http断点续传简单实现（java)

亚文隆

级别: 经院学前班

发帖: 8

铜板: 1641

人品值: 95

贡献值: 0

交易币: 0

好评度: 8

信誉值: 0

金币: 0

所在楼道

只看楼主更多操作楼层直达

0 发表于: 2006-05-10

/*
**SiteFileFetch.java
*/
package NetFox;
import java.io.*;
import java.net.*;

public class SiteFileFetch extends Thread {

SiteInfoBean siteInfoBean = null; //文件信息Bean
long[] nStartPos; //开始位置
long[] nEndPos; //结束位置
FileSplitterFetch[] fileSplitterFetch; //子线程对象
long nFileLength; //文件长度
boolean bFirst = true; //是否第一次取文件
boolean bStop = false; //停止标志
File tmpFile; //文件下载的临时信息
DataOutputStream output; //输出到文件的输出流

//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
public SiteFileFetch(SiteInfoBean bean) throws IOException
{
siteInfoBean = bean;
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
if(tmpFile.exists ())
{
bFirst = false;
read_nPos();
}
else
{
nStartPos = new long[bean.getNSplitter()];
nEndPos = new long[bean.getNSplitter()];
}

}

public void run()
{
//获得文件长度
//分割文件
//实例FileSplitterFetch
//启动FileSplitterFetch线程
//等待子线程返回
try{
if(bFirst)
{
nFileLength = getFileSize();
if(nFileLength == -1)
{
System.err.println("File Length is not known!");
}
else if(nFileLength == -2)
{
System.err.println("File is not access!");
}
else
{
for(int i=0;i<nStartPos.length;i++)
{
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tQrF A2F
} X0QY:?
for(int i=0;i<nEndPos.length-1;i++) iY|zv|;]=
{ ;s^br17z~
nEndPos = nStartPos[i+1]; *A^j>lV
} wqB 5KxO
nEndPos[nEndPos.length-1] = nFileLength; v+), uj
} 6w?l I
} +qWrm|O]
~PTqR2x
gv6}GE
//启动子线程 Zb \E!>V
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vU4Gw4
for(int i=0;i<nStartPos.length;i++) 0mb|JoE(
{ zL^`r)H
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Kyr3)1#J
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \!*3bR
nStartPos,nEndPos,i); n?UFFi+a
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gp l
fileSplitterFetch.start(); OI8Hf3d=
} =do*(
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M1Frn n
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lc:dKGF6
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (plsL
nEndPos = " + nFileLength); E43Gk!/|(
// fileSplitterFetch[nPos.length-1].start(); #`g..3ey
/'[m6zm]
w[K!m.p,u
//等待子线程结束 C;m,{MD
//int count = 0; 9<" .1
//是否结束while循环 (t.OqgY
boolean breakWhile = false; qe/|u3I<lF
i[+cNJ|$B0
A89n^@
while(!bStop) ]* #k|>Fl
{ Np.] W(
write_nPos(); @5[9iY
Utility.sleep(500); Tc3~~X
breakWhile = true; nEG+TRZ)\
'j#J1xwJ
oP"X-I
for(int i=0;i<nStartPos.length;i++) UI?AM 34
{ @)\{u$
if(!fileSplitterFetch.bDownOver) 1xBg^
{ Q.b<YRZ
breakWhile = false; x;w^&<hQ\
break; G*`H2-,
} ,Ky-3p>
} bV3az/U
if(breakWhile) =V[ey
break; "3?N*,U_
@W|N1,sp
!5wuBJ0
//count++; mY'c<>6t
//if(count>4) aFbIJm=!
// siteStop(); US.7:S-r"
} q^I/
h1A/:/_M6
pBbfU2p
System.err.println("文件下载结束！"); >RTmfV
} 7GFE5>H
catch(Exception e){e.printStackTrace ();} DHnO ,"
} ^&Exa6=*FT
6-+q3#e
NDqvt$
//获得文件长度 C4].egVg
public long getFileSize() "44A#0)B'l
{ NI%&Xhn!*>
int nFileLength = -1; Cj +{%^#
try{ H}p5qW.tH:
URL url = new URL(siteInfoBean.getSSiteURL()); @:ojt$
