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http断点续传简单实现(java)

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/* ><=gV~7lx  
**SiteFileFetch.java J!DF^fLe  
*/ frBX{L  
package NetFox; Y[ N^p#t{  
import java.io.*; O iFS}p  
import java.net.*; +}-@@,  
u a\,->  
@JRNb=?a  
public class SiteFileFetch extends Thread { pAk/Qxl3eo  
wfjnA~1h  
YZ+RWu9K  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ka,^OW}<%q  
long[] nStartPos; //开始位置 ]%!u7z|\6  
long[] nEndPos; //结束位置 57 #6yXQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <r3J0)r}  
long nFileLength; //文件长度 *s;|T?~i  
boolean bFirst = true; //是否第一次取文件 5[Pr|AY  
boolean bStop = false; //停止标志 pa{re,O"e  
File tmpFile; //文件下载的临时信息 *& m#qEv  
DataOutputStream output; //输出到文件的输出流 5 QO34t2  
Yf[Qtmh]I  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Vi$-Bw$@  
public SiteFileFetch(SiteInfoBean bean) throws IOException K).n.:vYZ  
{ yZ!T8"mz{  
siteInfoBean = bean; K!KMQr`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); R-P-i0 ~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  ;vb8G$  
if(tmpFile.exists ()) IVW1]y  
{ 'fL"txW  
bFirst = false; 5#QXR+ T  
read_nPos(); o`.R!wm:W  
} Y{*u&^0{  
else J sEa23  
{ ./$cMaDJ  
nStartPos = new long[bean.getNSplitter()]; HfLLlH<L`&  
nEndPos = new long[bean.getNSplitter()]; J6jwBo2m  
} W}|'#nR  
4BwQA #zE  
t5lO'Ll*Q]  
CwX Z  
} >YUoh-]`  
w4LScvBg  
*~/OOH$"  
public void run() ;Q+xK h%  
{ 4Yl;  
//获得文件长度 sm$ (Y.N  
//分割文件 `f'K@  
//实例FileSplitterFetch Dk5Zh+^  
//启动FileSplitterFetch线程 1 n%?l[o  
//等待子线程返回 07Ed fe  
try{ ,<:!NF9  
if(bFirst) @X3{x\i'I  
{ "l >Igm  
nFileLength = getFileSize(); y ^;l*qq  
if(nFileLength == -1) o!~Jzd.=h  
{ t^ZV|s 1  
System.err.println("File Length is not known!"); *SO{\bu  
} M?/jkc.8H  
else if(nFileLength == -2) SwU\ q]^|Z  
{ iZZ (4  
System.err.println("File is not access!"); +78CvjG  
} =~I-]4  
else wKH ::!  
{ ,j5&6X=1M  
for(int i=0;i<nStartPos.length;i++) /\) a  
{ s[gKc'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a" H WGY  
} IL_d:HF|1  
for(int i=0;i<nEndPos.length-1;i++) <9sO  
{ F]m gmYD%  
nEndPos = nStartPos[i+1]; X w.p  
} =YG _z^'  
nEndPos[nEndPos.length-1] = nFileLength; `HuCT6O  
} n8hRaNHl2  
} ^2wLxXO6  
R<x'l=,D(  
.ZMW>U>  
//启动子线程 G Xt4j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v=95_l  
for(int i=0;i<nStartPos.length;i++) >E,U>@+  
{ $F.kK%-*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ESoAz o,u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gKg-O  
nStartPos,nEndPos,i); kw`WH)+F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Il`tNr  
