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http断点续传简单实现(java)

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/* iOI8'`mk  
**SiteFileFetch.java "' g*_  
*/ :hYV\8 $  
package NetFox; hO3>Gl5<  
import java.io.*; z_vFf0  
import java.net.*; 1*aw~nY0  
 FVOR~z  
!\.%^LK1  
public class SiteFileFetch extends Thread { [!E pv<G  
k 9 Xi|Yj  
F+r3~T%  
SiteInfoBean siteInfoBean = null; //文件信息Bean $i&u\iL  
long[] nStartPos; //开始位置 '&{`^l/ MH  
long[] nEndPos; //结束位置 |T:' G  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e1ru#'z  
long nFileLength; //文件长度 >gqM|-uY  
boolean bFirst = true; //是否第一次取文件 MM8r*T4g/  
boolean bStop = false; //停止标志 }Z5#{Sd  
File tmpFile; //文件下载的临时信息 D_fgxl  
DataOutputStream output; //输出到文件的输出流 q~9Y&>D  
y'ULhDgq^B  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) O(BAw  
public SiteFileFetch(SiteInfoBean bean) throws IOException QEIu}e6b  
{ ;C,D1_20Z  
siteInfoBean = bean; {Muw4DV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ng $`<~=)\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SB R=  
if(tmpFile.exists ()) A7!!kR":  
{ :=u Ku'~  
bFirst = false; c}K>#{YeB  
read_nPos(); R(Y4nw+Y-  
} Jybx'vZj  
else >(Mu9ie*`  
{ bgs2~50  
nStartPos = new long[bean.getNSplitter()]; Ym~*5|  
nEndPos = new long[bean.getNSplitter()]; KF&1Y>t=  
} .iFd  
#Pi}2RBRu  
hawE2k0p(  
S~auwY,<  
} 6A$ \I44  
cl s-x@ Kd  
FFGG6r  
public void run() 5yO %|)  
{ u`Kjs}F'  
//获得文件长度 _:|/4.]`_  
//分割文件 \Q[u?/TF  
//实例FileSplitterFetch n DLr17  
//启动FileSplitterFetch线程 "NqB_?DT  
//等待子线程返回 {J-kcD!bz`  
try{ }lzUl mRTe  
if(bFirst) alM ^ X  
{ -x i]~svg  
nFileLength = getFileSize(); ghq#-N/t  
if(nFileLength == -1) s UX%{|T_  
{ VY }?Nb<&  
System.err.println("File Length is not known!"); *gHGi(U(U  
} .0$$H"t  
else if(nFileLength == -2) .<8kDyi m  
{ <=KtRE>$  
System.err.println("File is not access!"); 5N=QS1<$5  
} ?ysC7 ((  
else KrNu7/H  
{ (vHB`@x  
for(int i=0;i<nStartPos.length;i++) ;<qv-$P  
{ RM2<%$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G5~ Jp#uA  
} nY7 ZK  
for(int i=0;i<nEndPos.length-1;i++) 7I>@PV N  
{ C^vB&3ghi  
nEndPos = nStartPos[i+1]; fba QXM  
} v{7Jzjd  
nEndPos[nEndPos.length-1] = nFileLength; 6BT o%  
} ;Js-27_0  
} fg1_D  
-ZXC^zt  
x O`#a=  
//启动子线程 UR;F W`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  'Q\I@s }  
for(int i=0;i<nStartPos.length;i++) mouLjT&p  
{ Q)}_S@v|%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _G]f v'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VFLxxFJ  
nStartPos,nEndPos,i); \OMWE/qMy  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  +c@s  
fileSplitterFetch.start(); cTW3\S=  
} NEInro<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ra%" +=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l*;Isz:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V@6,\1#`|  
nEndPos = " + nFileLength); P9j[ NEV  
// fileSplitterFetch[nPos.length-1].start(); 8. 9TWsZ  
A1`y_ Aj  
=<nx [J  
//等待子线程结束 7VWq8FH`  
//int count = 0; 5c*kgj:x  
//是否结束while循环 |> mx*G  
boolean breakWhile = false; WVPnyVDc  
 XI+m  
WJ)( *1  
while(!bStop) cfn\De%.  