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zK_+UT
httpConnection.setRequestProperty("User-Agent","NetFox"); iPuX
2VZdtz
[bK5q;#U4
int responseCode=httpConnection.getResponseCode(); h{5K9$9=
if(responseCode>=400) 7<Yf
{ $oo`]R_
processErrorCode(responseCode); 4[.DQ#r
return -2; //-2 represent access is error C 7a$>#%
} GdlzpBl
eF06B'uL
rZi\
String sHeader; p!_3j^"{
C@ns`Eh8w
P\nz;}nv
for(int i=1;;i++) RP9jZRDbZ
{ nF#1B4b>
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :ot^bAyt|
//Utility.log(in.readLine()); |GLh|hr
sHeader=httpConnection.getHeaderFieldKey(i); b<]Ae!I'
if(sHeader!=null) m8:9Uv
{ *%#Sa~iPo
if(sHeader.equals("Content-Length")) N+3]C9 2o
{ +5k^-
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ER'zjI>t@
break; {: H&2iF
} s{:l yp
} N6%wHNYZ
else ^F?}MY>
break; .m^L,;+2
} e%wzcn
} {pR4+g
catch(IOException e){e.printStackTrace ();} ~ 7^#.
catch(Exception e){e.printStackTrace ();} xaw)iC[gI{
|Vj@;+/j
EG&97lb
Utility.log(nFileLength); )/{zTg8$?/
p "Cxe
R?E< }\!
return nFileLength; Xk]:]pl4W
} /]@1IC{Lk
a:V2(nY
2Vwv#NAV k
//保存下载信息（文件指针位置） 1!P\x=Nn_
private void write_nPos() 7/>#yR
{ Hdxon@,+cd
try{ jY|fP!?[
output = new DataOutputStream(new FileOutputStream(tmpFile)); m5'nqy F
output.writeInt(nStartPos.length); .I#ss66h
for(int i=0;i<nStartPos.length;i++) {Y7dE?!`7
{ +~{Honj[
// output.writeLong(nPos); vWh]1G#'p[
output.writeLong(fileSplitterFetch.nStartPos); &&s3>D^Ta
output.writeLong(fileSplitterFetch.nEndPos); f$|AU-|<
} a^xt9o`
output.close(); Kwmtt
} '&+5L.
catch(IOException e){e.printStackTrace ();} 02RZ>m+
catch(Exception e){e.printStackTrace ();} 6^VPRp
} EC`=nGF
TJ_pMU
iY;>LJmp
//读取保存的下载信息（文件指针位置） @aC9O9|~
private void read_nPos() uFYcVvbT@
{ khQ@DwO*\=
try{ (8td0zq
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \<u
int nCount = input.readInt(); T?k!%5,Kj
nStartPos = new long[nCount]; H~<w*[uT
nEndPos = new long[nCount]; Xx?~%o6
for(int i=0;i<nStartPos.length;i++) =OamN7V=
{ S.R|Bwj}(Y
nStartPos = input.readLong(); q(\kCUy!
nEndPos = input.readLong(); _@@.VmZL
} Csf!I@}Z
input.close(); pB:/oHV
} 3XSfXS{lwP
catch(IOException e){e.printStackTrace ();} 21sXCmYR,t
catch(Exception e){e.printStackTrace ();} {v}BtZ
} (Tv~$\=
TOw;P:-
bc]SY =
private void processErrorCode(int nErrorCode) `qm$2
{ NiBly
System.err.println("Error Code : " + nErrorCode); cq"#[y$r
} f-`C1|\w
CLgfNrW~
~v6]6+
//停止文件下载 '1"vwXJ"
public void siteStop() ^i!I0Q2yd
{ vw6DHN)k
bStop = true; qGdoRrp0Ov
for(int i=0;i<nStartPos.length;i++) ST1c`0e
fileSplitterFetch.splitterStop(); #+8G`
Sb.%B^O
vLIaTr gz
} x5R|,bY
} 6PT"9vR`)
//负责部分文件的抓取 +?v2MsF']
**FileSplitterFetch.java Zg$RiQ^-{J
*/ B^@X1EE
package NetFox; Slv91c&md,
w>wzV=R
H>F j
import java.io.*; 9`tSg!YOh
import java.net.*; k]rc -c-
'fPDODE
"t%Jj89a\
public class FileSplitterFetch extends Thread { C."\ a_p
+!mEP>
:6J&%n
String sURL; //File URL dWP<,Z>
long nStartPos; //File Snippet Start Position M{g.x4M@W
long nEndPos; //File Snippet End Position }H:wgy`
int nThreadID; //Thread's ID jI%glO'2
boolean bDownOver = false; //Downing is over ^s\T<;
