http断点续传简单实现（java)

/* PdD,~N#  
**SiteFileFetch.java ))xP]Muv  
*/ Oz1S*<]=,~  
package NetFox; b haYbiX?  
import java.io.*; U6xs'0  
import java.net.*; ;&} rO.0  
^Q9!DF m  
Sg+0w7:2  
public class SiteFileFetch extends Thread { b[Qe} `W  
^rh{  
0-at#r:  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2tqj]i  
long[] nStartPos; //开始位置 CzfGb4  
long[] nEndPos; //结束位置
|r<#>~*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +t7n6  
long nFileLength; //文件长度 ?,z/+/:  
boolean bFirst = true; //是否第一次取文件 ad#4W0@S  
boolean bStop = false; //停止标志 Oe)B.{;Ph  
File tmpFile; //文件下载的临时信息 \r`><d
 
DataOutputStream output; //输出到文件的输出流 }!9KxwC(  
.P#+V$qhv  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lS96sjJp@  
public SiteFileFetch(SiteInfoBean bean) throws IOException w#!b #TNc  
{ =im7RgIBo  
siteInfoBean = bean; J ?^
R1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xcM*D3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OzA'd\|  
if(tmpFile.exists ()) (iJ9ekB  
{ 3aUWQP2  
bFirst = false; J.Fy0W@+k4  
read_nPos(); [4 y7tjar^  
} $2/v8  
else ,LodP%%UV  
{ U9(p ^  
nStartPos = new long[bean.getNSplitter()]; ! _p
(H  
nEndPos = new long[bean.getNSplitter()]; vw)lD9-"  
}
k];NTALOG  
)cV*cDL1j  
sLze/D_M*  
kCHYLv3.  
} ?F"mZu  
QzilivJf  
yFY:D2  
public void run() l|j}Ggen  
{ yp?a7t M  
//获得文件长度 %DhM}f
 
//分割文件 uA;vW\fHr  
//实例FileSplitterFetch C8W4~~1S  
//启动FileSplitterFetch线程 9D[Jn}E:  
//等待子线程返回 /8Ru
O  
try{ 0BrAgv"3a_  
if(bFirst) $_f"NE}  
{ .I%`yhCW  
nFileLength = getFileSize(); E+z"m|G  
if(nFileLength == -1) <44A*ux  
{ kHbH{])  
System.err.println("File Length is not known!"); *
bSxobn  
} Xy]Pmt  
else if(nFileLength == -2) yvIzgwN%s!  
{ P$#{a2
 
System.err.println("File is not access!"); SX]uIkw  
} 5j~1%~,
#  
else H&SoVi_V  
{ ~UNK[  
for(int i=0;i<nStartPos.length;i++) A-f,&TO  
{ h,zM*zA_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ac!!1lwA  
} \ef:H&r  
for(int i=0;i<nEndPos.length-1;i++) BOWO
H  
{ 5M/~|"xk  
nEndPos = nStartPos[i+1]; d^f rKPB  
} [X91nUz#  
nEndPos[nEndPos.length-1] = nFileLength; }|%1LL^pB  
} Mi;Pv*  
} 3YJ"[$w='(  
u HW'F(;  
=t`cHs29  
//启动子线程 yO}5.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #IJeq0TVB  
for(int i=0;i<nStartPos.length;i++) w {"1V7|  
{ Cv}^]_`Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uaz!ze+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p!5'#\^f  
nStartPos,nEndPos,i); gJCZ9{Nl  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }8POm#  
fileSplitterFetch.start(); NJ]3qH  
} a9UXg<4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kIX1u<M~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s<rV1D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Svb>s|D  
nEndPos = " + nFileLength); tJ 2GSZ`  
// fileSplitterFetch[nPos.length-1].start(); .`Q^8|$-K  
tbWfm5$  
{VKFw=$8  
//等待子线程结束 ]Axz}:  
//int count = 0; EY:IwDA.}  
//是否结束while循环 *AYq:n6  
boolean breakWhile = false; ""Da2Md  
;1s+1G}_z  
#n}~u@,o_  
while(!bStop) 6i2%EC9  
{ L7d1)mV  
write_nPos(); 0{g*\W*+~  
Utility.sleep(500); X6",Xr!{  
breakWhile = true; DU0/if9.  
;AE-=/<  
}f]Y^>-Ux  
for(int i=0;i<nStartPos.length;i++) wD=]U@t`,  
{ z9*e%$+
S  
if(!fileSplitterFetch.bDownOver) __2<v?\  
{ 2ozh!8aL  
breakWhile = false; t*=[RS*  
break; r!+{In+Z  
} W*t] d  
} wWy;dma#  
if(breakWhile) TI8r/P? ]V  
break; 'gvR?[!t  
mL=d EQ  
|Ha#2pt{bc  
//count++; B*,)
@h  
//if(count>4) d<6F'F^w.7  
// siteStop(); PDuc;RG
 
