http断点续传简单实现（java)

/* L6>pGx  
**SiteFileFetch.java g'];Estb~  
*/ mAk{"65V  
package NetFox; .qk]$LJF7  
import java.io.*; eMRar<)+#*  
import java.net.*; `.y}dh/+0W  
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x.1-)\  
public class SiteFileFetch extends Thread { !ZDzEP*  
]pEV}@7  
:S$l"wrh\  
SiteInfoBean siteInfoBean = null; //文件信息Bean a?yMHb{F  
long[] nStartPos; //开始位置 Z ,^9Z  
long[] nEndPos; //结束位置 2iu_pjj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]nhr+;of/-  
long nFileLength; //文件长度 b;|55Y  
boolean bFirst = true; //是否第一次取文件 KYJjwXT28W  
boolean bStop = false; //停止标志 K/ &?VIi`z  
File tmpFile; //文件下载的临时信息 ND<!4!R^  
DataOutputStream output; //输出到文件的输出流 8@NH%zWBp  
:Q+5,v-c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I ];M7  
public SiteFileFetch(SiteInfoBean bean) throws IOException ylKmj
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{ 9+,R`v  
siteInfoBean = bean; t6c<kIQ:-O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v){ .Z^_C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jkiTj~WE-  
if(tmpFile.exists ()) I8OD$`~*U6  
{ uS&|"*pR  
bFirst = false; Ax oD8|  
read_nPos(); M5T9JWbN  
} xoB},Xl$D  
else k%[3Q>5iM  
{ xUF_1hY  
nStartPos = new long[bean.getNSplitter()]; RvJ['(-  
nEndPos = new long[bean.getNSplitter()]; 6.t',LTB  
} I2(zxq&2M\  
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} C8a*Q"  
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public void run() IPuA#C  
{ 6)pH|d.FR  
//获得文件长度 w@
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//分割文件 reo{*)%  
//实例FileSplitterFetch (I@bkMp  
//启动FileSplitterFetch线程 E^w:KC2@  
//等待子线程返回 ZxGP/D  
try{ = sAn,ri  
if(bFirst) p8wyEHB  
{ 2tayP@$  
nFileLength = getFileSize(); \b[9ebME  
if(nFileLength == -1) )a}"^1  
{ \U%#nU{  
System.err.println("File Length is not known!"); %iJ%{{f`  
} (2?G:+C 7  
else if(nFileLength == -2) W:i?t8y\y  
{ z}SND9-"  
System.err.println("File is not access!"); P
LM_#+R>  
} 1 4LI5T  
else *zO&N^X.4  
{ cYNJhGY  
for(int i=0;i<nStartPos.length;i++) ,? E&V_5  
{ 9>/wUQs!]  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
iE0ab,OF  
} \3Oij^l0  
for(int i=0;i<nEndPos.length-1;i++) @|yeqy_:  
{ 2?Ye*-  
nEndPos = nStartPos[i+1]; ry};m_BY  
} =Nz0.:  
nEndPos[nEndPos.length-1] = nFileLength; !gwjN_ZJ^  
} 3E}EBJLsZ  
} Dj\e@?Y  
DjMf,wX-{  
(Lh#`L?x  
//启动子线程 s!/TU{8J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I[o*RKT'"  
for(int i=0;i<nStartPos.length;i++) {Hr$wa~  
{ wLuv6\E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {|9}+ @5Q1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4t4olkK3Oa  
nStartPos,nEndPos,i); "S~_[/q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (_* wt]"'  
fileSplitterFetch.start(); A`O<6   
} +.[\g|G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _9:@Vl]Q@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xChI,~i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lA>\Ko  
nEndPos = " + nFileLength); j:5%ppIY  
// fileSplitterFetch[nPos.length-1].start(); ,1Qd\8N9  
31Cq22"  
{5c]Mn"r  
//等待子线程结束 N#N0Q0W=  
//int count = 0; X7UBopm&  
//是否结束while循环 EjEFg
#q  
boolean breakWhile = false; <<MjC5  
I
 5ag6l  
_i}wK?n  
while(!bStop) L{gE'jCC  
{ ,xJrXPW  
write_nPos(); rl:KJ\*D  
Utility.sleep(500); b syq*  
breakWhile = true; G,&%VQ3P>  
8F;>5i  
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for(int i=0;i<nStartPos.length;i++) _BnTv$.P  
{ E]^5I3=O  
if(!fileSplitterFetch.bDownOver) /I&wj^  
{ _17|U K|N  
breakWhile = false; e^).W3SK]  
break; Z+s%;f;  
} @-.? B  
} Z\X'd_1!  
