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http断点续传简单实现(java)

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/* 6Z#Nh@!+C  
**SiteFileFetch.java ^x O](,H  
*/ y p{Dl  
package NetFox; %W D^0U|  
import java.io.*; KU$,{Sn6@  
import java.net.*; J(#6Cld`c  
i. 6b%  
L-?ty@-i  
public class SiteFileFetch extends Thread { D@uVb4uK  
xbCR4upS  
Ne<S_u2nT  
SiteInfoBean siteInfoBean = null; //文件信息Bean dnD@BQ  
long[] nStartPos; //开始位置 ZJs~,Q  
long[] nEndPos; //结束位置 &l2xh~L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [G8EX3  
long nFileLength; //文件长度 I=&i &6v8G  
boolean bFirst = true; //是否第一次取文件 -b!Z(}JK  
boolean bStop = false; //停止标志 >C_G~R  
File tmpFile; //文件下载的临时信息 Ich^*z(F$  
DataOutputStream output; //输出到文件的输出流 iqB5h| `  
YNV, dKB  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) MUl7o@{'  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9oc_*V0<  
{ eV}"L:bgJ  
siteInfoBean = bean; npzp/mcIe)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h'em?fN(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =At" Q6-O  
if(tmpFile.exists ()) tUH?N/qn  
{ yOz6a :r  
bFirst = false; H'#06zP>5  
read_nPos(); }h Wv  p  
} fD[O tc  
else Q SF0?Puf  
{ ^=^\=9" b  
nStartPos = new long[bean.getNSplitter()]; TsT5BC63  
nEndPos = new long[bean.getNSplitter()]; e bp t/q[  
} h%F.h![*  
'MW%\W;  
0^S$_L  
?`e@ o?  
} RN 4?]8  
>z%YKdq  
P `@Rt  
public void run() o#6QwbU25  
{ .g}N@  
//获得文件长度 :qxWANUa  
//分割文件 h=`$ec  
//实例FileSplitterFetch M rgj*|  
//启动FileSplitterFetch线程 C~4SPCU  
//等待子线程返回 J|{50?S{^  
try{ 8<}=f4vUj5  
if(bFirst) vrb@::sy0T  
{ ^k7I+A  
nFileLength = getFileSize(); b||usv[or  
if(nFileLength == -1) (U# ,;  
{ pW.WJ`Rk  
System.err.println("File Length is not known!"); >?K=l]!(*  
} v)*MgfS  
else if(nFileLength == -2) G7Ck P  
{ M`K]g&57hL  
System.err.println("File is not access!"); ?=4oxPe  
} ox`Zs2-a  
else eik_w(xPT  
{ >3D1:0Sg  
for(int i=0;i<nStartPos.length;i++) ZqrS]i@$  
{ 6bUP]^d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6M&ajl`o  
} @2. :fK  
for(int i=0;i<nEndPos.length-1;i++) R98YGW_ dT  
{ Qq.$! $  
nEndPos = nStartPos[i+1]; AJ>E\DK0]  
} \( V1-,  
nEndPos[nEndPos.length-1] = nFileLength; +`wr{kB$~  
} m%u`#67oK  
} kOo  Vqu  
TYD( 6N  
`AE6s.p?  
//启动子线程 !yj1X Ar  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #2i$:c~  
for(int i=0;i<nStartPos.length;i++) 7.VP7;jys  
{ N KgEs   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^A&{g.0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K_Y{50#  
nStartPos,nEndPos,i); +|bmUm<2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zs/-/C|  
fileSplitterFetch.start(); Dti-*LB1  
} <2@t ~ 9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0vLx={i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -w2^26 ax  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XGR63hXND  
nEndPos = " + nFileLength); w uY-f4  
// fileSplitterFetch[nPos.length-1].start(); 2|\mBP`ok  
u q 9mq"  
V^FM-bg%9  
//等待子线程结束 yx`@f8Kr  
//int count = 0; bj0HAgY@  
//是否结束while循环 d(t)8k$  
boolean breakWhile = false;  ::02?  