fileSplitterFetch.start(); }qjCTEs}  
} !Oi~:Pp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NU (AEfF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yFhB>i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C[WCg9Av  
nEndPos = " + nFileLength); V3mAvmx  
// fileSplitterFetch[nPos.length-1].start(); u>pBB@  
 Yav2q3  
1|8<H~&  
//等待子线程结束 _8G>&K3T<  
//int count = 0; TEsnNi 1  
//是否结束while循环 DF{OnF  
boolean breakWhile = false; +%\oO/4Fs  
,%YBG1E[y  
%PJhy2  
while(!bStop) s/Xb^XjS1  
{ 7< 9L?F2  
write_nPos(); [@fz1{*  
Utility.sleep(500); _GqS&JHSf  
breakWhile = true; V[a[i>,Z  
0iEa[G3  
amQz^^  
for(int i=0;i<nStartPos.length;i++) 69#8Z+dw7  
{ nT#JOmv  
if(!fileSplitterFetch.bDownOver) N~ANjn/wL  
{ }%n5nLU`  
breakWhile = false; }jSj+*  
break; Ml>( tec  
} }%{MPqg  
} nws"RcP+Z  
if(breakWhile) F=)eLE{W  
break; *@V*~^V"J[  
ix Z)tNz  
VF0dE  
//count++; pJ, @Y>  
//if(count>4) *Zd84wRSj  
// siteStop(); /-0' Qa+*  
} TOI4?D]  
h7qBp300  
DlE_W+F  
System.err.println("文件下载结束!"); bdh(WJh%  
} G%TL/Z40  
catch(Exception e){e.printStackTrace ();} &d`^ E6#  
} wX1ig  
o4=Yu7L  
iz}sM>^  
//获得文件长度 )WR_ ug  
public long getFileSize() < 8(?7QI  
{ INMP"1  
int nFileLength = -1; dYOF2si~%  
try{ p*;Qz  
URL url = new URL(siteInfoBean.getSSiteURL()); UCqs}U8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Z\2*1y6  
httpConnection.setRequestProperty("User-Agent","NetFox"); p {%t q$}.  
ACBQ3   
:X .,  
int responseCode=httpConnection.getResponseCode(); heD,& OX  
if(responseCode>=400) T%CxvZ  
{ V"d=.Hb>  
processErrorCode(responseCode); .?#uxd~>  
return -2; //-2 represent access is error Sw! j=`O  
} =L 0fZf  
VTh$a_P>  
`"y{;PCt_  
String sHeader; +?N}Y{Y&  
? J|4l[x  
kC^.4n om  
for(int i=1;;i++) j.c8}r&  
{ MguL$W&l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IbdM9qo7  
//Utility.log(in.readLine()); q9}2  
sHeader=httpConnection.getHeaderFieldKey(i); B/YcSEY;  
if(sHeader!=null) k0&lu B%  
{  Q&+c.S  
if(sHeader.equals("Content-Length")) ,hE/II`-d'  
{ *)PG-$6X&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~'BUrX\  
break; lIDl1Z@Z  
} |>s v8/!  
} $Qq_qTJu?G  
else Tt6{WDscZ  
break; .98.G4J>  
} QAaF@Do  
} ( Yi=v'd  
catch(IOException e){e.printStackTrace ();} w#{l 4{X|  
catch(Exception e){e.printStackTrace ();} tBl#o ^  
+L6" vkz  
91;HiILgT  
Utility.log(nFileLength); 5^|"_Q#:  
6:RMU  
!1-&Y'+  
return nFileLength; Qk7J[4  
} }vsO^4Sjc  
.wri5  
T:#S86m  
//保存下载信息(文件指针位置) {h^c  
private void write_nPos() D% @KRcp^b  
{ |B|@GF?:  
try{ C "9"{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3B"7VBK{  
output.writeInt(nStartPos.length); # `58F.  
