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http断点续传简单实现(java)

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/* uG\~Hxqw7O  
**SiteFileFetch.java _)45G"M  
*/ "0HUaU,e  
package NetFox; s70Z&3A  
import java.io.*; `=Ip>7T&  
import java.net.*; 0j@mzd2  
&Ym):pc  
M hN;GMH  
public class SiteFileFetch extends Thread { u+V*U5v  
F'XQoZ* 1  
-+ByK#<%  
SiteInfoBean siteInfoBean = null; //文件信息Bean k ]NZ%.  
long[] nStartPos; //开始位置 _^E NRk@  
long[] nEndPos; //结束位置 Um+_ S@h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Dck/Ea  
long nFileLength; //文件长度 MtJ-pa~n  
boolean bFirst = true; //是否第一次取文件 kk78*s {6  
boolean bStop = false; //停止标志 >W>rhxU  
File tmpFile; //文件下载的临时信息 es7;eH*O9  
DataOutputStream output; //输出到文件的输出流 "VZ1LVI  
=2&\<Q_Fi  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0%bCP/  
public SiteFileFetch(SiteInfoBean bean) throws IOException bqbG+ g  
{ ^BF}wQb :j  
siteInfoBean = bean; 1h@qcom9K_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wlNL;W@w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :$D*ab^^P  
if(tmpFile.exists ()) TO Hz3=  
{ 7 z    
bFirst = false; _9>,9aL  
read_nPos(); 5qrD~D '  
} [~N;d9H+*1  
else IRbyW?/Xv  
{ ]0D-g2!|A  
nStartPos = new long[bean.getNSplitter()]; =n,;S W  
nEndPos = new long[bean.getNSplitter()]; ;7\Fx8"s[  
} {L;sF=d  
KZ2[.[(Ph  
F>\,`wP  
1"y !wsM%  
} Rs=Fcvl  
o"JH B  
[WDzaRzd  
public void run() s* GZOz  
{ w>2lG3H<  
//获得文件长度 P|Aac,nE+^  
//分割文件 $$ND]qM$M  
//实例FileSplitterFetch W5u5!L/  
//启动FileSplitterFetch线程 qlcd[Y*B  
//等待子线程返回 yu6~:$%H  
try{ x/<ow4C  
if(bFirst) v:SHaUS  
{ Qm[((6}  
nFileLength = getFileSize(); wKpGJ& {  
if(nFileLength == -1) eP2Q2C8g  
{ >Cr"q*  
System.err.println("File Length is not known!"); <4TI;yy6?  
} ~k34#j:J65  
else if(nFileLength == -2) q.J6'v lj/  
{ A'w+Lc.2  
System.err.println("File is not access!"); _-fLD  
} }4>u_)nt  
else CRo'r/G  
{ u [qy1M0  
for(int i=0;i<nStartPos.length;i++) =\]gL%N-|  
{ Gxd/t#;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4&NB xe  
} Kvg=7o  
for(int i=0;i<nEndPos.length-1;i++) k$v 7@|Aw  
{ Mzg'$]N  
nEndPos = nStartPos[i+1]; ZTTA??}Y  
} HJr/N)d  
nEndPos[nEndPos.length-1] = nFileLength; D&m1yl@\J  
} P{dR pH|  
} b!g)/%C  
q5g_5^csM{  
q<\r}1Dm  
//启动子线程 ^:?z7m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ScJ:F-@>  
for(int i=0;i<nStartPos.length;i++) (&m1*  
{ Y#lAG@$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eQQVfEvS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6No.2Oo  
nStartPos,nEndPos,i); ~^.,Ftkb@7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qF3S\ C  
fileSplitterFetch.start(); nxN("$'cq  
} 7h9oY<W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1%M^MT%&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Mxz X@GBX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3=]/+{B  
nEndPos = " + nFileLength); /,7#%D  
// fileSplitterFetch[nPos.length-1].start(); vasw@Uto)  
HV`u#hZ7C  
bY`Chb.  
