http断点续传简单实现（java)

/* '-BD.^!!  
**SiteFileFetch.java gle<{ `  
*/ 48,uO!  
package NetFox; 3ESrd"W=  
import java.io.*; /?1^&a  
import java.net.*; [a!)w@I:  
]m :Y|,:6  
n= q7*<l  
public class SiteFileFetch extends Thread { d/[kky}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z~th{4#E;  
long[] nStartPos; //开始位置 cAn_:^
 
long[] nEndPos; //结束位置 A[`2Mnj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )~CNh5z6Y  
long nFileLength; //文件长度  (F&o!W  
boolean bFirst = true; //是否第一次取文件 P @~)9W  
boolean bStop = false; //停止标志 ]2c0?f*Y7  
File tmpFile; //文件下载的临时信息 N<O<wtXIj  
DataOutputStream output; //输出到文件的输出流 Khh}flRy  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F+]cFx,/  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ri>ZupQ6  
{ Dqc2;>  
siteInfoBean = bean; XM)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5FE&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f#\Nz>tOhE  
if(tmpFile.exists ()) 0$_WIk  
{ h!7Lvh`o  
bFirst = false; NpxgF<G  
read_nPos(); s &f\gp1  
} Ek60[a  
else hOYP~OR  
{ NFPWh3),f  
nStartPos = new long[bean.getNSplitter()]; ZA\;9M=  
nEndPos = new long[bean.getNSplitter()]; !j&#R%D  
} "TVmxE%(  
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} q7p
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public void run() Hb[
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{ T_d)1m fl  
//获得文件长度 }/4),W@<  
//分割文件 aK8s0G!z?5  
//实例FileSplitterFetch J$d']%Dwb  
//启动FileSplitterFetch线程 "y60YYn-#J  
//等待子线程返回 KV! (   
try{ Q\}Ck+d`a  
if(bFirst) R+El/ya:6  
{ [{: l?  
nFileLength = getFileSize(); *;F:6p4_  
if(nFileLength == -1) Yq
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{ <O.|pJus  
System.err.println("File Length is not known!"); +$F,!rV-s  
} S~
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else if(nFileLength == -2) iz0:  
{ j^/=.cD|  
System.err.println("File is not access!"); $EL:Jx2<  
} !;Ke#E_d  
else wG73GD38  
{ agq4Zy  
for(int i=0;i<nStartPos.length;i++) m;0ZV%c*j  
{ h@TP=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :sttGXQX  
} /6Kx249Dw  
for(int i=0;i<nEndPos.length-1;i++) 7.]H9
 
{ yY]E~  
nEndPos = nStartPos[i+1]; tO?-@Qf/9<  
} HQnc`2  
nEndPos[nEndPos.length-1] = nFileLength; G=LK irj(  
} @)wsHW%cjz  
} |D_4 iFC  
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//启动子线程 #N;&^El  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h^,av^lg^  
for(int i=0;i<nStartPos.length;i++) ZZ T 9t#~  
{ ]0g p.R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h"[:$~/UJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^9><qKb
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nStartPos,nEndPos,i); |7Qe{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \Yn0|j
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fileSplitterFetch.start(); 5~d=,;yE  
} pK ^$^*#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xc4zUEO9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <+<Nsza  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /(?s\}O  
nEndPos = " + nFileLength); clk]JA (  
// fileSplitterFetch[nPos.length-1].start(); t*)!BZ  
y.-Kqa~  
c|K:oi,z  
//等待子线程结束 D/=k9[b!  
//int count = 0; a}iP +#;  
//是否结束while循环 zFQm3!.  
boolean breakWhile = false; Zy.3yQM9i  
B*9?mcP\  
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while(!bStop) d%RH]j4  
{ 9aX!<Z  
write_nPos(); #$]8WSl  
Utility.sleep(500); +"1-W>HV  
breakWhile = true; (g&@E(@]?  
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for(int i=0;i<nStartPos.length;i++) C=IN "  
{ Ktu~%)k%  
if(!fileSplitterFetch.bDownOver) nPDoK!r'  
{ -<sW`HpD'  
breakWhile = false; .gM6m8l9wp  
break; 7u
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} c&E
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} C XNYWx  
if(breakWhile) -wf>N:  
break; Z{/GT7 /  
8n:N#4Dh^  