for(int i=0;i<nStartPos.length;i++) U 1F-~ {r  
{ 5\?3$<1 I  
// output.writeLong(nPos); :tlE`BIp  
output.writeLong(fileSplitterFetch.nStartPos); w7ZG oh(  
output.writeLong(fileSplitterFetch.nEndPos); =f4< ({9  
} Ge~,[If+  
output.close(); ~1d!hq?/q  
} iha9!kf  
catch(IOException e){e.printStackTrace ();} Ut':$l=  
catch(Exception e){e.printStackTrace ();} wzxdVn 'S  
} z1}1*F"  
)DRkS,I  
DOT=U _  
//读取保存的下载信息(文件指针位置) ,$PFI(Whk  
private void read_nPos() %2zas(b9j  
{ edTMl;4  
try{ 9IOGc}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $ {@q?iol  
int nCount = input.readInt(); 1M=   
nStartPos = new long[nCount]; uNg'h/^NZ|  
nEndPos = new long[nCount]; zw< 4G[u  
for(int i=0;i<nStartPos.length;i++) G#'Q~N  
{ 'hy?jQ'|e  
nStartPos = input.readLong(); pIvfmIm  
nEndPos = input.readLong(); psu OJ-  
} "'~|}x1Uv  
input.close(); 8Kk3_ y  
} W?=$V>)  
catch(IOException e){e.printStackTrace ();} [jy0@Q9  
catch(Exception e){e.printStackTrace ();} /=q.tDH=I  
} RP(a,D|  
76$*1jB  
D{Oq\*  
private void processErrorCode(int nErrorCode) "* +\KPCU  
{ k06xz#pL  
System.err.println("Error Code : " + nErrorCode); \hrrPPD1z  
} UKOFT6|  
))p$vU3  
rAM *\=  
//停止文件下载 3;y_qwA  
public void siteStop() LSSW.Oz2L  
{ m$,cH>E  
bStop = true; G5Je{N8W  
for(int i=0;i<nStartPos.length;i++) amMjuyW  
fileSplitterFetch.splitterStop(); (=`Z0)=  
Sf=F cb  
 oHOW5  
} ujiZM  
} Ap% d<\,Z  
//负责部分文件的抓取 KUF$h Er  
**FileSplitterFetch.java *X~B-a|nJ  
*/ _2]O^$L  
package NetFox; |MR%{ZC^i  
Ze#Jhn@  
v#iFQVBq  
import java.io.*; vc )9Re$  
import java.net.*; m dC`W&r  
.F4oo=  
a#^_"GX  
public class FileSplitterFetch extends Thread { oDz*~{BHg  
>vHH  
'BqrJfv  
String sURL; //File URL u/_Gq[Q,u  
long nStartPos; //File Snippet Start Position (L`l+t1  
long nEndPos; //File Snippet End Position $[j-C9W  
int nThreadID; //Thread's ID ZEL/Ndk  
boolean bDownOver = false; //Downing is over C5>{Q:.`e'  
boolean bStop = false; //Stop identical #!w:_T%  
FileAccessI fileAccessI = null; //File Access interface *4-r`k|@>/  
be&6kG  
Sc%aJ1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tDEXm^B2Sv  
{ 2_Pz^L  
this.sURL = sURL; ? UxG/]",  
this.nStartPos = nStart; 4Sg<r,G  
this.nEndPos = nEnd; #:]vUQ  
nThreadID = id; $/NGNkl[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v;K{|zUdB  
} ]&&I|K_  
5OPS&:  
L v  
public void run() PXOrOK  
{ -;sJ25(  
while(nStartPos < nEndPos && !bStop) 3js)niT9u  
{ `K$:r4/[  
HT{F$27W  
TvQWdX=  
try{ TjKzBAX  
URL url = new URL(sURL); $.ymby  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !JT< (I2  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;6DR .2}?>  
String sProperty = "bytes="+nStartPos+"-"; D /,|pC  
httpConnection.setRequestProperty("RANGE",sProperty);  rE/}hHU  
Utility.log(sProperty); WpZy](,  
e 7Yb=/F  
F@>w&A ~K  
InputStream input = httpConnection.getInputStream(); N b#H@zm  
//logResponseHead(httpConnection); 1.hOE>A%  
/AK*aRU^  
j zxf"X-  
byte[] b = new byte[1024]; @)aXNQY  
int nRead; /V#MLPA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~@b9  
{ <wIp$F.  
nStartPos += fileAccessI.write(b,0,nRead); I T*fjUY&  
//if(nThreadID == 1) OhA^UP01-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [i,5>YIk  
} U p]VU9z  
 @oe3i  
x]yHBc  
Utility.log("Thread " + nThreadID + " is over!"); r?Ev.m  
bDownOver = true; X}65\6  
//nPos = fileAccessI.write (b,0,nRead); TzD:bKE&  
} ~G|{q VO7A  
catch(Exception e){e.printStackTrace ();} {GGO')p  
} :ofE8]  
} :Olj  
 3L 1lq .  
