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http断点续传简单实现(java)

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/* #x%O0  
**SiteFileFetch.java ,bH  
*/ 2G'G45Q  
package NetFox; T+.wJ W:jh  
import java.io.*; u YH{4%  
import java.net.*; "?S#vUS+ 2  
2qn~A0r  
&=7ur  
public class SiteFileFetch extends Thread { xHL{3^  
BM3)`40[]  
NKI&n]EO  
SiteInfoBean siteInfoBean = null; //文件信息Bean `zsKc 6%  
long[] nStartPos; //开始位置 !.w S+  
long[] nEndPos; //结束位置 ~I^]O \?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 74[}AA  
long nFileLength; //文件长度 Ic r'l$PE  
boolean bFirst = true; //是否第一次取文件 ` 86b  
boolean bStop = false; //停止标志 {< wq}~  
File tmpFile; //文件下载的临时信息 $8eq&_gJ  
DataOutputStream output; //输出到文件的输出流 i$NnHj|  
#pVk%5N  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *yX_dgC>[  
public SiteFileFetch(SiteInfoBean bean) throws IOException k~hL8ZT[  
{ ( Rf)&KN  
siteInfoBean = bean; +V7p?iEY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~O|0.)71]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #/1Bam6  
if(tmpFile.exists ()) <T&$1m{  
{ AzQ}}A;TSx  
bFirst = false; WW_X:N~~e\  
read_nPos(); d6n6= [*  
} ;x7SY;0*  
else |zUDu\MZ{  
{ +?L~fM69B  
nStartPos = new long[bean.getNSplitter()]; oJR!0nQ  
nEndPos = new long[bean.getNSplitter()]; EgO4:8$h  
} hQ\]vp7V  
G.N3R  
" DFg"  
dy0!Zz  
} ew0 )  
ov+qYBuFw  
|On6?5((e  
public void run() yZ  P+  
{ nDo|^{!L`  
//获得文件长度 -WYJ1B0v  
//分割文件 :V"}"{ (6  
//实例FileSplitterFetch 'nLv0.7*  
//启动FileSplitterFetch线程 N; hq  
//等待子线程返回 kP6r=HH@  
try{ t3WlVUtq3  
if(bFirst) {.2C>p  
{ 4EELaP|%  
nFileLength = getFileSize(); PNG'"7O  
if(nFileLength == -1) K0v,d~+]  
{ X >**M  
System.err.println("File Length is not known!"); J'7Oxjlg  
} .xD-eWw3R  
else if(nFileLength == -2) jgYiuM3c\  
{ RHBEC@d[}  
System.err.println("File is not access!"); ewLr+8  
} w9oiu$7),  
else Gmwn:  
{ J2R<'(  
for(int i=0;i<nStartPos.length;i++) OW.ckYt%  
{ 2#&K3v  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jv7zvp  
} &@Q3CCDS  
for(int i=0;i<nEndPos.length-1;i++) 9UwDa`^  
{ I;`V*/s8"  
nEndPos = nStartPos[i+1]; j4l7Tx  
} |fA[s7)  
nEndPos[nEndPos.length-1] = nFileLength; g &za/F  
} *= D$  
} x?%vqg^r  
!1l2KW<be  
<ya3|ycnS  
//启动子线程 ]juXm1)>W1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mkWIJH  
for(int i=0;i<nStartPos.length;i++) YF"D;.  
{ z XvWo6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '[HFIJ0K!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a@7we=!  
