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http断点续传简单实现(java)

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/* g>dA$h%  
**SiteFileFetch.java \>C YC|  
*/ 4?-.Z UT-1  
package NetFox; l-ct?T_@  
import java.io.*; 9G+V;0Q  
import java.net.*; B x (uRj  
p;W.lcO`0  
}; f#^gz'  
public class SiteFileFetch extends Thread { T}"6wywM  
uO=aaKG  
);Z1a&K5k  
SiteInfoBean siteInfoBean = null; //文件信息Bean 91$]Qg,lB  
long[] nStartPos; //开始位置 2Z3('?\z~  
long[] nEndPos; //结束位置 *e-A6S h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'UMXq~RMe  
long nFileLength; //文件长度 G(~;]xNW+  
boolean bFirst = true; //是否第一次取文件 :'*DPB-  
boolean bStop = false; //停止标志 x\J#]d.  
File tmpFile; //文件下载的临时信息 K91)qI;BD  
DataOutputStream output; //输出到文件的输出流 aj?a^}X  
zxf"87se  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) W2z*91$  
public SiteFileFetch(SiteInfoBean bean) throws IOException q*2N{  
{ 3bDQk :L  
siteInfoBean = bean; I =1+h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]|sAK%/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PSPmO'C+  
if(tmpFile.exists ()) PJ2qfYsH=>  
{ TpHfS]W-P  
bFirst = false; [+OnV&  
read_nPos(); gS:A'@&  
} glDh([  
else i:Zm*+Gi  
{ Fr%d}g  
nStartPos = new long[bean.getNSplitter()]; JqMDqPIQ  
nEndPos = new long[bean.getNSplitter()]; kWNV%RlSx  
} 8X I?  
v$=QA:!U  
XEdzpkB  
<a[Yk 2  
} )x]3Zq  
OQ,NOiNkap  
|=EZ1<KzD  
public void run() @c ~)W8  
{ m~dC3}e8/?  
//获得文件长度 ^1wA:?uN}  
//分割文件 l27\diKPJ  
//实例FileSplitterFetch kFQ8 y~>y}  
//启动FileSplitterFetch线程 06Gt&_Q  
//等待子线程返回 P<Zh XN'  
try{ t w(JZDc  
if(bFirst) Uz7^1.-g4  
{ oX4q`rt  
nFileLength = getFileSize(); VL[kJi   
if(nFileLength == -1) '}rRzD:  
{ nN~~cV  
System.err.println("File Length is not known!"); 7c;9$j  
} YhRWz=l  
else if(nFileLength == -2) Vf`7V$sr  
{ )NO<s0?&  
System.err.println("File is not access!"); [j"9rO" +  
} m] W5+  
else 2>\v*adG  
{ fi+R2p~vs  
for(int i=0;i<nStartPos.length;i++) n3lE, b  
{ C_ \q?>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :=9] c17=  
} 1RKW2RCaW_  
for(int i=0;i<nEndPos.length-1;i++) !J =sk4T  
{ Pub0IIs  
nEndPos = nStartPos[i+1]; g!i45-n3gt  
} qClHP)<  
nEndPos[nEndPos.length-1] = nFileLength; r|*&GHo L  
} fGv#s X  
} @Eb2k!T  
N-g8}03  
BI:k#jO!  