} \
xj;{xc  
$2Whb!7Z(  
8o$rF7.-  
System.err.println("文件下载结束！"); p
 1'l D  
} BVw2skOT  
catch(Exception e){e.printStackTrace ();} y %Q.(  
} d_,5;M^k  
P[2!D)A  
-GAF
>  
//获得文件长度 x,!Dd  
public long getFileSize() sD:o 2(G*  
{ 9%"7~YCDas  
int nFileLength = -1; ?T/]w-q>  
try{ }OpUG  
URL url = new URL(siteInfoBean.getSSiteURL()); @up,5`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D%p*G5Bg3  
httpConnection.setRequestProperty("User-Agent","NetFox"); r3l1I}  
L"qJZU  
;
:P4~R  
int responseCode=httpConnection.getResponseCode(); HIXAA?_eh=  
if(responseCode>=400) ^#HaH  
{ i6WH^IQM  
processErrorCode(responseCode); cb|+6m~  
return -2; //-2 represent access is error @>)VQf8s1  
} j_~KD}  
h2ROQKL"B  
N1a]y/  
String sHeader; wJy]Vyd  
<]qNjsdb9"  
wa"0`a:`;  
for(int i=1;;i++) S6<o?X9,
I  
{ [';o -c"!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'J,UKK\5  
//Utility.log(in.readLine()); (?jK|_  
sHeader=httpConnection.getHeaderFieldKey(i); 1dQA
o1  
if(sHeader!=null) aZN?V}^+  
{ FDMQLxf  
if(sHeader.equals("Content-Length")) Zhfp>D  
{ Uwc%'=@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Lce,]z\_  
break; g\q .  
} xMJ-=  
}  FA+HR  
else 6}^x#9\  
break; y2A\7&7  
} @t%da^-HS"  
} 74Jx\(d  
catch(IOException e){e.printStackTrace ();} \ND]x]5d  
catch(Exception e){e.printStackTrace ();} \p4*Q}t  
.]v>LsbhF  
dn(!wC]  
Utility.log(nFileLength); kR<sSLEb  
f2WVg;Z  
aTvyzr1  
return nFileLength; C'JI%HnQ  
} TO6F  
U,WOP7z  
N[_T3
(  
//保存下载信息（文件指针位置） 7{#p'.nc5  
private void write_nPos() $--8%gh dG  
{ q8{Bx03m6  
try{ TGJz[Ny  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,}t%7I  
output.writeInt(nStartPos.length); ug9Ja)1|  
for(int i=0;i<nStartPos.length;i++) ;jzJ6~<  
{ K*@?BE  
// output.writeLong(nPos); k79OMf<v  
output.writeLong(fileSplitterFetch.nStartPos); 3f`Uoh+  
output.writeLong(fileSplitterFetch.nEndPos); 56pj(}eq  
} !VD$uT  
output.close(); b] 5dBZ(  
} {"p ~M7  
catch(IOException e){e.printStackTrace ();} w7MRuAJ4  
catch(Exception e){e.printStackTrace ();} x1@,k=qrd  
} >WZ.Dj0n  
OX;bA^+}P  
O60T.MM`  
//读取保存的下载信息（文件指针位置） =[n !3M+X  
private void read_nPos() JI@iT6.%IX  
{ h4n~V:nNm  
try{ AROHe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C. .|O  
int nCount = input.readInt(); Z\0wQ;}  
nStartPos = new long[nCount]; |j+JLB  
nEndPos = new long[nCount]; T!x/^  
for(int i=0;i<nStartPos.length;i++) E2zL-ft.  
{ 4rhHvp  
nStartPos = input.readLong(); @WazSL;N  
nEndPos = input.readLong(); ug%7}&  
} t]B`>SL3W  
input.close(); EZj rX>"#  
} 6nA9r5Ghv  
catch(IOException e){e.printStackTrace ();} o