//等待子线程结束 6AD&%v  
//int count = 0; Uj 3{c  
//是否结束while循环 -C^qN7Bz  
boolean breakWhile = false; [9?]|4  
y~_x  
A f?&VD4K  
while(!bStop) w}}+8mk[  
{ .WOF:Nu4  
write_nPos(); 'PMzm/;8st  
Utility.sleep(500); >VjtKSN  
breakWhile = true; 3!;o\bgK  
rGH7S!\AM  
Ahd{f!  
for(int i=0;i<nStartPos.length;i++) Kc9)Lzu+  
{ tSDp>0yZ3  
if(!fileSplitterFetch.bDownOver) 6w<p1qhW  
{ ?fs#K;w  
breakWhile = false; \l6mX In=>  
break; YVHDk7s  
} w*SFQ_6YE  
} kGq<Zmy|  
if(breakWhile) n;b 9f|&z  
break; a(o[ bH.|;  
0txSF^x  
e ]>{?Z  
//count++; If9!S} wa  
//if(count>4) qmnCa&C9  
// siteStop(); ]*S_fme  
} =7P; /EV  
DA4!-\bt@  
] )x z  
System.err.println("文件下载结束!"); ,KibP_<%&P  
} $PbN=@  
catch(Exception e){e.printStackTrace ();} OaxE3bDT  
} ^_ZQf  
Q^V`%+  
**YNR:#Y  
//获得文件长度 h$zPQ""8  
public long getFileSize() +ACV,GG  
{ +FVcrL@  
int nFileLength = -1; .Lu=16  
try{ :S7yM8 b`  
URL url = new URL(siteInfoBean.getSSiteURL()); qXW2a'~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N<Q}4%^c  
httpConnection.setRequestProperty("User-Agent","NetFox"); `TsfscN  
XWy iS\  
Xhkw<XbV  
int responseCode=httpConnection.getResponseCode(); B&Ci*#e  
if(responseCode>=400) Y.*lO  
{ SS~Txt75m  
processErrorCode(responseCode); :U[_V4? 7  
return -2; //-2 represent access is error ?R{?Qv  
} 0Rk'sEX,  
;09J;sf  
"RX?"pB  
String sHeader; _&![s]  
x}>tX  
'}YXpB  
for(int i=1;;i++) b~1p.J4  
{ et ~gO!1:*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }EIwkz8  
//Utility.log(in.readLine()); FW.dHvNX  
sHeader=httpConnection.getHeaderFieldKey(i); >`\*{]  
if(sHeader!=null) qiF~I0_0  
{ g4$%)0x%  
if(sHeader.equals("Content-Length")) X9gC2iSs]  
{ pn7 :")Zx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tB3CX\e  
break; tr/dd&(Y1  
} i:8^:(i  
} 7VXeu+-P  
else C[&&.w8Pm  
break; Y-c~"#  
} i }g xq  
} 7~Ga>BK  
catch(IOException e){e.printStackTrace ();} -pGt ;  
catch(Exception e){e.printStackTrace ();} eo_T .q  
Q%xY/xH]  
k51s*U6=  
Utility.log(nFileLength); udZ: OU<  
#rr-4$w+  
{G0)mp,  
return nFileLength; fBOPd =  
} -d3y!| \>a  
66Xt=US  
g&vEc1LNo  
//保存下载信息(文件指针位置) ` ;=Se_  
private void write_nPos() ,;-*q}U  
{ e,*[5xQ  
try{ LG|,g3&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L-R}O 8  
output.writeInt(nStartPos.length); qU n>  
for(int i=0;i<nStartPos.length;i++) bC{8yV=)  
{ KTEis!w  
// output.writeLong(nPos); MX0B$yc$  
output.writeLong(fileSplitterFetch.nStartPos); \-0`%k"&  
output.writeLong(fileSplitterFetch.nEndPos); RHbp:Mlk  
} JrAc]=  
output.close(); !v L :P2  
} {@$3bQ  
catch(IOException e){e.printStackTrace ();} =x'%zUgE  
catch(Exception e){e.printStackTrace ();} -*M:OF"Zh  
} ~m?~eJK#a  
1F,_L}=o1s  
o?FUVK  
//读取保存的下载信息(文件指针位置) q_&IZ,{Vk  
private void read_nPos() <6~;-ZQY  
{ !?*!"S-Sl  
try{ sK?-@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5,ahKB8  