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//count++; 5m;BL+>YE  
//if(count>4) GDb Vy)&  
// siteStop(); g9=_^^Tg  
} \}X[0ct2!  
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System.err.println("文件下载结束！"); F)Z9Qlo  
} u \<APn  
catch(Exception e){e.printStackTrace ();} k3KT':*  
} "d/uyS$6  
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//获得文件长度 '4,IGxIq  
public long getFileSize() -s1.v$g  
{ x 0#u2j?zj  
int nFileLength = -1; )."dqq^ q  
try{ ~)zxIO!  
URL url = new URL(siteInfoBean.getSSiteURL()); r8!pk~R5]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gf>GK/^HH  
httpConnection.setRequestProperty("User-Agent","NetFox"); TKiYEh  
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!6z{~Z:   
int responseCode=httpConnection.getResponseCode(); B@#vS=g  
if(responseCode>=400) N1.fV-  
{ 0{u%J%;  
processErrorCode(responseCode); NjPQT9&3h  
return -2; //-2 represent access is error AX Q.E$1g  
} G}LV"
0?  
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String sHeader; b`%!\I  
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for(int i=1;;i++) Z9*@w`x^u  
{ UJ(UzKq8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z[B:6\oQ  
//Utility.log(in.readLine()); E|jU8qz>P  
sHeader=httpConnection.getHeaderFieldKey(i); 7\ZSXQy1W  
if(sHeader!=null) g_A#WQyh\'  
{ 7%[ YX  
if(sHeader.equals("Content-Length")) e,Y<$kPV  
{ .}uri1k"@k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y9&na&vY?  
break; U0iV E+)Bt  
} jw 5 U-zi  
} t;-F]  
else X[f)0w%  
break; c-!3wvt)  
} 2$`Y 4b3t  
} zL3zvOhu}  
catch(IOException e){e.printStackTrace ();} `M. I.Z
_  
catch(Exception e){e.printStackTrace ();} %<'.c9u5  

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Utility.log(nFileLength); Xr'b{&  
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return nFileLength; HgBu:x?&  
} Aa]3jev  
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//保存下载信息（文件指针位置） CS5[E-%}T=  
private void write_nPos() -WR<tkK  
{ 2;J\Z=7  
try{ ,V^$Meh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^".6~{  
output.writeInt(nStartPos.length); Azp!;+  
for(int i=0;i<nStartPos.length;i++) ULgp]IS  
{ {"2CI^!/U.  
// output.writeLong(nPos); )[r=(6?n  
output.writeLong(fileSplitterFetch.nStartPos); lV$#>2Hh5  
output.writeLong(fileSplitterFetch.nEndPos); ckv8QAm  
} [tElt4uG  
output.close(); ^4Ff8Y  
} x8~*+ j  
catch(IOException e){e.printStackTrace ();} k g Rys  
catch(Exception e){e.printStackTrace ();} OdNcuiLa  
} Zm7,O8  
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NV@$\<  
//读取保存的下载信息（文件指针位置） m6]6!_  
private void read_nPos() JNJ6HyCU  
{ '5~l{3Lw  
try{ b`,Sd.2=('  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ' I!/I  
int nCount = input.readInt(); t7sEY  
nStartPos = new long[nCount]; UI%4d3   
nEndPos = new long[nCount]; K{V.N</  
for(int i=0;i<nStartPos.length;i++) 9?~6{!m_9  
{ x25zk4-  
nStartPos = input.readLong(); 6l &!4r@}  
nEndPos = input.readLong(); 98 ]pkqp4  
} &A`,hF8  
input.close();
Y(2Z<d  
} Jf\`?g3#  
catch(IOException e){e.printStackTrace ();} (0.JoeA`y  
catch(Exception e){e.printStackTrace ();} V<;_wO^  
} 0IA'5)  
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private void processErrorCode(int nErrorCode) +Ar4X-A{y  
{ [!8bjc]c
 
System.err.println("Error Code : " + nErrorCode); 81!;Wt(?  
} o)x&|0_  
}gB^C3b6  
;ceg:-Zqo  
//停止文件下载 ccp9nXv  
public void siteStop() $J,$_O6  
{ V0&7MY*  
bStop = true; {XUSw8W'  
for(int i=0;i<nStartPos.length;i++) ~l{Qz0&
  
