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http断点续传简单实现(java)

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/*  8DsXw@o  
**SiteFileFetch.java rG*Zp7{  
*/ mgxoM|n6  
package NetFox; g:sn/Zug]  
import java.io.*; SuU_psF  
import java.net.*; ?-`G0(  
sw'?&:<"Ow  
:"4Pr/}rT  
public class SiteFileFetch extends Thread { ~Yw`w 2  
D+ )R_  
<-1(G1v  
SiteInfoBean siteInfoBean = null; //文件信息Bean L-T3{I,3  
long[] nStartPos; //开始位置 bo  J  
long[] nEndPos; //结束位置 l12_&o"C~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P~5[.6gW  
long nFileLength; //文件长度 _*SA_.0  
boolean bFirst = true; //是否第一次取文件 >K2Md*[P3q  
boolean bStop = false; //停止标志 5D32d1A  
File tmpFile; //文件下载的临时信息 Wp[R$/uT  
DataOutputStream output; //输出到文件的输出流 _k0 X)N+li  
t4a/\{/#9|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pohA??t2:  
public SiteFileFetch(SiteInfoBean bean) throws IOException r+}5;fQJ  
{ L"w% ew  
siteInfoBean = bean; 1e 8J-Nkj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D5wy7`c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `h>a2   
if(tmpFile.exists ()) %6\e_y%  
{ 6^vMJ82U  
bFirst = false; >IL[eiiPG  
read_nPos(); U4J9b p|  
} nhfHY-l} 7  
else tSr.0'CE  
{ /B $9B  
nStartPos = new long[bean.getNSplitter()]; y<Hka'(%  
nEndPos = new long[bean.getNSplitter()]; R6^U9 fDG  
} {bxTODt@  
j4ARGkK5B  
I Xm}WTgF!  
CCCd=s.  
} gWxpGW^eZ~  
I[r  
Hm>M}MF3  
public void run() t% -"h|  
{ {*gO1TZt9  
//获得文件长度 cs]N%M^s  
//分割文件 SLzxF uV  
//实例FileSplitterFetch {XT3M{`rWL  
//启动FileSplitterFetch线程 Md~% e'  
//等待子线程返回 K,uTO7Mk[  
try{ F/MzrK\':m  
if(bFirst) [0M2`x4`  
{ k<aKT?Ek>  
nFileLength = getFileSize(); -8j<`(M' 5  
if(nFileLength == -1) >zYO1.~  
{ S7{L-"D =y  
System.err.println("File Length is not known!"); I9sx*'  
} o5!"dxR  
else if(nFileLength == -2) n|t?MoUP  
{ 8db J'  
System.err.println("File is not access!"); K+9oV[DMs  
} <78]OZ] Z  
else +~gqP k  
{ D}n&`^1X+  
for(int i=0;i<nStartPos.length;i++) 3=6`'PKRQ  
{ t`PA85.|d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); / v";u)  
} W<J".2D  
for(int i=0;i<nEndPos.length-1;i++) aBo8?VV]8  
{ ]_cBd)3P}  
nEndPos = nStartPos[i+1]; YeN /J.R  
} ttEQgkd`  
nEndPos[nEndPos.length-1] = nFileLength; Z3:M%)e_u$  
} I6bekOvP  
} G8c 8`~t  
Irk@#,{<  
HPc7Vo(  
//启动子线程 deD%E-Ja  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r"yA=d'c  
for(int i=0;i<nStartPos.length;i++) JsNqijVC  
{ F[q:jY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ye-o'%{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0_Gi1)  
nStartPos,nEndPos,i); +f{CfWIKs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .'3&!#3  
fileSplitterFetch.start(); JNQiCK,)}M  
} l `D>h2]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [kdt]+'+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F-!,U)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7qfo%n"  
nEndPos = " + nFileLength); X!+#1NPM  
// fileSplitterFetch[nPos.length-1].start(); vmI2o'zi  
h @{U>U7  
