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http断点续传简单实现(java)

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/* c/zJv*}x ?  
**SiteFileFetch.java 'f[T&o&L/  
*/ &$]v h  
package NetFox; zRq-b`<7V  
import java.io.*; 30XR 82P/  
import java.net.*; sA'6ty  
--HF8_8;'  
%1O;fQL  
public class SiteFileFetch extends Thread { p$h4u_  
_h X]%  
!X"K=zt"  
SiteInfoBean siteInfoBean = null; //文件信息Bean <(-3_s6-  
long[] nStartPos; //开始位置 !OA]s%u  
long[] nEndPos; //结束位置 }&n<uUDH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BB~OqZIP  
long nFileLength; //文件长度 "Jt.lL ]5  
boolean bFirst = true; //是否第一次取文件 4zJtOK?r"  
boolean bStop = false; //停止标志 f2^r[kPX"  
File tmpFile; //文件下载的临时信息 wtc!>  
DataOutputStream output; //输出到文件的输出流 r9 ui|>U"  
v=_6XF  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *Txl+zTY  
public SiteFileFetch(SiteInfoBean bean) throws IOException !eEHmRgg4  
{ #bl6sa{E  
siteInfoBean = bean; 5Cq{XcXV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ix(=3 /Dgz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x9;gT&@H  
if(tmpFile.exists ()) EGZb7:Y?  
{ O9EKRt  
bFirst = false; fcNL$U&-,i  
read_nPos(); .2>p3|F  
} XVKfl3'%  
else 5]HS^II"  
{ s<oNE)xe  
nStartPos = new long[bean.getNSplitter()]; r:F  
nEndPos = new long[bean.getNSplitter()]; "Qja1TQ  
} Q\cjPc0y  
~.UrL(l=  
4eikLRD,  
0%m)@ukb  
} $% 1vW=d  
<Wp QbQM  
vgUb{D  
public void run() 5m9*85Ib  
{ {@tv>!WW  
//获得文件长度 )yTm.F  
//分割文件 QNA RkYY~|  
//实例FileSplitterFetch iMs5zf <M  
//启动FileSplitterFetch线程 HYD"#m'TkB  
//等待子线程返回 >B2:kY F  
try{ W Dg+J  
if(bFirst) 9(6I<]#  
{ >2,Gy-&"0  
nFileLength = getFileSize(); }; f#^gz'  
if(nFileLength == -1) 2I&o69x?  
{ >y[oP!-|P  
System.err.println("File Length is not known!");  ^}:#  
} 3'^k$;^  
else if(nFileLength == -2) 6xZ=^;H  
{ tQ H+)*  
System.err.println("File is not access!"); %*&UJpbA  
} 2Z3('?\z~  
else U2`'qsR1  
{ iVG-_RsKK  
for(int i=0;i<nStartPos.length;i++) ^my].Qpt  
{ P#fM:z@[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qUxRM_7U  
} | fSe>uVZ  
for(int i=0;i<nEndPos.length-1;i++) U7I qST  
{ Kt"BE j  
nEndPos = nStartPos[i+1]; k'#(1(xj  
} Nkp)Ax&  
nEndPos[nEndPos.length-1] = nFileLength; 6S+U&Ce\  
} " t7M3i_  
} LxpuhvIO  
xA9:*>+>  
VY)9|JJCO  
//启动子线程 z}{afEb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #{=;NuP  
for(int i=0;i<nStartPos.length;i++) 5g9; +}X;  
{ DSt]{fl`P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nzmDA6d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !OT-b>*w  
nStartPos,nEndPos,i); :dLAs@z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cIp D~0\  
fileSplitterFetch.start(); /r-aPJX  
} * 1Od-3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uPRQU+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ay !G1;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @DZB9DDR  
nEndPos = " + nFileLength); CT1ja.\;  
// fileSplitterFetch[nPos.length-1].start(); 2AtLyN'.  