fileSplitterFetch.splitterStop(); gs0`nysM#  
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} LU`)  
} w"#rwV&  
//负责部分文件的抓取 ]gm3|-EiY  
**FileSplitterFetch.java G"kX#k0S  
*/ 51H6 W/$  
package NetFox; |W@Ko%om  
}9#GJ:x`  
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import java.io.*; V[kn'QkWv  
import java.net.*; 0uPcEpIA  
jG)66E*"  
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public class FileSplitterFetch extends Thread { *yo'Nqu  
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String sURL; //File URL ^Jdg%U?  
long nStartPos; //File Snippet Start Position #o9CC)q5G  
long nEndPos; //File Snippet End Position ITi#p%  
int nThreadID; //Thread's ID `T ^0&#  
boolean bDownOver = false; //Downing is over 7!FiPH~kM  
boolean bStop = false; //Stop identical TBba3%  
FileAccessI fileAccessI = null; //File Access interface a2i:fz=[  
@PhAg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Br&&#  
{ 9F6dKPN:  
this.sURL = sURL; \Cin%S.C  
this.nStartPos = nStart; "wKJ8  
this.nEndPos = nEnd; a|[f%T<<  
nThreadID = id; 3u^wK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qe(C>qjMbG  
} :,
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public void run() @T>^ >  
{ b&1hj[`)  
while(nStartPos < nEndPos && !bStop) U2vb&Qu/  
{ fb^R3wd$ff  
;E5XH"L\  
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try{ &TrL!9FtJ  
URL url = new URL(sURL); >1]hR)Ip  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )`\Q/TMl5  
httpConnection.setRequestProperty("User-Agent","NetFox"); j]5e$e{  
String sProperty = "bytes="+nStartPos+"-"; KV9~L`=]i  
httpConnection.setRequestProperty("RANGE",sProperty); gSyBoY  
Utility.log(sProperty); $#W^JWN1  
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InputStream input = httpConnection.getInputStream(); B4+u/hkbh?  
//logResponseHead(httpConnection); -49I3&  
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byte[] b = new byte[1024]; ba ,n/y
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int nRead; o_kZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O*,O]Q  
{ e7&RZ+s#wZ  
nStartPos += fileAccessI.write(b,0,nRead); wc"~8Ah  
//if(nThreadID == 1) }j2t8B^&:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D;+Y0B  
} {Dy,|}7s  
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Utility.log("Thread " + nThreadID + " is over!"); \:q@I]2  
bDownOver = true; QyZ'%T5J  
//nPos = fileAccessI.write (b,0,nRead); XH/!A`ZK  
} D@[#7:rHL  
catch(Exception e){e.printStackTrace ();} -HuIz6  
} HJpx,NU'  
} ?6x&A t  
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}NdLd!  
//打印回应的头信息 !,5qAGi0  
public void logResponseHead(HttpURLConnection con) DZb0'+jQ  
{ aM,g@'.=  
for(int i=1;;i++) 2~r2ErtS  
{ v~._]f$:  
String header=con.getHeaderFieldKey(i); s=E6HP@q  
if(header!=null) K>XZrt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HL>l.IG?  
Utility.log(header+" : "+con.getHeaderField(header)); EUH9R8)  
else w Bm4~~_  
break; p}wysVB  
} X(DP=C}v9  
} 7X
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public void splitterStop() ^%g8OP  
{ r(wtuD23q  
bStop = true; O(.eHZ=  
} h2:TbQ  
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} !A|}_K1Cr  
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/* q9InO]s&~=  
**FileAccess.java =i7CF3  
*//文件访问(定位，写) 16.?45  
package NetFox; >Apa^Bp  
import java.io.*; dI=&gz  

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public class FileAccessI implements Serializable{ 19oyoi"  
d+