nStartPos,nEndPos,i); XJlun l)(K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w7 QIKsI0  
fileSplitterFetch.start(); `KL`^UqR  
} }:BF3cH> 0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1S=I(n?E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +<iw|vr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %0]&o, w{  
nEndPos = " + nFileLength); YF;8il{p  
// fileSplitterFetch[nPos.length-1].start(); H"-p^liw  
_W!g'HP-D  
XGUF9arN  
//等待子线程结束 1xx-}AIH#  
//int count = 0; 1{,WY(,c  
//是否结束while循环 MAR;k?d  
boolean breakWhile = false; e8[ *=&  
Og,,s{\  
KavRW.w  
while(!bStop) [A3hrSw  
{ -aO3/Ik [q  
write_nPos(); $;@s  
Utility.sleep(500); @^P=jXi<  
breakWhile = true; lP@9%L  
xLGAP-mx]  
fkx 9I m4  
for(int i=0;i<nStartPos.length;i++) 8n'C@#{WV  
{ 6IvLr+I  
if(!fileSplitterFetch.bDownOver) d8x$NW-s  
{ aMHIOA%Kh  
breakWhile = false; :H?p^d e  
break; v5*SoUOF  
} %;zA_Wg  
} MjLyB^ M  
if(breakWhile) [szwPNQ_  
break; xR%CS`0R  
#cApk  
;/YSQt)rc>  
//count++; i=SX_#b^  
//if(count>4) HDC`g  
// siteStop(); ;id  
} >`lf1x  
M r@M~ -  
8HWY]:| oh  
System.err.println("文件下载结束!"); "#p)Z{v"!  
} {)Gh~~57_W  
catch(Exception e){e.printStackTrace ();} *rqih_j0  
} RJg# A`  
$y`|zK|G-  
{UwJg  
//获得文件长度 +]AE}UXZoh  
public long getFileSize() '9b<r7\@  
{ n ,H;PB  
int nFileLength = -1; x-q er-  
try{ I]} MK?  
URL url = new URL(siteInfoBean.getSSiteURL()); Q}1PPi,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VNMhtwmK,  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?X eRL<n  
mDo]5 i<  
5[I 9/4,  
int responseCode=httpConnection.getResponseCode(); 8^HMK$  
if(responseCode>=400) VGe/;&1h  
{ lv{Qn~\y&  
processErrorCode(responseCode); kWr*+3Xq  
return -2; //-2 represent access is error fPspJug  
} LtC kDnXk  
_tYt<oB~%  
Gd"lB*^Ht  
String sHeader; O/Da8#S<  
R*QL6t  
%Uuhi&PA-l  
for(int i=1;;i++) lMlXK4-  
{ U-|g tND  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =`{!" 6a  
//Utility.log(in.readLine()); Prr<:q  
sHeader=httpConnection.getHeaderFieldKey(i); R` /n sou  
if(sHeader!=null) & {B,m%G  
{ XD*$$`+#  
if(sHeader.equals("Content-Length")) 2< ^B]N  
{ b$VdTpz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DGp'Xx_8  
break; iT I W;Cv  
} 0Wk}d(f  
} z07!i@ue~  
else 9t;aJFI  
break; |QXW$  
} '9i:b]Hru  
} UD"e:O_  
catch(IOException e){e.printStackTrace ();} Px)VDs=k  
catch(Exception e){e.printStackTrace ();} [7L1y) I(  
#B>Hq~ vrC  
 c~dX8+  
Utility.log(nFileLength); .lRO; D  
T w/CJg  
U<o,`y[Tn  
return nFileLength; t?{E_70W  
} AnIENJ  
d(R3![:  
H@OYtPHGR  
//保存下载信息(文件指针位置) KXYq|w  
private void write_nPos() dZv-lMYBE  
{ 1\_4# @')  
try{ <gJ|Wee  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5GC{)#4  
output.writeInt(nStartPos.length); ]Kil/Y  
for(int i=0;i<nStartPos.length;i++) >|H=25N>;  
{ yS lN|8d  
// output.writeLong(nPos); C{+~x@  
output.writeLong(fileSplitterFetch.nStartPos); Vk8:;Hj  
output.writeLong(fileSplitterFetch.nEndPos); Rl<~:,D  
} 9 /q4]%`  
output.close(); ;V`~'357%  
} \tU91 VIj  
catch(IOException e){e.printStackTrace ();} :6Bk<  
catch(Exception e){e.printStackTrace ();} eH79,!=2  
} .2Gn)dZU  
c tTbvXP  
a&4>xZU #  
//读取保存的下载信息(文件指针位置) aCy2 .Qn  
private void read_nPos() O*!+D-  
{ 3E:wyf)i"  
try{ T3+hxS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I6h{S}2  
int nCount = input.readInt(); M HlP)'  
nStartPos = new long[nCount]; c :hOQZ  
nEndPos = new long[nCount]; )vhHlZ *+  
for(int i=0;i<nStartPos.length;i++) 3mpEF<z  
{ OZ$u&>916  
nStartPos = input.readLong(); \O72PC+  
nEndPos = input.readLong(); Kx$?IxZ  
} ]p@7[8}  
input.close(); cfa#a!Y4  
} F(}d|z@@  
catch(IOException e){e.printStackTrace ();} `N ;!=7y7Y  
catch(Exception e){e.printStackTrace ();} [m!$01=  
} Z'PL?;&+R  
Vad(PS0  
jHTaG%oh  
private void processErrorCode(int nErrorCode) 86.!s Q8b  
{ Q/-YLf.  