'W<a54T?z  
//打印回应的头信息 b&U5VA0=1  
public void logResponseHead(HttpURLConnection con) ql%]$`IV6  
{ kVB}r.NHP  
for(int i=1;;i++) EkfGw/WDw  
{ 2i4Dal  
String header=con.getHeaderFieldKey(i); <.y^  
if(header!=null) n@ yd{Rc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ggxrj'r  
Utility.log(header+" : "+con.getHeaderField(header)); EmBfiuX  
else ;GSfN  
break; {ra Esb-X  
} W~W?<%@  
} gZ79u  
]R2Z-2  
45!`g+)  
public void splitterStop() \fQgiX  
{ $fU/9jTa  
bStop = true; 9X^-)G>  
} hQW#a]]V:  
#h5Hi9LKf  
Jn^Wzn[q  
} j:vD9sdQ  
@Tj  6!v  
EC\rh](d 1  
/* 9g^./k\8%  
**FileAccess.java 5]2!B b6>  
*//文件访问(定位,写) 802]M  
package NetFox; |[n|=ORI'  
import java.io.*; L>R!A3G1  
Y9(i}uTi  
Zqe[2()  
public class FileAccessI implements Serializable{ 5xn0U5U  
0"D?.E"$r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \FaB!7*~  
RandomAccessFile oSavedFile; khO<Z^wi[  
long nPos; 5x L,~"  
@+Anv~B.  
*dn-,Q%`  
public FileAccessI() throws IOException ^/RM;`h0  
{ \2VZkVO9  
this("",0); =_~'G^`tu  
} JeSkNs|vB  
'5+, lRu  
"9Fv!*<-W  
public FileAccessI(String sName,long nPos) throws IOException F@*r%[S/  
{ jzOMjz~:)  
oSavedFile = new RandomAccessFile(sName,"rw"); (Gb{ckzs  
this.nPos = nPos; ,;- cz-,  
oSavedFile.seek(nPos); uC$4TnoQx.  
} N`mC_)  
[}g5Z=l  
*{n,4d\..  
public synchronized int write(byte[] b,int nStart,int nLen) '2B0D|r"a  
{ 7}HA_@[  
int n = -1; S>zKD  
try{ a*ixs'MJ  
oSavedFile.write(b,nStart,nLen); KQy\l+\gM  
n = nLen; hFF&(t2{^  
} '{_tDboY  
catch(IOException e) bsS| !KT  
{ JL*]9$o  
e.printStackTrace (); K^p"Z$$  
} 6Yi,%#  
\>CBam8d  
a\.?{/  
return n; cyn]>1ZM  
} f#JF5>o  
ZX RN?b  
uqH! eN5  
} 1JY90l$ME  
[+2^n7R  
A=>6$L];'  
/* .oOt(K +  
**SiteInfoBean.java  6}ewBAq%  
*/ +mel0ZStS  
package NetFox; 5 BG&r*U  
I(eR3d:  
1;sAt;/W8  
public class SiteInfoBean { ojI"<Q~g  
T</gWW  
+2enz!z#k  
private String sSiteURL; //Site's URL w4/)r-Z4I  
private String sFilePath; //Saved File's Path x{w?X.Nt  
private String sFileName; //Saved File's Name DWO:  
private int nSplitter; //Count of Splited Downloading File `o-<,  
?~9X:~6\  
=njj.<BO  
public SiteInfoBean() biuo.OG]  
{//nSplitter的缺省值为5 :Gk~FRA|  
//default value of nSplitter is 5 {?_)m/\  
this("","","",5); DO*C]   
} u8\QhUk'G  
H`..)zL|  
?n~j2-[<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lJ2/xE]  
{ !I  P*  
sSiteURL= sURL; :H k4i%hGk  
sFilePath = sPath; m$j;FKz+|  
sFileName = sName;  Ue Tp,  
this.nSplitter = nSpiltter; +OP'/  
dXN&<Q,  
WWz ns[$f  
} f4^_FK&  
