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http断点续传简单实现(java)

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/* &B^zu+J  
**SiteFileFetch.java ArFsr  
*/ F-\Swbx+  
package NetFox; h\oAW?^  
import java.io.*; 0{ZYYB&"~J  
import java.net.*; 'IorjR@ 40  
m15MA.R>  
I9! eL4e  
public class SiteFileFetch extends Thread { jRswGMx  
02Ftn&bi  
9`"o,wGX3  
SiteInfoBean siteInfoBean = null; //文件信息Bean WIytgM  
long[] nStartPos; //开始位置 Xq3n7d.  
long[] nEndPos; //结束位置 Ywj=6 +;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7}r!&Eb  
long nFileLength; //文件长度 Yy 4EM  
boolean bFirst = true; //是否第一次取文件 Qz T>h  
boolean bStop = false; //停止标志 7eQE[C  
File tmpFile; //文件下载的临时信息 }(g`l)OX  
DataOutputStream output; //输出到文件的输出流  T4}SF  
wq|~[+y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) o/EN3J  
public SiteFileFetch(SiteInfoBean bean) throws IOException S?X2MX  
{ "(@W^qF}d  
siteInfoBean = bean; T ;Ga G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =h?Q.vad  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4?#0fK  
if(tmpFile.exists ()) BrW1:2w >\  
{ \5+?wpH  
bFirst = false; IrAc&Ehul  
read_nPos(); 3Y\7+975m  
} 'C l}IDF  
else r52X}Y  
{ wzw`9^B  
nStartPos = new long[bean.getNSplitter()]; MA:2]l3e  
nEndPos = new long[bean.getNSplitter()]; Bg^k~NX%  
} 87/!u]q  
pUvbIbg+  
kI|Vv90l  
Zk#^H*jgx  
} .YvE  
<Tq&Va_w  
aZ$$a+  
public void run() *wNX<R.  
{ _n.2'  
//获得文件长度 G;:D6\  
//分割文件 V}1D1.@  
//实例FileSplitterFetch sGNVZx  
//启动FileSplitterFetch线程 rm7$i9DH2  
//等待子线程返回 6E9y[ %+  
try{ xy@1E;  
if(bFirst) ]J^ 9iDTTA  
{ ~Rzn =>a  
nFileLength = getFileSize(); +k!Y]_&(:f  
if(nFileLength == -1) m){.{Vn]  
{ Evz;eobW/  
System.err.println("File Length is not known!"); `={s*^Ta  
} >*xa\ve  
else if(nFileLength == -2) *7"R[!9  
{ b8V]/  
System.err.println("File is not access!"); $}d| ~q\  
} ^*7~ Wxk5  
else U D9&k^  
{ ILt95l  
for(int i=0;i<nStartPos.length;i++) 1Aq*|JSk(  
{ qp(F}@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r7tN(2;5  
} LEM{$Fxo&  
for(int i=0;i<nEndPos.length-1;i++) lFWN [`H  
{ 2#4_ /5(j*  
nEndPos = nStartPos[i+1]; ^}XKhn.S'  
} O?uT'$GT  
nEndPos[nEndPos.length-1] = nFileLength; K\ww,S  
} ETP}mo  
} ;!<WL@C~  
)!1; =   
k^q}F%UV  
//启动子线程 0G/VbS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :uZfdu  
for(int i=0;i<nStartPos.length;i++) nZ>bOP+,  
{ \Nc/W!r*9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fP`g#t)4Tu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^'S0A=1  
nStartPos,nEndPos,i); rs01@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9X8{"J  
fileSplitterFetch.start(); /#Y)nyE  
} QDlEby m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s)$N&0\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?3!"js B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7%Zl^c>q  
nEndPos = " + nFileLength); JZp*"UzQr  
// fileSplitterFetch[nPos.length-1].start(); F]~rA! g1  
OL]^4m  
= GirUW D  
//等待子线程结束 r}OK3J  
//int count = 0; .BGM1ph}~  
//是否结束while循环 yp=Hxf  
boolean breakWhile = false; %dTkw+J  
YmM+x=G:  
@Md%gEh;&  
while(!bStop) ~ \tI9L?|A  
{ ^Ye i9bXl  
write_nPos(); <8 MKjf  
Utility.sleep(500); bkkhx,Oi[G  
breakWhile = true; OKfJ  
EWPP&(u3  
<Vyv)#32o3  
for(int i=0;i<nStartPos.length;i++) <}b`2/wP  
{ <,d.`0:y  
if(!fileSplitterFetch.bDownOver) _[-+%RP  
{ 2wE?O^J  
breakWhile = false; $:"r$7  
break; W B)<B  
} #%k!`?^fbK  
} ~<Z;)e  
if(breakWhile) @-bX[}.  