{ >U/ m/H'  
write_nPos(); #sLyU4QV  
Utility.sleep(500); /(#;(]  
breakWhile = true; gWcl@|I;\  
$ekJs/I&  
qi!Nv$e  
for(int i=0;i<nStartPos.length;i++) $ f`\TKlN  
{ mx`C6G5  
if(!fileSplitterFetch.bDownOver) ]F:5-[V#  
{ +r0ItqkM  
breakWhile = false; IBYRuaEB  
break; (7 i@ @  
} vb 2mY  
} }%z {tn  
if(breakWhile) e.X*x4*>~  
break; 9|19ia@[\  
i}C9  
hq}kAv4B=  
//count++; D,FX&{TYU  
//if(count>4) p-d2HXo  
// siteStop(); S%ULGX:@ga  
} ESdjDg$[u  
:{za[,  
N5$IVz}  
System.err.println("文件下载结束!"); 1k&**!S]%  
} qcYF&  
catch(Exception e){e.printStackTrace ();} y%* hHnGd  
} ~y@,d  
yQ5F'.m9e  
R0>GM`{  
//获得文件长度 1\G S"4~P  
public long getFileSize() &_mOw.  
{ j*uc$hC"  
int nFileLength = -1; !)1r{u  
try{ 7g'jg7  
URL url = new URL(siteInfoBean.getSSiteURL()); 3f;W+^NY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jb. V4  
httpConnection.setRequestProperty("User-Agent","NetFox"); w9QY2v,U  
nW1Obu8x|  
Gn}G$uk61  
int responseCode=httpConnection.getResponseCode(); <pAN{:  
if(responseCode>=400) KW^#DI6tr  
{ qY^OO~[  
processErrorCode(responseCode); pwq a/Yi  
return -2; //-2 represent access is error &PJ&XTR  
}  j6zZ! k  
1:2 t4}  
!L..I2'  
String sHeader; )2 E7>SQc~  
{.vU;  
~j}7Fre  
for(int i=1;;i++) M'Ec:p=X"  
{ d@o1< Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `~${fs{-`/  
//Utility.log(in.readLine()); /yRP>CX~  
sHeader=httpConnection.getHeaderFieldKey(i); s d -5AE  
if(sHeader!=null) ["N{6d&Q  
{ qo2/?]  
if(sHeader.equals("Content-Length")) /%W&zd=%#  
{ mJjd2a"vi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !U}dYB:O  
break; =u M2l  
} lFHj]%Y  
} {rp5qgVE<  
else :el]IH  
break; xiv1y4(%  
} g\%vkK&I  
} D]NfA2B7  
catch(IOException e){e.printStackTrace ();} ,MH9e!  
catch(Exception e){e.printStackTrace ();} 9 U6cM-p?  
]xO`c  
+Usy  
Utility.log(nFileLength); |7 .WP;1  
JA .J~3  
H}TzNs  
return nFileLength; u 3&9R)J1  
} 0FL PZaRP  
zq(R!a6  
Q& p'\6~  
//保存下载信息(文件指针位置) 9NX/OctFa'  
private void write_nPos() Dwvd  
{ nYfZ[Q>v  
try{ LP_w6fjT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Knd2s~S  
output.writeInt(nStartPos.length); G5JZpB#o  
for(int i=0;i<nStartPos.length;i++) {yPJYF_l  
{ 8KQD w:  
// output.writeLong(nPos); &<Gs@UX~w  
output.writeLong(fileSplitterFetch.nStartPos); Qw&It  
output.writeLong(fileSplitterFetch.nEndPos); ?Q`u\G3.m  
} _*(n2'2B  
output.close(); 0~.OMG:=  
} n2<#]2h  
catch(IOException e){e.printStackTrace ();} +YS0yTWeX  
catch(Exception e){e.printStackTrace ();} Gag=GHG  
} (QARle(i  
$j ZU(<4,  
XMt5o&U1  
//读取保存的下载信息(文件指针位置)  3+[R !  
