http断点续传简单实现（java)

/* }?f%cRT$  
**SiteFileFetch.java Wj2s+L7,  
*/ *P4G}9B|9:  
package NetFox; c_#\'yeW  
import java.io.*; nic7RN?F<  
import java.net.*; ka_]s:>+  
gXtyl]K:  
asT*Z"/Q!  
public class SiteFileFetch extends Thread { fIOI  
XA`<*QC<  
=rBNEd  
SiteInfoBean siteInfoBean = null; //文件信息Bean ByR%2_6&  
long[] nStartPos; //开始位置
20[_eu)  
long[] nEndPos; //结束位置 :S Tj <  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B+:'Ld](  
long nFileLength; //文件长度 1EvAV,v"  
boolean bFirst = true; //是否第一次取文件 V=!tZ[4z$h  
boolean bStop = false; //停止标志 6?-vj2,  
File tmpFile; //文件下载的临时信息 Kyy CS>  
DataOutputStream output; //输出到文件的输出流 "S6'<~s  
]Lg$p  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mjdZ^  
public SiteFileFetch(SiteInfoBean bean) throws IOException CRy;>UI  
{ r+8%oWj  
siteInfoBean = bean; ]Bo !v*12  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d!0p^!3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;>?
NH6B,  
if(tmpFile.exists ()) ;m/%g{oV  
{ #R&Dgt  
bFirst = false; <"I#lib  
read_nPos(); N}0-L$@SL  
} V:?exJg9  
else \iFh-?(  
{ #DMt<1#:  
nStartPos = new long[bean.getNSplitter()]; yLfb'Ba  
nEndPos = new long[bean.getNSplitter()]; P]*,955*)  
} bYT,f.,5{  
}K\]M@  
DgOO\
 
h+o-h4X  
} 'F[m,[T%x  
%";bgU2
Q  
`TvpKS5.Y  
public void run() I$@0FSl  
{ Y*
-#yG9  
//获得文件长度 SH#-3&$[  
//分割文件 JTuU}nm+  
//实例FileSplitterFetch {"<D$*K~  
//启动FileSplitterFetch线程 vu^ '+ky  
//等待子线程返回 @dimZsi1  
try{ . IBy'  
if(bFirst) ;0lHi4
c0  
{ +an.z3?w  
nFileLength = getFileSize(); 3DH} YAUU  
if(nFileLength == -1) Q[t|+RNKv2  
{ h^E"eC  
System.err.println("File Length is not known!"); :f?};t+  
}
(UWV#AR  
else if(nFileLength == -2) 
!Yx9=>R  
{ U~krv>I  
System.err.println("File is not access!"); tHe
zS~t_  
} g9 .b6}w!  
else OQt_nb#z`{  
{ '0z-duu  
for(int i=0;i<nStartPos.length;i++) {j%'EJ5  
{  Dh=?Hzw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m44Ab6gpsb  
} @1_M's;  
for(int i=0;i<nEndPos.length-1;i++) ~Rx:X4|H  
{ 1-`Il]@?8  
nEndPos = nStartPos[i+1]; |l)z^V!  
} o+e
:HjZZ  
nEndPos[nEndPos.length-1] = nFileLength; &S/@i|_  
} ?kfLOJQ:I  
} v8Ga@*  
F91'5D,u0  
tOx)t$ix  
//启动子线程 |E/r64T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `w@8i[2J  
for(int i=0;i<nStartPos.length;i++) &)4#0L4  
{ 5;{Q >n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ke0j8|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :77dl/d%  
nStartPos,nEndPos,i); K.k%Tg[ ~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G:'hT=8  
fileSplitterFetch.start(); xVOoYr>O  
} fUy:TCS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r+6=b"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I<p- o/TP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z(F`M;1>xI  
nEndPos = " + nFileLength); JHN{vB  
// fileSplitterFetch[nPos.length-1].start(); b4o`eR  
`acX1YWh5  
Z_iVOctP  
//等待子线程结束 G.CkceWRn  
//int count = 0; g"pjWj)?  