int nCount = input.readInt(); 6w;|-/:`  
nStartPos = new long[nCount]; .A/H+.H;  
nEndPos = new long[nCount]; ! VZj!\I  
for(int i=0;i<nStartPos.length;i++) PWu2;JF  
{ NF!1)  
nStartPos = input.readLong(); r_E)HL/A  
nEndPos = input.readLong(); Z|% 2495\  
} 3]es$Jy  
input.close(); # :w2Hf6Q  
} ONiI:Z>%  
catch(IOException e){e.printStackTrace ();} ]Hy PJ  
catch(Exception e){e.printStackTrace ();} E57{*C  
} ha! "BR  
ok2~B._+;  
a3O_#l-Z  
private void processErrorCode(int nErrorCode) X", 0VO  
{ ](:FW '-  
System.err.println("Error Code : " + nErrorCode); Q5n : f+  
} Pm(:M:a  
g+)\ /n|  
8I0T u  
//停止文件下载 PZRn6Tc  
public void siteStop() ~C7<a48x  
{ rOb"S*  
bStop = true; ]NV ]@*`tO  
for(int i=0;i<nStartPos.length;i++) eSNSnh]'  
fileSplitterFetch.splitterStop(); n(YHk\2  
"IS^a jaq  
cievC,3*  
} lN>C#e<]  
} 65#:2,s  
//负责部分文件的抓取 {V% O4/  
**FileSplitterFetch.java \R\@t] >Y  
*/ 0&IXzEOr  
package NetFox; q,+kPhHEgy  
"Lq|66  
*8.@aX3  
import java.io.*; 'Rd*X6dv  
import java.net.*; N^( lUba  
s~X*U&}5  
,,gLrV k  
public class FileSplitterFetch extends Thread { @ PoFxv  
[ 7Lxt  
W#jZRviyq!  
String sURL; //File URL Iei7!KLW  
long nStartPos; //File Snippet Start Position u@_!mjXQ  
long nEndPos; //File Snippet End Position ~K-*q{6Q  
int nThreadID; //Thread's ID B5,QJ W*  
boolean bDownOver = false; //Downing is over &M3ES}6  
boolean bStop = false; //Stop identical UcLNMn|  
FileAccessI fileAccessI = null; //File Access interface Jhsv2,8 {  
zP(=,)d  
C7 ]DJn  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f UF;SqT  
{ l P$r   
this.sURL = sURL; u2-@?yt  
this.nStartPos = nStart; ocl47)  
this.nEndPos = nEnd; &xBK\  
nThreadID = id; '`]n_$f'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x #tu  
} e@:P2(WW l  
,]uX:h-EM  
q]N?@l]  
public void run() EN-H4F  
{ ~S^X"8(U  
while(nStartPos < nEndPos && !bStop) ?VZ11?u  
{ Y0PGT5].@'  
h-La'}>?  
^s2m\Q(  
try{ \U!@OX.R'M  
URL url = new URL(sURL); [EmOA.6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;;YcuzQI3  
httpConnection.setRequestProperty("User-Agent","NetFox"); OHHNWg_5  
String sProperty = "bytes="+nStartPos+"-"; 9'n))%CZ.  
httpConnection.setRequestProperty("RANGE",sProperty); XJmFJafQD  
Utility.log(sProperty); e|b~[|;*=  
T,WKo B  
Jm %ynW  
InputStream input = httpConnection.getInputStream(); Ns.3s7&  
//logResponseHead(httpConnection); [arTx ^  
){+[$@9  
a1g6}ym\  
byte[] b = new byte[1024]; kUn2RZ6$#  
int nRead; f`hyYp`d5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }iua] 4 |  
{ QGH h;  
nStartPos += fileAccessI.write(b,0,nRead); selP=Q!  
//if(nThreadID == 1) ?{ B[^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |jahpji6  
} (VYR!(17  
"WYA  
NZo<IKD$  
Utility.log("Thread " + nThreadID + " is over!"); w0Fwd  
bDownOver = true; 01LZE,.  