private void read_nPos() EfTuHg$pe  
{ [N$#&4{Je  
try{ =!@5!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gO{XD.s  
int nCount = input.readInt(); KJ/ *BBf  
nStartPos = new long[nCount]; ^o`;C\  
nEndPos = new long[nCount]; *b< a@  
for(int i=0;i<nStartPos.length;i++) .?C-J  
{ cjTV~(i'4A  
nStartPos = input.readLong(); . fZ*N/  
nEndPos = input.readLong(); ;cye 'E  
} v61'fQ1Qg!  
input.close(); pA ,xDs@37  
} VR/*h%  
catch(IOException e){e.printStackTrace ();} 4tv}5llSG  
catch(Exception e){e.printStackTrace ();} &W'X3!Te  
} ?8{x/y:  
:E$<!q  
%TOYU (k  
private void processErrorCode(int nErrorCode) $-tgd<2h  
{ F_Pv\?35z  
System.err.println("Error Code : " + nErrorCode); g;|3n&  
} /hNZ7\|P  
@zz4,,]  
T B!z:n  
//停止文件下载 _[eAA4h  
public void siteStop() rKK{*%n  
{ UK{6Rh ;  
bStop = true; GS!7HphR  
for(int i=0;i<nStartPos.length;i++) ;rD M%S@  
fileSplitterFetch.splitterStop(); Rds_Cd C  
=TTk5(m  
7RH1,k  
} )Ha`>  
} "4 Lt:o4x  
//负责部分文件的抓取 dIQxU  
**FileSplitterFetch.java , [V#o-Z  
*/ L?W F[nF R  
package NetFox; G;^},%<  
b.Yl0Y  
1WArgR  
import java.io.*; %fv;C  
import java.net.*; ]\fXy?2  
A7|CG[wZ  
BCrX>Pp }r  
public class FileSplitterFetch extends Thread { @raw8w\Zj+  
@W{VT7w  
J.R|Xd  
String sURL; //File URL "s:eH"_s  
long nStartPos; //File Snippet Start Position -AJ$-y  
long nEndPos; //File Snippet End Position 0`{3|g  
int nThreadID; //Thread's ID dKKh^D`~  
boolean bDownOver = false; //Downing is over Z9TUaMhF  
boolean bStop = false; //Stop identical .Mn+Bd4f  
FileAccessI fileAccessI = null; //File Access interface eM3-S=R?<g  
I04GQql  
1c$<z~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UJ}Xa&*H\  
{ ZQ&A '(tt4  
this.sURL = sURL; @xO?SjH  
this.nStartPos = nStart; G`a,(<kT;  
this.nEndPos = nEnd; 9;fyC =  
nThreadID = id; 7W{xK'|]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3 &aBU [  
} Aqc Cb[1r  
fmDn1N-bG  
2l7Sbs7  
public void run() /b44;U`v5-  
{ hI&ugdf  
while(nStartPos < nEndPos && !bStop) Z~JX@s0v  
{ 3)? v  
*{ =5AW}o  
2jMV6S9  
try{ 72YL   
URL url = new URL(sURL); FuA8vTV{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y([""z3<w  
httpConnection.setRequestProperty("User-Agent","NetFox"); %Ydzzr3  
String sProperty = "bytes="+nStartPos+"-"; M[;N6EJH  
httpConnection.setRequestProperty("RANGE",sProperty); Qh 3V[br  
Utility.log(sProperty); QG|KZ8uO  
c@+;4Iz  
-{ae  
InputStream input = httpConnection.getInputStream(); 8 |@WuD  
//logResponseHead(httpConnection); %lr<;   
i?*_-NAm  
I6k S1  
byte[] b = new byte[1024]; [f_4%Now  
int nRead; rh8.kW-K_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :9_N Y"P  
{ sSh=Idrx  
nStartPos += fileAccessI.write(b,0,nRead); e)(m0m\  
//if(nThreadID == 1) B/iRR2h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j-?zB .jAh  
} %XpYiW#AK  
?gq',F FDq  
qWQ7:*DL  
Utility.log("Thread " + nThreadID + " is over!"); BIFuQ?j3  
bDownOver = true; -w0U }Te^  
//nPos = fileAccessI.write (b,0,nRead); Up(Jw-.  
