http断点续传简单实现（java)

/* o-=|}u]mz  
**SiteFileFetch.java PZ|I3z  
*/ h[>pC"s?K  
package NetFox; >=0]7k;  
import java.io.*; "K(cDVQ  
import java.net.*; $E@n;0P  
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public class SiteFileFetch extends Thread { Z^>4qf,k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !i torSl  
long[] nStartPos; //开始位置 zcP=+Y)YA  
long[] nEndPos; //结束位置 1b3 a(^^E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }[akj8U  
long nFileLength; //文件长度 @*y4uI6&  
boolean bFirst = true; //是否第一次取文件 e6taQz@}  
boolean bStop = false; //停止标志 fn,n'E]  
File tmpFile; //文件下载的临时信息 Ikdj?"+O  
DataOutputStream output; //输出到文件的输出流 a<&K^M&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Tow=B  
public SiteFileFetch(SiteInfoBean bean) throws IOException jc"sPrv5  
{ s6~;)(r  
siteInfoBean = bean; &<;T$Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  @*eY~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [_JdV(]$  
if(tmpFile.exists ()) q5_zsUR=  
{ dNgA C){w  
bFirst = false; %4LoEm=U  
read_nPos(); n}UJ-\$  
} oE+P=  
else qob!AU|  
{ x:Q\pZ  
nStartPos = new long[bean.getNSplitter()]; 3JGrJ!x  
nEndPos = new long[bean.getNSplitter()]; {N}az"T4f  
} $l*?Ce:  
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} \(pwHNSafk  
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public void run() QQW}.>N  
{ d
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//获得文件长度 |p/*OFC6  
//分割文件 '!^7 *@z  
//实例FileSplitterFetch Md~SzrU  
//启动FileSplitterFetch线程 _G'ki.[S7  
//等待子线程返回 5! );4+  
try{ rx9*/Q0F  
if(bFirst) oH w!~c7  
{ S%MDQTM  
nFileLength = getFileSize(); Nqj@p<y/q  
if(nFileLength == -1) u~OlJ1V  
{ {A==av  
System.err.println("File Length is not known!");  lPZ>#  
} }@HgFM"  
else if(nFileLength == -2) ~+1mH  
{ 3*I\#Z4p1  
System.err.println("File is not access!"); >s5}pkAv|e  
} b[:,p?:@  
else z@VL?A(3  
{ $\ZWQct  
for(int i=0;i<nStartPos.length;i++) 4vbGXb}!  
{ !U% |pa  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fof}I:vO  
} /!
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for(int i=0;i<nEndPos.length-1;i++)  +#,J`fV%  
{ cRs.@U\{R\  
nEndPos = nStartPos[i+1]; = vqJ0!  
} .T7CMkYt  
nEndPos[nEndPos.length-1] = nFileLength; MxpAh<u!vF  
} FQ0&{ulb  
} DU6j0lz  
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//启动子线程 h rSH)LbJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }~W/NP_F  
for(int i=0;i<nStartPos.length;i++) 2n3&uvf'TL  
{ a_!H_J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Evj%$7H1L1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iT&4;W=72~  
nStartPos,nEndPos,i); [q%`q`EG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nam]eW  
fileSplitterFetch.start(); *0" ojfVn  
} atpHv**D<i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =iB[sLEJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _LZ(HTX~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .+S%hT,v6i  
nEndPos = " + nFileLength); k~AtnI  
// fileSplitterFetch[nPos.length-1].start(); MH)V=xU|)  
!4Zy$69R  
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//等待子线程结束 3:Nc`tM_  
//int count = 0; tXA?[ S  
//是否结束while循环 8nBYP+t,e  
boolean breakWhile = false; yKUxjb^b\  
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while(!bStop) gdD|'h  
{ oJNQdW[  
write_nPos(); [2xu`HT02  
Utility.sleep(500); PeIi@0vA  
breakWhile = true; jMBMqQNU  
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for(int i=0;i<nStartPos.length;i++) s%y<FXUj  
{ DqY"N]  
if(!fileSplitterFetch.bDownOver) E4o{Z+C  
{ g$C]ln>"9m  
breakWhile = false; M 2| k.  
break; Q3& ?28  
} *YH!L{y  
} g&$5!ifgi  
if(breakWhile) i[LnU#+  
break; ^L.I9a#]  
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//count++; ORKJy)*"  
//if(count>4) Ep;?%o,G  
// siteStop();
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} %!-t7K^mFq  
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System.err.println("文件下载结束！"); [E<A/_z  
} B!`.,3  
catch(Exception e){e.printStackTrace ();} `0W"[BY  
} E)Qg^DHP/  
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//获得文件长度 PDc4ok`)  
public long getFileSize() &q4~WRnzJk  
{ 8Rw:SU9H?T  
int nFileLength = -1; 
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try{ JSh'iYJ.  
