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http断点续传简单实现(java)

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/* <ZxxlJS)6  
**SiteFileFetch.java ;(fDR8  
*/ >XjSVRO  
package NetFox; NduvfA4  
import java.io.*; lwaxj7  
import java.net.*; RxY ;'NY  
-mOSB(#bo  
"]Wrir?l  
public class SiteFileFetch extends Thread { +^YXqOXU  
E!&A[TlX\  
-bu.Ar-#;h  
SiteInfoBean siteInfoBean = null; //文件信息Bean =0TnH<`  
long[] nStartPos; //开始位置 mS5'q q;t  
long[] nEndPos; //结束位置 '+N!3r{G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1w/1k6`0  
long nFileLength; //文件长度 uA7~`78  
boolean bFirst = true; //是否第一次取文件 %+YLe-\?  
boolean bStop = false; //停止标志 \R yOexNZ  
File tmpFile; //文件下载的临时信息 N^pTj<M<g  
DataOutputStream output; //输出到文件的输出流 OACRw%J:X{  
N|Xx#/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) k{(R.gLZG  
public SiteFileFetch(SiteInfoBean bean) throws IOException os|8/[gT  
{ "qjkw f)\  
siteInfoBean = bean; 'Ar+k\.J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >{p&_u.r-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mk8xNpk B  
if(tmpFile.exists ()) }&Un8Rg"h  
{ sxIvL7jl  
bFirst = false; j+"i$ln+s  
read_nPos(); ^EWkJW,Yc  
} \:9dt8(-U  
else 0m7ANqE[Z  
{ 9{@[ l!]W  
nStartPos = new long[bean.getNSplitter()]; zD:"O4ZM^^  
nEndPos = new long[bean.getNSplitter()]; O-y/K2MC*  
} qZACX.Hw  
Mh"DPt9@J  
%yX?4T;b  
'd4I/  
} losm<  
[Hw  
rXc-V},az8  
public void run() QE*O~Yj  
{ 16ahU$@-  
//获得文件长度 M3ihtY  
//分割文件 UjxEbk5>^  
//实例FileSplitterFetch YyEW}2  
//启动FileSplitterFetch线程 8+K=3=05#U  
//等待子线程返回 v7&oHOk!  
try{ ["Mq  
if(bFirst) NC'+-P'y  
{ 'NHtCs=F   
nFileLength = getFileSize(); nXPl\|pXt  
if(nFileLength == -1) k=1([x  
{  al/Mgo  
System.err.println("File Length is not known!"); 9o5W\.A7[D  
} ?=,4{(/)  
else if(nFileLength == -2) I.BsKB  
{ {\z&`yD@  
System.err.println("File is not access!"); dCv@l7hE  
} &HBqweI  
else e^2e[rp0  
{ ya7PF~:E-  
for(int i=0;i<nStartPos.length;i++) F5la:0fb  
{ 7Mq4$|qhD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q)vdDdRe_  
} zmd,uhNc:  
for(int i=0;i<nEndPos.length-1;i++) 4.il4Qqy}i  
{ X^;[X~g  
nEndPos = nStartPos[i+1]; %;ZWYj`]n  
} yN}upYxp  
nEndPos[nEndPos.length-1] = nFileLength; FN jT?*  
} l3kYfq{";"  
} +Tz Z   
+@*}_%^l"  
P7ktr?V0a  
//启动子线程 D+edTAQ8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YuufgPE*H  
for(int i=0;i<nStartPos.length;i++) eS)2#=  
{ uG<VQ2LM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W*?mc2;/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CR8a)X4j#  
nStartPos,nEndPos,i); Z3jh-{0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }*eiG  
fileSplitterFetch.start(); |m{Q_zAB  
} 8 Z|c!QIU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4#hDt^N~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M]9oSi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I#lvaoeN  
nEndPos = " + nFileLength); YDh6XD<Z  
// fileSplitterFetch[nPos.length-1].start(); }xhat,9  
5'iJN$7  
Gt;@. jY&  
//等待子线程结束 oVi_X98R  
//int count = 0; a(Q4*XH4  
//是否结束while循环 =2+';Xk\  
boolean breakWhile = false; 81?7u!=ic+  
1$S;#9PQ  
WOqAVd\  
while(!bStop) ~{69&T}9  
{ Arvxl(R\4  
write_nPos(); i>=d7'oR  
Utility.sleep(500); "p]Fq,  
breakWhile = true; Qa*?iD  
_D{zB1d\0  
@ qFE6!  