System.err.println("Error Code : " + nErrorCode); q1`uS^3`  
} Xq+7l5LP  
'xvV;bi  
Ui'~d(F  
//停止文件下载 dV.)+X7<  
public void siteStop() 1K4LEg a`  
{  H[fD >  
bStop = true; j+PW9>Uh  
for(int i=0;i<nStartPos.length;i++) NS mo(c >5  
fileSplitterFetch.splitterStop(); L&q~5 9  
mWta B>f  
}0}J  
} y/4 4((O  
} W;OxH"eC  
//负责部分文件的抓取 &h8+ -  
**FileSplitterFetch.java .@/5Ln  
*/ :G$NQ* (z  
package NetFox; IeZ}`$[H  
X7Cou6r  
z| i$eF;x3  
import java.io.*; f+1)Ju~  
import java.net.*; daY^{u3  
4,wdIdSm4  
ukzXQe;l1  
public class FileSplitterFetch extends Thread { u.1u/o1"  
/p?h@6h@y  
64h r| v  
String sURL; //File URL &.K=,+0_R/  
long nStartPos; //File Snippet Start Position b;Q cBGwKT  
long nEndPos; //File Snippet End Position #oJ9BgDry  
int nThreadID; //Thread's ID \Vr(P>  
boolean bDownOver = false; //Downing is over J:5%ff~r\  
boolean bStop = false; //Stop identical }NiJDs  
FileAccessI fileAccessI = null; //File Access interface JY_+p9KfyQ  
ATPc ~f  
5 S7\m5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gj$gqO`B  
{ ]C}z3hhk  
this.sURL = sURL; @1^iWM j  
this.nStartPos = nStart; &&Vz=6N  
this.nEndPos = nEnd; ){L`hQ*=w  
nThreadID = id; LtXFGPQf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^mkplp a  
} {*yhiE,  
rR^VW^|f  
$ [M8G   
public void run() m80QMosp  
{ .ie\3q)  
while(nStartPos < nEndPos && !bStop) tg7%@SI5^-  
{ A)/_:  
3K_J"B*7  
,4)zn6tC  
try{ Ip|~j} }  
URL url = new URL(sURL); l)4KX{Rz{A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }BzV<8F  
httpConnection.setRequestProperty("User-Agent","NetFox"); :-69,e  
String sProperty = "bytes="+nStartPos+"-"; s1?N&t8c  
httpConnection.setRequestProperty("RANGE",sProperty); Zb^0EbV  
Utility.log(sProperty); VNp[J'a>VZ  
|Q@4F&k  
'[I?G6  
InputStream input = httpConnection.getInputStream(); Gh>Rt=Qu%  
//logResponseHead(httpConnection); UQ}[2x(Kb  
J)"2^?!&B  
x32hO;  
byte[] b = new byte[1024]; qm{(.b^  
int nRead; to|O]h2*U2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [?Cv^t${+  
{ v1oq[+  
nStartPos += fileAccessI.write(b,0,nRead); !NuiVC]  
//if(nThreadID == 1) xVf AlN37(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @/9#Z4&d0  
} P\pHos  
$^?Mip  
*%=BcV+,  
Utility.log("Thread " + nThreadID + " is over!"); g=XvqD<  
bDownOver = true; +vIpt{733  
//nPos = fileAccessI.write (b,0,nRead); o:W>7~$jr=  
} ^ Vso`(Ss  
catch(Exception e){e.printStackTrace ();} M ~z A  
} "v@Y[QI  
} PzMJ^H{  
%JF^@\E!|  
ePv3M&\J  