W (TTsnnx  
+&"W:Le:  
while(!bStop) A4l"^dZc  
{ [wSoZBl  
write_nPos(); Mfz(%F|<  
Utility.sleep(500); wH@< 0lw`<  
breakWhile = true; GB `n  
< hy!B4  
_3wJ;cn.  
for(int i=0;i<nStartPos.length;i++) RgFpc*.T  
{ o"RE4s\G~r  
if(!fileSplitterFetch.bDownOver) o/ \o -kC}  
{ Kc r)W  
breakWhile = false; W'k&DKhTqF  
break; 1G`5FU  
} nUONI+6Z/  
} .Sw4{m[g  
if(breakWhile) ;w%g*S  
break; `,pBOh|'  
}T902RL0  
w0js_P-uv  
//count++; *URY8 a`bO  
//if(count>4) 05 6yhB  
// siteStop(); .-s!} P"  
} aAoAjVNkK  
T06w`'aL  
X+emJ&Z$@  
System.err.println("文件下载结束!"); UlN}SddI9  
} ,t1s#*j\!q  
catch(Exception e){e.printStackTrace ();} /mE:2K]C  
} PK?}hz  
{QK9pZB  
hhjsg?4uL  
//获得文件长度 ]]V=\.y  
public long getFileSize() ]6=opvm  
{ QKz2ONV=)  
int nFileLength = -1; H-5f!>)  
try{ ,,9vk\  
URL url = new URL(siteInfoBean.getSSiteURL()); /$vX1T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <N 80MU L|  
httpConnection.setRequestProperty("User-Agent","NetFox"); /e*<-a  
< R@&<E6  
&:+_{nc,  
int responseCode=httpConnection.getResponseCode(); kgmb<4p  
if(responseCode>=400) Yic'p0< ?V  
{ CA"`7<,  
processErrorCode(responseCode); Git2Cet  
return -2; //-2 represent access is error C$c.(5/O  
} yNx"Ey dk`  
)>=|oY3  
gY=+G6;=<  
String sHeader; S 1Ji\  
x2f_>tu2  
qn\>(&  
for(int i=1;;i++) >y q L  
{ J Y> I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D3 E!jQ1  
//Utility.log(in.readLine()); i%B$p0U<  
sHeader=httpConnection.getHeaderFieldKey(i); :\1&5Pm]  
if(sHeader!=null) :(x 90;DW  
{ 9=~jKl%\vJ  
if(sHeader.equals("Content-Length")) Fn%:0j  
{ ?at~il$z'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y.Ew;\6U  
break; *KV] MdS  
} & l|B>{4v  
} g(;ejKSR  
else MN)<Tr2f  
break; AB#hh i#  
} tv|=`~Y  
} [K9q+  
catch(IOException e){e.printStackTrace ();} E3KPJ`=!*"  
catch(Exception e){e.printStackTrace ();} 2W~2Hk=0+%  
!8s:3]  
~E`A,  
Utility.log(nFileLength); )5V1H WjU  
$S cjEG:6  
wy&*6>.  
return nFileLength; "|&*MjwN6  
} MDCf(LhEH  
C,z]q$4  
pcl _$2_  
//保存下载信息(文件指针位置) SoY&R=  
private void write_nPos() {S&&X&A`v  
{ yq,5M1vR  
try{ ;~q)^.K3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1!NaOfP;@  
output.writeInt(nStartPos.length); " 7 4L  
for(int i=0;i<nStartPos.length;i++) t[ MRyi)LF  
{ mLYB6   
// output.writeLong(nPos); &]c9}Ic  
output.writeLong(fileSplitterFetch.nStartPos); \%^3Izsc  
output.writeLong(fileSplitterFetch.nEndPos); ! O>mu6:Rf  
} +%~g$#tlJo  
output.close(); K^vMIoh  
} 5m3sjcp_  
catch(IOException e){e.printStackTrace ();} y|mR'{$I  
catch(Exception e){e.printStackTrace ();} 8UZE C-K  
} %qv7;E2C  
Z n!SHj  
cK } Qu  
//读取保存的下载信息(文件指针位置) t8[:}[Jx  
private void read_nPos() A| +{x4s`  
{ $7*Ml)H!9  
try{ M;bQid@BG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <Jk|Bmw;  
int nCount = input.readInt(); }?^G= IP4(  
nStartPos = new long[nCount]; 5-QXvw(TH  
nEndPos = new long[nCount]; tpctz~ .  