if(breakWhile) qZ2&Xw.{1  
break; ScnY3&rc  
toa-Wa{  
8uG0^h}  
//count++; _3Q8n|  
//if(count>4) Mjpo1dw  
// siteStop(); @b!"joEy  
} WoL9V"]  
B_3QQtjAl  
exR^/|BR  
System.err.println("文件下载结束！"); O^{1RV3:,T  
} t7#lsd`_  
catch(Exception e){e.printStackTrace ();} WbjF]b\  
} #/J 'P[z  
upn8n vy4(  
8?TKN~ja  
//获得文件长度 U/MFhD(06  
public long getFileSize() ateUpGM QU  
{ aP
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int nFileLength = -1; ph30'"[Z}  
try{ Qb^q+C)o]  
URL url = new URL(siteInfoBean.getSSiteURL()); wN]J8Ir  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;M v~yb3v  
httpConnection.setRequestProperty("User-Agent","NetFox"); {'3D1#SK  
,-*iCs<  
u7]<=*V]  
int responseCode=httpConnection.getResponseCode(); _45cH{$sA  
if(responseCode>=400) O@U?IF$  
{ ,^T]UHRO  
processErrorCode(responseCode); $B\E.ml.  
return -2; //-2 represent access is error |:iEfi]j  
} }#9(Mul  
U
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='Oj4T  
String sHeader; H;vZm[\0N-  
~2%3FV^
 
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for(int i=1;;i++) Vk<k+=7  
{ \&|CM8A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?_4^le[;  
//Utility.log(in.readLine()); :F|\Ij
0T  
sHeader=httpConnection.getHeaderFieldKey(i); *c]KHipUIS  
if(sHeader!=null) <,39_#H?F3  
{ W04av_u 5  
if(sHeader.equals("Content-Length")) P;foK)AM  
{ i&tsYnP2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y,C!9l  
break; >Gd.&flSj
 
} u]vPy ria  
} k'13f,o}  
else Y5TS>iEE]  
break; swr"k6;G  
} 2bQ/0?.).-  
} s"mFt{Y  
catch(IOException e){e.printStackTrace ();} H:}}t]E  
catch(Exception e){e.printStackTrace ();} DnyYMe!r  
`q?RF+  
~ l )t|'6  
Utility.log(nFileLength); $+VgDe5{S  
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return nFileLength; mY2:m(9"5  
} )h"Fla  
}""p)Y&  
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//保存下载信息（文件指针位置） 8fO8Dob]\Y  
private void write_nPos() XL"=vbD  
{ v&0d$@6/U  
try{ >q|Q-I~gs  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PZ]5Hf1"  
output.writeInt(nStartPos.length); Kdt|i93  
for(int i=0;i<nStartPos.length;i++) o<\6Rm  
{ <c%n?QK{  
// output.writeLong(nPos); ;~ee[W$1  
output.writeLong(fileSplitterFetch.nStartPos); /Dd\PjIH{  
output.writeLong(fileSplitterFetch.nEndPos); pcpxe&S  
} kyAs'R@z  
output.close(); `!Ln|_,d  
} Y^eX@dEFR  
catch(IOException e){e.printStackTrace ();} u~Lu<3v  
catch(Exception e){e.printStackTrace ();} x`2p
r
 
} x70N8TQ_gK  
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//读取保存的下载信息（文件指针位置） #eEvF  
private void read_nPos() g~R/3cm4  
{ Uz>Yn&{y6  
try{ ~= 9Vv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 02M7gBS  
int nCount = input.readInt(); &t[|%c*D&  
nStartPos = new long[nCount]; gHH&IzHF  
nEndPos = new long[nCount]; TNsg pJ?\  
for(int i=0;i<nStartPos.length;i++) b+$o4l/x  
{ HWbBChDF  
nStartPos = input.readLong(); (4ZLpsbJ  
nEndPos = input.readLong(); aJQXJ,>Lv  
} # ITLz!gE  
input.close(); s>J3\PC  
} ;GQm[W([  
catch(IOException e){e.printStackTrace ();} fk\5D[j^  
catch(Exception e){e.printStackTrace ();} 6aSM*S)  
} _h~p:=  
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private void processErrorCode(int nErrorCode) 1}DerX6  
{ :|($,3*  
System.err.println("Error Code : " + nErrorCode); It\BbG=  
} -d_ 7*>m$  
&Q+]t"OA!  
