http断点续传简单实现（java)

/* h6T/0YhWLP  
**SiteFileFetch.java jle%|8m&@  
*/ ci_v7Jnwo  
package NetFox; Bpm5dT;  
import java.io.*; Xlqz8cI  
import java.net.*; U_}A{bFG  
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public class SiteFileFetch extends Thread { Ij6Wz.*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /@:up+$  
long[] nStartPos; //开始位置 ,8xP8T~Kmv  
long[] nEndPos; //结束位置 kF+}.x%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BvZ^^IUb  
long nFileLength; //文件长度 <`p75B  
boolean bFirst = true; //是否第一次取文件 APtselC  
boolean bStop = false; //停止标志 7tfivIj)e  
File tmpFile; //文件下载的临时信息 5e/qgI)M5  
DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） # +QWi0B  
public SiteFileFetch(SiteInfoBean bean) throws IOException Oa}V>a  
{ a:-)+sgHw  
siteInfoBean = bean; )pZekh]v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); te\h?H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7dlKdKH  
if(tmpFile.exists ()) C'8!cPFVv  
{ EOBs}M
;  
bFirst = false; jI{~s]Q  
read_nPos(); m,@1LwBH  
} F[7Kw"~J  
else KCJN<  
{ ?9(o*lp  
nStartPos = new long[bean.getNSplitter()]; ~gfA](N  
nEndPos = new long[bean.getNSplitter()]; }l}yn@hYC  
} pVV}1RDa  
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} Tbi]oB#  
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public void run() 4{*tn"y  
{ |ilv|UV  
//获得文件长度 L8bI0a]r"*  
//分割文件 OBI+<2`Oc  
//实例FileSplitterFetch 0~Iu7mPY  
//启动FileSplitterFetch线程 +-H}s`  
//等待子线程返回 Gq0]m  
try{ $c@w$2  
if(bFirst) 83 i1  
{ `sk!C7%  
nFileLength = getFileSize(); q6C6PPc  
if(nFileLength == -1) eC>"my`  
{ u(1J=h  
System.err.println("File Length is not known!"); C@y}*XV[b  
} N>A{)_k3  
else if(nFileLength == -2) 9@#h}E1$  
{ QM[A;WBr7  
System.err.println("File is not access!"); 3C rQBIj1  
} q:Y6fbt<7  
else CYPazOfj  
{ (2 T#/$  
for(int i=0;i<nStartPos.length;i++) t_I\P.aMA  
{ 1jH7<%y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6WE&((r^  
} @%EE0)IA  
for(int i=0;i<nEndPos.length-1;i++) XOysgX0g  
{ gf68iR.Gs  
nEndPos = nStartPos[i+1]; HDF!`  
} o%Be0~
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nEndPos[nEndPos.length-1] = nFileLength; ]g;^w?9h  
} J+)'-OFt0  
} MvFM,  
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{J,6iP{>ZN  
//启动子线程 =zeFK_S!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %6NO0 F^  
for(int i=0;i<nStartPos.length;i++) . ]o3A8  
{ <`R|a *  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \!+-4,CbZY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [ME}Cv`?<E  
nStartPos,nEndPos,i); u\{qH!?t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  SwdC,  
fileSplitterFetch.start(); I#|ocz  
} .q0218l:dF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;YK!EMM4!h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r-RCe3%g%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1Yc%0L(  
nEndPos = " + nFileLength); I?_E,.)[ I  
// fileSplitterFetch[nPos.length-1].start(); "El^38Ho  
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//等待子线程结束 rQ9*J  
//int count = 0; uy/y wm/?=  
//是否结束while循环 .A3DFm3t  
boolean breakWhile = false; -"W)|oC_  
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h [nH<m  
while(!bStop) n?'d|h  
{ &EAk z  
write_nPos(); [096CK  
Utility.sleep(500); <Ctyht0c.  
breakWhile = true; ,f}h}  
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for(int i=0;i<nStartPos.length;i++) [f<"p[  
{ JNh=fvO2i  
if(!fileSplitterFetch.bDownOver) ^C!mCTL1N  
{ [NYj.#,oR  
breakWhile = false; IE&_!ce  
break; No:^hY:F8  
} 3c c1EQ9  
} [^<SLTev  
if(breakWhile) !8.En8Z<D-  
break; ]EB6+x!G  
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//count++; :3JCvrq  
//if(count>4) g[/^cJHQ  
// siteStop(); O$a#2p&  
} }l~]b3@qu  
; ;<J x.  