s|7(VUPL  
//等待子线程结束 71AR)6<R  
//int count = 0; {`Ekv/XWa  
//是否结束while循环 yY,O=yOjq  
boolean breakWhile = false; l,FK\  
dXAKk[uf  
Kjbz\~  
while(!bStop) y`"~zq0D  
{ ~7Ji+AJA  
write_nPos(); @"BvyS,p  
Utility.sleep(500); IR*g>q  
breakWhile = true; goYRA_%cX  
a );>  
_dCsYI%  
for(int i=0;i<nStartPos.length;i++) n@pm5f  
{ `v*UY  
if(!fileSplitterFetch.bDownOver) .&:GO D  
{ GA19=gow  
breakWhile = false; bM]\mo>z<  
break; @(XX68  
} #UR4I2t*  
} wRgh`Hc\}  
if(breakWhile) t`b>iX%(1t  
break; &3x \wH/_  
cY+vnQm  
y %dUry%>  
//count++; Fs^d-I  
//if(count>4) "Aw| 7XII  
// siteStop(); \;0J6LBc  
} ?Ji.bnfK  
I(6k.PQ  
~z)diF<  
System.err.println("文件下载结束!"); :t &ib}v  
} R|PFGhi6"A  
catch(Exception e){e.printStackTrace ();} p5<2tSD  
} (2H e]M\  
fH_G;#q  
xPa>-N=*  
//获得文件长度 JpVV0x/Q/_  
public long getFileSize() 2ql7*g?Uq@  
{ +P C<#  
int nFileLength = -1; K&(}5`H0=  
try{ "y R56`=  
URL url = new URL(siteInfoBean.getSSiteURL()); 9/$D&tRN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wAHW@q9CK  
httpConnection.setRequestProperty("User-Agent","NetFox"); .r9-^01mG  
28l",j)S  
],ow@}  
int responseCode=httpConnection.getResponseCode(); ,BM6s,\  
if(responseCode>=400) 9*!C|gC9Ia  
{ <v<TsEI  
processErrorCode(responseCode); nQ\ +Za==  
return -2; //-2 represent access is error lQs|B '  
} bP;cDQ(g  
8i!~w 7z  
.lMIJN&/  
String sHeader; zh5{t0E}C  
76[O3%  
9XGzQ45R  
for(int i=1;;i++) F{*S}&q*)o  
{ &*TwEN^h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); du2q6"  
//Utility.log(in.readLine()); iqecm]Z0  
sHeader=httpConnection.getHeaderFieldKey(i); (5@9j  
if(sHeader!=null) HR'r~ #j  
{ 5TlPs_o  
if(sHeader.equals("Content-Length")) '>:mEXK}w  
{ sa\v9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xwxMVp`|o  
break; yb BLBJb  
} XcJ'w  
} O@U[S.IK  
else ?9qA"5  
break; J~z;sTR  
} EUdu"'=4a  
} 7+aTrE{  
catch(IOException e){e.printStackTrace ();} "rz|sbj  
catch(Exception e){e.printStackTrace ();} y}jX/Ln  
Va"_.8n|+  
M 7j0&>NTG  
Utility.log(nFileLength); x;NCW  
?'H);ou-p  
 /kGRN @  
return nFileLength; pyK|zvr-r  
} ua(y! Im  
A:3bL: ;t  
VNx|nP&  
//保存下载信息(文件指针位置) 8ID fYJ  
private void write_nPos() 0*^)n&O  
{ SJ1 1LF3)  
try{ i70TJk$fs  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >V:g'[b  
output.writeInt(nStartPos.length); (80#{4kl  
for(int i=0;i<nStartPos.length;i++) -d\O{{%>.z  
{ o"@y=n/  
// output.writeLong(nPos); 2BOe,giy  
output.writeLong(fileSplitterFetch.nStartPos); F,#)8>O  
output.writeLong(fileSplitterFetch.nEndPos); Yo:l@(  
} 8:,E=swe  
output.close(); -A}*Aa'\  
} 8XwAKN:f  
catch(IOException e){e.printStackTrace ();} uV<I!jyI  
catch(Exception e){e.printStackTrace ();} 2U,O e9  
} G.K3'^_  
| ]`gps  
U6qv8*~  
//读取保存的下载信息(文件指针位置) lp5`Kw\  
private void read_nPos() Fz7(Kuc  
{ [X:mmM0gd  
try{ ' pOtd7Vr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R}4o{l6  
int nCount = input.readInt(); pYV$sDlD  
nStartPos = new long[nCount]; q4vu r>m6  
