http断点续传简单实现（java)

/* b A)b`1lI  
**SiteFileFetch.java .-.q3ib  
*/ >"cr-LB  
package NetFox; s.^c..e75C  
import java.io.*; *nYB o\@g  
import java.net.*; K4j@j}zK9I  
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public class SiteFileFetch extends Thread { W *YW6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0=OD?48<  
long[] nStartPos; //开始位置 4@
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long[] nEndPos; //结束位置 X$Q2m{dR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B;eW/#`  
long nFileLength; //文件长度 x8 f6,  
boolean bFirst = true; //是否第一次取文件 RRx`}E9,  
boolean bStop = false; //停止标志 J3H.%m!V  
File tmpFile; //文件下载的临时信息 KU+( YF$1
 
DataOutputStream output; //输出到文件的输出流 d@-wi%,^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Sdgb#?MR|  
public SiteFileFetch(SiteInfoBean bean) throws IOException %S{o5txo  
{ nHSTeFI?  
siteInfoBean = bean; uDILjOT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d4d\0[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &bB6}H(  
if(tmpFile.exists ()) U+4HG  
{ /"(b.&  
bFirst = false; ]KsGkAG  
read_nPos(); 8]My k>  
} 54=}GnZN  
else 'To<T  
{ 3QCMK^#Z:  
nStartPos = new long[bean.getNSplitter()]; ewo*7j4*  
nEndPos = new long[bean.getNSplitter()]; XDHLEG-u(  
} q z=yMIy=  
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} j,}4TDWa  
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public void run() rwoF}}  
{ ;)gLjF/F7  
//获得文件长度 5+`=t07^et  
//分割文件 }W1^t  
//实例FileSplitterFetch /M 0 p_4  
//启动FileSplitterFetch线程 =Q@6c   
//等待子线程返回 PM@XtL7J  
try{ j\
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if(bFirst) f](I.lm:  
{ gC0;2  
nFileLength = getFileSize(); 6%>/og\%  
if(nFileLength == -1) !2(.$}E  
{ ;JYoW{2  
System.err.println("File Length is not known!"); m6-76ma,hi  
} NvcHv7,  
else if(nFileLength == -2) 9KXym
}  
{ /;DjJpwf0  
System.err.println("File is not access!"); ^,Xa IP+[  
} :#Ty^-"]1  
else _~PO  
{ hPcS, p{%  
for(int i=0;i<nStartPos.length;i++) 1c'79YU  
{ 5KK{%6#f\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NNgK:YibD  
} @Eo4U]-  
for(int i=0;i<nEndPos.length-1;i++) $;y1Qiel  
{ Cgo9
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nEndPos = nStartPos[i+1]; 3Mw}R6g@#  
} .M8=^,h^K  
nEndPos[nEndPos.length-1] = nFileLength; .U<F6I:<md  
} C]/&vh7ta  
} FK6K6wU52m  
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//启动子线程 )R~a;?T_c0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2@fa rx:  
for(int i=0;i<nStartPos.length;i++) +1x)z~q=  
{ O5O.><RP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
ikr7DBLt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XYts8}y5  
nStartPos,nEndPos,i); Uh*@BmDA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {f-XyF1`  
fileSplitterFetch.start(); )PwQ^||{  
} J8J!#j.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w3d34*0$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ^eobp.U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YN/u9[=`  
nEndPos = " + nFileLength); C*a,<`
  
// fileSplitterFetch[nPos.length-1].start(); `T=1<Twc  
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//等待子线程结束 ?;_H{/)m  
//int count = 0; <z',]hy  
//是否结束while循环 cg{Gc]'1#  
boolean breakWhile = false; @/LiR>,  
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while(!bStop) @O'I)(To  
{ bTiBmS  
write_nPos(); >d97l&W  
Utility.sleep(500); u7[pLtOwN  
breakWhile = true; $]1qbE+  
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for(int i=0;i<nStartPos.length;i++) 2Q}7fht  
{ z#RuwB+  
if(!fileSplitterFetch.bDownOver) O~atNrHD  
{ 7u|%^Ao6  
breakWhile = false; *.o"ZVl  
break; 3+%nn+m  
} 5*Btb#:  
} ?T <rt  
if(breakWhile) ~~@y_e[N#l  
break; 'aZASPn[  
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//count++; r,0@~;zA  
//if(count>4) L$kgK#T  
// siteStop(); oK$'9c5<  
} ]hL:33  
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System.err.println("文件下载结束！"); 12-EDg/1  
} 1U'ZVJ5bpK  
catch(Exception e){e.printStackTrace ();} fq=:h\\G  
} AC'lS >7s  
>P<'L4;  
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//获得文件长度 qEZ!2R^`G  
public long getFileSize() 1LX)4TCC  
{ 'mJ1
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int nFileLength = -1; R B%:h-t4  
try{ SwX@I6huM  
URL url = new URL(siteInfoBean.getSSiteURL()); n7S; Xve#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =-5[Hn%  
httpConnection.setRequestProperty("User-Agent","NetFox"); @i{]4rk lv  
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AX K95eS  
int responseCode=httpConnection.getResponseCode(); (7~%B"  
if(responseCode>=400) 2eHx"Ha  
{ 2qjyFTT  
processErrorCode(responseCode); Hr&Ere8.4p  
return -2; //-2 represent access is error 6#v
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} ` jyKCm.$#  
&//2eL  
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String sHeader; ?9Ma^C;}  
 E>"8/  
{"t5\U6cKM  
for(int i=1;;i++) \FXp*FbQ  
{ ~?d>fR:X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;Yv14{T!  
