http断点续传简单实现（java)

/* }}2kA  
**SiteFileFetch.java j\vK`.z  
*/ bXW)n<y  
package NetFox; vBpg6 fX  
import java.io.*; </%H'V@  
import java.net.*; T/K.'92S  
KZE.}8^%D  
UVLcR  
public class SiteFileFetch extends Thread { WY,t> 1c  
/;0>*
ft4  
h<M7[p=  
SiteInfoBean siteInfoBean = null; //文件信息Bean yI%> w4Z  
long[] nStartPos; //开始位置 w?*KO?K  
long[] nEndPos; //结束位置 ]UI+6}r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GKSy|z  
long nFileLength; //文件长度 o`U\Nhq  
boolean bFirst = true; //是否第一次取文件 K4yYNlY  
boolean bStop = false; //停止标志 2%8Y
-o?  
File tmpFile; //文件下载的临时信息 $SXxAS1  
DataOutputStream output; //输出到文件的输出流 %(Ys-GeGr  
b>z.d-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qIT{`hX  
public SiteFileFetch(SiteInfoBean bean) throws IOException L,Nr,QC-  
{ J*Hn/m  
siteInfoBean = bean; CJOl|"UyJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vw]nqS~N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;40m goN  
if(tmpFile.exists ()) 9O Q4\  
{ ZX;k*OrW  
bFirst = false; =QfKDA  
read_nPos(); {|h"/  
} h%s  
else $te,\$&}  
{ nc~d*K\!  
nStartPos = new long[bean.getNSplitter()]; }Yl=lcvw  
nEndPos = new long[bean.getNSplitter()]; +E~`H^  
} ?<?C*W_  
%`1vIr(7  
g)A0PvEu  
UK>=y_FYO  
} V^z;^mdd  
\#jDQ  
)JQQ4D  
public void run() RM1uYFs<  
{ y7-:l u$9  
//获得文件长度 /A.i5=k  
//分割文件 J_|}Xd)~t6  
//实例FileSplitterFetch k#5e:VOb  
//启动FileSplitterFetch线程 -!>ZATL<B  
//等待子线程返回 X9A[  
try{ 9sjW  
if(bFirst) AdW2o|Uap  
{ Mgs|*u-5  
nFileLength = getFileSize(); FqxOHovE  
if(nFileLength == -1) W+ '}O<  
{ zZc@;S#  
System.err.println("File Length is not known!"); SzlfA%4+GR  
} %Dls36F  
else if(nFileLength == -2) +4g%?5'  
{ )
UZ0gfx  
System.err.println("File is not access!"); F]A~~P  
} 7 eQoc2X2  
else m'(;uR`  
{ 6q[!X0u  
for(int i=0;i<nStartPos.length;i++) HL}~W
}!j  
{ (g/
X(3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 62l0 Z-  
} Ru^ ONw"  
for(int i=0;i<nEndPos.length-1;i++) zO5u{  
{ BH0#Q5  
nEndPos = nStartPos[i+1]; !8@rK$DB  
} EKd3$(^  
nEndPos[nEndPos.length-1] = nFileLength; sMS9!{A  
} Ipz 1+ #s'  
} z2Y_L8u2  
?)[zLnxc&  
Rs F3#H  
//启动子线程 n*i'vtQ8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NVc!g  
for(int i=0;i<nStartPos.length;i++) dXcPWbrU4  
{ q_]   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8yWu{'G
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k=mT!  