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System.err.println("文件下载结束！"); "$GK.MP5  
} 5^\m`gS  
catch(Exception e){e.printStackTrace ();} (~S<EUc$  
} _1sP.0 t  
[}z?1Gj;W(  
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//获得文件长度 e#tIk;9Xz  
public long getFileSize() nz^nptw  
{ XJe/tR  
int nFileLength = -1; E]NY (1  
try{ GGH;Z WSe  
URL url = new URL(siteInfoBean.getSSiteURL()); "X`RQ6~]>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BsKbn@'uC  
httpConnection.setRequestProperty("User-Agent","NetFox"); p~h4\.*`  
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+,  
int responseCode=httpConnection.getResponseCode(); g;8M<`qvf  
if(responseCode>=400) UmJUt|  
{ Zp`~}LV{  
processErrorCode(responseCode); My. dD'C  
return -2; //-2 represent access is error B$ui:R/ t  
} 9qEOgJ  
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String sHeader; #zxd;;p3  
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for(int i=1;;i++) TZ'aNcGg  
{ f3!n$lj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h6g:(3t6m  
//Utility.log(in.readLine()); L/BHexOB  
sHeader=httpConnection.getHeaderFieldKey(i); Vn'?3Eb<  
if(sHeader!=null) P@C c]Z  
{ d<#p %$A4  
if(sHeader.equals("Content-Length")) QO2Ut!Y  
{ W,Ty=:qm*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3Y`>
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break; zO%w_7w  
} :<|Z.4}kJb  
} [UoqIU  
else Uj,g]e8e  
break; *6XRjq^#  
} V{0%xz #  
} ! tGiTzzp  
catch(IOException e){e.printStackTrace ();} UxeL cUP  
catch(Exception e){e.printStackTrace ();} ABcBEv3  
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Utility.log(nFileLength); k d+l k:  
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return nFileLength; I0iY+@^5  
} _lP4}9p  
;}D-:J-z_  
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//保存下载信息（文件指针位置） U+} y %3l  
private void write_nPos() ;|!MI'Af  
{ >b>gr OX  
try{ ^7Lk-a7gp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Wab.|\c  
output.writeInt(nStartPos.length); 8b7;\C~$p  
for(int i=0;i<nStartPos.length;i++) )!eEO [\d  
{ VD/&%O8n  
// output.writeLong(nPos); Lyr2(^#:  
output.writeLong(fileSplitterFetch.nStartPos); G?<pBMy  
output.writeLong(fileSplitterFetch.nEndPos);  iS  
} u
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output.close(); %K?iNe  
} .fEwk  
catch(IOException e){e.printStackTrace ();} .b,~f  
catch(Exception e){e.printStackTrace ();} <(YF5Xm6$h  
} FZp<|t  
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//读取保存的下载信息（文件指针位置） !!WJn}  
private void read_nPos() K6hfauWd[  
{ MqdB\OW&  
try{ -2 xE#r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @h#Xix7  
int nCount = input.readInt(); i=L8=8B`  
nStartPos = new long[nCount]; nWGR5*e:  
nEndPos = new long[nCount]; x%6hM|U  
for(int i=0;i<nStartPos.length;i++) *Tp]h 0  
{ vTd-x>n  
nStartPos = input.readLong(); >jMH#TZaX  
nEndPos = input.readLong(); 4gOgWBv  
} | 3giZ{  
input.close(); C2G
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} C_G1P)k  
catch(IOException e){e.printStackTrace ();} Fg=v6j4W  
catch(Exception e){e.printStackTrace ();} sKd)BA0`  
} /UHp [yod  
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private void processErrorCode(int nErrorCode) EeB3 }  
{ $)*xC!@6X  
System.err.println("Error Code : " + nErrorCode); '
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} Pbe7SRdr^  
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//停止文件下载 c&*l"  
public void siteStop() {y6C0A*  
{ 5 `=KyHi:b  
bStop = true; D0ruTS  
for(int i=0;i<nStartPos.length;i++) TsD;Kl1  
fileSplitterFetch.splitterStop(); QKccrAo  
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} tOH0IE c  
} zMGzReJ  
//负责部分文件的抓取 >vVw!.fJ  
**FileSplitterFetch.java -:SIS`0s  
*/ El (/em  
package NetFox; 8l23%iWxe  
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import java.io.*; <*Ub2B[m  
import java.net.*; =}R~0|^  
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public class FileSplitterFetch extends Thread { .z
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String sURL; //File URL Spgg+;9  
long nStartPos; //File Snippet Start Position tjxvN 4l  
long nEndPos; //File Snippet End Position C:GvP>  
int nThreadID; //Thread's ID fxtxu?A>  
boolean bDownOver = false; //Downing is over `6F+Rrn  
boolean bStop = false; //Stop identical w$>3pQ8
d  
FileAccessI fileAccessI = null; //File Access interface z+/LS5$  
}
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rla4L`X;  
{ ETp'oh}?  