//nPos = fileAccessI.write (b,0,nRead); =5y`(0 I`U  
} tS\=<T  
catch(Exception e){e.printStackTrace ();} &l. x:eD  
} JsmbW|t^  
}  6R;)  
M`0(!Q}  
N@Xg5huO  
//打印回应的头信息 ug^om{e-  
public void logResponseHead(HttpURLConnection con) 9?uqQ  
{ e7@li<3>d  
for(int i=1;;i++) G*i.a*9<)  
{ XVQL.A7  
String header=con.getHeaderFieldKey(i); 0jR){G9+  
if(header!=null) 8#+`9GI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); paW'R+Rck  
Utility.log(header+" : "+con.getHeaderField(header)); .aNO( /kO  
else f%2%T'Q  
break; p QluGIX0V  
}  bt;lq!g  
} qE>i,|rP`  
jEUx q%BH  
SK's!m:r=  
public void splitterStop() hIR@^\?  
{ @. "q  
bStop = true; 7egq4gN]2Y  
} \WWG>OUh.U  
%fHH{60  
aT&t_^[]   
} p` $fTgm  
avlqDi1l  
s~L`53A  
/* Q-[3j  
**FileAccess.java (FuEd11R  
*//文件访问(定位,写) SGt5~T xj  
package NetFox; 8+9\7*  
import java.io.*; ze&#i6S  
vyE{WkZxR  
oWI!u 5  
public class FileAccessI implements Serializable{ "c6<zP  
?fV?|ZGZI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C?/r;  
RandomAccessFile oSavedFile; /^Y[*5  
long nPos; DacN {r"3  
6;gLwOeOHY  
1DUb [W8  
public FileAccessI() throws IOException x.ba|:5  
{ sMP:sCRC  
this("",0); /N>} 4Ay  
} K!p,x;YX  
*,17x`1e  
+,z) #  
public FileAccessI(String sName,long nPos) throws IOException e^zHw^js  
{ JRXRi*@  
oSavedFile = new RandomAccessFile(sName,"rw"); i0\)%H:z  
this.nPos = nPos; S nW7x  
oSavedFile.seek(nPos); tU{\ev$x  
} m^Glc?g<  
44~hw:   
j1A|D   
public synchronized int write(byte[] b,int nStart,int nLen) 33 : @*  
{ X &D{5~qC  
int n = -1; D^|9/qm$  
try{ a$}NW.  
oSavedFile.write(b,nStart,nLen); gGEIK0\{  
n = nLen; z3W3=@  
} Yk'm?p#~  
catch(IOException e) wN(&5rfS  
{ 9Sz7\W0  
e.printStackTrace (); DHv2&zH  
} wG8 nw;  
;}K62LSR  
wx*1*KZ  
return n; i'=2Y9S}  
} ~>g+2]Bn>$  
%m`zWg-  
dw9T f^V  
}  L=]p_2+  
0q#"clw  
w#9_eq|3  
/* :RiF3h(  
**SiteInfoBean.java 8Q=ZH=SQK  
*/ _~&9*D$ {>  
package NetFox; pawl|Z'Ez  
yQ%"U^.m  
~x#vZ=]8  
public class SiteInfoBean { Om9jtWk  
JNi=`X&A  
N 9LgU)-Jt  
private String sSiteURL; //Site's URL Q|c|2byb  
private String sFilePath; //Saved File's Path - {{[cT I  
private String sFileName; //Saved File's Name VD [pZ2;4  
private int nSplitter; //Count of Splited Downloading File G\kpUdj}  
: G=FiC  
59lj7  
public SiteInfoBean() <cj{Qk  
{//nSplitter的缺省值为5 ]iVLHVqz  
//default value of nSplitter is 5 u-:Ic.ZV  
this("","","",5); 4TZ cc|B5  
} cP rwW 6  
jDX>izg;V  
(>7>3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -c+]Wm"\  
{ Ej"u1F14J  
sSiteURL= sURL; h/m6)m.D  
sFilePath = sPath; |`0n"x7  
sFileName = sName; gKi{Y1  
this.nSplitter = nSpiltter; |]sx+NlNc  
H M:r0_  
v"!4JZ%K  
} # {PmNx%M  
yWb4Ify  
^R~~L  
public String getSSiteURL() Z a(|(M H  
{ e|lD:_1i  
return sSiteURL; uM S*(L_  
} v("wKHWTI@  
L0"~[zB]N  
J ^ G  
public void setSSiteURL(String value) 2*1ft>Uty  
{ MbA\pG'T  
sSiteURL = value; +B"0{>n}F  
} xDjV `E]  
nc?B6IV  
|.U)ll(c  
public String getSFilePath() {' 5qv@3  
{ rRb+_]Lg  
return sFilePath; ^4pto$#@O:  
} ,hRN\Kt)p  
FHg0E++?  