} Rk1B \L|M  
catch(Exception e){e.printStackTrace ();} ^m3[mY [a  
} QGWfF,q  
} oAMB}a;  
\Mujx3Fmvx  
<@Lw '  
//打印回应的头信息 (>E}{{>2r  
public void logResponseHead(HttpURLConnection con) L>,j*a_[  
{ @YH<Hc  
for(int i=1;;i++) CL~21aslI  
{ MzF9 &{N  
String header=con.getHeaderFieldKey(i); 'CrBxaA]s  
if(header!=null) &$'=SL(Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LC!ZeW35  
Utility.log(header+" : "+con.getHeaderField(header)); bIX'|=  
else d1MVhE  
break; ]<V,5'xh  
} _li\b-  
} 1j_x51p  
NXwlRMbo  
Gk.;<d  
public void splitterStop() Esc*+}ck  
{ !'-|]xx(  
bStop = true; !k=>Wb8n2  
} Ik92='Z  
dIOj]5H3F  
<2\4eusk  
} LPg1G+e  
@Ju!|G9z/p  
NwK(<dzG  
/* )$# Ku2X  
**FileAccess.java QQd%V#M?  
*//文件访问(定位,写) *@M7J  
package NetFox; SqiLp!Y`  
import java.io.*; /1Xji 0LK  
v{R:F  
jh3LD6|s}  
public class FileAccessI implements Serializable{ `7;I*|  
D]I]I!2c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  IX|2yu4  
RandomAccessFile oSavedFile; ?\HXYCi0r  
long nPos; :&]THUw  
. PzlhTL7  
 2Z ? N  
public FileAccessI() throws IOException dM A"% R  
{ ~}SOd<n)|  
this("",0); UUxDW3K  
} $ }u,uI  
/r4QDwu  
aZe[Nos  
public FileAccessI(String sName,long nPos) throws IOException yM3]<~m  
{ Qi_De '@  
oSavedFile = new RandomAccessFile(sName,"rw"); G1Qc\mp  
this.nPos = nPos; (HHVup1f  
oSavedFile.seek(nPos); -?8;-h, h  
} (IbT5  
)8H5ovj.  
zUw9  
public synchronized int write(byte[] b,int nStart,int nLen) Z/z(P8#U\  
{ u>G#{$)  
int n = -1; FyXz(l:  
try{ _&/FO{F@m  
oSavedFile.write(b,nStart,nLen); -L9I;]:KY  
n = nLen; cVzOW|NVx  
} &ZjQa.-U>  
catch(IOException e) pg}9baW?  
{ H8>u:  
e.printStackTrace (); EDm,Y  
} =h~\nTN  
MDfE(cn2q  
/Z:\=0`  
return n; D4:c)}  
} w$JG:y#  
BF*]l8p  
{ r9fKA  
} yDt3)fP#  
FW)G5^Tf  
49o5"M(  
/* Kn]c4h}@b5  
**SiteInfoBean.java -U6" Ce  
*/ DA[s k7  
package NetFox; RH,1U3?  
p,y(Fc~]g'  
R<}Yf[TQ  
public class SiteInfoBean { |%F[.9Dp  
$K)9(DD  
0|0<[:(hc  
private String sSiteURL; //Site's URL uvo2W!  
private String sFilePath; //Saved File's Path C|kZT<,]  
private String sFileName; //Saved File's Name MIcF "fB![  
private int nSplitter; //Count of Splited Downloading File e1e2Wk  
*mQOW]x%  
3>[_2}l  
public SiteInfoBean() Z4\$h1tl  
{//nSplitter的缺省值为5 *$ZLu jy7  
//default value of nSplitter is 5 *"N756Cj  
this("","","",5); )V!dmVQq{g  
} +LwE=unS  
:y)'_p *l/  
<y+8\m  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S[o_$@|  
{ Qrt[MJ+#  
sSiteURL= sURL; +L4_]  
sFilePath = sPath; i,=CnZCh  
sFileName = sName; b|i94y(  
this.nSplitter = nSpiltter; mQQ5>0^m  
QdM&M^  
pN+lC[C  
} ^-3R+U- S  
90%alG 1>y  
)v!>U<eprD  
public String getSSiteURL() D`=hP( y^  
{ QI@!QU$K&  
return sSiteURL; 9JHu{r"M  
} 6?U2Et  
.P[ %t=W  
*KP 60T  
public void setSSiteURL(String value) 9aw- n*<  
{ ~]71(u2  
sSiteURL = value; o=`FGowF  
} W s!N%%g  
X<4h"W6  
gi;#?gps  
public String getSFilePath() ~eH+*U|\|M  
{ \lVX~r4  
return sFilePath; $I%75IZ  
}  *$nz<?  