nStartPos,nEndPos,i); R=amKLD?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;*-@OLT_K  
fileSplitterFetch.start(); (}FW])y  
} $EQT"ZX>%i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N+s?ZE*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NB3Syl8g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RZ|HwYG  
nEndPos = " + nFileLength); 02W4-*)  
// fileSplitterFetch[nPos.length-1].start(); H6k
y)kF&  
xQ#Akd=  
,%?; \?b%h  
//等待子线程结束 mS:j$$]u  
//int count = 0; d
{2y/  
//是否结束while循环 s(
"Cn/ZkS  
boolean breakWhile = false; gVa+.x]  
+f X}O9  
QtnM(m  
while(!bStop) M9Nk=s! 3  
{ [+%d3+27  
write_nPos(); 1 ;\]D9i  
Utility.sleep(500);  :Hzz{'  
breakWhile = true; T/GgF&i3  
>[|GC/
C  
cuQ7kECV  
for(int i=0;i<nStartPos.length;i++) }fJ:wku  
{ FQk_#BkK  
if(!fileSplitterFetch.bDownOver) V8sH{R-  
{ .'^6QST  
breakWhile = false; O t *K+^I  
break; p.rdSv(8'  
} 5\akI\  
} /nC{)s?S'  
if(breakWhile) sf |oNOz  
break; Rwc[:6;fn  
]aC':55(  
yu`KzIU  
//count++; a=J@yK  
//if(count>4) QKp+;$SE'  
// siteStop(); a>o"^%x  
} qri}=du&F  
z5XYpi_;[  
Rk($lW)  
System.err.println("文件下载结束！"); r{t.c?/  
} ^M`>YOU2+  
catch(Exception e){e.printStackTrace ();} <i\UMrD]`:  
} 2d-TU_JqX  
yz[%MXI  
/=8O&1=D  
//获得文件长度 + ,@ FxZl  
public long getFileSize() .S~@BI(|<  
{ m b%C}8D  
int nFileLength = -1; Jj2g5={  
try{ |-~b$nUe  
URL url = new URL(siteInfoBean.getSSiteURL()); b8rp8'M)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f ,tW_g  
httpConnection.setRequestProperty("User-Agent","NetFox"); kQ@gO[hS  
l6iw=b[?  
^I]LoG:  
int responseCode=httpConnection.getResponseCode(); B$cOssl  
if(responseCode>=400) rHvF%o  
{ B4`2.yRis  
processErrorCode(responseCode); 2]L=s3  
return -2; //-2 represent access is error L +L9Y}  
} &Fw[YGJayz  
-glugVq  
1TKEm9j]u  
String sHeader; V?OuIg%=:  
TqIAWbb&  
3^{8_^I  
for(int i=1;;i++) d)N^PJ/  
{ ?#d6i$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^;.T}c%N  
//Utility.log(in.readLine()); O/mR9[}  
sHeader=httpConnection.getHeaderFieldKey(i); GxxDY]!  
if(sHeader!=null) yH*hL0mO  
{ lK0s=4c{  
if(sHeader.equals("Content-Length")) @&;(D!_&  
{ NwguP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?-pi,O~(p  
break; t{!/#eQC  
} _}D%iJg#  
} `)T&~2n
 
else yH^f\u0  
break; AIb>pL{  
} tv0Ha A  
} ;(7-WnU8N  
catch(IOException e){e.printStackTrace ();} te i`/  
catch(Exception e){e.printStackTrace ();} N#4N?BBP"  
+=7:4LFOL  
#<4--$Xo  
Utility.log(nFileLength); Jm4#V~w  
-OrR $w|e  
f-4.WW2FN  
return nFileLength; PY?8[A+  
} b(l0js  
ld.7`)  
/Y,r@D  
//保存下载信息（文件指针位置） |m)kN2w  
private void write_nPos() 6gnbkpYi  
{ OiF{3ae(  
try{ &iqw! ud  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qy ,"X)^#  
output.writeInt(nStartPos.length); YGp)Oy}:  
for(int i=0;i<nStartPos.length;i++) VevNG*  
{ S/.^7R7{f  
// output.writeLong(nPos); A?8\Y{FQ  
output.writeLong(fileSplitterFetch.nStartPos); ,X68xk.'  
output.writeLong(fileSplitterFetch.nEndPos); 4/'N|c.  
} sHdp  
output.close(); &+01+-1hW  
} $ KB  
catch(IOException e){e.printStackTrace ();} %D`o  
catch(Exception e){e.printStackTrace ();} :_xh(W+2<  
} =xL)$DTg)  
n*<v]1  
w^HjZV  
//读取保存的下载信息（文件指针位置） )6-9)pH@)  
private void read_nPos() Z(e^iH  
{ hi|!  
try{ w2
dcH4&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;JT(3yK4>p  
int nCount = input.readInt(); ut_pHj@  
nStartPos = new long[nCount]; !:3.D,  
nEndPos = new long[nCount]; 6ZOy&fd,Ty  
for(int i=0;i<nStartPos.length;i++) fPqr6OYz  
{ ~Y7dH Dn  
nStartPos = input.readLong(); c?E{fD"Fc3  
nEndPos = input.readLong(); `)Ky0&?  