//打印回应的头信息 O2g9<H   
public void logResponseHead(HttpURLConnection con) SR!EQ<  
{ [uU"=H|  
for(int i=1;;i++) &kUEnwQ -  
{ $P&{DOiKS  
String header=con.getHeaderFieldKey(i); ' ^E7T'v%  
if(header!=null) Iv+JEuIi  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f>!)y-7  
Utility.log(header+" : "+con.getHeaderField(header)); hjf!FY*F  
else ~" |MwR!0  
break; ]9qY(m  
} ;-sZaU;  
} _N)/X|=~s  
nsn  
0)F.Y,L  
public void splitterStop() Oy EOb>  
{ u_H=Xm)9  
bStop = true; !ij R  
} W>TG!R 5  
VaP9&tWXj  
nilis-Bk_  
} }?G([s56  
?#s9@R1  
qlSI|@CO  
/* #dA9v7  
**FileAccess.java *.%z  
*//文件访问(定位,写) 5"sd  
package NetFox; _D+pJ{@W  
import java.io.*; Z9wKjxu+  
aa2 vk)~  
5PY4PT=G  
public class FileAccessI implements Serializable{ mrmm@?  
=hRo#]{(K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HuT4OGBFpC  
RandomAccessFile oSavedFile; H4B|c42  
long nPos; 6v"WI@b4  
W&~\@j]!D  
i+qt L3  
public FileAccessI() throws IOException eI,'7u4q  
{ >}T}^F  
this("",0); 'p FK+j  
} rU4;yy*b  
B4@1WZn<8  
8Z|A'M  
public FileAccessI(String sName,long nPos) throws IOException =jEVHIYt  
{ o5B]?ekpq  
oSavedFile = new RandomAccessFile(sName,"rw"); CCHGd&\Z  
this.nPos = nPos; tm1#Lh0  
oSavedFile.seek(nPos); Qli#=0{`  
} |LV}kG(2  
A)#w~X4  
3AcS$.G  
public synchronized int write(byte[] b,int nStart,int nLen) hbdB67,  
{ ;fW`#aE  
int n = -1; y(ceEV  
try{ 15z(hzU?#  
oSavedFile.write(b,nStart,nLen); |&"/u7^  
n = nLen; 1%$t;R  
} s6F0&L;N&  
catch(IOException e) |2E:]wT}qg  
{ .[r1Qz7G  
e.printStackTrace (); YEa<zhO8  
} ;il+C!6zpf  
2FN E ;y(  
,|g&v/WlC%  
return n; X2|&\G9c  
} {[4.<|26  
oI5^.Dr FW  
SoWMP2/  
} eZ]>;5  
6u'E}hAx|  
rf^ u&f  
/* ?bH`  
**SiteInfoBean.java mBxMDnh  
*/ ]VR79l  
package NetFox; "/G] M&  
YSzC's[  
!LQzf(s;  
public class SiteInfoBean { DUSQh+C  
x~i\*Ox^  
v .ow`MO=;  
private String sSiteURL; //Site's URL e,xJ%f  
private String sFilePath; //Saved File's Path s{OV-H  
private String sFileName; //Saved File's Name /2''EF';  
private int nSplitter; //Count of Splited Downloading File L#?mPF  
#)#J`s1R  
Q;ZV`D/FA  
public SiteInfoBean() B8unF=u  
{//nSplitter的缺省值为5 Y[|9 +T  
//default value of nSplitter is 5 ly69:TR7I  
this("","","",5); B}P!WRNmln  
} <`WDNi$Y  
W9{i~.zo  
-'}#j\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9@?|rj e9  
{ JC`;hY  
sSiteURL= sURL; DxD\o+:r  
sFilePath = sPath; L{GlDoFk  
sFileName = sName; bxPJ5oT  
this.nSplitter = nSpiltter; l*(L"]  
z}iz~WZ  
03A QB;.  