"r  
catch(Exception e){e.printStackTrace ();} 3cJ'tRsp<  
} #
?Ix6 {R  
y>C !cYB  
Y~Uf2(7b5  
private void processErrorCode(int nErrorCode) / B!j`UK  
{ $?ss5: S  
System.err.println("Error Code : " + nErrorCode); ?8753{wk  
} %g?M?D8Ud3  
}oD^tU IK  
N1Y uLG:  
//停止文件下载 MgiW9@_(  
public void siteStop() H ezbCwsx&  
{ U%Fa.bL~  
bStop = true; P,8TO-e7  
for(int i=0;i<nStartPos.length;i++) &DW !$b  
fileSplitterFetch.splitterStop(); i6bU
JtL  
e\}@w1  
l9QIlTc7  
} %|4Kak]:Q  
} 3XY"s"
  
//负责部分文件的抓取 UK6x]tE  
**FileSplitterFetch.java _E9[4%f  
*/ @Ov}X]ELi  
package NetFox; 7b~uU@L`  
s58dHnj5+  
hrX/,D -c  
import java.io.*; j~bNH~3  
import java.net.*; \6AM?}v
 
rX^uHq8  
N(i.E5&9  
public class FileSplitterFetch extends Thread { W /v &V#  
0<V/[$}\D  
$JOtUB{  
String sURL; //File URL y:E$n!  
long nStartPos; //File Snippet Start Position =F
e4-B?I  
long nEndPos; //File Snippet End Position {yNeZXA>  
int nThreadID; //Thread's ID z}SJ~WY'[  
boolean bDownOver = false; //Downing is over k/F#-},Q.  
boolean bStop = false; //Stop identical wKJ|;o4;L  
FileAccessI fileAccessI = null; //File Access interface _ow7E\70  
\Ec*Gq?.  
[$} \Gv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _gH$ ,.j/  
{ Ho#nM_ q  
this.sURL = sURL; bRggt6$z  
this.nStartPos = nStart; `\##M=  
this.nEndPos = nEnd; `)$G}7cRUH  
nThreadID = id; P*[wB_^&UP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E;H9]*x/  
} H{*rV>%  
jcC"vr'u|  
)M8,Tv*~  
public void run() zv"NbN  
{ id,'+<  
while(nStartPos < nEndPos && !bStop) C`ZU.|R  
{ OGW3Pe0Z'  
o]I8Ghk>/z  
vMY!Z1.*  
try{ D\;5{,:d  
URL url = new URL(sURL); g'!"klS93  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N*[b26  
httpConnection.setRequestProperty("User-Agent","NetFox"); N=U`BhL_  
String sProperty = "bytes="+nStartPos+"-"; fJNK@F  
httpConnection.setRequestProperty("RANGE",sProperty); ~[F7M{LS  
Utility.log(sProperty); "C3J[) qC  
{ZdF6~+H(!  
WNeBthq6  
InputStream input = httpConnection.getInputStream(); \(`2@  
//logResponseHead(httpConnection); Y9-F\t=~  
e1b?TF@lz  
yFd.tQs  
byte[] b = new byte[1024]; }T PyHq"  
int nRead; {\k }:)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `'3&tAy  
{ w)&4i$Lk6  
nStartPos += fileAccessI.write(b,0,nRead); eU)QoVt  
//if(nThreadID == 1) Aua}.Fl,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UvU@3[fw  
} $KT)Kz8tF  
T++q.oFc  
@#^Y# rxb  
Utility.log("Thread " + nThreadID + " is over!"); iDcYyNE  
bDownOver = true; "J*>g(H53  
//nPos = fileAccessI.write (b,0,nRead); q77qdmq7  
} |aU8WRq  
catch(Exception e){e.printStackTrace ();} 9,&xG\z=  
} gB%"J
Dn8  
} _PGd\>Ve  
p,f$9t4  
}%c>Hh  
//打印回应的头信息 |Y6;8e`H  
public void logResponseHead(HttpURLConnection con) MtF^}/0w!`  
{ Xk'Pc0@a  
for(int i=1;;i++)
' -9=>  
{ O> _ F   
String header=con.getHeaderFieldKey(i); qnQ".  
if(header!=null) y8C8~-&OK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i`<L#6RBT  
Utility.log(header+" : "+con.getHeaderField(header)); *:+ZEFMq  
else _u;pD-  
break; G$KQgUN~[  
} hi(e%da  
} [+l
6x1Am  
j(k%w  
Jqgm>\y  
public void splitterStop() E ?bqEW(  
{ l{]KA4  
bStop = true; Yv)c\hm(7j  
} }/\`'LQ  
\ntUxPox.  
[n&ES\o#(  
} 2wPc yD  
T.')XKP)1N  
!Ea9 fe  
/* 9 !UNO  
**FileAccess.java `'5vkO>  
*//文件访问(定位，写) Z5F#r>>`  
package NetFox; a[z$ae7  
import java.io.*; LXJ;8uW2y  
\Wg_ gA  
4Z=`;  
public class FileAccessI implements Serializable{ ] >w@@A  
&tf(vU;,'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z'uiU e`&  
RandomAccessFile oSavedFile; A)j!Wgs^z  
long nPos; ~H   
}kItVx  
n'q:L(`M  
public FileAccessI() throws IOException 5`:d$rv  
{ 0y/31hp  
this("",0); IC8%E3
 