for(int i=0;i<nStartPos.length;i++) K&1o!<|  
{ u=j|']hp#&  
if(!fileSplitterFetch.bDownOver) j5hM |\]  
{ Mou@G3  
breakWhile = false; +Smt8O<N  
break; :CH*~o  
} \1` L-lz  
} bOIVe  
if(breakWhile) %Xm3m0nsv{  
break; VrG4wLpLs  
\=n0@1Q=>  
O<}^`4d  
//count++; /WIO@c  
//if(count>4) gkxEy5c[  
// siteStop(); s=)0y$  
} 1|K>V;C  
#$\cRLPg  
;=rMIi  
System.err.println("文件下载结束!"); HbQvu@  
} #Bo/1G=  
catch(Exception e){e.printStackTrace ();} lo}[o0X  
} m3|KIUP  
%y@iA91K  
-I, _{3.S  
//获得文件长度 44s K2  
public long getFileSize() Y>OL2g  
{ R<r"jOd]  
int nFileLength = -1; qg7] YT&  
try{ 79.J`}#  
URL url = new URL(siteInfoBean.getSSiteURL()); 5f54E|vD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8mjP2  
httpConnection.setRequestProperty("User-Agent","NetFox"); iU)-YFO  
D+ki2UVt&  
NW-l_]k  
int responseCode=httpConnection.getResponseCode(); >v4k_JX  
if(responseCode>=400) {d|R67~V  
{ # Sm M5%  
processErrorCode(responseCode); ~cE;k@  
return -2; //-2 represent access is error zs+[Aco)  
} apW0(&\  
vBUl6EmWu  
!;Mh5*-  
String sHeader; ETu7G5?  
o?G^=0T  
)B d`N^k+  
for(int i=1;;i++) ~;ink   
{ Ru%: z>Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K;2]c3T  
//Utility.log(in.readLine()); ^$][ah  
sHeader=httpConnection.getHeaderFieldKey(i); 0m5Q;|mH  
if(sHeader!=null) -25#Vh  
{ d6lhA7  
if(sHeader.equals("Content-Length")) !g? ~<`   
{ -Q@jL{Ue  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `I$qMw,@  
break; ;qI5GQ {  
} rT`D@ I  
} #vO3*-hs  
else o3H+.u$  
break; 1SBc:!2  
} qa![oMKc  
} )k&pp^q\  
catch(IOException e){e.printStackTrace ();} ujcS>XN,1  
catch(Exception e){e.printStackTrace ();} fgxsC7P$  
c$f|a$$b   
`R@24 )  
Utility.log(nFileLength); lY}mrb  
;F&wGe  
^H+j;K{5,  
return nFileLength; @LY 5]og  
} $,k SR}  
O$ i6r]j_  
;(w=}s%]+  
//保存下载信息(文件指针位置) 6'C!Au  
private void write_nPos() ";~}"Yz?[  
{ X$JO<@x  
try{ {nQ}t }B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1A23G$D  
output.writeInt(nStartPos.length); *D1fSu!  