(ZY@$''  
V^\8BVw  
//等待子线程结束 j%y$_9a7  
//int count = 0; 6$ Gep  
//是否结束while循环 }J7zTj~{  
boolean breakWhile = false; <x&%~6j  
Tp0bS  
.N*Pl(<[  
while(!bStop) VMCLHpSfW  
{ Gkp< o  
write_nPos(); $2u 'N:o  
Utility.sleep(500); WdnIp!  
breakWhile = true; :"l-KQ0  
%zSuK8kxV  
fwBRWr9  
for(int i=0;i<nStartPos.length;i++) .VkbYK  
{ Dgx8\~(E'  
if(!fileSplitterFetch.bDownOver) J]q%gcM  
{ 1*dRK6  
breakWhile = false; 7{xh8#m  
break; k<cgO[m   
} l2&`J_"  
} # hlCs  
if(breakWhile) ^k Cn*&  
break; |QMhMGjV  
V=lfl1Ev0J  
*b xzCI7b  
//count++; l983vKr  
//if(count>4) %/>Y/!;  
// siteStop(); IXb}AxB f  
} =&},;VOh  
}=|!:kiE  
qY >{cjo  
System.err.println("文件下载结束!"); ?_v{| YI=  
} EZYBeqv  
catch(Exception e){e.printStackTrace ();} 8o/}}=m$  
} 5r?m&28X  
NuYkz"O]  
]XTu+T.aT  
//获得文件长度 Z( 9 u<  
public long getFileSize() 8HZs>l  
{ lhi_6&&[8  
int nFileLength = -1; ;r6jx"i  
try{ t w(JZDc  
URL url = new URL(siteInfoBean.getSSiteURL()); 9{$'S 4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HFqm6|  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4<x'ocKlD  
/'hCi]b@v  
W,K%c=  
int responseCode=httpConnection.getResponseCode(); (?H0+zws^  
if(responseCode>=400) & u!\<\  
{ YOrrkbJ(  
processErrorCode(responseCode); NBF MN%  
return -2; //-2 represent access is error de]zT^&C  
} ,&d@O>$E:  
t!2(7=P30(  
Vf`7V$sr  
String sHeader; Iu{kPyx  
XTd3|Pm  
I"1;|`L~:  
for(int i=1;;i++) c5Q<$86  
{ &|aqP \Q5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i[ $0a4  
//Utility.log(in.readLine()); >5wx+n)/)  
sHeader=httpConnection.getHeaderFieldKey(i); DaH?@Q  
if(sHeader!=null) gZEi]/8_  
{ 5"/J^"!h  
if(sHeader.equals("Content-Length")) Lgz$]Jbl8  
{ 2jbIW*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $46{<4.  
break; -!)xQvagD.  
} !I\!;b  
} &h~Xq^  
else k6kM'e3V  
break; \3Q&~j  
} h!#:$|Q  
} Sggq3l$Qc  
catch(IOException e){e.printStackTrace ();} 0oh]61g C  
catch(Exception e){e.printStackTrace ();} E0/mSm"(T  
Z--@.IYoJ  
#UtFD^h  
Utility.log(nFileLength); `y+-H|%?  
WO6/X/#8b  
$HG}[XD?  
return nFileLength; fA=#Fzk2  
} n$aA)"A #  
'&99?s`u  
xcJ `1*1N  
//保存下载信息(文件指针位置) 5*\\J&H  
private void write_nPos() kSc{^-<R  
{ ^ZM0c>ev=l  
try{ 2S8P}$mM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); P"lBB8\eku  
output.writeInt(nStartPos.length); ;Efcw[<  
for(int i=0;i<nStartPos.length;i++) F3oQ^;xB  
{ +f0~D(d!_  
// output.writeLong(nPos); hfcIvs/!  