//启动子线程 5*\\J&H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {ls+d x/  
for(int i=0;i<nStartPos.length;i++) SSBg?H'T  
{ zd]D(qeX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kF;5L)o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \*\R1_+  
nStartPos,nEndPos,i); ^VT1vu %03  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uu7dSU  
fileSplitterFetch.start(); ez3Z3t`  
} s!+"yK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HP.E3yYK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a{[+<8=@1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :y2p@#l#  
nEndPos = " + nFileLength); ~dHM4lGY  
// fileSplitterFetch[nPos.length-1].start(); 93IFcmO.H@  
]0B|V2D#e  
Gq#~vr  
//等待子线程结束 B$?qQ|0:=  
//int count = 0; NDO\B,7  
//是否结束while循环 i{^Z1;Yl  
boolean breakWhile = false; -xg2q V\c  
pbHsR^  
rg_Q"g  
while(!bStop) +KEkmXZ  
{ 3E^M?N2oc  
write_nPos(); 1\L[i];L8  
Utility.sleep(500); ?@6/Alk  
breakWhile = true; @OV-KT[>  
2eQdQwX  
JM.XH7k  
for(int i=0;i<nStartPos.length;i++) _U| 7'^|  
{ _kFYBd  
if(!fileSplitterFetch.bDownOver) ;oH ,~|K  
{ kJs^ z  
breakWhile = false; N"[B=fU}  
break; (/ " &  
} "()sb?&  
} !.5),2  
if(breakWhile) 1U\$iy8}  
break; /"qcl7F  
7yI @"c#O  
FZpKFsPx  
//count++; (y4#.vZh:  
//if(count>4) M] V.!z9B  
// siteStop(); FdOFE.l  
} ts9pM~_~  
PHM:W%g:  
7q9gngT1LA  
System.err.println("文件下载结束!"); $<)Yyi>6E  
} a?cn9i)#  
catch(Exception e){e.printStackTrace ();} ?Ce#BwQ>  
} H ;@!?I  
-[#n+`M  
N1--~e  
//获得文件长度 0_<Nc/(P  
public long getFileSize() 6DSH`-;  
{  h=RD O  
int nFileLength = -1; @y~P&HUN  
try{ J>S3sP  
URL url = new URL(siteInfoBean.getSSiteURL()); Il~01|3+m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [!*xO?yCJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0^!Gib  
<ZPZk'53<f  
1-;?0en&0  
int responseCode=httpConnection.getResponseCode(); l`n5~Fs  
if(responseCode>=400) - HOnB=  
{ CUmH,`hu  
processErrorCode(responseCode); \MYU<6{u  
return -2; //-2 represent access is error ij)Cm]4(2  
} {/M\Q@j  
^o<[. )  
X}JWf<=q  
String sHeader; D,W\ gP/h%  
L=1 ~ f-  
] V G?+  
for(int i=1;;i++) !QC<n/  
{ H*U`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2*[Un(  
//Utility.log(in.readLine()); |+EKF.K  
sHeader=httpConnection.getHeaderFieldKey(i); 6&!l'[hU  
if(sHeader!=null) $AwZ2HY  
{ LDX*<(  
if(sHeader.equals("Content-Length")) LcUlc)YH5  
{ W%8+t)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?n*fy  
break; ]tVl{" .{  
} )A83A<~  
} d(l|hmj4j9  
else  nP_=GI  
break; XJFnih  
} q+/l"&j.  
} F.KrZ3%4iB  
catch(IOException e){e.printStackTrace ();} k:0P+d  
catch(Exception e){e.printStackTrace ();} Ow3a0cF[9  
46ChMTt  
o>u!CL<  
Utility.log(nFileLength); {})y^L  
h DtK nF  
YC)hX'A\  
return nFileLength; uX0 Bp8P  
} TzY!D *%z  
Q&wYc{TUbm  
"t+r+ipf])  
//保存下载信息(文件指针位置) :0dfB&7  
private void write_nPos() 2?1}ZXr  
{ hT=f;6$  
try{ ]PVt o\B=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I =b'j5c  
output.writeInt(nStartPos.length); .\4l'THn,0  
for(int i=0;i<nStartPos.length;i++) yM17H\=  
{ lVT&+r~r  
// output.writeLong(nPos); SY8U"Qc;9  
output.writeLong(fileSplitterFetch.nStartPos); k!c7a\">{  
output.writeLong(fileSplitterFetch.nEndPos); GiqBzV3"  
} {9{J^@@  
output.close(); 7<4xtK`+b  
} yjv&4pIc1  
catch(IOException e){e.printStackTrace ();} H oS|f0  
catch(Exception e){e.printStackTrace ();} i0i`k^bA  
} eEie?#Z/6  
cP('@K=p  
b\M b*o  
//读取保存的下载信息(文件指针位置) F#^L9  
private void read_nPos() kpWzMd &RK  
{ :'ihE\j  
try{ hqWbp*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jRwa0Px(  
int nCount = input.readInt(); e9}8RHy1$  
nStartPos = new long[nCount]; "$Y(NFb  
nEndPos = new long[nCount]; ] EV`dIk  
for(int i=0;i<nStartPos.length;i++) @oA0{&G{  
{ L3g9b53\  
nStartPos = input.readLong(); [{/$9k-aF?  