N#k61x  
public void setSFilePath(String value) &c%Y<1e`%  
{ ^jSsa  
sFilePath = value; uY#TEjGh]  
} }NCL>l;q  
dh -,E  
o\=n4;S  
public String getSFileName() #wR;|pN  
{ D4u% 6R|F  
return sFileName; X#p Wyo~  
} A9:NKY{z  
)!W45"l-3M  
I'!/[\_  
public void setSFileName(String value) Wf26  
{ !8RwO%c(  
sFileName = value; anN#5jt  
} osP\D iQ  
=Lp7{09u  
=o7}]k7  
public int getNSplitter() +OHGn;C  
{ K[?Xm"4  
return nSplitter; 5.0e~zlM -  
} [(mlv42"  
K_&MoyJJ9f  
1KE:[YQ1  
public void setNSplitter(int nCount) _aS;!6b8W  
{ Gc,_v3\  
nSplitter = nCount; +[-i%b3q  
} +9A\HQ|22  
} ]uh3R{a/  
DXR:1w[^  
A[N{  
/* [ .,>wo~  
**Utility.java j}JZ  
*/ gzn^#3b  
package NetFox; MgMD\  
k;^ :  
{S.>BXX  
public class Utility { mTDVlw0dh  
*%FA:Y  
6" B%)0  
public Utility() x!< yT?A  
{ t+Bf#:  
/bRg?Q  
]$iqa"{  
} :l u5Uu~  
2f:^S/.A  
//线程睡眠 Sm{>rR  
public static void sleep(int nSecond) Q[4: xkU  
{ w Iv o"|%  
try{ %yS3&Ju  
Thread.sleep(nSecond); `)$_YZq|SR  
} ro~+j}*   
catch(Exception e) #s5N[uK^m  
{ JK_OZ  
e.printStackTrace (); }?8uH/+ZA  
} Yl cbW0'c  
} ed!>)Cb  
~.g3ukt  
//日志 )X+mV  
public static void log(String sMsg) ?\=/$Gt  
{ oMH.u^b]fT  
System.err.println(sMsg); <'U]`L p  
} 4Ft1@  
{Tp2H_EG  
Rd*[%)  
public static void log(int sMsg) E+95WF|4k"  
{ ~+F;q vq  
System.err.println(sMsg); rJyCw+N0  
} J4$! 68  
} %|W.^q  
?X$, fQ#F|  
sN=6gCau  
/* xl9aV\W  
**TestMethod.java pL1i|O  
*/ OW;tT=ql  
package NetFox; $D1w5o-  
C@\{ehG  
]jMKC8uz  
public class TestMethod { 6=_~ 0PcY  
c7uG9  
\;5\9B"i  
public TestMethod() f>jwN@(  
{ ///xx/weblogic60b2_win.exe )=pD%$iq  
try{ OTWkUB{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }j5 a[L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J97R0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a dfR!&J  
fileFetch.start(); w&h 2y4  
} 6rti '  
catch(Exception e){e.printStackTrace ();} I5ss0JSl/  
LwqC ~N  
+\ _{x/u1  
} q Dd~2"er  
^?"\?M1  
,:n| ?7  
public static void main(String[] args) 4Aes#{R3v  
{ q}|U4MJm  
new TestMethod(); % ~ ]xuP[  
} +ZsX*/TOn  
} q(o/yx{bm  
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