output.writeLong(fileSplitterFetch.nStartPos); lc6i KFyG  
output.writeLong(fileSplitterFetch.nEndPos); -B$~`2-  
} u4"SH(  
output.close(); E`j-6:  
} i-U4RZE  
catch(IOException e){e.printStackTrace ();} za'6Y*CGgX  
catch(Exception e){e.printStackTrace ();} 1 ^g t1o  
} |+U<S~  
f(D_FTTO  
]MtFf6&  
//读取保存的下载信息(文件指针位置) gq"k<C0  
private void read_nPos() iU+nqY'  
{ h7X_S4p/Mg  
try{ 1ZJQs6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N 4K8 u'f^  
int nCount = input.readInt(); XCsiEKZ_i  
nStartPos = new long[nCount]; ^Cv^yTj;&  
nEndPos = new long[nCount]; ]l~V&#i_c  
for(int i=0;i<nStartPos.length;i++) O8U<{jgAG  
{ !TAp+b  
nStartPos = input.readLong(); as+GbstN  
nEndPos = input.readLong(); $3X-r jQtW  
} /Jf~25F  
input.close(); ,&HR(jTo  
} OOBhbpg!D  
catch(IOException e){e.printStackTrace ();} Zc"B0_&?:7  
catch(Exception e){e.printStackTrace ();} >%Ee#m  
} >\<*4J$PZ  
}]UB;id'  
L?Yoh<  
private void processErrorCode(int nErrorCode) N:VX!w  
{ W YW|P2*  
System.err.println("Error Code : " + nErrorCode); o$.e^XL  
} r,(e t  
nsb4S {  
~e@>zoM'^  
//停止文件下载 @OV-KT[>  
public void siteStop() zVv04_:  
{ jy2IZ o  
bStop = true; .7ayQp  
for(int i=0;i<nStartPos.length;i++) Fk=}iB#(  
fileSplitterFetch.splitterStop(); Hqz?E@bc@  
Wk4.%tpeO7  
r C[6lIP  
} B6}FIg)  
} Dbx~n#nG  
//负责部分文件的抓取 $!A:5jech  
**FileSplitterFetch.java f]8I64  
*/ ]J2:194  
package NetFox; rAdacnZV  
Gi^Ha=?J%  
.wrL3z_  
import java.io.*; n uQM^2  
import java.net.*; :Zw @yt  
!SHj$Jwa'  
7@%'wy&A  
public class FileSplitterFetch extends Thread { _L.n,  
% 0:p)Z0  
vOI[Z0Lq9h  
String sURL; //File URL -m 5}#P89  
long nStartPos; //File Snippet Start Position *B)yy[8j+  
long nEndPos; //File Snippet End Position io4A>>W==/  
int nThreadID; //Thread's ID tZWrz e^  
boolean bDownOver = false; //Downing is over M] V.!z9B  
boolean bStop = false; //Stop identical Ix DWJ#k  
FileAccessI fileAccessI = null; //File Access interface zGcqzYbuA  
]"fsW 9s  
&B{8uge1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |-2}j2'  
{ IF k  
this.sURL = sURL; t@bt6J .{  
this.nStartPos = nStart; `BZ&~vJ_  
this.nEndPos = nEnd; |I[7,`C~  
nThreadID = id; '3l$al:H^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3mt%!}S  
} 6\d X  
Md; /nJO~{  
T9y;OG  
public void run() ZX`J8lZP  
{ M"^K 0 .  
while(nStartPos < nEndPos && !bStop) u>T76,8|\  
{ QYE7p\  
WN a0,  
U Lmg$T&  
try{ U!q[e`B  
URL url = new URL(sURL); NSLVD[yT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iT )WR90  
httpConnection.setRequestProperty("User-Agent","NetFox"); q(z7~:+qNr  
String sProperty = "bytes="+nStartPos+"-"; eTE2J~\  
httpConnection.setRequestProperty("RANGE",sProperty); Z&yaSB  
Utility.log(sProperty); ,WTTJN  
2C+(":=}  
OjnJV  
InputStream input = httpConnection.getInputStream(); T>]sQPg  
//logResponseHead(httpConnection); t)1phg4H)  
nZvU 'k:  
f_r0})  
byte[] b = new byte[1024]; u"VS* hSH  
int nRead; K!8zwb=fq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?p8Qx\%*  
{ Ns~&sE:  
nStartPos += fileAccessI.write(b,0,nRead); 1IA5.@G:  
//if(nThreadID == 1) &,W$-[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KHj6Tg;)  
} 6!7Pm>ml  
+$beo2x6  
[ F([  
Utility.log("Thread " + nThreadID + " is over!"); ^o<[. )  
bDownOver = true; s^|\9%WD  
//nPos = fileAccessI.write (b,0,nRead); 99ASIC!  