for(int i=0;i<nStartPos.length;i++) z(< E %  
{ f{e*R#+&  
// output.writeLong(nPos); PF.sM(  
output.writeLong(fileSplitterFetch.nStartPos); ~H0~5v F  
output.writeLong(fileSplitterFetch.nEndPos); < /y V  
} aMTY{  
output.close(); ]P0DPea  
} C# r_qn  
catch(IOException e){e.printStackTrace ();} hoC}@8_  
catch(Exception e){e.printStackTrace ();} +N[dYm  
} bcpH|}[F)  
?xf59mY7  
yZ&By?.0  
//读取保存的下载信息(文件指针位置) Pyi PhOJe  
private void read_nPos() \3q{E",\>@  
{ m@JU).NKCS  
try{ Pi?*rr5WZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =nnS X-x  
int nCount = input.readInt(); yh_s(>sh  
nStartPos = new long[nCount]; I#l9  
nEndPos = new long[nCount]; Tu_dkif'  
for(int i=0;i<nStartPos.length;i++) OxF\Hm)(  
{ ZNB*Azi  
nStartPos = input.readLong(); 3Gn2@`GC  
nEndPos = input.readLong(); 9BANCW"  
} lGB7(  
input.close(); X_ >B7(k   
} ^OG^% x"  
catch(IOException e){e.printStackTrace ();} V`69%35*@  
catch(Exception e){e.printStackTrace ();} >1ZMQgCG  
} ^F?H)[0  
_0F6mg n  
iy tSC  
private void processErrorCode(int nErrorCode) MbnV5b:X  
{ zi>f436-  
System.err.println("Error Code : " + nErrorCode); 62EJ# q[  
} [ur/`   
mC~W/KReA  
RqHxKj  
//停止文件下载 e;3$7$n Pv  
public void siteStop() Lu:!vTRmw  
{ q\#3G  
bStop = true; {>FA ~}cX.  
for(int i=0;i<nStartPos.length;i++) &P3B  
fileSplitterFetch.splitterStop(); B_5q}Bp<  
Wr)% C  
d; #9xD'  
} ^Hq}9OyS9  
} kq%`9,XE  
//负责部分文件的抓取 6}NvVolr  
**FileSplitterFetch.java FA{I S0  
*/ uy\YJ.WMQ  
package NetFox; 4 d]  
6%S>~L66  
aDZLabRu  
import java.io.*; A#1y>k  
import java.net.*; iI&SI#; _  
=r0!-[XCa  
5!nZvv  
public class FileSplitterFetch extends Thread { YSrFHVq  
ObM5vrEk|  
FeV=4tsy  
String sURL; //File URL UjKHGsDi4  
long nStartPos; //File Snippet Start Position D'nV &m  
long nEndPos; //File Snippet End Position ZQBo|8*  
int nThreadID; //Thread's ID uaDU+y wL  
boolean bDownOver = false; //Downing is over #gN{8Yk>  
boolean bStop = false; //Stop identical ]Vwky]d  
FileAccessI fileAccessI = null; //File Access interface Zt!l3(*tt  
W>@%d`>o5  
6AQ;P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #-lk=>  
{ [/#n+sz.A  
this.sURL = sURL; %7|qnh6  
this.nStartPos = nStart; CKBi-q FH  
this.nEndPos = nEnd;  Mx r#  
nThreadID = id; 5 h{Hf]A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LnJ7i"Q  
} coLn};W2  
t*}<v@,  
8=nm`7(]  
public void run() +^69>L2V  
{ JAiV7v4&R  
while(nStartPos < nEndPos && !bStop) G,"$Erx  
{ vY;Lc   
;,4J:zvZdQ  
PPq*_Cf  
try{ ptDA))7M/  
URL url = new URL(sURL); r*p%e\ 3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3:;%@4f  
httpConnection.setRequestProperty("User-Agent","NetFox"); b6/:reH{  
String sProperty = "bytes="+nStartPos+"-"; Fk9(FOFg  
httpConnection.setRequestProperty("RANGE",sProperty); /Cg/Rwl  
Utility.log(sProperty); F 1zc4l6  
9MYt4  
(/KF;J^M  
InputStream input = httpConnection.getInputStream(); &0C!P=-p  
//logResponseHead(httpConnection); 8v6rS-iHP  
`UJW:qqW  
{W4t]Ff  
byte[] b = new byte[1024]; {(MG: B  
int nRead; |y=gp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x< 3vA|o  
{ Rw\DJJrz  
nStartPos += fileAccessI.write(b,0,nRead); ud#8`/!mq  
//if(nThreadID == 1) &1u ?W%(Px  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O0{v`|w9+  
} RCX4;,DHx  
B+B v(p  
qnm9L w#  
Utility.log("Thread " + nThreadID + " is over!"); 3}gK`1Nq1  
bDownOver = true; 2mT+@G  
//nPos = fileAccessI.write (b,0,nRead); ~w*ojI  
} ``z="oD  
catch(Exception e){e.printStackTrace ();} y(z U:.  