}  &;c>O  
input.close(); pK}=*y~$  
} =-#G8L%Q  
catch(IOException e){e.printStackTrace ();} V5p0h~PK  
catch(Exception e){e.printStackTrace ();} nlGHT  
} -tLO.JK<  
"& 25D  
taWqSq!  
private void processErrorCode(int nErrorCode) ?X9UTOx  
{ [ MyE2^  
System.err.println("Error Code : " + nErrorCode); e,0-)?5R  
} $_Nf-:D*  
nP3 E  
;11x"S  
//停止文件下载 vScjq5"p  
public void siteStop() d`y!cu2}  
{ @'6"7g  
bStop = true; *O~e T  
for(int i=0;i<nStartPos.length;i++) Bc5+ss  
fileSplitterFetch.splitterStop(); h6:#!Rg  
`A@w7J'  
E4z)Mr#  
} 6%Mt  
} 3=mr "&]r:  
//负责部分文件的抓取 78 f$6J q  
**FileSplitterFetch.java ]?+{aS-]?k  
*/ V3Z]DA  
package NetFox; }baR5v  
i3$$,W!  
`G9 l  
import java.io.*; tc+WWDP#"
 
import java.net.*; soRv1)el  
4?\:{1X=  
tq1CwzRX  
public class FileSplitterFetch extends Thread { #W>QY Tp  
C1kYl0zR[  
^D%Za'  
String sURL; //File URL $sHP\{  
long nStartPos; //File Snippet Start Position QS[L~97m2M  
long nEndPos; //File Snippet End Position zAzP,1$?  
int nThreadID; //Thread's ID RE2&mYt  
boolean bDownOver = false; //Downing is over o\b-_E5"?  
boolean bStop = false; //Stop identical kYzKU2T\W  
FileAccessI fileAccessI = null; //File Access interface v=@TWEE  
~^jq(:d)  
Pz*_)N}j >  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ElhRF{R  
{ -a,-J]d0+  
this.sURL = sURL; "\C$   
this.nStartPos = nStart; @mP]*$00  
this.nEndPos = nEnd; *iBTI+"]  
nThreadID = id; O/s$SX%g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  ^zzP.  
} H %JaZ?(  
{9Y
+.46S  
i<kD  
public void run() #'D" 'B  
{ ULrr=5&8  
while(nStartPos < nEndPos && !bStop) J]lrS  
{ gxz-R?.  
fZ04!R  
^bg2[FV  
try{ #} ~qqJ G2  
URL url = new URL(sURL); Unj.f>U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~(!XY/0e  
httpConnection.setRequestProperty("User-Agent","NetFox"); %VYAd)gC  
String sProperty = "bytes="+nStartPos+"-";
{;toI  
httpConnection.setRequestProperty("RANGE",sProperty); Nkxmm/Z  
Utility.log(sProperty); zJP6F.Ov!  
*n"/a{6>  
B~o\+n  
InputStream input = httpConnection.getInputStream(); 7S/G B  
//logResponseHead(httpConnection); S}APQ  
(?_S6HE  
O5$/55PI  
byte[] b = new byte[1024]; +fvaUV_-  
int nRead; ?]D"k4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) il|1a8M2~  
{ ee%fqVQ8P  
nStartPos += fileAccessI.write(b,0,nRead); MZ Aij  
//if(nThreadID == 1) 3"o"fl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dJT]/g  
} ?A(QyaKz  
TIp:FW[  
GpZc5c  
Utility.log("Thread " + nThreadID + " is over!"); ml\4xp,  
bDownOver = true; n6s}ww)  
//nPos = fileAccessI.write (b,0,nRead); TXe$<4"  
} /|xra8?H
[  
catch(Exception e){e.printStackTrace ();} w"R:\@ F  
} !9Aaj<yxm  
} FQ g~l4WX  
CPNL 94x  
EwOV;>@T?  