w%~qB5wF6  
//停止文件下载 Zjt9vS)  
public void siteStop() R`3x=q  
{ JJNmpUJ  
bStop = true; |0DP} `~  
for(int i=0;i<nStartPos.length;i++) Bfn]-]>sD  
fileSplitterFetch.splitterStop(); CRd_}  
-&7=uRQk  
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} Ei~]iZ}  
} yUj;4vd  
//负责部分文件的抓取 o3= .T+B  
**FileSplitterFetch.java '}fel5YV  
*/ 5Q;dnC  
package NetFox; [wIKK/O  
-g$OOJB6  
_X?y,#  
import java.io.*; z=%IcSx;  
import java.net.*; &08Tns"  
8tC+ lc  
5D-BIPn=JV  
public class FileSplitterFetch extends Thread { clC~2:  
 3:"AFV  
kFnUJM$r  
String sURL; //File URL (Z'WR  
long nStartPos; //File Snippet Start Position 3liq9P_  
long nEndPos; //File Snippet End Position a(g$ d2H  
int nThreadID; //Thread's ID iUpSN0XkMM  
boolean bDownOver = false; //Downing is over KwQXA'  
boolean bStop = false; //Stop identical +}\29@{
W  
FileAccessI fileAccessI = null; //File Access interface i63?"  
vnF g%M!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >pa\n9=Q^  
{ =Y:5,.U  
this.sURL = sURL; @Z,qu2~|!  
this.nStartPos = nStart; (OQi%/Oy  
this.nEndPos = nEnd; q>c+bo 6  
nThreadID = id; h#;?9DP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [I_BCf  
} a\Tr!Be,  
bL#sn_(m  
J;7s/YH^  
public void run() @b8X%0B7  
{ ScsWnZ  
while(nStartPos < nEndPos && !bStop) u`nt\OF  
{ '|J)ds  
,%.:g65%  
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try{ ;q'DGzh  
URL url = new URL(sURL); y K=S!7p\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |\rSa^:5  
httpConnection.setRequestProperty("User-Agent","NetFox"); /;[
}=JL<Q  
String sProperty = "bytes="+nStartPos+"-"; }q/(D?  
httpConnection.setRequestProperty("RANGE",sProperty); pEJ#ad  
Utility.log(sProperty); TIKEg10I  
fWqv3nY^  

<b3x(/  
InputStream input = httpConnection.getInputStream(); ;cnnqT6  
//logResponseHead(httpConnection); +q$xw}+PK  
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j#4+-  
byte[] b = new byte[1024]; ,K`E&hS  
int nRead; <tGI]@Nwk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #IbS  
{ m`[oT\  
nStartPos += fileAccessI.write(b,0,nRead); cYE./1D a  
//if(nThreadID == 1) i=x.tsJ:hB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?hP<@L6K  
} \IO$+Guh  
{c&qB`y<.  