this.sURL = sURL; M<(u A'  
this.nStartPos = nStart; H]Wp%"L  
this.nEndPos = nEnd;  $Nu)E  
nThreadID = id; !O{z 3W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h|p[OecG  
} R1'`F{56  
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public void run() GMm'of#  
{ A5XR3$
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while(nStartPos < nEndPos && !bStop) :woa&(wN;1  
{ <Wy>^<`  
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try{  O<GF>  
URL url = new URL(sURL); hhmGv9P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TpP8=8_Lh  
httpConnection.setRequestProperty("User-Agent","NetFox"); wL2XNdo}<  
String sProperty = "bytes="+nStartPos+"-"; &Rp"rMeW  
httpConnection.setRequestProperty("RANGE",sProperty); e<5Y94YE  
Utility.log(sProperty); <TxC!{<  
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InputStream input = httpConnection.getInputStream(); xR908+>5  
//logResponseHead(httpConnection); :3?|VE F  
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byte[] b = new byte[1024]; ;&,.TC?l  
int nRead; ]MAT2$"le  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A*'V+(  
{ nbxR"UH  
nStartPos += fileAccessI.write(b,0,nRead); U)[ty@zyF  
//if(nThreadID == 1) y
 $V[_TN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LC-)'Z9}5  
} (vQ+e
 
<v$QM;Ff  
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Utility.log("Thread " + nThreadID + " is over!"); Gzm$OHbn  
bDownOver = true; o~C('1Fdb  
//nPos = fileAccessI.write (b,0,nRead); Qb`C)Nh:  
} E*|tOj9`1n  
catch(Exception e){e.printStackTrace ();} -_~)f{KN@  
} jTSOnF}C~+  
} 5 =Z!hQ}  
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//打印回应的头信息 #D)x}#V\  
public void logResponseHead(HttpURLConnection con) R8<eN9bJ9  
{ 9;KJr[FQV  
for(int i=1;;i++) .Z%G@X*  
{ >;nS8{2o  
String header=con.getHeaderFieldKey(i); Coa-8j*R7  
if(header!=null) @J vZ[T/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >V!LitdJ  
Utility.log(header+" : "+con.getHeaderField(header)); sR*Nq5F#9  
else '[Gm8K5  
break; Y\?j0X;  
} arh@`'Q  
}  @E_zR  
^ vbWRG~  
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public void splitterStop() 8QF`,o
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{ gb 4pN  
bStop = true; nG
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} +t]Xj1Q  
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}  @Fx@5e  
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rt b*n~  
/* k dU! kj  
**FileAccess.java @]'SeiNp  
*//文件访问(定位，写) g%\L&}Jd  
package NetFox; qm(1:iK,0  
import java.io.*; 1^{`lK~2  
o&
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 T-8J  
public class FileAccessI implements Serializable{ 77Q}=80GU;  
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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 #":a6%0Q  
RandomAccessFile oSavedFile; 7g6RiH}  
long nPos; 59!)j>f  
fLB1)kTS  
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public FileAccessI() throws IOException UR3$B%i  
{ Alz~-hqQ  
this("",0); kx{!b3"  
} q)iTn)Z!  
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|}S1o0v{(a  
public FileAccessI(String sName,long nPos) throws IOException t26ij`V  
{ ^ KH>1!  
oSavedFile = new RandomAccessFile(sName,"rw"); DQgH_!  