}  k{'<J(Hb  
I]HLWF  
tJ* /5k &  
public String getSSiteURL() zJh!Q**  
{ m^zD']  
return sSiteURL; Bp5 %&T k  
} @=}NMoNH  
t\]kVo)  
I %sw(uoE  
public void setSSiteURL(String value) 1;+77<  
{ ]T(qk  
sSiteURL = value; <(~Wg{  
} \ KsKb0sM  
I. Xbowl  
A/&u /?*C  
public String getSFilePath() NG RXNh+  
{ ,Y#f0  
return sFilePath;  $C,` ^n'  
} yRD tPK"E-  
)Jw$&%/{1  
qG2P?DR  
public void setSFilePath(String value) J0YNzC4  
{ 4#t=%}  
sFilePath = value; uKTYb#E7  
} &|h9L'mr  
dtj b(*x  
ug'^$geM  
public String getSFileName() >) Bv>HM  
{ . Y$xNLoP[  
return sFileName; Ef@)y&hn  
} O;&5> W,Z  
' QjJ^3A  
YG5mzP<T  
public void setSFileName(String value) @7;}6,)  
{ -i_XP]b&  
sFileName = value; f)V6VNW.3  
} 16nU`TN  
>z% WW&Z'  
m;TekJXm  
public int getNSplitter() &' y}L'  
{ i=hA. y`  
return nSplitter; +tG'  
} @3U=kO(^+\  
r^ '  
K$s{e0 79  
public void setNSplitter(int nCount) ?%D nIl>  
{ ttt4h  
nSplitter = nCount; /)dyAX(  
} L. S/Mv  
} zyt >(A1  
>7 cDfv"  
nQg_1+  
/* Hq?dqg'%~  
**Utility.java ~EvGNnTL  
*/ SP>&+5AydX  
package NetFox; MOi1+`kwh  
[L ' >  
nyOmNvZf  
public class Utility { Sogt?]HB$  
jz>b>;  
+=nWB=iCb  
public Utility() $U)nrn i  
{ pTncx%!W5  
)M"xCO3a  
9ESV[  
} R:f ,g2  
k%aJ%(  
//线程睡眠 hrXk7}9  
public static void sleep(int nSecond) 5ci1ce  
{ ;0uiO.  
try{ a(G}<  
Thread.sleep(nSecond); wLvM<p7OX  
} M~+DxnJ=  
catch(Exception e) $H&:R&Us  
{ NK:! U  
e.printStackTrace (); [N<rPHT  
} 7*He 8G[W  
} A5_r(Z-5  
rfr]bq5  
//日志 )HX(-"c  
public static void log(String sMsg) 2h)Qz+|7  
{ 'q@vTM'-  
System.err.println(sMsg); FJT0lC  
} )l`VE_(|  
I<+:Ho=6  
d"Zyc(Jk  
public static void log(int sMsg) BPVOBL@   
{ s%RG_"l  
System.err.println(sMsg); dfZ`M^NU  
} Q\btl/?  
} gP |>gy#e  
P?zaut  
W! J@30  
/* =hY/Yr%P  
**TestMethod.java vUDMl Z  
*/ *M$'dLn  
package NetFox; !fjB oK+  
eo.B0NZsF  
'E\4/0 !  
public class TestMethod { Iyb_5 UmpF  
z<.?8bd  
M5L/3qLh1  
public TestMethod() l kyK  
{ ///xx/weblogic60b2_win.exe [ugr<[6  
try{ hML-zZ   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '|<S`,'#hg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yhs:.h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z\woTL6D]  
fileFetch.start(); %E"Z &_3{  
} II Amx[ b  
catch(Exception e){e.printStackTrace ();}  T;V!>W37  
qwO@>wQ}~  
?0?3yD-!9  
} -Zp BYX5e_  
?nWzJ5w3  
C7DwA/$D  
public static void main(String[] args) tBX71d T  
{ /'b7q y  
new TestMethod(); \f)GW$`  
} ^)(tO$S  
} 0=K8 nxdx  
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