//Utility.log(in.readLine()); hJLT!33:  
sHeader=httpConnection.getHeaderFieldKey(i); {!r#f(?uT  
if(sHeader!=null) _ ~[M+IO   
{ %4/xH9  
if(sHeader.equals("Content-Length")) C5MqwNX  
{ W "k|K:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); # M>wH`Q#  
break; +|0t  
} xh r[A  
} }#bZ8tm&  
else 7O$ &  
break; >4c`UW  
} &oEyixe  
} %N1"*</q  
catch(IOException e){e.printStackTrace ();} djGs~H>;U_  
catch(Exception e){e.printStackTrace ();} ]'g:B p  
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Utility.log(nFileLength); Sc{Tq\t;%  
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return nFileLength; |T y=7d,  
} G1[(F`t>  
p#=;)1  
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//保存下载信息（文件指针位置） s[T{c.F  
private void write_nPos() /B[}I}X  
{ U!Mf]3  
try{ x,uBJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U6c@Et,  
output.writeInt(nStartPos.length); Pk:zfC?4  
for(int i=0;i<nStartPos.length;i++) ^vaL8+  
{ 5k~\or 5_  
// output.writeLong(nPos); g}Mi9Kp  
output.writeLong(fileSplitterFetch.nStartPos); !5~k:1=  
output.writeLong(fileSplitterFetch.nEndPos); O2lIlCL  
} B\0t&dai|'  
output.close(); S<pk
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} 2vvh|?M  
catch(IOException e){e.printStackTrace ();} C`EY5"N r  
catch(Exception e){e.printStackTrace ();} zR/IqW.`9  
} R\y'_S=#a  
RY<%'\A`~  
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//读取保存的下载信息（文件指针位置） `M0YAiG  
private void read_nPos() ( OXY^iq  
{  p[Hr39o  
try{ ~ k<SbFp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6klD22b2$  
int nCount = input.readInt(); AK;^9b-}q:  
nStartPos = new long[nCount]; y]^#$dK(z  
nEndPos = new long[nCount]; 7UDq/:}Fo  
for(int i=0;i<nStartPos.length;i++) L#!$hq9{_  
{ ~j]d
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nStartPos = input.readLong(); jzMg'z/@J  
nEndPos = input.readLong(); `)2[ST  
} oLw|uU-
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input.close(); mw
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} +4HlRGH  
catch(IOException e){e.printStackTrace ();} s>r ^r%uK  
catch(Exception e){e.printStackTrace ();} tUv3jq)n%  
} F9O`HFVK  
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private void processErrorCode(int nErrorCode) %l;*I?0H  
{ 8,y{q9O  
System.err.println("Error Code : " + nErrorCode); m_$JWv\|\  
} K( z[}  
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//停止文件下载 :G0+;[?N  
public void siteStop() fyrd`R  
{ (7L/eDMT  
bStop = true; MX?}?"y  
for(int i=0;i<nStartPos.length;i++) 5QOZ%9E&M  
fileSplitterFetch.splitterStop(); ]!