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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 3(.Y>er%U  
RandomAccessFile oSavedFile; k{ZQM  
long nPos; [W<j  
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5C*-v,hF  
public FileAccessI() throws IOException A L|,\s  
{ Fy.!amXu  
this("",0); U56g|V  
} Eb29tq  
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public FileAccessI(String sName,long nPos) throws IOException S'@Ok=FSy  
{ MBQ|*}+;  
oSavedFile = new RandomAccessFile(sName,"rw"); Uz]=`F8  
this.nPos = nPos; l6IT o@&J  
oSavedFile.seek(nPos);
]}]+aB  
} j[t2Bp  
} z7yS.{  
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public synchronized int write(byte[] b,int nStart,int nLen) g^i\7'  
{ M$6;&T  
int n = -1; B LZ<"npn  
try{ _Vc4F_  
oSavedFile.write(b,nStart,nLen); TvRm 7  
n = nLen; vn@sPT  
} /&c>*4)  
catch(IOException e) bV#j@MJ~0  
{ n1'i!NWt  
e.printStackTrace (); @XcrHnH9  
} Ggv*EsN/cC  
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return n; n \&H~0X  
} /WX&UAG  
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} Q(BZg{  
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/* cnG>
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**SiteInfoBean.java 
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*/ $!\L6;:  
package NetFox; n+vv %  
5fmQ+2AC1  
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public class SiteInfoBean { $8[JL\  
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private String sSiteURL; //Site's URL vP%:\u:{  
private String sFilePath; //Saved File's Path #9qX:*>h  
private String sFileName; //Saved File's Name z> N73 u  
private int nSplitter; //Count of Splited Downloading File -7Kstc-  
P4E_<v[  
l)EtK&er(}  
public SiteInfoBean() 4>Nig.#   
{//nSplitter的缺省值为5 : 'pK  
//default value of nSplitter is 5 W(.svJUgb.  
this("","","",5); dLR[<@E  
} s)sT\crP@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MY(
51)*  
{ Jt?`(H  
sSiteURL= sURL; |Fq\%y#  
sFilePath = sPath; m/,8\+  
sFileName = sName; a%/x  
this.nSplitter = nSpiltter; H87k1^}HV  
!D/W6Ic@  
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} _skE\7&>X  
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public String getSSiteURL() J DOs.w  
{ =~21.p  
return sSiteURL; eX0[C0#  
} <LX-},?P  
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public void setSSiteURL(String value) dw| VH1fS  
{ 98UI]? 4  
sSiteURL = value; +NOq>kH@  
} 4:kDBV;v  
}5B\:*yW  
koj*3@\p/  
public String getSFilePath() gf/<sH2}  
{ fA),^  
return sFilePath; /\E3p6\*  
} nD=N MqQ &  
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public void setSFilePath(String value) LftGA7uGJ)  
{ zq|Nlt
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sFilePath = value;  ]l  
} SxX  
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public String getSFileName() S*WLb/R2  
{ '\"5qB  
return sFileName; 81)i>]  
} (>*L-&-  
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public void setSFileName(String value) Hig.` P  
{ W/%9=g$m  
sFileName = value; D\DwBZ>  
} ~!/agLwY  
?H8dyQ5"  
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public int getNSplitter() veS) j?4  
{ "R% RI( y{  
return nSplitter; xhMAWFg|  
} c/Li,9cT'  
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public void setNSplitter(int nCount) q'uGB fE.  
{ LO38}w<k  
nSplitter = nCount; Y&$puiH-j  
} x l=i_  
} Lo=n)cV1,  
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/* }8`>n4  
**Utility.java >g{b'Xx  
*/ /!*=*  
package NetFox; 0sF|Y%N  
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public class Utility { -Q%Pg<Q-#  
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public Utility() !y$+RA7\  
{ VaO[SW^  
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} .(yJ+NU  
#jPn7  
//线程睡眠 caV DV
  
public static void sleep(int nSecond) OLqyn
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{ ?0lz!Nq'S  
try{ U7-*]i
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Thread.sleep(nSecond); f#gV>.P;h\  
} 2_)gJ_kP  
catch(Exception e) @H}Hjg_>m  
{ 9d!mGnl  
e.printStackTrace (); nt%p@e!,  
} Hv%$6,/*v  
} V$dhi
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//日志 #IU^(W  
public static void log(String sMsg) 6S0Gjekr  
{ y8} /e@&  
System.err.println(sMsg); J_9[xmM  
} XcL%0%`  
as[! 9tB]
 
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public static void log(int sMsg) '@HCwEuz  
{ *<X*)A{C  
System.err.println(sMsg); |n~,{=  
} Mu6DTp~k  
} -]QP#_   
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/* @
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**TestMethod.java A>_,tt  
*/ Y)l=r^Ap>  
package NetFox; i4&V+h"  
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public class TestMethod { j}6h}E&dEr  
V~do6[(  
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public TestMethod() i>dFpJ  
{ ///xx/weblogic60b2_win.exe jWd
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try{ g2A#BMe'.$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >B;KpO"+m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]kF1~kXBe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +
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fileFetch.start(); zU_dk'&,  
} %OP|%^2  
catch(Exception e){e.printStackTrace ();} Fqh./@o  
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} #L57d  
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public static void main(String[] args) =y`-:j\  
{ 6;;2e> e  
new TestMethod(); :39arq  
} d ,.=9
  
} ]EG8+K6  
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