//打印回应的头信息 N[kwO1  
public void logResponseHead(HttpURLConnection con) PO6&bIr  
{ @V03a )6,h  
for(int i=1;;i++) )M)7"PC  
{ V<Z[ nq  
String header=con.getHeaderFieldKey(i); aN"DkUYZM  
if(header!=null) 0
GJn_@hr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 76u&EG%  
Utility.log(header+" : "+con.getHeaderField(header)); 5nsq[Q`  
else v{}#?=I5  
break; 7Hm3;P.  
} *Z|y'<s  
} $@UN4B?y  
J~#;<e{\"  
6`f2-f9%iq  
public void splitterStop() \Gc+WpS(  
{ tKpmm`2  
bStop = true; qK)73eNSR  
} V0)fZS@tf  
F&&$Qn_+  
&L^+BQ`O?  
} V7/I
>^X  
$sEy%-  
vd8{c7g:n  
/* 9/nn)soC3  
**FileAccess.java l5"OIq  
*//文件访问(定位，写) #-bA[eQV  
package NetFox; 7}X[ 4("bB  
import java.io.*; t+eVR8  
>Q(3*d >  
ub|V\M{  
public class FileAccessI implements Serializable{ }mAa}{_  
ONe# rKJ_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;Rv!k&Df  
RandomAccessFile oSavedFile; o_'p3nD  
long nPos; h=:Q-?n-  
M8tRjNWS?  
cJrmm2.0kD  
public FileAccessI() throws IOException DCZ\6WY1G)  
{ L31HGH2l  
this("",0); rnF/H=I/  
} <WcR,d  
\Cii1\R=  
<TP=oq?I/  
public FileAccessI(String sName,long nPos) throws IOException l g-X:Z.  
{ m&?#;J|B$  
oSavedFile = new RandomAccessFile(sName,"rw"); RRI"d~~F6  
this.nPos = nPos; v#!%GEg1r  
oSavedFile.seek(nPos); %T~ig[GstX  
} |>#{[wko  
^_f+15]D  
(JM5`XwM  
public synchronized int write(byte[] b,int nStart,int nLen) 'nwx9]q  
{ `5C,N!d8X  
int n = -1; gntxNp[9T  
try{ TTKs3iTXz  
oSavedFile.write(b,nStart,nLen); Ba!J"b]  
n = nLen; PBp^|t]E>  
} 7:2WgLo  
catch(IOException e) gy_>`16K  
{ zR{W?_cV  
e.printStackTrace (); k<"oiCE  
} D/Mi^5H)  
4B^ZnFJ%m  
`-p:vq`  
return n; nYX@J6!  
} c|#8T*`C  
P9vA7[  
BDjn !3  
} d&+h}O  
< Pky9o;  
tQBRA/  
/* ;oc&Hb  
**SiteInfoBean.java |563D#?cR  
*/ <kx&w(=  
package NetFox;  7*?}:  
9T*v9d  
rv|)n>m  
public class SiteInfoBean { )3>hhuaa  
<psZQdH  
:R~MO&  
private String sSiteURL; //Site's URL ~V\D|W9  
private String sFilePath; //Saved File's Path w.\&9]P3~  
private String sFileName; //Saved File's Name n\^Tq<] a  
private int nSplitter; //Count of Splited Downloading File \Ol kM<  
`0Oh_8"  
Jz2N  
public SiteInfoBean() "-+\R}q$  
{//nSplitter的缺省值为5 ,f[>L|?e  
//default value of nSplitter is 5 [O?z@)dx  
this("","","",5); 2(#7[mgPI  
} "-vW,7y  
j'MO(ev  
9f<MQ6_UU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v%iof1 T'  
{ YJJB.hR+  
sSiteURL= sURL; 5 4L\Jx  
sFilePath = sPath; AMyIAZnYq)  
sFileName = sName; V7Ek-2M  
this.nSplitter = nSpiltter; }x07^4$j  
c'S,hCe*  
(q(~de  
} ]Ccg`AR{  
'a\%L:`  
%)0*&a 4  
public String getSSiteURL() U'<KC"f:'!  