URL url = new URL(siteInfoBean.getSSiteURL()); 4 }_}3.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n|=yw6aV'  
httpConnection.setRequestProperty("User-Agent","NetFox"); jMR9E@>~E  
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int responseCode=httpConnection.getResponseCode(); ByWad@-6i  
if(responseCode>=400) c7?|Tipc  
{ A-\n"}4  
processErrorCode(responseCode); z}VCiS0  
return -2; //-2 represent access is error }LIf]YK  
} |~D~#Nz  
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String sHeader; c3Ig4n0Y>  
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for(int i=1;;i++) K,HR=5  
{ X.)1>zk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |TBKsx8  
//Utility.log(in.readLine()); {}PBYXR  
sHeader=httpConnection.getHeaderFieldKey(i); H&ZsMML/%  
if(sHeader!=null) a<D]Gz^h  
{ 0ipYXbC  
if(sHeader.equals("Content-Length")) f9E.X\"  
{ F>3fP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~hA;ji|I  
break; fNi_C"<  
} &_c5C  
} J 9k~cz  
else ?#;zB  
break; G9\@&=  
} ~rU{Q>c  
} >*mLbp"  
catch(IOException e){e.printStackTrace ();} ]O;Rzq{D(  
catch(Exception e){e.printStackTrace ();} cvf#^Cu   
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Utility.log(nFileLength); (PCv4:`g  
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return nFileLength; I806I@ix  
} ztS'Dp}q<  
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q y8=4~40
 
//保存下载信息（文件指针位置） P}QuGy[  
private void write_nPos() 4RqOg1  
{ ;2;Kq)j_=  
try{ Q4MTedj1H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 29#;;n}p  
output.writeInt(nStartPos.length); 0:(@Y  
for(int i=0;i<nStartPos.length;i++) =e,2/Ep{i  
{ f13%[RA9N  
// output.writeLong(nPos); n'JwT! A  
output.writeLong(fileSplitterFetch.nStartPos); bgm$<;`U  
output.writeLong(fileSplitterFetch.nEndPos); f&Bu_r  
} *Gm
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output.close(); BS#@ehdig  
} |:tFQ.Z'2  
catch(IOException e){e.printStackTrace ();} yl%F}kBR  
catch(Exception e){e.printStackTrace ();} dt 4_x1  
} rK2*DuE  
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//读取保存的下载信息（文件指针位置） XH0R:+s  
private void read_nPos() _~DFZt@T  
{ %9=^#e+pE  
try{ !\8j[QS!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F#Oqa^$(  
int nCount = input.readInt(); 8lt P)K4  
nStartPos = new long[nCount]; [Qv%  
nEndPos = new long[nCount]; t_WNEZW7f  
for(int i=0;i<nStartPos.length;i++) Ne.W-,X^cL  
{ o;\0xuM@  
nStartPos = input.readLong(); z$`=7 afp  
nEndPos = input.readLong(); kN;l@>  
} !w98[BE7  
input.close(); EZc!QrY  
} ZV_Z)<  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} ~c`@uGw  
} 6,0pkx&Nv  
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private void processErrorCode(int nErrorCode) yGH'|`  
{ ^Y~ ,s  
System.err.println("Error Code : " + nErrorCode); o'%F*>#v  
} #* 
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//停止文件下载 X c,UR.  
public void siteStop() ||}|=Sz  
{ 1?)<*[  
bStop = true;  #d*mG =  
for(int i=0;i<nStartPos.length;i++) )~O{jd  
fileSplitterFetch.splitterStop(); DhY9)>4M  
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} Zo;@StN3}T  
} ~DPg):cZ  
//负责部分文件的抓取 2ADUJ  
**FileSplitterFetch.java 7l7eUy/z  
*/ .ymR%X_k  
package NetFox; ZHICpL  
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import java.io.*; L`x:Y>C(  
import java.net.*; {+z+6i  
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public class FileSplitterFetch extends Thread { . ~G>vVb  
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String sURL; //File URL %9-).k  
long nStartPos; //File Snippet Start Position 05DK-Wh?  