boolean bStop = false; //Stop identical d:{}0hmxI
FileAccessI fileAccessI = null; //File Access interface :!wl/X ~
.Bojb~zt
<"yL(s^u"
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?\$6"c<G
{ Of>2m<
this.sURL = sURL; O9rA3qv B
this.nStartPos = nStart; S0`u!l89(
this.nEndPos = nEnd; !~tf0aY
nThreadID = id; Xi;<O&+
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]CDUHz
} R>B6@|}?
<R?S
NAOCQDk{
public void run() Qna*K7kv
{ beB3*o
while(nStartPos < nEndPos && !bStop) $LVzhQlD
{ xnHB <xrE}
tIS.,CEQF
S]NT+XM
try{ Lngf,Of.e
URL url = new URL(sURL); &+3RsIlW
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "R"{xOQl
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Y/kF1,*
String sProperty = "bytes="+nStartPos+"-"; r7FJqd
httpConnection.setRequestProperty("RANGE",sProperty); GT\yjrCd
Utility.log(sProperty); w c
\BX9Wn*)a
F\^\,hy
InputStream input = httpConnection.getInputStream(); {yDQncq'^
//logResponseHead(httpConnection); 8tVSai8[
%y7ZcH'
iNc!zA4
byte[] b = new byte[1024]; =~5N/!
int nRead; YRMe<upo
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bGkLa/?S
{ 'Va<GHr>+
nStartPos += fileAccessI.write(b,0,nRead); al9( 9)
//if(nThreadID == 1) =zu;npM
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8nWPt!U:
} Uf MQ?(,
gAVD-]`
OZC yg/K
Utility.log("Thread " + nThreadID + " is over!"); T+B8SZw#}!
bDownOver = true; +v$W$s&b-h
//nPos = fileAccessI.write (b,0,nRead); I@\D tQZ
} 9tb-;|
catch(Exception e){e.printStackTrace ();} e7bMK<:r
} [4aw*M1z}.
} e=aU9v L
6nREuT'k
o 0T1pGs'
//打印回应的头信息 'IT]VRObP
public void logResponseHead(HttpURLConnection con) '$eJATtC
{ JVxja<43
for(int i=1;;i++) ~mwIr
{ k2tSgJW
String header=con.getHeaderFieldKey(i); 3o0ZS^#eB
if(header!=null) ~I9o*cq
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w^("Pg`
Utility.log(header+" : "+con.getHeaderField(header)); Pf<yLT]
else =9W\;xE S
break; Yi)s=Q:
} +S[3HX7H
} 7!h> < sx
MJrPI a[pN
!s?SI=B8
public void splitterStop() vU5}E\Ny
{ 6GPI gPL,
bStop = true; mwyB~,[d+W
} aWH
M_-L#FHX
jwBJG7\
} gujP{Z
eO(U):C2
!c{F{t-a
/* 1_A_)l11
**FileAccess.java `CC=?E
*//文件访问(定位，写) yP>025o't
package NetFox; 8D,*_p
import java.io.*; 6>)nkD32g
Bf]Bi~w<
iP;"-Mj
public class FileAccessI implements Serializable{ NdSuOkwwt
Ej 5_d
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -{8K/!
RandomAccessFile oSavedFile; #.[eZ[
long nPos; KX7fgC
B2P@9u|9
CaO-aL
public FileAccessI() throws IOException P9f`<o
{ 2<y9xvp
this("",0); @2a!T03
} %2\tly!{ %
z7gX@@T
CfSP*g0rW
public FileAccessI(String sName,long nPos) throws IOException 3Jt# Mp
{ vJ=Q{_D=\
oSavedFile = new RandomAccessFile(sName,"rw"); CswKT9
this.nPos = nPos; i%i/>;DF
oSavedFile.seek(nPos); 1JfZstT
} 0Ci/-3HV!
{>9ED.t
X(X[v]
public synchronized int write(byte[] b,int nStart,int nLen) ,Kl?-W@
{ X-kOp9/.
int n = -1; +egwZ$5I
try{ n*A1x8tn
oSavedFile.write(b,nStart,nLen); _oCNrjt9
n = nLen; {\%I;2X
} XD|g G
catch(IOException e) x: _[R{B
{ |*UB/8C^/!
e.printStackTrace (); u4w!SD
} z\A ),;
S#v3%)R
uf9&o#
return n; %)?jaE}[
} RR ^7/-
?6&8-zt1?
H~nZ=`P9&
} FX|&o>S(8