nEndPos = input.readLong(); Ba<#1p7_  
} 2gH _$  
input.close(); <YSg~T  
} Djyp3uUA/  
catch(IOException e){e.printStackTrace ();} \E~Q1eAJT  
catch(Exception e){e.printStackTrace ();} pbFYiu+  
} [}@n*D$  
$oc9 |Q 7  
@,GjeF]!  
private void processErrorCode(int nErrorCode) O68bzi]  
{ VZIKjrKs  
System.err.println("Error Code : " + nErrorCode); =}"R5  
} h2AGEg'g2[  
S>(z\`1qm  
a&8l[xe1  
//停止文件下载 ^b:Xo"q#H  
public void siteStop() QW,cn7  
{ kO jEY  
bStop = true; #*+;B93 )  
for(int i=0;i<nStartPos.length;i++) ]|t9B/()i  
fileSplitterFetch.splitterStop(); 0}6QO  
>2nF"?"=  
a4:`2  
} f8R+7Ykx  
} CJ0$;et  
//负责部分文件的抓取 FF8WTuzB+  
**FileSplitterFetch.java }Z^FEd"y  
*/ Q Xsfp  
package NetFox; j`{fB}  
%bEGv:88s  
gYRqqV  
import java.io.*; >y&[BB7S6  
import java.net.*; b_q! >&c  
pb~Ps#"Zg  
+}&pVe\t  
public class FileSplitterFetch extends Thread { bb*c+XN0  
RA! x  
#W_i{bdO  
String sURL; //File URL 3O#~dFnp  
long nStartPos; //File Snippet Start Position rve7YS'  
long nEndPos; //File Snippet End Position 5T7_[{  
int nThreadID; //Thread's ID "tqS|ok.  
boolean bDownOver = false; //Downing is over Ma% E&.ed  
boolean bStop = false; //Stop identical /,=Wy"0TJ  
FileAccessI fileAccessI = null; //File Access interface ,oC= {^l{  
pHq{S;R2G  
~3LhcU-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?psOj%  
{ wa9'2a1?  
this.sURL = sURL; B.h0" vJ  
this.nStartPos = nStart; Wh#os,U$  
this.nEndPos = nEnd; B)_!F`9  
nThreadID = id; #-l!`\@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dY/|/eOt<K  
} 46QYXmNQ}  
8:;u v7p  
J R 8 Z6  
public void run() gEcnn .(S  
{ 1^n5CI|7u  
while(nStartPos < nEndPos && !bStop) l:>qR/|m  
{ < P?3GT/  
yt]Oj*nn0K  
YzforM^F  
try{ >[A6 5q'  
URL url = new URL(sURL); ymzPJ??!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o3kt0NuF,  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pf^Ly 97  
String sProperty = "bytes="+nStartPos+"-"; r"Hbr Qn  
httpConnection.setRequestProperty("RANGE",sProperty); xCmI7$uQ#  
Utility.log(sProperty); Z<$E.##  
S)Ub/`f{s  
1{;[q3a  
InputStream input = httpConnection.getInputStream(); p@!@^1j=  
//logResponseHead(httpConnection); y \mutm  
B.CH9M  
ai<MsQQ:=  
byte[] b = new byte[1024]; 4{Yy05PFS  
int nRead; YU ]G5\UU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cq@_*:~Or  
{ O?4vC5x  
nStartPos += fileAccessI.write(b,0,nRead); hPEp0("  
//if(nThreadID == 1) O,V6hU/ *  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S4aHce5PXA  
} ~|0F?~eR7  
*'AS^2'  
Npf7p  
Utility.log("Thread " + nThreadID + " is over!"); e!2%ku  
bDownOver = true; K@$L~G  
//nPos = fileAccessI.write (b,0,nRead); :<WQ;q  
} N.Wdi  
catch(Exception e){e.printStackTrace ();} Ma*dIwEp  
} N8MlT \+r  
} zw%n!wc_\  
SceCucT  
aJa^~*N/Aa  
//打印回应的头信息 ;([tf;  
public void logResponseHead(HttpURLConnection con) #pm-nU%|_j  
{ +=B}R  
for(int i=1;;i++) *n|0\V<  
{ /i~^LITH  
String header=con.getHeaderFieldKey(i); z kX-"}$8  
if(header!=null) Jq+$_Uqd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4W//Oc@e  
Utility.log(header+" : "+con.getHeaderField(header)); UmD-7Fd  
else :z0>H5  
break; fO|~Oz<S  
} !$KhL.4P  
} BtNW5'^  
rM >V=|9,  
w#G=Z_Tt  
public void splitterStop() g0:4zeL  
{ *_).UAP.  