} $?GO|.59  
} 7> ]C2!  
~ dk1fh  
(Z5#;rgem  
//打印回应的头信息 UD(#u3z  
public void logResponseHead(HttpURLConnection con) `dNb%f>  
{ Q$zlxn 7\  
for(int i=1;;i++) vSL{WT]m  
{ h/VYH(Tj  
String header=con.getHeaderFieldKey(i); CFA>  
if(header!=null) 2M1mdkP3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ky%%H;  
Utility.log(header+" : "+con.getHeaderField(header)); .R"L$V$RU.  
else 3gh^a;uC  
break; $G}Q}f  
} W P&zF$  
} "|%fA E  
E4.IS =4S  
UmuFzw^  
public void splitterStop() fh 3 6  
{ $3Ia+O   
bStop = true; )gLasR.1  
} hzH5K  
iTvCkb48m  
n 3]y$wK  
} .KSGma6]  
?!66yn  
`qgJE_GC  
/* Og npzN  
**FileAccess.java ?n+\T'f!  
*//文件访问(定位,写) q<8HG_  
package NetFox; Z}C%%2Iz  
import java.io.*; aKy|$ {RC  
{cI<4><  
,m8*uCf  
public class FileAccessI implements Serializable{ "F}Ip&]hAG  
Oe!&Jma*>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h:NXO'  
RandomAccessFile oSavedFile; !;a<E:  
long nPos; i5"q1dRQ  
iD`XD\.?  
mTgn}rXk  
public FileAccessI() throws IOException |{K:.x#^  
{ 8gxLL59  
this("",0); q}i87a;m  
} y^rg%RV  
#*/h*GNMs  
Z#O3s:`  
public FileAccessI(String sName,long nPos) throws IOException hH/ O2  
{ g1|c?#fwo  
oSavedFile = new RandomAccessFile(sName,"rw"); UXJl;M b  
this.nPos = nPos; ~-%A@Lt  
oSavedFile.seek(nPos); QAwj]_  
} 7A6sSfPUy  
}b(e  
J5T#}!f  
public synchronized int write(byte[] b,int nStart,int nLen) LNE[c  
{ xTZ5q*Hqx  
int n = -1; uSJP"Lw  
try{ >>D i  
oSavedFile.write(b,nStart,nLen); mK-:laIL"  
n = nLen; 1 %`:8  
} '7R'fhiO/3  
catch(IOException e) eV0S:mit  
{ ]IV; >94[  
e.printStackTrace (); O :^[4$~  
} &/F[kAy  
qI^jwl|k  
(^9M9+L[i  
return n; ;I'/.gW;{  
} nL!@#{z  
B vc=gW  
%5gJ6>@6Z  
} 88j ;7  
CK</2w+  
2A|6o*s"  
/* 9(WC#-,  
**SiteInfoBean.java KOx#LGz  
*/ rg}kxvu  
package NetFox; '4sD1LD~}  
1_C6KS  
]:s|.C%qI  
public class SiteInfoBean { NN'<-0~  
auW]rwY  
O$/ swwB!  
private String sSiteURL; //Site's URL I+t38 un%  
private String sFilePath; //Saved File's Path T}[vfIJD  
private String sFileName; //Saved File's Name C>dJ:.K%H  
private int nSplitter; //Count of Splited Downloading File ooSd6;'  
Dt.Wb&V_w  
/ nFw  
public SiteInfoBean() X)OP316yx  
{//nSplitter的缺省值为5 VH6|(=8  
//default value of nSplitter is 5 <1BK 5%?  
this("","","",5); o7XRa]O  
} #U D  
qu+2..3  
vP?S0>gh  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YO0x68  
{ B31-<w  
sSiteURL= sURL; ! hr@{CD  
sFilePath = sPath; (Nb1R"J `  
sFileName = sName; >L`mF_WG  
this.nSplitter = nSpiltter; ;_5 =g  
~HRWKPb  
3y B6]U  
} R}9jgB  
2z# @:Q  
/exl9Ilt]  
public String getSSiteURL() M&c1iK\E8  
{ kw ^ Sbxm  
return sSiteURL; em!R9J.  