nEndPos = new long[nCount]; 10 dVV[=  
for(int i=0;i<nStartPos.length;i++) +F ~;Q$T  
{ .:,RoK1  
nStartPos = input.readLong(); lpkg( J#&  
nEndPos = input.readLong(); T{u!4Yu  
} dwks"5l  
input.close(); LH.. 8nfl  
} %7BVJJp2  
catch(IOException e){e.printStackTrace ();} ?}sh@;]*h  
catch(Exception e){e.printStackTrace ();} MjC;)z  
} Ky`rf}cI>  
+=%13cA*U  
[w l:"rm  
private void processErrorCode(int nErrorCode) .['@:}$1  
{ [6qa"Ie  
System.err.println("Error Code : " + nErrorCode); ~T<#HSR`  
} HGmgQ>q@M$  
BM{GSX  
YMP:T?vMVh  
//停止文件下载 ^a|$z$spf  
public void siteStop() /_E:sI9(  
{ $enh>!mU  
bStop = true; u4B,|_MK  
for(int i=0;i<nStartPos.length;i++) *!UY;InanX  
fileSplitterFetch.splitterStop(); 5=Mm=HyI2  
|jm|/{lc  
3ydOBeY  
} w\=zTHo88  
} 13Ga #  
//负责部分文件的抓取 eN{[T PPCq  
**FileSplitterFetch.java yyh L]Uq"=  
*/ 8%JxXtWW`  
package NetFox; (5{|']G  
IjN3 jU  
';??0M  
import java.io.*; e;pVoRI  
import java.net.*; vTjgW?9  
R|H9AM ~E  
<5/r  
public class FileSplitterFetch extends Thread { h{.KPK\  
2}]6~i  
AY:3o3M  
String sURL; //File URL 8 f%@:}H  
long nStartPos; //File Snippet Start Position =25q Y"Mf  
long nEndPos; //File Snippet End Position ?RvXO'ml  
int nThreadID; //Thread's ID VE^NSk Oa&  
boolean bDownOver = false; //Downing is over _:0<]<x?  
boolean bStop = false; //Stop identical C1P{4 U  
FileAccessI fileAccessI = null; //File Access interface 7P9n. [  
1Nw&Z0MI  
I"@X~Y7}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y|q4d(P.  
{ d9|dHJf  
this.sURL = sURL; #/@U|g  
this.nStartPos = nStart; ([UuO}m-  
this.nEndPos = nEnd; AL! ^1hCF  
nThreadID = id; c&)H   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $G5m/[KDI  
} j11\t  
,Ihuo5>/z  
[6BL C{2  
public void run() /7*jH2  
{ zB\g'F/  
while(nStartPos < nEndPos && !bStop) 8-cG[/|0  
{ sl|s#+Z  
_3tHzDSG#  
 m3 ;  
try{ wq_c^Ioy  
URL url = new URL(sURL); 7Upm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C=@BkneQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); zy4AFW  
String sProperty = "bytes="+nStartPos+"-"; &d`Umm]  
httpConnection.setRequestProperty("RANGE",sProperty); rMSB|*_  
Utility.log(sProperty); xPb;_~  
j2lo~J)  
F}0QocD  
InputStream input = httpConnection.getInputStream(); gB&]kHLO  
//logResponseHead(httpConnection); z=!$3E ecr  
E xKH%I  
nFW^^v<  
byte[] b = new byte[1024]; vX)6N#D!  
int nRead; MjE.pb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EG&^;uU  
{ n=r}jRH1  
nStartPos += fileAccessI.write(b,0,nRead); :7Rs$ -*Uk  
//if(nThreadID == 1) (U2G"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )(*A1C[  
} Di9yd  
D/V. o}X$  
*)ed(+b  
Utility.log("Thread " + nThreadID + " is over!"); J:f>/  
bDownOver = true; hiaj!&+Q  
//nPos = fileAccessI.write (b,0,nRead); <,Sy:>:"  
} 0ang~_  
catch(Exception e){e.printStackTrace ();} /OgXNIl]  
} r4JXbh6Tt  
} ixBM>mRK  
<Nv w w  
 -6~*:zg,  
//打印回应的头信息 S n.I ]:l  
public void logResponseHead(HttpURLConnection con) ) EEr?"  