bStop = true; N>nvt.`P  
} 5q_OuZ/6  
u0 oYb_Yv  
>eG&gc@$1$  
} Vg,>7?]6h  
`2(R}zUHN  
*A1TDc$  
/* 3Llj_lf  
**FileAccess.java r(in]7  
*//文件访问(定位,写) )x:j5{>(  
package NetFox; Y7t{4P  
import java.io.*; ME10dr  
%`\_l  
n\"LN3  
public class FileAccessI implements Serializable{ Y\z\{JW  
R5;eR(24G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V&+$V q  
RandomAccessFile oSavedFile; L|1zHDxQ  
long nPos; zI:5I@ X  
$t H.np  
v4>"p!_C  
public FileAccessI() throws IOException "`3 ^M vC  
{ >eTgP._  
this("",0); n `T[eb~  
} 5<?c_l9X^  
hCvLwZ?LF  
S}[:;p?F`  
public FileAccessI(String sName,long nPos) throws IOException cYwC,\ uF  
{ j _9<=Vu  
oSavedFile = new RandomAccessFile(sName,"rw"); P~ pbx  
this.nPos = nPos; ;$L!`"jn  
oSavedFile.seek(nPos); = 4WZr  
} I;Fy k70w;  
ApJf4D<V  
p>tdJjnt  
public synchronized int write(byte[] b,int nStart,int nLen) |wb(rua  
{ *n_4Rr  
int n = -1; 0#/ 6P&6  
try{ /N{@g.edL  
oSavedFile.write(b,nStart,nLen); TIh zMW\/K  
n = nLen; J$/BH\  
} @OY-(cW  
catch(IOException e) })SdaZ  
{ jL%}y1m?  
e.printStackTrace (); ]a|;G  
} b-zX3R;  
:QL p`s  
h}&IlDG  
return n; 4"(zi5`e  
} Jo$Dxa z  
~[y+B0I3  
y/6LMAI  
} &p4<@k\L  
T|2%b*/  
6jo&i  
/* >b?)WNk  
**SiteInfoBean.java E(LE*J  
*/ Byj~\QMD|  
package NetFox; pDq_nx9  
I8;[DP9  
gK\7^95  
public class SiteInfoBean { c!^}!32j)  
H^:|`T|,  
8vW`E_n  
private String sSiteURL; //Site's URL Q b{5*>  
private String sFilePath; //Saved File's Path HWOH8q{f!  