} ,~1sZ`C  
01&E.A  
5}w  
public FileAccessI(String sName,long nPos) throws IOException -I6t ^$HA  
{ Og@{6>  
oSavedFile = new RandomAccessFile(sName,"rw"); $`%Om WW{  
this.nPos = nPos; NOkgG0Z  
oSavedFile.seek(nPos); XjP;O,x  
} SsZSR.tD  
XR[=W(m}  
M=&,+#z<V  
public synchronized int write(byte[] b,int nStart,int nLen) /J!:_Nq  
{ @x743}Y\  
int n = -1; nN-S5?X#  
try{ S-3hLw&?  
oSavedFile.write(b,nStart,nLen); RjgJIVm(  
n = nLen; :?y Ma$  
} d:^B2~j  
catch(IOException e) H[OgnnM  
{ IoK/2Gp  
e.printStackTrace (); u^JsKG+,:  
} i'>5vU0?3  
)cP)HbOd=  
4 83r
U  
return n; 'DpJ#w\81  
} q{B?j%.o  
3Z me?o*bY  
f{[0;qDJ  
} liLhvcd  
%m[ZU<v  
Z_S{$D  
/* Gky^S#  
**SiteInfoBean.java 0WSZhzNyY  
*/ 7OG:G z+)x  
package NetFox; 5U+4vV/*  
O1t$]k:  
kcg\f@d$  
public class SiteInfoBean { `=,emP&(H&  
M;OMsRCVO  
{i8zM6eC  
private String sSiteURL; //Site's URL LGW_7&0<<  
private String sFilePath; //Saved File's Path <m1v+cnqo  
private String sFileName; //Saved File's Name -MTYtw(  
private int nSplitter; //Count of Splited Downloading File Kr|.I2?"  
^[Ka+E^Q  
 O&|<2Qr  
public SiteInfoBean() -<5{wQE;|  
{//nSplitter的缺省值为5 GQCdB>  
//default value of nSplitter is 5 Z(Y:  
this("","","",5);  |Nj6RB7  
} C&*1H`n  
[>\|QS|  
]PoWL;E'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a@qc?  
{ >{:hadUH  
sSiteURL= sURL; dY~z6bT  
sFilePath = sPath; p)?6#~9$  
sFileName = sName; EEL3~H{
(  
this.nSplitter = nSpiltter; S7PWP<9  
sO6=w%l^  
iQ2j ejd3(  
} S >CKm:7  
PcU~1m1  
4:N*C7P  
public String getSSiteURL() v}V[sIs}  
{ 1
TGRIe)  
return sSiteURL; {)!>e  
} p:Lmf8EI  
5~:/%+F0=  
fPPP|  
public void setSSiteURL(String value) bDtb6hL  
{ M~|7gK.m1  
sSiteURL = value; hdrsa}{g  
} vI5lp5( -3  
,bdjk(  
?&~q^t?u  
public String getSFilePath() lNa+NtQu  
{ mJk\$/Kh  
return sFilePath; zp1ym}9M  
} ` K{k0_{  
T:Klr=&V  
R( FQ+h  
public void setSFilePath(String value) Q zaD\^OF  
{ !+^'Ej)z  
sFilePath = value; Wx{E\ l  
} KBN% TqH|  
X(nyTR8  
cpltTJFg  