//是否结束while循环 6_KO6O7g  
boolean breakWhile = false; {9>LF  
p%;n4*b2  
9"T&P_   
while(!bStop) g\;&Z  
{ !Zf< j  
write_nPos(); J]|Zh  
Utility.sleep(500); oC"1{ybyl  
breakWhile = true; :m~R<BQ"  
[wHGt?R  
4hRc,Vq  
for(int i=0;i<nStartPos.length;i++) *}mk$bA  
{ cj=6_
k  
if(!fileSplitterFetch.bDownOver) |$
AoI  
{ 6Z2a5zO8  
breakWhile = false; 5Q
$6~\  
break; PtR8m=O  
} !% 'dyj  
} 'Z^-(xG,+  
if(breakWhile) -_<rmR[:]  
break; wGRMv1|lIu  
9 b?Nlk8d  
rUJIf;Zwo  
//count++; yHrYSE
M  
//if(count>4) z=YHRS  
// siteStop(); r$7zk<01  
} 1DzI@c~X  
-M{.KqyW  
mU d['Z  
System.err.println("文件下载结束！"); ;;r}=0V*=  
} :PJ5~7C  
catch(Exception e){e.printStackTrace ();} a#Yo^"*1  
} 1?6zsA%N  
&w4~0J>v!  
bq+Q$#F2X  
//获得文件长度 V4~`yT?*"  
public long getFileSize() gaBVD*>  
{ .(D,CGtYb  
int nFileLength = -1; S3cV^CzNg  
try{ HN7C+e4U~  
URL url = new URL(siteInfoBean.getSSiteURL()); |}hV
_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s2`:NS  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9d5|rk8VS  
~57.0?IK  
l)1FCDV  
int responseCode=httpConnection.getResponseCode(); x^0MEsR  
if(responseCode>=400) rV *`0hA1  
{ 'WF Ey>1#  
processErrorCode(responseCode); _VvXE572  
return -2; //-2 represent access is error 0m`{m'B4n  
} MlbQLtw  
@fjVCc;  
'aLTiF+  
String sHeader; [PRQa[_  
qKL:#ny  
R]Iv?)Y  
for(int i=1;;i++) $0(~ID  
{ V~tZNRJ-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NG)Xk[q4  
//Utility.log(in.readLine()); y9/x:n&]  
sHeader=httpConnection.getHeaderFieldKey(i); 9hbn<Y  
if(sHeader!=null) a,>`ab%>  
{ -Y?C1DbKz  
if(sHeader.equals("Content-Length")) -chk\75  
{ 3Gr:.V9=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *=b#>//  
break; Py}] {?  
}
f`^\v  
} e\Igc.  
else LBCat=d<  
break; ]U
LE>a  
} T/9`VB%N  
} &O&;v|!9  
catch(IOException e){e.printStackTrace ();} G; onJ>  
catch(Exception e){e.printStackTrace ();}
G\\0N^v  
xRTr
@  
Y1=.46Ezf  
Utility.log(nFileLength); j B.ZF7q  
Oo-%;l`&  
=.<S3?  
return nFileLength; cz{5-;$9Z  
} *|OP>N  
DrY5Q&S  
2%i3[N*  
//保存下载信息（文件指针位置） ,o?yS>L_r  
private void write_nPos() =x QLf4>  
{ \R}`S`fIw`  
try{ I4Y;
9Gg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !}+rg2  
output.writeInt(nStartPos.length); f\/'Fy0  
for(int i=0;i<nStartPos.length;i++) z[E gMS!  
{ mW+QJ`3  
// output.writeLong(nPos); W)OoHpdw  
output.writeLong(fileSplitterFetch.nStartPos); dI$U{;t  
output.writeLong(fileSplitterFetch.nEndPos); H.H$5(?O  
} IegZ)&_n  
output.close(); JGZxNUr^  
} +DpiX&^h   
catch(IOException e){e.printStackTrace ();} 6`V2-zv$  
catch(Exception e){e.printStackTrace ();} `8D)j>Yh~  
} 3Mlwq'pzD  
vwc)d{ND  
7y/Pch  
//读取保存的下载信息（文件指针位置） )|Il@unp/  
private void read_nPos() VK~ OL  
{ "&@v[O)!xu  
try{ &OX
nZT3P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )9PP3"I  
int nCount = input.readInt(); eG F{.]  