private String sFileName; //Saved File's Name '\\Cpc_g  
private int nSplitter; //Count of Splited Downloading File m9c T}x&j  
6|cl`}g_j  
S5a<L_  
public SiteInfoBean() 8mLU ~P |  
{//nSplitter的缺省值为5 NWK_(=n  
//default value of nSplitter is 5 1^^D :tt  
this("","","",5); bI(98V,t  
} oz@6%3+  
2<@!m @  
&:K?-ac  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K({,]<l5  
{ C~V$G}mM  
sSiteURL= sURL; )1 j2  
sFilePath = sPath; w/6@R 4)p  
sFileName = sName; P< x  
this.nSplitter = nSpiltter; In M'zAhb  
dwMwd@*j  
Ps\^OJR  
} oF xVK  
MV \zwH  
0%+k>(@ R  
public String getSSiteURL()  +'.Q-  
{ #?6RoFgMe  
return sSiteURL; N@0scfO6<  
} 1tpD|  
Ngnjr7Q={T  
rSn7(3e4^  
public void setSSiteURL(String value) cyNLeg+O*  
{ G].KJ5,y  
sSiteURL = value; OhEL9"\<  
} ;xwQzu%M>5  
q|J]  
Hp!F?J7sx  
public String getSFilePath() i>2_hn_UR  
{ I#U44+c  
return sFilePath; `f]O  
} y9)",G!  
`l"~"x^Rr  
{+Yo&F}n  
public void setSFilePath(String value) ? Q}{&J  
{ PK" C+o;:  
sFilePath = value; [_n|n"M  
} KK</5Aw9p  
2l?J9c}Wo  
Kq$1lPI  
public String getSFileName() K<GCP2  
{  7I|Mq  
return sFileName; UhK,H   
} g\'sGt3O  
S# #W_OlrI  
gp=0;#4 4  
public void setSFileName(String value) RMK U5A7  
{ #SueT"F  
sFileName = value; k W,|>  
} ?9+;[X  
1zRO== b  
odDt.gQXU  
public int getNSplitter() zlE kP @)  
{ 7Y/_/t~Y  
return nSplitter; h%%'{^>~  
} LKa_ofY  
*?{)i~  
;q Z2V  
public void setNSplitter(int nCount) F <(Y  
{ Lst5  
nSplitter = nCount; YC~+r8ME$j  
} h.nzkp5  
} b11C3TyQT  
I$$!YMm.N  
+Ji dP  
/* eo!z>9#.  
**Utility.java !SnpesTn  
*/ `|R{^Sk1o  
package NetFox; "TPMSx&Ei  
R-ci?7dt3  
]P.S5s'  
public class Utility { ^IpS 3y  
Liofv4![  
#]rw@c  
public Utility() -Db(  
{ Hogr#Sn2  
fw<'ygd  
"'%x|nB  
} 7 UR)4dYA  
/9sUp} *  
//线程睡眠 Rzp-Q5@M Y  
public static void sleep(int nSecond) AK[c!mzx  
{ - 0zo>[c/p  
try{  m{~r6@  
Thread.sleep(nSecond); yDPek*#^"q  
} 6(.&y;  
catch(Exception e) K|iNEhuc  
{ OnG?@sW+4!  
e.printStackTrace (); t;'__">:q  
} `| fF)kI  
} IySlu^a  
%lujme  
//日志 -Jb I7Le  
public static void log(String sMsg) bcQ$S;U)  
{ ~! @a  
System.err.println(sMsg); nv|&|6?`oK  
} N7|ctO  
 ST{<G  
JWLQ9U X  
public static void log(int sMsg) Q~jUZ-qN  
{ b(wiJ&t  
System.err.println(sMsg); h>4\I;Ij  
} tYnNOK*|  
} =T[kGg8`  
zzM 'uo  
nfc&.(6x<  
/* ;:v:pg8qc  
**TestMethod.java q?`bu:yS  
*/ 1Eh (U  
package NetFox; }_K7}] 1  
X[R/j*K  
W}Z'zU?[  
public class TestMethod { vFQ'sd]C  
U\+o$mU^  
9%|!+!j  
public TestMethod() -|g~--@Q  
{ ///xx/weblogic60b2_win.exe G"wy?  
try{ L\pe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ri6_u;Ch  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Nb-;D)W;B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d&F8nBIM5  
fileFetch.start(); _E3*;  
} -r[l{ce  
catch(Exception e){e.printStackTrace ();} _L9`bzZj  
G >bQlZG  
;8H m#p7,  
} =}F &jl  
5Osx__6$t  
:2}zovsdj  
public static void main(String[] args) %+qD-{&  
{ 525W; mu{  
new TestMethod(); $0 eyp]XC\  
} y^?7de}  
} 3 cu`U`  
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