5F% h>tqh  
Utility.log("Thread " + nThreadID + " is over!"); jM{(8aUG  
bDownOver = true; ^n6)YX  
//nPos = fileAccessI.write (b,0,nRead); d%S=$}o  
} [BJ$|[11  
catch(Exception e){e.printStackTrace ();} rDK;6H:u{  
} $:T<IU[E  
} *vRNG 3D/  
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" &_$V@S  
//打印回应的头信息 _K*\}un2  
public void logResponseHead(HttpURLConnection con) &?}kL= h  
{ 5B8V$ X  
for(int i=1;;i++) TW'E99wG  
{ e4[-rkn{hl  
String header=con.getHeaderFieldKey(i); `%KpTh  
if(header!=null) 0\8*S3,q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VyB\]EBu  
Utility.log(header+" : "+con.getHeaderField(header)); -G(3Y2  
else l{M;PaJ`}  
break; )Ix-5084  
} @>qx:jx(-S  
} /5L'9e  
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+,ZUTG  
public void splitterStop() 7yc9`j}]  
{ *%P>x}6w3  
bStop = true; ^.ZSpc}<  
} !:]s M-cCt  
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2GHXn:V  
} i*mZi4URN  
 '7S!6kd?  
34/]m/2NZK  
/* lBizC5t!o  
**FileAccess.java 4*@G&v?n  
*//文件访问(定位，写) .(TQ5/ ~  
package NetFox; uW\@x4  
import java.io.*; GoGohsj  
<M5{.`o  
7/5NaUmPTt  
public class FileAccessI implements Serializable{ 0~PXa(!^K  
I?^Q084  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3D 4]yR5  
RandomAccessFile oSavedFile; ~#HH;q_7m  
long nPos; M~d+HE  
a2(D!_dZR  
=UI,+P:  
public FileAccessI() throws IOException .(P@Bl]XJ  
{ Fy4<  
this("",0); c<JM1  
} KZp,=[t  
XwKZv0ub  
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public FileAccessI(String sName,long nPos) throws IOException _rWM]  
{ c5T~0'n  
oSavedFile = new RandomAccessFile(sName,"rw"); i5L+8kx4  
this.nPos = nPos; ,T,B0  
oSavedFile.seek(nPos); K4h-4Qbn  
} !4qp
s$p{  

p[af[!  
:>AW@SoTp  
public synchronized int write(byte[] b,int nStart,int nLen) 1`2);b{@  
{ Tb!B!m  
int n = -1; rA1zyZlz  
try{ ^5FJ}MMJf  
oSavedFile.write(b,nStart,nLen); ,Do$`yO+  
n = nLen; 2m)kyQ  
} 6\)8mK  
catch(IOException e) o1p$9PL\:  
{ TNX%_Q<  
e.printStackTrace (); Hm.&f2|(  
} IDiUn!6Q  
4acP*LkkQ  
9" }^SI8  
return n; Z,N7nMJf  
} <manv8*6  
8a":[Q[  
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} -Z/6;2
Q  
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+_-)0[+p  
/* BW;=i.  
**SiteInfoBean.java m"?'hR2  
*/ \U<F\i  
package NetFox; k Nf!j  
^t^<KL;  
YN5OuKMUd'  
public class SiteInfoBean { R5'Z4.~  
v4,syd*3|V  
kw}ISXz v  
private String sSiteURL; //Site's URL i$fjr[$B  
private String sFilePath; //Saved File's Path 1S)0 23N  
private String sFileName; //Saved File's Name Fb\2df{@  
private int nSplitter; //Count of Splited Downloading File sa0^1$(<  
n{qw]/  
9>.<+b(>!'  
public SiteInfoBean() ,,C~j`F  
{//nSplitter的缺省值为5  ycAi(K  
//default value of nSplitter is 5 KOAz-h@6   
this("","","",5); XCqfAcNQ  
} =xlYQ}-(a  
gR_b~^  
hNR>Hy\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yoA*\V  
{ -;/@;W  
sSiteURL= sURL; A Eyr_!G,  
sFilePath = sPath; ]~g|SqPA@  
sFileName = sName; =aCIaL&9Y  
this.nSplitter = nSpiltter; 00.iMmJ  
u%gm+NneK  
?:;hTY  
} O+8ApicjTc  
8^f[-^%  
43orR !.Z  
public String getSSiteURL() (Aov}I+  
{ ;t@ 3Go  
return sSiteURL; Vp{RX8?.  