} w^VSj%XH!  
catch(Exception e){e.printStackTrace ();} whkJpK(  
} L=1 ~ f-  
} 0'ZYO.y  
mc@M,2@D  
{K.rl%_|N  
//打印回应的头信息 {gkwOMW  
public void logResponseHead(HttpURLConnection con) 2)LX^?7R  
{ /(6zsq'v|  
for(int i=1;;i++) }ymvC  
{ nmE5]Pcg  
String header=con.getHeaderFieldKey(i); 0^<,(]!  
if(header!=null) ,w\ wQn>]K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %O) Z  
Utility.log(header+" : "+con.getHeaderField(header)); af>3V(7  
else #vnT&FN0[  
break; {OxWcK\2@h  
} ^e9aD9  
} :0Te4UE;P7  
Ee?;i<u  
(:}<xxl  
public void splitterStop() zHFTCL>"  
{ Wvr+y!F  
bStop = true; $pu3Ig$^  
} 4]BJ0+|mT  
 nP_=GI  
x0x $  9  
} kEAhTh&g*  
zA{8C];~  
3q~Fl=|.o  
/* @InJ_9E  
**FileAccess.java KS! iL=i  
*//文件访问(定位,写) (|0b7 |'T  
package NetFox; r@$B'CsLj  
import java.io.*; 6&],WGz  
46ChMTt  
.~<]HAwq  
public class FileAccessI implements Serializable{ )fCMITq.|  
f'_ S1\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \!PV*%P  
RandomAccessFile oSavedFile; Jr?!Mh-  
long nPos; t,Q'S`eTU  
V4?Oc2mS  
hZF(/4Z2  
public FileAccessI() throws IOException ,kE=TR.|  
{ Tf l;7w.(A  
this("",0); 7|~:P $M  
} 3/tJDb5  
q!2<=:f  
;Uk!jQh  
public FileAccessI(String sName,long nPos) throws IOException u%aFb*  
{ M71R -B`-  
oSavedFile = new RandomAccessFile(sName,"rw"); (HSw%e  
this.nPos = nPos; $[Q cEk  
oSavedFile.seek(nPos); @U7Dunu*f  
} 51/sTx<Z}  
Vj7Hgc-,  
nt`<y0ta  
public synchronized int write(byte[] b,int nStart,int nLen) |8;? *s`H  
{ i@{*O@m  
int n = -1; 8_awMVAy  
try{ ~h|m&XK+Q  
oSavedFile.write(b,nStart,nLen); |$Xf;N37t  
n = nLen; XW:%vJu^`  
} &fHc"-U}  
catch(IOException e) \)GR\~z0h  
{ @YNGxg~*g  
e.printStackTrace (); #fzw WP  
} 7<4xtK`+b  
[iXi\Ex  
/fC\K_<N  
return n; MBv/  
} LH.%\TMN$  
4]u,x`6C  
w=$'Lt!  
} JP_kQ  
q-uLA&4  
#-dK0<:  
/* NCxn^$/+>9  
**SiteInfoBean.java 500> CBL0O  
*/ @:IL/o*  
package NetFox; |Ib.)  
Y`=z.D{  
1!s!wQgS  
public class SiteInfoBean { &$Ci}{{n#  
-PXoMZx%  
7A[Ogro  
private String sSiteURL; //Site's URL jRwa0Px(  
private String sFilePath; //Saved File's Path Wa{%0inZ  
private String sFileName; //Saved File's Name hJ4S3b  
private int nSplitter; //Count of Splited Downloading File r?]%d!   