public String getSFileName() '!Hs"{~{  
{ 4r1\&sI$~  
return sFileName; &R_7]f+%)  
} `<X-3)>;G  
iT4*~(p 3  
- Fbp!*. u  
public void setSFileName(String value) e;6KxvX~  
{ ,=m.WmXE  
sFileName = value; hb5K"9Y  
} !`Rh2g*o9  
cu0IFNF}[  
k5.5$<< T  
public int getNSplitter() U@mznf* J  
{ P#~B@d  
return nSplitter; l:!L+t*}6  
} XZM3zlg*  
<'
I["Um  
&&X,1/  
public void setNSplitter(int nCount) }#O!GG{  
{ XWp8[Cxs  
nSplitter = nCount; -[V-f> :  
} EMW6'  
} KeQcL4<  
YZBh}l6t  
G:=
hg6'  
/* 3`HK^((o  
**Utility.java @0?!bua_|  
*/ >0IZ%Wiz  
package NetFox; C|$qVh>  
pSw/QO9  
7C{ yNX#  
public class Utility { *Y m?gCig  
Dsg>~J'  
3yZmW$E.  
public Utility() d,"LZ>hNY*  
{ F1t(P 8  
`a& kD|Yh  
FM@iIlY"  
} K T}  
&r5q,l&@n  
//线程睡眠 @^W`Yg)C  
public static void sleep(int nSecond) 18>cfDh;N  
{ %t9C  
try{ DmiBM6t3N  
Thread.sleep(nSecond); jhNFaBrS  
} 0CrsZtX  
catch(Exception e) p~qe/  
{ Z'JS@dV  
e.printStackTrace (); hArY$T&MB  
} TC\+>LXiZ  
} 9t"Rw ns  
|W">&Rb<t#  
//日志 @c3xUK  
public static void log(String sMsg) SiratkP9n7  
{ SAx9cjj+  
System.err.println(sMsg); ]k0 jmE  
} NK_|h%  
{m.$EoS  
<>cS@V5j  
public static void log(int sMsg) Ux[<g%F"  
{ gb ga"WO  
System.err.println(sMsg); 200yN+ec  
} ~U9K<_U  
} 'Zfg
Cu)St  
Ey46JO"  
c3A\~tHW  
/* |\5^ub,m  
**TestMethod.java "F<CGSo  
*/ BX,)G HE  
package NetFox; #%0V`BS7n  
#WpkL]g2+%  
{meX2Z4  
public class TestMethod { nM )C^$3<t  
O !L`0 =%c  
VM"cpC_8  
public TestMethod() *Z5^WHwg  
{ ///xx/weblogic60b2_win.exe [VCC+_  
try{ tZrc4$D-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kNEEu!G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lsmcj{1d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^PksXfk  
fileFetch.start(); J3K=z  
} 7|P kc(O  
catch(Exception e){e.printStackTrace ();} U@lc1#  
NR{wq|"  
l\HdB"nT  
} aER|5!7(2\  
9(CvGzco<  

|y\Km  
public static void main(String[] args) (!os&/",  
{ /HC:H,"i  
new TestMethod(); [m t.2.  
} pm&THd  
} Ac7^JXh%
 
点击下载更多相关资料