nStartPos = new long[nCount]; 0}:wM':G  
nEndPos = new long[nCount]; |K7zN\ Wq  
for(int i=0;i<nStartPos.length;i++) }BR@vY'd  
{ bAd$ >DI[  
nStartPos = input.readLong(); Ie<`WU K  
nEndPos = input.readLong();
p%?VW  
} /&T"w,D  
input.close(); ophQdJM  
}  )ld !(d=  
catch(IOException e){e.printStackTrace ();} Gv$}>YJ  
catch(Exception e){e.printStackTrace ();} :SUU)jLq  
} p1mY@  
@ff83Bg  
vT&xM  
private void processErrorCode(int nErrorCode) \_#Z~I{  
{ 'TdO6-X  
System.err.println("Error Code : " + nErrorCode); k`u:Cz#aB  
} X (0`"rjg  
L{i,.aE/nO  
=ghN)[AZV  
//停止文件下载 *pOdM0AE  
public void siteStop() .=u8`,sO  
{ sC^
9  
bStop = true; jQ 'r};;  
for(int i=0;i<nStartPos.length;i++) >U2[]fu  
fileSplitterFetch.splitterStop(); :VB{@ED  
tt%lDr1A)  
a2vZ'  
} U>@st="  
} 4?vTuZ/ M  
//负责部分文件的抓取 hG8!aJo  
**FileSplitterFetch.java u\uYq  
*/ >bo_  
package NetFox; 55<f  
eX1<zzd  
Px$4.b[{_Y  
import java.io.*; fzhCV  
import java.net.*; ZB|y  
F(5(cr 7K  
TSPFi0PP  
public class FileSplitterFetch extends Thread { $v
#\bqY  
VEtdp*ot  
MD62ObK!  
String sURL; //File URL =;!$Qw4  
long nStartPos; //File Snippet Start Position jJB+UF=  
long nEndPos; //File Snippet End Position =MP?aH [  
int nThreadID; //Thread's ID ;%/Kh :Vg  
boolean bDownOver = false; //Downing is over b;AGw3SF  
boolean bStop = false; //Stop identical e2@{Ab  
FileAccessI fileAccessI = null; //File Access interface i!U,qV1  
W-ctx"9DS  
k>ERU]7[  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pod=
|(c  
{ foi@z9  
this.sURL = sURL; "PI]k  
this.nStartPos = nStart; 6(FkcC$G  
this.nEndPos = nEnd; ,o\-'   
nThreadID = id; At?]FjL6S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L+rMBa  
} xKZLXQ'e-  
gFx2\QV  
/@!%/Kl  
public void run() '%}k"&t$i  
{ nJ]oApb/-  
while(nStartPos < nEndPos && !bStop) ( \ \BsK  
{ FU~xKNr  
oOj7y>Nm  
[;E~A  
try{ 82z\^a  
URL url = new URL(sURL); &/}reE*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p}r1@L s  
httpConnection.setRequestProperty("User-Agent","NetFox"); R}S@u@mOE  
String sProperty = "bytes="+nStartPos+"-"; MzWVsV  
httpConnection.setRequestProperty("RANGE",sProperty); lebwGW,!  
Utility.log(sProperty); !i`HjV0wS  
x)h|!T=B~  
:zWI"  
InputStream input = httpConnection.getInputStream(); >&mNC\PA  
//logResponseHead(httpConnection); =jWcD{;1I}  
63EwV p/|  
-%5O:n  
byte[] b = new byte[1024]; 9 K.