#O><A&FrF`  
s%bUgO%&  
public SiteInfoBean() ~RCg.&[ou  
{//nSplitter的缺省值为5 M0 L-u  
//default value of nSplitter is 5 7>KQRLw  
this("","","",5); `M6YblnJZ  
} k)Zn>  
2gH _$  
AW62~*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mMslWe  
{ fxOE]d8v  
sSiteURL= sURL; lnjL7x  
sFilePath = sPath; `L;OY 4  
sFileName = sName; Bjtj{B  
this.nSplitter = nSpiltter; CJ:uYXJJ:z  
/xF 9:r  
6VGo>b;  
} fvO;lA>`  
BZ}`4W'  
z=[l.Af_  
public String getSSiteURL() Slo9#26  
{ |C|:i@c H  
return sSiteURL; a /QIJ*0  
} `{%-*f^  
h2AGEg'g2[  
V3 qT<}y|  
public void setSSiteURL(String value) >Rr!rtc'x  
{ *qbRP"#[$  
sSiteURL = value; ^b:Xo"q#H  
} y3Y2 QC(  
)'=V!H#U*  
_J` |<}?t;  
public String getSFilePath() > Z]P]e  
{ #*+;B93 )  
return sFilePath; gfx oJihE  
} ]u~Os<   
l,^xX =,  
pAMo XJ`  
public void setSFilePath(String value) >2nF"?"=  
{ 7Onk!NH  
sFilePath = value; 3V"dG1?  
} q$3HvZP  
kGruo5A  
CJ0$;et  
public String getSFileName() nhp)yW  
{ x Ridc^  
return sFileName; %;'~%\|dZM  
} B%)zGTp6  
QZ#3Bn%B5  
:l4^iSf  
public void setSFileName(String value) ysL0hwir  
{ j-j'phK  
sFileName = value; RFhU#  
} gYRqqV  
MPqY?KF  
m9%yR"g9  
public int getNSplitter()  {`tHJ|8  
{ 4$ ..r4@  
return nSplitter; w4NZt|>5j;  
} |&9tU  
l.sm~/  
]~$c~*0g  
public void setNSplitter(int nCount) gv`%Z8u(  
{ ]aREQ?ma&z  
nSplitter = nCount; *X%?3"WH8  
} sV]i/B  
} @wg&6uQ  
/DK*y S  
zUe#Wp[  
/* rve7YS'  
**Utility.java jM{qRfOrg  
*/ \MfR #k0  
package NetFox; |:~("rA+v  
*QMF <ze  
Ma% E&.ed  
public class Utility { 22l|!B%o  
2=i+L z^  
jn0t-":  
public Utility() u!hqq^1  
{ Bidqf7v  
6(\q< fx  
q] 2}UuM|U  
} "K9vm^xP  
UDhwnGTq(l  
//线程睡眠 _HSTiJVr  
public static void sleep(int nSecond) 8h55$j  
{ y.L|rRe@P  
try{ Wh#os,U$  
Thread.sleep(nSecond); jI@bTS o  
} U/}AiCdj@  
catch(Exception e) P c/.*kOT  
{ cP/F| uG5  
e.printStackTrace (); MBnK&GS  
} .%-6&%1  
} Tb>IHoil  
8:;u v7p  
//日志 k#{lt-a/  
public static void log(String sMsg) 3(oZZz  
{ I8E\'`:<  
System.err.println(sMsg);  f'7 d4  
} .Y=Z!Q  
K8e4ax  
]L5Z=.z&  
public static void log(int sMsg) SQz$kIZR  
{ g?k#wj1uH  
System.err.println(sMsg); yt]Oj*nn0K  
} Fm-q=3  
} &!3VqHQ`  
`kaR@t  
a!s.850@  
/* ymzPJ??!  
**TestMethod.java <z~2d  
*/ HYa$EE2  
package NetFox; hlABu)B'1  
_47j9m]f  
r"Hbr Qn  
public class TestMethod { X^?|Sz<^E  
7]<F>97  
vV$hGS(f~  
public TestMethod() p*(U*8Q  
{ ///xx/weblogic60b2_win.exe M ,.0[+  
try{ )'/nS$\E:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j\jL[hG_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); x mrugNRg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); WrIL]kJw^  
fileFetch.start(); 6Zl.Lh  
} 8AC. 2 v?_  
catch(Exception e){e.printStackTrace ();} %_%f# S  
KoxGxHz^Y3  
{ ="Su{i}}  
} ebl)6C  
q.u[g0h;  
YU ]G5\UU  
public static void main(String[] args) UIm[DYMS  
{ (}/.4xE  
new TestMethod(); R-2FNl  
} ,YAPCj  
} d~P<M3#>  
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