{ 7t5X  
for(int i=1;;i++) 7oF`Os+U  
{ oF.Fg<p (  
String header=con.getHeaderFieldKey(i); N ED`GU  
if(header!=null) Cd'P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I.R3?+tZ  
Utility.log(header+" : "+con.getHeaderField(header)); 10}oaL S  
else PZNo.0M70  
break; vbqI$F[s  
} w?C _LP  
} )g:UH Ns  
[2 2IF  
h|=^@F_\`  
public void splitterStop() HCHP15otfe  
{ E}k#-+u<S4  
bStop = true; eN/s W!:P|  
} sl6p/\_w  
{,IWjt &>  
?MKf=! w  
} P)1@HDN==  
2@08 V|  
`"AjbCL  
/* }S*6+4  
**FileAccess.java F Paj p  
*//文件访问(定位,写) -J[zJ4z #  
package NetFox; *^Zt5 zk  
import java.io.*; t8i"f L  
g ywI@QD%#  
[.6>%G1C  
public class FileAccessI implements Serializable{ (&x~pv"+  
:m#vvH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 MFW?m,It)  
RandomAccessFile oSavedFile; E>4#j PK  
long nPos; ~pzaX8!  
W:(:hT6`j9  
Lom%eoH)  
public FileAccessI() throws IOException 32~Tf,  
{ e"r}I!.  
this("",0); /lr RbZ  
} KG>.7xVWV7  
6sP;O,UX  
~|DF-t V  
public FileAccessI(String sName,long nPos) throws IOException LvWU %?  
{ GZZLX19s q  
oSavedFile = new RandomAccessFile(sName,"rw"); zNE!m:s  
this.nPos = nPos; q{U -kuui  
oSavedFile.seek(nPos); OzO_E8Kb\  
} ]XPGlM  
d[~c-G6  
|o!<@/iH=  
public synchronized int write(byte[] b,int nStart,int nLen) E*(Q'p9C  
{ GGJ_,S*  
int n = -1; _'I9rGlx3  
try{ n:*+pL;  
oSavedFile.write(b,nStart,nLen); N e^#5T  
n = nLen; jb7=1OPD_  
} 'Fonn  
catch(IOException e) < ht >>  
{ Phb<##OB  
e.printStackTrace (); N23s{S t  
} }rO4b>J  
MO _9Yi  
8z/^Ql  
return n; d\)v62P  
} ]ei] ) JI  
G x,D'H'  
1c}'o*K_%  
} nn=JM7e\9  
1Rczf(,aT  
=x7ODBYW^  
/* Ev^Xs6 }"  
**SiteInfoBean.java dHp6G^Y  
*/ L1F){8[  
package NetFox;  vo::y"  
{#[a4@B0  
"Q/3]hc.  
public class SiteInfoBean { =pk'a_P 8-  
CC)9Ks\  
y.O? c &!  