%dg[ho
K)~aH
/* oD9n5/ozo
**SiteInfoBean.java zU+q03l8Ur
*/ 0 }od Q#
package NetFox; QAp]cE1ew
y^}uL|=
$Oy&POe
public class SiteInfoBean { BLO ]78
?z&%VU"
7[1|(6$
private String sSiteURL; //Site's URL iW>^'W#
private String sFilePath; //Saved File's Path %kV7 <:y
private String sFileName; //Saved File's Name p^|l ',e
private int nSplitter; //Count of Splited Downloading File ,&WwADZ-s
=urGs`\
4}v|^_x-i
public SiteInfoBean() ;-kDJi
{//nSplitter的缺省值为5 BR@m*JGajz
//default value of nSplitter is 5 URrx7F98
this("","","",5); B6k<#-HAT
} 6X%g-aTs
ix4]^
h )5S4)
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ybE2N
{ YnU)f@b#
sSiteURL= sURL; T!KwRxJ23
sFilePath = sPath; HdI)Z<Krp
sFileName = sName; 9%iQ~
this.nSplitter = nSpiltter; N\ !
/}m*|cG/
o!":mJy
} y7fy9jQ 8.
SnmUh~`L~
a~$Y;C_#<
public String getSSiteURL() 3S7"P$q
{ z77>W}d
return sSiteURL; @e GBF Ns
} >VkBQM-%
3}8o 9
0~^RHb.NA8
public void setSSiteURL(String value) mQ"uG?NE
{ pLtw|S'4
sSiteURL = value; 2icQ (H;
} e@W+ehx"
m)Kg6/MV.
-;L'Jb>s76
public String getSFilePath() , i5_4
{ WJnGF3G>
return sFilePath; @CmKF
} !EhKg)y=
Nb`qM]&
(;},~( 2B
public void setSFilePath(String value) IUFc_uL@\
{ @nY]S\if
sFilePath = value; src+z#
} `{G&i\"n
>9dD7FH
! I0xq"
public String getSFileName() 7}UG&t{
{ 6_bL<:xtY
return sFileName; =zcvR {Dkp
} yEI@^8]s
ezp%8IZ;
^0OP&s;"
public void setSFileName(String value) bTaKB-
{ i9DD)Y<
sFileName = value; M>]A!W=
} \MOwp@|y
j,+]tHC-
]$[sfPKA
public int getNSplitter() ujX;wGje
{ V^5d5Ao
return nSplitter; Km8aHc]O~
} D![v{0er
:]m.&r S,
+ '_t)k^
public void setNSplitter(int nCount) LnI
{ rQVX^
nSplitter = nCount; {}$7Bp
} EyE#x_A
} Z_\p8@3aH
MVsFi]-
akzGJ3g
/* 4\Y5RfLB_
**Utility.java 0+*NHiH
*/ pi?MAE*f
package NetFox; GT&}Burl/n
-V|"T+U
%'=*utOxy
public class Utility { zXn-E
"s(~k
Go)$LC0Mi
public Utility() lb-1z]YwQ
{ LKu\Mh|
S%i^`_=Q
ZNX38<3h
} l4oyF|oJTH
Icnhet4
//线程睡眠 l}))vf=i
public static void sleep(int nSecond) 27e!KG[&
{ YB5"i9T2
try{ g"evnp
Thread.sleep(nSecond); -)`_w^Ox
} 5QMra5Nk
catch(Exception e) %L+q:naZe
{ L=4+rshl!_
e.printStackTrace (); `r`8N6NQ&]
} :}lqu24K
} X g6ezlW
FPDTw8" B;
//日志 CI'RuR3y]Z
public static void log(String sMsg) FmL]|~
{ ::|~tLFu
System.err.println(sMsg); `<C<[JP:o
} a[-!X7,IU
bO=|utpk
w7V\_^&Id
public static void log(int sMsg) to'7o8Z
{ :aesG7=O
System.err.println(sMsg); }Y~Dk]*
} WPRk>j
} &|XgWZS5
nG'Yo8I^5
%"f85VfZ
/* sg,\!'
**TestMethod.java ^# $IoW
*/ &`qYe)1Eo
package NetFox; QG*hQh
FXr^ 4B}
7"Xy8]i{z
public class TestMethod { ~Fb@E0 }!
=CFjG)L
Gt*<Awn8
public TestMethod() {Z/iYHv~#c
{ ///xx/weblogic60b2_win.exe N 8[rWJ#
try{ qR.FjQOvn
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iOZ9A~Ywy
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M1eh4IVE?
SiteFileFetch fileFetch = new SiteFileFetch(bean); "9xJ},:-
fileFetch.start(); `e ZDG
} (/uN+
catch(Exception e){e.printStackTrace ();} !ldEy#"X
JAHg_!
4vL\t uoz
} igQzL*X
jP<6J(
"=Z=SJ1D
public static void main(String[] args) V<WWtu;3
{ C@*x
new TestMethod(); -F/)-s6#!'
} FZgf"XM>
} YQD`4ND
点击下载更多相关资料