this.nPos = nPos; h<3p8eB  
oSavedFile.seek(nPos); P s#>y&  
} kO ![X^V  
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. U/k<v<)6  
public synchronized int write(byte[] b,int nStart,int nLen) G5c7:iGm/c  
{ ~_PYNY`"  
int n = -1; Ew4g'A:H  
try{ x9V {R9_gf  
oSavedFile.write(b,nStart,nLen); 5py R~+  
n = nLen; KQ)T(mIqp  
} lbkLyp2  
catch(IOException e) #T%zfcUj  
{ 3N<&u   
e.printStackTrace (); Qpu3(`d<  
} 4lz{G*u  
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return n; $G[KT):N  
} zj20;5o>U&  
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} XO wiHW{  
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4/MNqit+  
/* u~'OcO  
**SiteInfoBean.java T]71lRY5  
*/ )zJ=P
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package NetFox; gaeOgP.0  
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%h+uD^^$  
public class SiteInfoBean { hKksVi  
g42T#p8^  
4vqNule  
private String sSiteURL; //Site's URL WK;(P4Z  
private String sFilePath; //Saved File's Path 9} *$n&B  
private String sFileName; //Saved File's Name ~3=2=Uf  
private int nSplitter; //Count of Splited Downloading File /DU*M,  
kxo.v|)8  
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public SiteInfoBean() KO,_6>8]U  
{//nSplitter的缺省值为5 iz`jDa Q|1  
//default value of nSplitter is 5 V^En8  
this("","","",5); cU+>|'f&  
} d8
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k
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e@j8T gI)  
{ #:{6b*}  
sSiteURL= sURL; hTw}X.<4  
sFilePath = sPath; %dmfBf Ev  
sFileName = sName; Uu5C%9^s  
this.nSplitter = nSpiltter; pULsGb  
|s|/]aD}o  
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} 8^X]z|2  
l0`'5>
  
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public String getSSiteURL() fn1pa@P  
{ O71BM@2<  
return sSiteURL; s.y}U5Ty?P  
} g1qi\axm  
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public void setSSiteURL(String value) D5`(}  
{ *V|zx#RN  
sSiteURL = value; p7UTqKi  
} @L;C_GEa  
k7Oy5$##  
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public String getSFilePath() f)^t')  
{ B] i:)   
return sFilePath; M(5D'4.  
} /{we;Ut=g  
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public void setSFilePath(String value) .Cr1,Po  
{ &<h?''nCy  
sFilePath = value; R3G@G  
} Jvj=I82  
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public String getSFileName() XU-*[\K  
{ ]) n0MF)p  
return sFileName; g7Z9F[d  
} DMMLzS0A  
 _8S4Q!  
d*%Mv[X:<  
public void setSFileName(String value) rIlBH*aT  
{ i4VK{G~g"  
sFileName = value; $e1:Q#den2  
} V6+Zh>'S  
%EoH4LzT  
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public int getNSplitter() f0FP9t3k  
{ KZ3B~#oQ  
return nSplitter; F[`vH  
} W.$6pzB(  
yFO)<GLk  
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public void setNSplitter(int nCount) [<Jp#&u6sb  
{ bK7.St  
nSplitter = nCount; 9K$]h2  
} 8^T2^gs  
} M5u_2;3  
[R\=M'  
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/* 7@~QkTH~y  
**Utility.java Y^3)!>  
*/ 4d-q!lRpa  
package NetFox; :<UtHf<=k  
4k$0CbHx0  
!tr9(d  
public class Utility { `Sx.|`x8  
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public Utility() yM|g|;U  
{ qmID-t"  
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} |hD~6a  
cIZ[[(Db  
//线程睡眠 mQ=sNZ-d]  
public static void sleep(int nSecond) (HJ$lxk<2h  
{ tj0Qr-/  
try{ Y"oDFo,  
Thread.sleep(nSecond); .FJj  
} 6=3(oUl  
catch(Exception e) a7=YG6[  
{ 6Ty3e|do  
e.printStackTrace (); QES^^PQe:  
} req-Q |  
} (GNEYf|  
\-d'9b?  
//日志 7@@<5&mN  
public static void log(String sMsg) LUG9 #.  
{  feN!_-  
System.err.println(sMsg); dFMAh&:>  
} E@mkm  
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public static void log(int sMsg) Pv[ykrm/  
{ 2_.CX(kI  
System.err.println(sMsg); L?Tu)<Mn  
} kz_M;h>  
} kkL(;H:%  
<K,[sy&Qy  
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/* !^-OfqIHfV  
**TestMethod.java ]f5c\\)  
*/ Z:TFOnJ  
package NetFox; S[^nSF  
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4`6< {  
public class TestMethod { ExqM1&zpK  
dXDXRY.FMQ  
6qf-Y!D5  
public TestMethod() k|5k8CRX  
{ ///xx/weblogic60b2_win.exe +8eVj#N  
try{ o Fi) d[`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IF e+B"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IE}Sdeqi)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P]-#wz=S  
fileFetch.start(); Y=|CPE%V  
} /wlFD,+8  
catch(Exception e){e.printStackTrace ();} I[%M!_+  
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5E0wn'  
} )Z&HuEg{ZR  
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public static void main(String[] args) ~7dF/Nn5  
{ oHk27U G  
new TestMethod(); [)0 R'xL6  
} f:&)"  
} IBDVFA  
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