long nEndPos; //File Snippet End Position '8i np[_  
int nThreadID; //Thread's ID Puily9#  
boolean bDownOver = false; //Downing is over 5^GUuFt5m  
boolean bStop = false; //Stop identical /_x?PiL  
FileAccessI fileAccessI = null; //File Access interface &{x5 |$SD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k-Jj k3  
{ BA A)IQF  
this.sURL = sURL; pL.r 9T.  
this.nStartPos = nStart; &Zd{ElM  
this.nEndPos = nEnd; *@cXBav/<  
nThreadID = id; t \DS}3pv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 22}J.'Zb  
} ]#j]yGV  
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public void run() wcsUb9(  
{ Ls5|4%+&  
while(nStartPos < nEndPos && !bStop) %:N5k+}  
{ oSx]wZZ  
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try{ fg*IHha  
URL url = new URL(sURL); \uQ(-ji  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y71io^td~j  
httpConnection.setRequestProperty("User-Agent","NetFox"); LUHj3H  
String sProperty = "bytes="+nStartPos+"-"; vbmi_[,U  
httpConnection.setRequestProperty("RANGE",sProperty); nP0|nPWz#  
Utility.log(sProperty); ou
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InputStream input = httpConnection.getInputStream(); //3iai  
//logResponseHead(httpConnection); crz )F"  
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byte[] b = new byte[1024]; :~~}|Eu  
int nRead; W[AX?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %qV=PC  
{ u+&BR1)C  
nStartPos += fileAccessI.write(b,0,nRead); =;l.<{<VH  
//if(nThreadID == 1) z{]$WVs:^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?k TVC  
} D\}^<HW  
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f<=<:+  
Utility.log("Thread " + nThreadID + " is over!"); |cEJRs@B  
bDownOver = true; aqQ YU5l4~  
//nPos = fileAccessI.write (b,0,nRead); =3]}87  
} Qj.]I0d  
catch(Exception e){e.printStackTrace ();} <4ccTl  
} ]>tYU   
} $5yH(Z[[
 
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//打印回应的头信息 |_
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public void logResponseHead(HttpURLConnection con) [CL.Xil=  
{ m2F2  
for(int i=1;;i++) Y,w'Op  
{ PIR#M('  
String header=con.getHeaderFieldKey(i); ]VtVw^ir  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); }Qyuy~-&^  
Utility.log(header+" : "+con.getHeaderField(header)); ^,*ED Yz  
else )9I>y2WU~  
break; \X.CYkgK  
} s~ ||Vv!  
} Yv<'QC  
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public void splitterStop() ,5!&}  
{ i[_(0P+Da  
bStop = true; f++MH]I;  
} 701a%Jq_2  
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} [.J&@96,b  
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/* KaVNRS  
**FileAccess.java wcr3ugvT  
*//文件访问(定位，写) eS#kDa/ %  
package NetFox; & -r^Q  
import java.io.*; S!+c1q: ].  
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public class FileAccessI implements Serializable{ <P
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z$g cK>@l  
RandomAccessFile oSavedFile; F/pq9  
long nPos; z<_&4)2{  
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public FileAccessI() throws IOException 7bV(eV  
{ l7h6R$7; 0  
this("",0); 26M:D&|ZB  
} TxJoN]Z.  