private String sSiteURL; //Site's URL r p @=  
private String sFilePath; //Saved File's Path i44:VR|  
private String sFileName; //Saved File's Name \6lXsu;I.X  
private int nSplitter; //Count of Splited Downloading File iEU(1?m2-  
Etl7V  
'@fk(~|  
public SiteInfoBean() &>s(f-\8  
{//nSplitter的缺省值为5 AoR`/tr,  
//default value of nSplitter is 5 &a|oJ'clz  
this("","","",5); TM"-X\e~{  
} <=zGaU,  
IK W!P1  
zu^ AkMc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $< aBawLZO  
{ "|Pl(HX  
sSiteURL= sURL; /C(L(X  
sFilePath = sPath; fk"{G>&8  
sFileName = sName; 3% P?1s  
this.nSplitter = nSpiltter; "(xS  
.H>Rqikj  
S5d{dTPq  
} q6ikJ8E8b  
kl={L{r  
5sE^MS1  
public String getSSiteURL() {c J6Lq&  
{ h)<R#xw  
return sSiteURL; )ld7^G  
} %/^d]#  
#>,cc?H-  
1z`,*eD7  
public void setSSiteURL(String value) }UO,R~q~  
{ `j(+Y  
sSiteURL = value; T2->  
} $?s^HKF~  
s{IoL_PJP  
7d<v\=J}  
public String getSFilePath() z=fag'fzM  
{ ew"Fr1UGYZ  
return sFilePath; 7&QVw(:)M  
} uqyf3bK  
ry T8*}o  
n (|>7  
public void setSFilePath(String value) q-RGplx  
{ |4c==7.  
sFilePath = value; e56#Qb@$\  
} ((5zwD  
XgbGC*dQ  
7*5ctc!dG  
public String getSFileName() I,S'zHR  
{ dL\8^L  
return sFileName; Ax%BnkU  
} NV gLq@F  
~mp$P+M(%p  
3(&.[o Z  
public void setSFileName(String value) K]u|V0c  
{ Lg?'1dg  
sFileName = value; ~h@tezF  
} U<t-LF3  
<2 Q@^  
Y/^<t'o&  
public int getNSplitter() n>4S P_[E7  
{ S?{5DxilO  
return nSplitter; '-vy Q^  
} 3dbf!   
VZ,T`8"  
&8pXkD#A  
public void setNSplitter(int nCount) 9,W-KM  
{ Chua>p!$g  
nSplitter = nCount; O)Qz$  
} @( t:E`8  
} z(WpOD   
e ?YbG.(E9  
y#0w\/<  
/* uaKB   
**Utility.java 3wE8y&  
*/ -b$OHFL  
package NetFox; Q#N+5<]J)#  
|z'?3?,~  
2{CSH_"Z7  
public class Utility { 64lEB>VNm  
eTc`FXw`  
v2{O67j} o  
public Utility() k~R[5W|'  
{ [FL I+;gY  
, .I^ekF  
2UF94  
} mc'p-orAf  
@"!SU' *  
//线程睡眠 `/zt&=`VB  
public static void sleep(int nSecond) %Let AR  
{ 2FzS_\":I  
try{ RV` j>1  
Thread.sleep(nSecond); =M 5M;  
} P1wRt5  
catch(Exception e) H1nQ.P]_  
{ 0vp I#q  
e.printStackTrace (); F4Uk+|]Bu  
} 3\+p1f4  
} ~N9-an  
{9".o,  
//日志 F 29AjW86  
public static void log(String sMsg) 1%"` =$q%  
{ IFxI>6<&  
System.err.println(sMsg); >#?: x*[  
} d*$<%J  
L_mqC(vn  
G 7]wg>*  
public static void log(int sMsg) Bx- ,"Z \  
{ zfb _ )  
System.err.println(sMsg); c0&'rxi( B  
} v|@n8ED|@K  
} C8:"+;  
YZRB4T9  
wF8\  
/* j\f$r,4  
**TestMethod.java *]WXM.R8  
*/ LFyceFbm  
package NetFox; l7,qWSsn K  
Zk UuniO  
ok[=1gA#h  
public class TestMethod { SAh054/St  
v4_OUA>z,  
}G+A_HF ^  
public TestMethod() 5Kj4!Ai  
{ ///xx/weblogic60b2_win.exe `uVW<z{ l  
try{ ;6nZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b:Kw_Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WN +Jf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _|3TC1N$n  
fileFetch.start(); I&8SP$S>J  
} 2j7d$y*'  
catch(Exception e){e.printStackTrace ();} %J7mZB9  
v8bl-9DQ  
xsDa!  
} <C%-IZv$  
(V.,~t@  
$sF#Na4^  
public static void main(String[] args) %8CT -mQ  
{  \t# 9zn>  
new TestMethod(); G.nftp(*}  
} 5w)^~#  '  
} 9jGuelwN  
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