for(int i=0;i<nStartPos.length;i++) y%y#Pb |  
{ 1$W!<:uh  
nStartPos = input.readLong(); PrcM'Q  
nEndPos = input.readLong(); _ Owz%  
} dd+).*  
input.close(); XDGZqkt  
} aU!UY(  
catch(IOException e){e.printStackTrace ();} :[&X*bw[  
catch(Exception e){e.printStackTrace ();} b,W '0gl  
} hg~fFj3ST  
{%Y7]*D  
=EJ"edw]%0  
private void processErrorCode(int nErrorCode) a*8}~p,  
{ {mQJ6 G'ny  
System.err.println("Error Code : " + nErrorCode); B+LNDnjO]  
} @:@rks&  
Y(f-e,  
wMoAvA_oS  
//停止文件下载 #rwR)9iC0  
public void siteStop() F8I <4S  
{ JNz0!wi  
bStop = true; `dZ|}4[1  
for(int i=0;i<nStartPos.length;i++) $%-?S]6)  
fileSplitterFetch.splitterStop(); u| c+w)a  
5PPpX=\  
lUEyo.xVt  
} gib]#n1!p  
} M=A9a x  
//负责部分文件的抓取 M)7enp) F.  
**FileSplitterFetch.java ~}*;Ko\  
*/ Izu.I_$4  
package NetFox; \t@`]QzG:  
!Xi>{nV  
F{ ,O+\  
import java.io.*; fna>>  
import java.net.*; s_LSs yqo  
3D0I5LF&  
z sPuLn9G  
public class FileSplitterFetch extends Thread { Bl];^W^P  
(&,R1dLo  
*lAdS]I  
String sURL; //File URL 3~ZVAg[c  
long nStartPos; //File Snippet Start Position w ZAXfNA  
long nEndPos; //File Snippet End Position #+0 R!Y  
int nThreadID; //Thread's ID 5nAF=Bj  
boolean bDownOver = false; //Downing is over h$\h PLx  
boolean bStop = false; //Stop identical ;[ueNP%*y|  
FileAccessI fileAccessI = null; //File Access interface di2=P)3  
w>_EM&r6~u  
5FI>T=QF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RfG$Px '  
{ 0pa^O$?p  
this.sURL = sURL; ^6>|!  
this.nStartPos = nStart; g"S+V#R  
this.nEndPos = nEnd; ,&] ` b#Rc  
nThreadID = id; NfF:[qwh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )fc"])&8  
} `r(J6,O  
uTGvXKL7  
#9VY[<  
public void run() +lJ]-U|P  
{ RLNuH2y;  
while(nStartPos < nEndPos && !bStop) @(fY4]K  
{ bGc|SF<V  
e~]e9-L>I  
yuDd% 1k  
try{ .fY<"2g  
URL url = new URL(sURL); AiK4t-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ':)j@O3-  
httpConnection.setRequestProperty("User-Agent","NetFox"); S@NhEc  
String sProperty = "bytes="+nStartPos+"-"; VQMd[/  
httpConnection.setRequestProperty("RANGE",sProperty); _6zP] |VBr  
Utility.log(sProperty); kTc5KHJ7  
9XvM%aHs:  
n4T2'e  
InputStream input = httpConnection.getInputStream(); {eN{Zh5"  
//logResponseHead(httpConnection); vqz#V=J{  
.+L_!A  
f?^Oy!1]  
byte[] b = new byte[1024]; {<4?o? 1 g  
int nRead; '4lT*KN7\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xh^ZI6L<  
{ udI: ]:,P  
nStartPos += fileAccessI.write(b,0,nRead); <sYw%9V  
//if(nThreadID == 1) rRrW   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C| IQM4  
} c&?a ,fpb  
3nC#$L-   
O8~U<'=*  
Utility.log("Thread " + nThreadID + " is over!"); !2U7gVt"*  
bDownOver = true; ^ R^N`V   
//nPos = fileAccessI.write (b,0,nRead); `=$jc4@J  
} A+1]Ql)$  
catch(Exception e){e.printStackTrace ();} :F w"u4WI  
} xc<eU`-' b  
} Sb9=$0%\  
)bXx9,VL  
V&j.>Y  
//打印回应的头信息 h*%0@  
public void logResponseHead(HttpURLConnection con) \g:qQ*.  