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public FileAccessI(String sName,long nPos) throws IOException H1GmC`\<[:  
{ N5PW]  
oSavedFile = new RandomAccessFile(sName,"rw"); mkE_ a>  
this.nPos = nPos; R$XHjb)  
oSavedFile.seek(nPos); GB%kxtGD;\  
} n;@.eC,T/  
6|mHu2qXm  
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public synchronized int write(byte[] b,int nStart,int nLen) /^]/ iTg  
{ c,2OICj  
int n = -1; g6 H}a  
try{ 3S5`I9I  
oSavedFile.write(b,nStart,nLen); dhX$b!DA  
n = nLen; ')
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} MzFFWk  
catch(IOException e) 1[yy/v'q  
{ ["O_Phb|  
e.printStackTrace (); q+znb'i-x  
} KqN;a i,F  
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return n; A`--*$8\  
} Dm
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} 0HO'%'Ga*  
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/* !kG|BJ$j  
**SiteInfoBean.java v.&c1hKHb  
*/ ?I8r2M]  
package NetFox; ?KB] /gT^  
}rvX}   
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public class SiteInfoBean { ~ulcLvm:i  
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private String sSiteURL; //Site's URL 3-=AmRxW't  
private String sFilePath; //Saved File's Path %Z+**>1J  
private String sFileName; //Saved File's Name *8J0yv  
private int nSplitter; //Count of Splited Downloading File ]%ewxF  
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public SiteInfoBean() d
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{//nSplitter的缺省值为5 g${JdxR:  
//default value of nSplitter is 5
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this("","","",5); rq^%)tR  
} s3T7M:DM4  
c|d,:u#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }VRl L>HAC  
{ &qK:LHhj  
sSiteURL= sURL; F\hVunPVx  
sFilePath = sPath; Z^}[CQ&Am  
sFileName = sName; (t\U5-
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this.nSplitter = nSpiltter; QFnpp\K  
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} u;]xAr1  
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public String getSSiteURL() yoJ.[M4q  
{ '!ks $}$`h  
return sSiteURL; g1?9ge1  
} o<iU;15  
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public void setSSiteURL(String value) .j
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{ Y8^Wu
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sSiteURL = value; u]7wd3(  
} A)4XQF  
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public String getSFilePath() JBLUX,  
{ ez!W0  
return sFilePath; Ef?hkq7X<  
} i\l}M]Z#  
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*!JB^5(H  
public void setSFilePath(String value) 09anQHa  
{ "g#%d  
sFilePath = value; p/RT*?<   
} qljsoDG  
9M3"'^ {$  
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public String getSFileName() 9]w?mHslE  
{ {+7FBdxVB  
return sFileName; {QylNC
9  
} |%F,n2  
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public void setSFileName(String value) pvsa?z;rP  
{ q)Nw$dW<  
sFileName = value; @-L]mLY  
} z8awND  
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public int getNSplitter() -u'"l(n)~  
{ S<Gm*$[7  
return nSplitter; gee~>l  
} o}114X4q;  
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public void setNSplitter(int nCount) [UZr|F  
{ >h;]rMD!|  
nSplitter = nCount; C&H'?0Y@  
} Dk^AnMx%_  
} ,7Hyrx`  
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/* SK'h!Ye5Z  
**Utility.java zT78FliY6  
*/ [m0X kvd  
package NetFox; {sC Ni  
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public class Utility { "x=\mA#`  
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public Utility() 5N|LT8P}Z  
{ y ;[~(Yg[  
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} kPs?  
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//线程睡眠 |?^<=%  
public static void sleep(int nSecond) uxU-N  
{ ?CQE6ch  
try{ 4<#ItQ(  
Thread.sleep(nSecond); }MRgNr'k  
} rS BI'op  
catch(Exception e) rc8HZ  
{ _ 
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e.printStackTrace (); (WT\
HR  
} 2O=$[b3  
} ..8t1+S6]  
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//日志 ~JL
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public static void log(String sMsg) F+H]{ss>  
{ #H~55))F  
System.err.println(sMsg); .z,-ThTH@\  
} |D)CAQn,  
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public static void log(int sMsg) o!BC
R:  
{ FvT4?7-  
System.err.println(sMsg); $l7}e=1
 
} eQ[akVMk  
} M$EF 8  
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/* >k"O3Pc@  
**TestMethod.java ~},H+A!?  
*/ @JlT*:Dz  
package NetFox; Vl1.]'p_  
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public class TestMethod { }` 3-  
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bnfeZR1m_  
public TestMethod() \/1~5mQ+  
{ ///xx/weblogic60b2_win.exe <.Tllk@r)  
try{ bq7+l4CGTv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |5;,]lbt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;0WAfu}#H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M %zf?>])  
fileFetch.start(); GThGV"  
} =Jl\^u%H(x  
catch(Exception e){e.printStackTrace ();} D?E VzG  
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} JL_(%._J  
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public static void main(String[] args) jR1^e$  
{ P
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new TestMethod(); L`M{bRl+1  
} v0WB.`rO  
} ?z)
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