B  
int nRead; 42{\u08Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Z fQ)q\  
{ a*oqhOTQ  
nStartPos += fileAccessI.write(b,0,nRead); B]""%&! O  
//if(nThreadID == 1) )fRZ}7k:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aT[qJbp1  
} -!~T$}/F  
I>(3\z4s  
^)|!nd  
Utility.log("Thread " + nThreadID + " is over!"); LrL ZlJf  
bDownOver = true; KO~_  
//nPos = fileAccessI.write (b,0,nRead); :L E&p[^  
} a(qij&>  
catch(Exception e){e.printStackTrace ();} ;nDCyn4i]  
} 3kc.U  
} ]rpU3 3  
VD,p<u{r  
PGE|){ <  
//打印回应的头信息 #2XX[d%  
public void logResponseHead(HttpURLConnection con) _~=qByD   
{ !(-lY(x  
for(int i=1;;i++) R[%ZyQ_  
{ Ep.Q&(D >  
String header=con.getHeaderFieldKey(i); ~eVq Fc  
if(header!=null) Ui^~A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zn=Ifz)#|  
Utility.log(header+" : "+con.getHeaderField(header)); YEg(QOn3Q  
else 19r4J(pV  
break; `~0^fSww  
} 3t*e|Ih&j5  
} 1hz:AUH  
z;#DX15Rj  
2!7)7wlj0  
public void splitterStop() {`Jr$*;  
{ O@Ro_sPG(  
bStop = true; W$I^Ej}>$  
} #jc+2F,+{  
NQFMExg,  
aR2Vvo  
} 0|D^_1W`R  
_
gGI&0(VM  
f4h|Nn%;  
/* e\[z Q 2Z3  
**FileAccess.java h8
ikM&fl  
*//文件访问(定位，写) >`3wEJ"<  
package NetFox; |\ZsoA  
import java.io.*; Hju7gP=y}  
lU}y%J@  
4Z&i\#Q  
public class FileAccessI implements Serializable{ ~)ecQ  
t=K;/1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (D?%(f  
RandomAccessFile oSavedFile; 4F-r}Fj3  
long nPos; MKnG:)T<?l  
<#[_S$
54  
6c?;-5.  
public FileAccessI() throws IOException 5 aT>8@$Z^  
{ o`]o(OP  
this("",0); ZSBa+3;z  
} +# 38  
{x-iBg9#l2  
|SO?UIWp  
public FileAccessI(String sName,long nPos) throws IOException 'R{X
qHP  
{ 2i~tzo  
oSavedFile = new RandomAccessFile(sName,"rw"); =)2sehU/  
this.nPos = nPos; \e=Iw"yd  
oSavedFile.seek(nPos); tiTJ.uz6  
} zm&D#)  
"<#-#j  
FE0}V}\=h  
public synchronized int write(byte[] b,int nStart,int nLen) e]1&f.K  
{ z<T(afM{*  
int n = -1; ae&i]K;  
try{ TIs~?wb$  
oSavedFile.write(b,nStart,nLen); TpHvZ]c  
n = nLen; DaA9fJ7a   
} d~G, *  
catch(IOException e) "&_$%#HUv  
{ ]YO &_#  
e.printStackTrace (); 61XLL/=P  
} S,=#b 4\#%  
zKY 9'y  
f>*D@TrU  
return n; xla64Qld  
} !mM`+XH  
H/rJ:3  
aB=&XGV9  
} 0ESxsba  
Xscm>.di  
U)f;*{U  
/* (O&R-5m  
**SiteInfoBean.java :RxWHh3O  
*/ +b9gP\Hke  
package NetFox; WN5`zD$  
n^a&@?(+  
v$P<:M M  
public class SiteInfoBean { 'e/= !"T  
F+c4v A})  
by:"aDGK.  
private String sSiteURL; //Site's URL E#0_y4  
private String sFilePath; //Saved File's Path Epl\(  
private String sFileName; //Saved File's Name _$Wj1h  
private int nSplitter; //Count of Splited Downloading File c,v?2*<  
)P>}uK;  
;Nd,K C0k  
public SiteInfoBean() ;cFlZGw   
{//nSplitter的缺省值为5 KKCzq |  
//default value of nSplitter is 5 <{z*6FM!'  
this("","","",5); 'l&),]|$)  
} 4YT d  
 .# Jusd  
JKXb$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l2&s4ERqSm  
{ T>!Y-e.q  
sSiteURL= sURL; THOXs; k0  
sFilePath = sPath; :c_>(~  
sFileName = sName; mPmg6Qj(W  
this.nSplitter = nSpiltter; @_ZE_n   
u>K(m))5W3  
Im<i.a <`  
} RqONVytx  
iB1+4wa  
jNC@b>E?~  
public String getSSiteURL() .?Pghqq.  