{ lJ]\  
for(int i=1;;i++) ?"<r9S|[O  
{ 0H&U=9'YT  
String header=con.getHeaderFieldKey(i); vWi. []  
if(header!=null) !0csNg!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qwNKRqT  
Utility.log(header+" : "+con.getHeaderField(header)); Xt,,AGm}  
else <AAZ8#^  
break; G<^]0`"+)t  
} IL[|CB1v  
} P2Qyz}!wo  
) 4L%zl7  
 2H K  
public void splitterStop() ogc('HqF^'  
{ !ga (L3vf  
bStop = true; 4>"cc@8&~  
} #u<o EDQ  
'f?&EsIV?  
n@07$lY@;  
} ?y*+^E0  
.xLF}{u  
97]a-)SA  
/* Il^ \3T+  
**FileAccess.java [#>$k 6F*  
*//文件访问(定位,写) igj={==m  
package NetFox; qzH qj;  
import java.io.*; dp[w?AMhM9  
^0s\/qyqm  
3?*M{Y|  
public class FileAccessI implements Serializable{ `Ge+(1x  
VTJIaqw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aZawBU.:  
RandomAccessFile oSavedFile; s7.p$r  
long nPos; ^0`<k  
`z?KL(rI  
E/dO7I`B   
public FileAccessI() throws IOException hLyTUt~\L  
{ |,1bkJt  
this("",0); =~\]3g  
} %7NsBR!y  
5U)ab3 :  
kh<pLI>$h  
public FileAccessI(String sName,long nPos) throws IOException >St. &#c  
{ 0j{F^rph  
oSavedFile = new RandomAccessFile(sName,"rw"); C?w <$DU  
this.nPos = nPos; Y3P.|  
oSavedFile.seek(nPos); +-H}s`  
} 'n l RY5@2  
[:nx);\  
bSrRsgKvT  
public synchronized int write(byte[] b,int nStart,int nLen) ':!3jZP"m  
{ a@fE46o6<  
int n = -1; c?!YFm  
try{ 2/v35| ?  
oSavedFile.write(b,nStart,nLen); mFqSD  
n = nLen; E7X!cm/2<  
} poXLy/K  
catch(IOException e) $N}/1R^?r  
{ * MSBjH|  
e.printStackTrace (); o%Be0~n'  
} fJ)N:q`  
> $w^%I  
&jV9*  
return n; ;dqk@@O"(  
} uFwU-LCe  
c Ndw9?Z  
G3RrjWtO  
} On{~St'V  
DR k]{^C~  
^Yj"RM$;N  
/* AIZW@Nq.5  
**SiteInfoBean.java g d337jw  
*/ `6a]|7|f  
package NetFox; I86e&"40  
"sF Xl  
e#>tM  
public class SiteInfoBean { iD>G!\&  
cPpu  
n K+lE0  
private String sSiteURL; //Site's URL r1i$D  
private String sFilePath; //Saved File's Path <,jAk4  
private String sFileName; //Saved File's Name x}tKewdOSe  
private int nSplitter; //Count of Splited Downloading File CJzm}'NY  
Eo%UuSi  
W8f`J2^"M  
public SiteInfoBean() U?bG`. X  
{//nSplitter的缺省值为5 Q`H# fS~  
//default value of nSplitter is 5 1#grB(p?  
this("","","",5); p/r~n'g$  
} CN$I:o04C  
(# JMB)  
'@'B>7C#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ecn}iN  
{ `vudS?  
sSiteURL= sURL; %$Aqbd  
sFilePath = sPath; $bk>kbl P  
sFileName = sName; E@:Q 'g%  
this.nSplitter = nSpiltter; wD`[5~C{  
Yt -W1vl  
nz^nptw  
} /:U1!9.y  
5N\+@grp  
SU/G)&Mi  
public String getSSiteURL() aSUsyOe  
{ }/20%fP  
return sSiteURL; |VK:2p^ u  
} <nBo}0O}  
`%|u!  