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#// %&k  
} >>j+LRf*  
} #4N >d~  
//负责部分文件的抓取 p {?}g
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**FileSplitterFetch.java XECikld>  
*/ s6/cL|Ex  
package NetFox; 4]EvT=Ro  
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import java.io.*; g}YToOs  
import java.net.*; bO
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public class FileSplitterFetch extends Thread { *w|iu^G  
P8IRH#ED  
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String sURL; //File URL #w;;D7{@m  
long nStartPos; //File Snippet Start Position ?Nu#]u-  
long nEndPos; //File Snippet End Position NZfd_? 3  
int nThreadID; //Thread's ID 'QR4~`6I  
boolean bDownOver = false; //Downing is over s&0*'^'O[S  
boolean bStop = false; //Stop identical j3LNnZY  
FileAccessI fileAccessI = null; //File Access interface u]0!|Jd0  
zu<>"5}]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @ct#s:t  
{ 2]3G1idB  
this.sURL = sURL; c8q G\\t[  
this.nStartPos = nStart; F'XlJ M  
this.nEndPos = nEnd; "h$D7 mL  
nThreadID = id; xY+A]Up|w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /3s@6Ex}E  
} pJn>oGeJ&  
@BXaA0F4  
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public void run() ?`"<DH~:0B  
{ Bu':2"7  
while(nStartPos < nEndPos && !bStop) TG?fUD V  
{ pj+tjF6Np  
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try{ }^Z<
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URL url = new URL(sURL); T%w(P ^qk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y/H8+0sEk  
httpConnection.setRequestProperty("User-Agent","NetFox"); gsi<S6DQ8  
String sProperty = "bytes="+nStartPos+"-"; [RW,{A  
httpConnection.setRequestProperty("RANGE",sProperty); F=VoFmF@  
Utility.log(sProperty); a0 qj[+  
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- =  
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InputStream input = httpConnection.getInputStream(); sv@}x[L  
//logResponseHead(httpConnection); [|
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byte[] b = new byte[1024]; ]Px:d+wX:  
int nRead; ~O8]3+U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y^3,X_0  
{ |]I#CdO  
nStartPos += fileAccessI.write(b,0,nRead); ,d5ia4\K  
//if(nThreadID == 1) {8_:4`YZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S~}$Ly@  
} X
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t  
{<"[D([  
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Utility.log("Thread " + nThreadID + " is over!"); %bN"bxv^  
bDownOver = true; ga,
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//nPos = fileAccessI.write (b,0,nRead); #i6[4X?  
} ^g\h]RD}  
catch(Exception e){e.printStackTrace ();} -)<JBs>  
} WGluZhRuT3  
} N:5b1TdI,  
U24V55ZnI  
V.+DP  
//打印回应的头信息 omr:C8T>  
public void logResponseHead(HttpURLConnection con) -B",&yTV  
{ XPrY`,kN  
for(int i=1;;i++) Fv<]mu  
{ *%;6P5n%  
String header=con.getHeaderFieldKey(i); H#_}^cGPR=  
if(header!=null) G6f%/m`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j^:b-:F  
Utility.log(header+" : "+con.getHeaderField(header)); A-}PpH~.Z  
else bl6':m+  
break; UqY J#&MqY  
} zR_9D}  
} ^o,y5,  
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public void splitterStop() I):m6y@  
{ _$~ex ~v  
bStop = true; 34HFrMi  
} X}kVBT1w+x  
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} `Nc`xO?  
9*"[pt+tA  
W5M ]  
/* XT\Td}>  
**FileAccess.java 'cWlY3%t  
*//文件访问(定位，写)   eYPt  
package NetFox; /2=_B4E2  
import java.io.*; f'8B[&@L  
i+kFL$N  
o<9yaQ;  
public class FileAccessI implements Serializable{ }//8$Z<(  
94S .9A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !]n{l_5r  
RandomAccessFile oSavedFile; uMljH@xBc  
long nPos; 2y&_Z^kI?  
;F" kD  
}?\#_BCjx(  
public FileAccessI() throws IOException fq)Ohb  
{ mg/C Ux  
this("",0); \k2C 5f  
} Nn~tb2\vk  
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&6=TtTp"9  
public FileAccessI(String sName,long nPos) throws IOException ^R&_}bp  
{ <T4 7kLI  
oSavedFile = new RandomAccessFile(sName,"rw"); 1mvu3}ewx  
this.nPos = nPos; w-{#6/<kI5  
oSavedFile.seek(nPos); /@xr[=L  
} hnM9-hqm  
TPN:cA6[c  
&VtWSq-)  
public synchronized int write(byte[] b,int nStart,int nLen) !07FsPI#{  
{ xF\}.OfWG  
int n = -1;  Ep#<$6>  
try{ p0%6@_FT~  
oSavedFile.write(b,nStart,nLen); zM3H@;}m  
n = nLen; ;@h'Mb  
} 98"z0nI%  
catch(IOException e) sYW1T @  
{ 3"2<T^H]  
e.printStackTrace (); n]kQ
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} fS8XuT  
_ d(Ks9  
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return n; i75?*ld  
} `"^@[1  
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} *IjdN,wox  
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Cz$Hk;3\6  
/* jSOa   
**SiteInfoBean.java q_%w l5\F  
*/ 4q@9  
package NetFox; Z]1z*dv  
A1=$kzw{UH  
[xp~@5r'  
public class SiteInfoBean { <*b]JY V@  
iPtm@f,bI  
 CU7iva  
private String sSiteURL; //Site's URL j|VlHDqR  
private String sFilePath; //Saved File's Path eX]9mQ]E  
private String sFileName; //Saved File's Name ,&O:/|c E  
private int nSplitter; //Count of Splited Downloading File T^-H_|/M  
,i$(yx?  