} {7M4SC@p|  
|+4E 8;4_  
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public void setSSiteURL(String value) [}xIg
8  
{ GD6'R"tJ  
sSiteURL = value; <g|nmu)o$  
} 9(FcA5Y  
]a%\Q2[c  
te)g',#lT  
public String getSFilePath() ~i_R%z:y  
{ B"E(Y M  
return sFilePath; JY050FL  
} Velbq  
s$nfY.C  
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public void setSFilePath(String value) o y%g{,V  
{ n.H`1@  
sFilePath = value; Kjca>/id  
} in;+d~
?  
`v/tf|v6  
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public String getSFileName() [9W&1zY  
{ "*>QxA%c4  
return sFileName; GF.g'wYc)Y  
} ;xkf?|  
YWBP'Mo  
fY+ .#V  
public void setSFileName(String value) px(1Ppb9  
{ |#khwH  
sFileName = value; )mo|.L0  
} $GfxMt  
[#@p{[?r  
a~N)qYL:  
public int getNSplitter() }";hz*a  
{ DrCfC[A~]  
return nSplitter; nrD=[kc!w  
} $,@ rKRY  
CPCB!8-5  
^&w'`-ra  
public void setNSplitter(int nCount) ;uo|4?E:\(  
{ $}h_EI6hS  
nSplitter = nCount; qpEC!~y  
} MvjwP?J]  
} +P6  
m5Laq'~0_  
XuAc3~HAd  
/* Yr(f iI  
**Utility.java +WEO]q?K  
*/ ?Kz` O>"6  
package NetFox; ah@GSu;7  
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-3XnK5  
public class Utility { nh.v?|  
c$Nl-?W  
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public Utility() ;>hPHx  
{ >a] s  
MS^hsUj}  
F9G$$
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} [~r$US  
nv|y@!(  
//线程睡眠 <h>fip3o  
public static void sleep(int nSecond) "kuBjj2  
{ *q9$SDm  
try{ kd2'-9  
Thread.sleep(nSecond); @P*P8v8:  
} ).#D:eO[~  
catch(Exception e) %;XuA*e  
{ $,@+Ua  
e.printStackTrace (); =|t1eSzc  
} JU`'?b  
} XXdMppoR  
I Y-5/
 
//日志 :95_W/l  
public static void log(String sMsg) -8J@r2\
 
{ mp$II?hZ*  
System.err.println(sMsg); Rn^N+3o'M  
} MhB=+S[@  
?=o]Wx0(9  
HOI`F3#XI  
public static void log(int sMsg) sN/Xofh  
{ kR|DzB7  
System.err.println(sMsg); 2F)OyE  
} .\\#~r`t3  
} /]58:euR  
G!lykk]  
/u1zRw  
/* GnHf9 JrR  
**TestMethod.java Z"&ODVP  
*/ wx7>0[zE  
package NetFox; KD<`-b)7<  
JZ0+VB-3U  
!Dn1pjxc  
public class TestMethod { |&*rSp2iH  
_5 -"<  
e/~<\  
public TestMethod() wA+4:CF@  
{ ///xx/weblogic60b2_win.exe VFp)`+8  
try{ RR
{9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2MrR|hLx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3JO:n6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UE](`|4H  
fileFetch.start(); E)SOcM)  
} d`*vJ#$>2  
catch(Exception e){e.printStackTrace ();} %ieAY-<"  
Z.f<6<gF  
J\},o|WI  
} F#9KMu<<cI  
l@9:VhU(  
h.%Qn vL  
public static void main(String[] args) W| eG}`  
{ Hd}t=6  
new TestMethod(); ^8t*WphZC  
} M4]|(A  
} 1Ee>pbd  
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