{ e2}5< 7  
return sSiteURL; 4GL-3e  
} 8+?|4'\
`  
{SQ#n@Q&$  
d:_3V rRZ  
public void setSSiteURL(String value) )~Pj3  
{ ]y**ZFA  
sSiteURL = value; kwM1f=!-  
} W/\M9  
Jn+k$'6%#  
-J`
VXG:M  
public String getSFilePath() IHrG!owf  
{ i'\7P-a  
return sFilePath; $Y\-X<gRH  
} Y\e8oIYu7  
Q!T+Jc9N  
&|LP>'H;  
public void setSFilePath(String value) Mq#sSBE<K  
{ z0v|%&IK  
sFilePath = value; l)d(N7HME  
} 4(hHp6}b  
,l
UroO^^  
=8p *Ijs  
public String getSFileName() 1Fs:&*=  
{ hE9UWa.Q>  
return sFileName; QrX 5Kwq  
} *=KX0%3  
G|LJOq7QB  
hk7kg/"  
public void setSFileName(String value) s4&JBm(33N  
{ U.kTd
NSp  
sFileName = value; gE}+`w/X  
} `nvm>u~[Hq  
|_H{B+.  
O^_$cq  
public int getNSplitter() fPj*qi  
{ 9?6]Zag  
return nSplitter; (9A`[TRwi  
} jW!x!8=  
5RUhrE   
5TB==Fj ?  
public void setNSplitter(int nCount) ;LhNz()b  
{ Vlka+$4!  
nSplitter = nCount; 4kr! Af  
} *.2[bQL@v  
} rmq^P;
At  
]rY3bG'&  
zfBaB0P  
/* iDdmr32E  
**Utility.java =a]B#uUn  
*/ W3h{5\d!  
package NetFox; P*kKeM
l  
DH*=IzcJf  
vp_$Ft-R  
public class Utility { R3<2Z0lqy  
(UGmbRf&  
c1 ~=   
public Utility() <:YD.zAh|  
{ G^6\OOSy  
Ev)a
XP  
{T=rsPp<@  
} )yyS59s  
7k==?,LG3  
//线程睡眠 J=OWXL!<a  
public static void sleep(int nSecond) yClbM5,  
{ ;'fn{j6C  
try{ @:M?Re`L  
Thread.sleep(nSecond); |E7)s;}D  
} nWzGb2Y  
catch(Exception e) ~=#jr0IZ  
{ Qk_Mx"  
e.printStackTrace (); 4hLv"R.  
} /qeSR3WC  
} 0D=7Mef  
a+_F^   
//日志 M?FbBJ`sF  
public static void log(String sMsg) `BGU   
{ Ozo)}  
System.err.println(sMsg); B*,Qw_3dG  
} ,iYKtS3  
;A3aUN;"I  
Cjn)`Q8  
public static void log(int sMsg) M%#H>X\/  
{ |TE\]  
System.err.println(sMsg); (+=TKI<=  
} ;xl_9Ht/  
} noLb  
wRLj>
nc  
Z7@~#)3  
/* 45DR%cz  
**TestMethod.java w*-1*XNA  
*/ X"z!52*3]  
package NetFox; 7K\H_YY8#  
OM4q/!)A]  
HX
g4 T  
public class TestMethod { S$egsK"~  
Ts~)0  
tc%0yr9  
public TestMethod() Zt7Gf  
{ ///xx/weblogic60b2_win.exe |:{H4  
try{ F,l%SQCyj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /[|ODfY
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;[[GA0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (9X>E+0E  
fileFetch.start(); `;OEdeAM  
} _hy<11S;  
catch(Exception e){e.printStackTrace ();} O:
>9yZhV  
x.:k0;%Q  
F#az&  
} 5uJ{#Zd  
s/=.a2\  
^HM9'*&KJ  
public static void main(String[] args) B<A=U r  
{ iO?Sf8yJ:  
new TestMethod(); W2CQk  
} %!_%%p,f  
} "k%B;!We)  
点击下载更多相关资料