5,fzB~$TX(  
k!rz8S"  
public String getSSiteURL() cM Kh+r  
{ kKO]q#9sO  
return sSiteURL; <T9m.:l  
} <o`]wOrl  
bm|8Jbsb&  
RGOwm~a  
public void setSSiteURL(String value) %ua5T9H Z  
{ `84yGXLK  
sSiteURL = value; J?DyTs3 Z  
} *Ux"3IXO  
ywBo9|%T  
w%na n=  
public String getSFilePath() )]Rr:i9n  
{ I>|?B( F  
return sFilePath; +[qy HTcG  
} ;trR' ~  
u{^Kyo#v  
:a`m9s 4  
public void setSFilePath(String value) ;B@l0)7(x  
{ ^4i3#}  
sFilePath = value; <ZEll[0L  
} rZ7 Ihof  
jeNEC&J  
AG%aH=TKp  
public String getSFileName() F*u;'K   
{ YTA  &G  
return sFileName; jiDYPYx;I  
} |M&/( 0  
3._fbAN%e  
?U[AE -*  
public void setSFileName(String value) ~I74'  
{ /PlsF  
sFileName = value; 75ob1h"  
} ujedvw;sO  
Qw+">  
#(G&%I A|;  
public int getNSplitter() Zl*!pQ  
{ N:.bnF(  
return nSplitter; h !1c(UR  
} * bK@A2`  
OX2\H  
<R$|J|  
public void setNSplitter(int nCount) WF7RMQ51j  
{ mBF?+/l  
nSplitter = nCount; 5;*C0m2%i  
} %K4-V5f  
} lAQ&PPQ  
195(Kr<5$  
n1|%xQBU@  
/* Q2o:wXvj  
**Utility.java Syb:i(Y  
*/ <|@9]>z  
package NetFox; pWqahrWh  
*SZ<ori  
OR O~(%-(e  
public class Utility { ZJqmD  
C*$/J\6xy  
(~#9KA1A}  
public Utility() ~H.;pJ{ 8  
{ Ic*Q(X  
:c>,=FUT  
`^/Q"zH  
} NTC,Vr\A  
Z=xrj E  
//线程睡眠 2WoB;=  
public static void sleep(int nSecond) Wd7*sa3T  
{ >HDK< 1>  
try{ 3 f3?%9  
Thread.sleep(nSecond); B0:O]Ax6.^  
} {_Y\Y&#  
catch(Exception e) t?s1@}G^  
{ TS;MGi0`}  
e.printStackTrace (); o]vdxkU]  
} b(yY.L=K  
} !@Ox%vK  
+$%o#~  
//日志 mVxS[Gq  
public static void log(String sMsg) m4EkL  
{ 09Fr1PL  
System.err.println(sMsg); bV"0}|A~K  
} -6? 5|\  
` p)#!  
0P|WoC X  
public static void log(int sMsg) /+rHy7(\  
{ 6 R!0v8  
System.err.println(sMsg); &0 @2JS/!  
} \t}!Dr+yN  
} 4 1Ru@  
!nTq"d%(W  
B"G;"X  
/* +Ta7b)  
**TestMethod.java P? >p+dM  
*/ GSypdEBj+w  
package NetFox; (`T:b1  
o0AREZ+I  
<jxTI%'f59  
public class TestMethod { +YP,LDJ!v  
BwbvZfV|  
9]l7 j\L  
public TestMethod() 7Ij'!@no  
{ ///xx/weblogic60b2_win.exe Ur_~yX]Mo  
try{ oM J5;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d<xBI,g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sq*sbdE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [$B  
fileFetch.start(); HuG|BjP  
} EyozhIV  
catch(Exception e){e.printStackTrace ();} E: #VS~  
nNf/$h#;O  
[9X1;bO#f  
} gzxLHPiw  
ZfS-W&6Z  
_ u/N#*D  
public static void main(String[] args) >!?u8^C  
{ D[ny%9 :  
new TestMethod(); ;4%^4<+3  
} K@6$|.bc  
} jf@#&%AC9  
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