{ B4i!/@0s  
return sSiteURL; {z")7g ]l  
} Y]B)'[=h  
".<DAs j  
<U!`J[n%  
public void setSSiteURL(String value) *fn*h[pV&  
{ IHcD*zQ  
sSiteURL = value; l@\#Ywz  
} 8q,6}mV  
3tZ]4ms}  
3< 2}V  
public String getSFilePath() VrxQc qPr`  
{ Zf65`K3  
return sFilePath; SBIj<Yy]  
} ?C&z]f3(:  
~e+\k>^eN  
@AIaC-,~]  
public void setSFilePath(String value) RIY,K*f.  
{ #nK>Z[  
sFilePath = value; +gJ8{u!=k  
} k=4N.*#`y  
/p+>NZ"b  
H\:lxR^  
public String getSFileName() s3R(vd  
{ p%*%n3bw  
return sFileName; jO1r)hw N>  
} nysUZB  
O"c;|zCc>  
06N}k<10O  
public void setSFileName(String value) Z`KC%!8K  
{ 3 %|86:*  
sFileName = value; &'}RrW-s  
} fM^qQM[lG  
.tzG_  
o8-^cP1  
public int getNSplitter() j
+["JXy  
{ 7w/4QiI  
return nSplitter; 4bw4c
qY;  
} jkt_5+S  
w &(|e <  
S>]pRV9rT  
public void setNSplitter(int nCount) b7wvaRe.  
{ _;UE9S%  
nSplitter = nCount; {yB&xj[z  
} #R.-KUW:  
} U~j ^I^  
twlk-2yT!  
MgNU``  
/* Ksy -e{n  
**Utility.java dK2p7xo  
*/ T3pmVl  
package NetFox; kMt 8/E`  
"t_-f7fS7  
e[/dv)J  
public class Utility { _G.>+!"2/  
2VJR$Pao  
J1:1B,^y  
public Utility() <c,u3cp  
{ vbD{N3p)?n  
HO}Hh[{V9  
V` 1/SQX  
} q~vDz]\G  
/gu%:vq  
//线程睡眠 j(k: @  
public static void sleep(int nSecond) 8qEVOZjV&  
{ -OA?BEQ=I  
try{ PX n;C/  
Thread.sleep(nSecond); Bxfc}vC.  
} YA +E\  
catch(Exception e) m:WyuU<  
{ ,
;Hu=;  
e.printStackTrace (); -
qy6Un+  
} PUBWZ^63  
} |<.lW  
Qe}`~a9P  
//日志 J<dVTxK12  
public static void log(String sMsg)
3+G@g#MY  
{ 7qg{v9|,  
System.err.println(sMsg); EVV
P]ND  
} X'`~s}vGO  
:SGF45>B@  
3`ELKq  
public static void log(int sMsg) kM
Opi =Z1  
{ v%s`~~u%^  
System.err.println(sMsg); , 'ZD=4_  
} ,XIz?R>;c  
} OZTPOz.  
dUF&."pW e  
;r>snJ=M  
/* MV\|e1B}  
**TestMethod.java bBS,-vN  
*/ 8-_QFgY  
package NetFox; 2cqI[t@0  
Z6_N$Z.A  
AQ+]|XYo_  
public class TestMethod { <X7FMNr[  
&*7?)eI!i  
j^;I3_P  
public TestMethod() KA){''>8  
{ ///xx/weblogic60b2_win.exe z-LB^kc8oQ  
try{ @:U+9[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qd#sY.|1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }p!HT6 tZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fVt9X*xKS  
fileFetch.start(); F^5?\  
} q@@T]V6  
catch(Exception e){e.printStackTrace ();} VGceD$<  
8g:;)u4$P  
n%k!vJ)]  
} xZQg'IT  
=9z[[dQ|L  
H]$)Eg%6  
public static void main(String[] args) F6K4#t+9  
{ +> WM[o^I  
new TestMethod(); 05spovO/'  
} r4QxoaM  
} EC\yzH*X  
点击下载更多相关资料