplitter(int nCount) $VvL  
{ *[]7l]XK.  
nSplitter = nCount; 'JsP9>)  
} zF[kb%o  
} >)YaWcI  

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p~Fc*g[!  
/* xL3-(K6e
 
**Utility.java ycg5S rg  
*/ ow,I|A  
package NetFox; ;f:}gMK  
\{ r%.G  
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public class Utility {  )`!i"  
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public Utility() hF"yxucj$  
{ D4g$x'  
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} _w/w~;7  
ijOUv6=-  
//线程睡眠 nsQx\Tnhx  
public static void sleep(int nSecond) ~5<-&Dyp
7  
{ I,OEor6%R(  
try{ h[b;_>7  
Thread.sleep(nSecond); O~N0JK_>  
} LE%3.. !  
catch(Exception e) 4:GVZR|-  
{ M<hX!B  
e.printStackTrace (); qn}4PVn4  
} "a %5on  
} k\8]fh)J\7  
ln-+=jk  
//日志 vY&[=2=  
public static void log(String sMsg) 78&jaw*1A  
{ {s&6C-  
System.err.println(sMsg); ~1jSz-s  
} JE9SPFQx9M  
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'B ocMjRA  
public static void log(int sMsg) *Hx{eqC  
{ RoCX*3d  
System.err.println(sMsg); qN%i$mJTo  
} A0Pg|M  
} tu8n1W  
&i179Qg!  
\_;zm+ <{  
/* &,/_"N"?D  
**TestMethod.java #!(OTeL  
*/ \yP\@cpY{  
package NetFox; ,)^4H>~V  
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BO)K=gl;8  
public class TestMethod { :Lu=t3#  
$a|C/s+}7>  
LxaR1E(Cc'  
public TestMethod() qOAK`{b  
{ ///xx/weblogic60b2_win.exe Qxr&zT7f  
try{ T|RW-i3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wN'Q\l+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?.Z4GWyXa
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); mxUM&`[  
fileFetch.start(); Khp`KPxz%  
} k`ulDQu
 
catch(Exception e){e.printStackTrace ();} u hW@ Y+  
^GMM%   
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} ]w ^9qS  
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public static void main(String[] args) Y~@@{zP  
{ d;1%Ei3K  
new TestMethod(); z2p@d1  
} Al
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} qXC>DGy  
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