C5Xof|#p|  
public void setSSiteURL(String value) pjACFVMFX  
{ dgXg kB'  
sSiteURL = value; :AZp}  
} qmEoqU  
<KtBv Ip]  
TM0b-W (H  
public String getSFilePath() Vn'?3Eb<  
{ 6z Ay)~  
return sFilePath; D3y>iQd   
} o5P&JBX<  
CJp-Y}fGEA  
gV|Y54}T  
public void setSFilePath(String value) Rs2-94$!5  
{ okz]Qc>G  
sFilePath = value; 5C B%=iL{  
} UxeL cUP  
Je^Y&a~  
&3I$8v|!?  
public String getSFileName() ilv_D~|  
{ IP04l;p/  
return sFileName; :9`qogF>  
} 45) D+  
&mcR   
(xL :;  
public void setSFileName(String value) x9%-plP  
{ q[P~L`h S  
sFileName = value; Y''6NGf  
} d@ZoV  
&$F[/[Ds+  
i j/o;_  
public int getNSplitter()  i S  
{ D"cKlp-I6|  
return nSplitter; ,Aj }]h\L  
} Ukc'?p,*  
Q2"WV  
333u]  
public void setNSplitter(int nCount) r1G8]agO  
{ )Oievu_"|  
nSplitter = nCount; MtUY?O.P2  
} ~ M*gsW$  
} `VZZ^K9zR  
WYLX?x  
(B:uc_+  
/* .!yq@Q|=u  
**Utility.java skR,-:"8  
*/ z h%qS~8Yv  
package NetFox; ~KRnr0  
p+[} Hxx=  
X2^_~<I{,  
public class Utility { HN68!v}C|  
o?wt$j-  
R hio7C  
public Utility() K/|  
{ v9rVpYc"  
S?4KC^Y5  
p=B?/Sqa  
} 7`fY*O6   
7|Dn+ =  
//线程睡眠 d}-'<Z#G  
public static void sleep(int nSecond) -:S IS`0s  
{ TwFb%YM  
try{ 2y kCtRe  
Thread.sleep(nSecond); iBoEZEHjw  
} jdM=SBy7q  
catch(Exception e) k[9A,N^lZB  
{ aZKXD! 4  
e.printStackTrace (); 5UO k)rOf  
} rzu s  
} 4AHL3@x  
C:GvP>  
//日志 /{X_ .fv<v  
public static void log(String sMsg) d>!p=O`>{q  
{ 3cC }'j  
System.err.println(sMsg); 9j#@p   
} zfjw;sUX  
f#P_xn&et  
 $Nu)E  
public static void log(int sMsg) "}zda*z8  
{ J]fS({(\I  
System.err.println(sMsg); t5) J;0/  
} 10MU-h.)  
} uTGcQs}  
;|TT(P:d  
^~l  $&~  
/* wiE]z  
**TestMethod.java RH1uVdJ1  
*/ ]k*1KP  
package NetFox; ``9 GY  
7lU.Ni t  
*48IF33&s  
public class TestMethod { };sMU6e  
D$nK`r  
g$3> ~D  
public TestMethod() G9RP^  
{ ///xx/weblogic60b2_win.exe M<[ ?g5=#  
try{ 'm O2t~n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2jA%[L9d^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h\y-L~2E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &1GUi{I  
fileFetch.start(); U8O(;+  
} 3ATjsOL  
catch(Exception e){e.printStackTrace ();} 6vp0*ww  
5 =Z!hQ}  
.wc = ]  
} }.{}A(^YR  
J_ J+cRwq  
7& 6Y  
public static void main(String[] args) @2e2^8X7f  
{ C5n?0I9  
new TestMethod(); CBHc A'L  
} ~ FUa: KYD  
} ^l!L)iw  
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