4_3 DQx9s  
?XVJ$nzW  
public void setSFilePath(String value) gB!K{ Io'  
{ m: 77pE&o  
sFilePath = value; UE4zmIq  
} h' OLj#H  
X0X!:gX  
F=C8U$'S  
public String getSFileName() X!0s__IOc  
{ V~y4mpfX  
return sFileName; !=(~e':Gv  
} N@UO8'"9K&  
EM+_c)d}  
]k[y#oB  
public void setSFileName(String value) pU`4bT(w%  
{ fDmGgD?  
sFileName = value; %(`4wo},  
} pb~&gliW  
c43" o  
N 3)OH6w"  
public int getNSplitter() pA9:1*+;;  
{ |q?I(b4Q@  
return nSplitter; i)V-q9\  
} PgZ~of&  
U!sv6=(y@  
:U`8s#  
public void setNSplitter(int nCount) UOrf wK  
{ 36D-J)-Z  
nSplitter = nCount; ;|v6^2H"  
} ]*+ozAG4  
} dB7E&"f  
^'DrU< o  
24 S,w>j  
/* t@-:e^ v  
**Utility.java v~:$]a8  
*/ 3\6 UH  
package NetFox; T!o 4k  
#2c-@),  
5-|fp(Ww_W  
public class Utility { Qci<cVgP  
FJ3Xeo s4|  
h3.wR]ut  
public Utility() pmAir:  
{ 5fS89?/?  
xUE9%qO  
Ue|]M36  
} ]@bo;.  
Au'[|Pr r  
//线程睡眠 Sk@~}  
public static void sleep(int nSecond) Fl GKy9k  
{ vkan+~H  
try{ ='=\!md  
Thread.sleep(nSecond); 2~+Iu +  
} ?6@Y"5 z3g  
catch(Exception e) e[}R1/! L  
{ w/s{{X<bF  
e.printStackTrace (); Qz;2RELz  
} >lqWni  
} 'sI=*c  
1c S{3  
//日志 z#b31;A@$  
public static void log(String sMsg) _Tyj4t0ElV  
{ 6C>x,kU  
System.err.println(sMsg); 6o&{~SV3  
} FA\gz?h  
}2M2R}D  
krm&.J  
public static void log(int sMsg) Y;>0)eP  
{ 93:s[b mx  
System.err.println(sMsg); H@er"boi  
} +O:Qw[BL/Z  
} ['m@RJm+  
W&y%fd\&3  
VA_\Z  
/* w5|az6wZB!  
**TestMethod.java ( B$;'U<  
*/ XiI@Px?FL  
package NetFox; pLL ^R  
Dq+rEt  
]J)WcM:  
public class TestMethod {  L's_lC  
C^RO@kM  
$(_Xt-6  
public TestMethod() uD_|/(  
{ ///xx/weblogic60b2_win.exe <1]# E@  
try{ RLr;]j8cm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *""'v   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uY5&93R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FLY#   
fileFetch.start(); [Fe`}F}Co8  
} *iS<]y  
catch(Exception e){e.printStackTrace ();} G}mJtXT#=  
+r9:n(VP  
p_ =^E*J]  
} YD$fN"}-  
;7&RmIXKh'  
~^=QBwDW8N  
public static void main(String[] args) lKEdpF<  
{ 9 8bmia&H  
new TestMethod(); v#:#w.]-Y  
} YS k,kU  
} 0*W=u-|s6  
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