)KT
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public SiteInfoBean() i85+p2i7  
{//nSplitter的缺省值为5 hz>yv@1  
//default value of nSplitter is 5 Rzn0-cG  
this("","","",5); 8gu7f;H/k  
} 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xbsj:Ko]]U  
{ A<*tn?M
]  
sSiteURL= sURL; tZc.%TU  
sFilePath = sPath; =":V WHf  
sFileName = sName; =."WvBKg  
this.nSplitter = nSpiltter; iu:p&h  
`)gkkZ$)j  
'8kL1  
} 5D02%U2N)G  
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bW 79<T'+  
public String getSSiteURL() ko7-%+0|]  
{ j)lM:vXR  
return sSiteURL; MlcoOi!  
} @Tm0T7C  
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-$!Pf$l@  
public void setSSiteURL(String value) v'
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{ Kw5+4R(5  
sSiteURL = value; bju,p"J1-E  
} "351s3ff  
]aMa*fF  
~]t2?SqNm  
public String getSFilePath() yI)RGOV  
{ `- uZv  
return sFilePath; (^@;`8Dy8  
} uBL~AC3>O  
xr7<(:d  

:O@,Z_"  
public void setSFilePath(String value)
uzn))/"  
{ >=q!!'$:  
sFilePath = value; W~@GK  
} %_X[{(  
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MdTd$ 4J3  
public String getSFileName() fN? Lz%z3  
{ v.8S V
]  
return sFileName; ]\b1~ki!F  
} Pt)}HF|u  
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[ QL<&:s&  
public void setSFileName(String value) cE8 _keR~  
{ H
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sFileName = value; d-S'y-V?d  
} '' A[`,3  
1J%qbh  
:R?| 2l  
public int getNSplitter() @BQBNGR1  
{
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return nSplitter; `LHfAXKN  
} 4sD:J-c  
I`}vdX)  
EA{*%9 A  
public void setNSplitter(int nCount) h,jAtL!  
{ q-)_Qco  
nSplitter = nCount; (R 2P<
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} R"kE5:  
} Chi<)P$^  
1Qe!  
l?<z1Acd&  
/* ke6cZV5w  
**Utility.java hy`)]>9z~  
*/ (9q{J(44  
package NetFox; N %/DN  
V$F.`O!hfi  
*gpD4c7A\  
public class Utility { !5 :[XvI#  
5qB=@O]|G;  
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public Utility() YbBH6RZr  
{ \ rWgA  
9PfU'm|
h  
1kw4'#J8  
} %IXW|mi  
%L|bF"K5;  
//线程睡眠 WMl^XZO  
public static void sleep(int nSecond) /Gv$1t^a  
{ HnY"6gTNK  
try{ ^3s&90  
Thread.sleep(nSecond); `Q^Sm`R  
} KIl.?_61O  
catch(Exception e) m-FDCiN>  
{ &B,& *Lp  
e.printStackTrace (); .E8p-R5)V>  
} EuA<{%i  
} 7?WBzo!!L  
w=>mG-  
//日志 +rO<'H:umJ  
public static void log(String sMsg) 4'[ V'c\  
{ cZT.vA#  
System.err.println(sMsg); oi4Wxcj  
} 3NZFW{u  
4'b]2Mn3   
0BD((oNg  
public static void log(int sMsg) &+iW:  
{ D)Rf  
System.err.println(sMsg); To? bp4  
} a-2 {x2O  
} zW`koRH@  
U+M?<4J)"  
cyeDZ)  
/* :Aiu!}\  
**TestMethod.java p+D6Z'B  
*/ sBI%lrO  
package NetFox; !T(Omve)  
"(VcYQ+  
=}lA|S  
public class TestMethod { ;7*@Gf}R  
M:f=JuAx  
C2i..iD  
public TestMethod() ~y^lNgujO  
{ ///xx/weblogic60b2_win.exe s""8V_,;  
try{ R*C+Yk)Tkt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dx)XC?'xO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fsuvg jlE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m6<0 hP  
fileFetch.start(); ZU'^%)6~o~  
} WfO$q^'?DP  
catch(Exception e){e.printStackTrace ();} >iJuR.:OO  
=@  
Yk&{VXU<  
} ,^C;1ph  
RyD$4jk+T"  
uelTsn  
public static void main(String[] args) 1e} 3L2rC  
{ y@JYkp>I  
new TestMethod(); 2oASz|  
} ;mlIWn  
} h!GixN?  
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