} {WOfT6y+  
G5J ZB7C  
%esZ}U   
public void setSSiteURL(String value) (1j$*?iGA  
{ 5)NBM7h  
sSiteURL = value; "mDrJTWa  
} t~K!["g  
4(GgaQFO?  
f+Li'?  
public String getSFilePath() C*e[CP@u  
{ g 'a?  
return sFilePath; D@W3;T^  
} =e-aZ0P  
x>" JWD  
TbAdTmW  
public void setSFilePath(String value) XPo'iI-  
{ igj@{FN  
sFilePath = value; )}\@BtcjA]  
} )ZyuF(C&  
!>Y\&zA  
]mo<qWRc>p  
public String getSFileName()  Rha3  
{ c$:=d4t5$  
return sFileName; Nw& }qSN  
} W(lKR_pF  
s{J!^q  
WTv\HI2X !  
public void setSFileName(String value) I jztj  
{ DLVs>?Y  
sFileName = value; H6S vU  
} gs8@b5 RSb  
9Sl|l.;!  
SH$cn,3F8  
public int getNSplitter() `oRs-,d|<  
{ 8yz((?LrDh  
return nSplitter; &|"I0|tJ  
} '!h0![OH  
h]DE Cd{  
MGyB8(  
public void setNSplitter(int nCount) KXA)i5z  
{ ::R00gd  
nSplitter = nCount; [pFu ] ^X  
} xp8f  
} seU^IC<  
yxWMatZ2  
=,8Eo"~\  
/* KM(9& 1/  
**Utility.java 9.OwH(Ax7  
*/ jy@i(@Z  
package NetFox; G$|;~'E  
UQ?OD~7  
,3- -ERf  
public class Utility { ,!%R5*?=D  
8Y~=\(5>  
Cm<j*Cnl  
public Utility() S}Y|s]6  
{ {r2|fgi  
(yAvDyJOn  
o"}&qA;  
} n.XhK_6n]M  
4J 51i*`  
//线程睡眠 A1t~&?  
public static void sleep(int nSecond) pvQK6r  
{ >g"M.gW  
try{ [gns8F#H\  
Thread.sleep(nSecond); Y0fO.k#C^  
} $gl<{{  
catch(Exception e) $#ju?B~  
{ SP?U@w%}  
e.printStackTrace (); chMc(.cN0  
} fDEu%fUYZ  
} i@R$g~~-D  
/< 7C[^h{-  
//日志 PWN'.HQ  
public static void log(String sMsg) ;, v L  
{ P9TBQW2G{  
System.err.println(sMsg); ^0tf1pV2  
} K _+;"G  
oSA*~N:  
b801O F  
public static void log(int sMsg) LUDJPIk  
{ |~b R.IA  
System.err.println(sMsg); DMcxa.Sd!  
} W aGcoj  
} X})Imk7&E  
.F$|j1y  
87pXv6'FQ  
/* !MJe+.  
**TestMethod.java ,Lun-aMd  
*/ ;y~{+{{Ow  
package NetFox; "`i:)Et  
Tq\~<rEo  
d1TdH s\  
public class TestMethod { |!?WQ[  
s\C8t0C  
it\DZGsg  
public TestMethod() D_n}p8blT  
{ ///xx/weblogic60b2_win.exe ZAX0n!db3  
try{ $S=~YzO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yB4H3Q )  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *fH_lG%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pba8=Z  
fileFetch.start(); 7.e7Fi{  
} 'uKkl(==%  
catch(Exception e){e.printStackTrace ();} %t`SSW7I  
ZG@M%|>  
B&i0j5L  
} T4~`e_  
Q1nDl  
]Q4PbW  
public static void main(String[] args) WfDX"rA  
{ M,t*nG  
new TestMethod(); P wB g  
} %nmY:}um  
} [l':G]  
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