break; 2g1[ E_?  
[-!   
R6HMi#eF  
//count++; cZKK\hf<  
//if(count>4) ^"\ jIP  
// siteStop(); `k65&]&d  
} W HO;;j  
T9]|*~ ,T  
yfeX=h  
System.err.println("文件下载结束!"); U'zW; Lt  
} Z<ozANbk  
catch(Exception e){e.printStackTrace ();} 78>)<$+d  
} $5y%\A  
U>6MT@\  
$$~x: iN  
//获得文件长度 :G9+-z{Y&  
public long getFileSize() v!?bEM3D  
{ T6JN@:8  
int nFileLength = -1; A_1cM#4  
try{ Ar4E $\W  
URL url = new URL(siteInfoBean.getSSiteURL()); R%o:'-~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qEr2Y/:i"  
httpConnection.setRequestProperty("User-Agent","NetFox"); }\}pSqW  
[H z_x(t26  
:#58m0YLA:  
int responseCode=httpConnection.getResponseCode(); fv_}7t7  
if(responseCode>=400) F+Rtoq|  
{ $u_0"sUV  
processErrorCode(responseCode); 'Ca6cm3Tg  
return -2; //-2 represent access is error L^} Z:I  
} m8eyAvi 6  
$A"kHS7T  
9{|JmgO!  
String sHeader; BJ!b LQ  
zF6 R\w  
:@)UI,  
for(int i=1;;i++) k@U8K(:x  
{ QU^*(HGip  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w~a^r]lPW  
//Utility.log(in.readLine()); dt(~)*~R  
sHeader=httpConnection.getHeaderFieldKey(i); 6s\niro2  
if(sHeader!=null) 0xrr9X<  
{ /^^t>L  
if(sHeader.equals("Content-Length")) O,R5csMh  
{ w naP?|/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '^ bB+  
break; O6Bs!0,  
} 6nh!g  
}  (n+2z"/  
else GL$!JKWp  
break; "V-k_d "  
} 3~Od2nk(x  
} E^w2IIw  
catch(IOException e){e.printStackTrace ();} `s5<PCq  
catch(Exception e){e.printStackTrace ();}  H"czF  
lxb+0fiN  
Qd;P?W6  
Utility.log(nFileLength); )9F-h8 &"  
wBZ=IMDu\  
LVKvPi  
return nFileLength; *I6z;.#  
} g^|}e?  
}U3+xl6g  
T<(1)N1H`  
//保存下载信息(文件指针位置) ITJ{]7N  
private void write_nPos() K ;\~otR^  
{ `i5U&K. 7  
try{ 4?Pdld  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eKjmU| H  
output.writeInt(nStartPos.length); gY\X?  
for(int i=0;i<nStartPos.length;i++) hhd%j6  
{ $/;D8P5/&=  
// output.writeLong(nPos); s}Phw2`1U  
output.writeLong(fileSplitterFetch.nStartPos); ,Y *unk<S  
output.writeLong(fileSplitterFetch.nEndPos); K~'!JP8@  
} ~hK7(K  
output.close(); `roos<F1D  
}  8:=&=9%  
catch(IOException e){e.printStackTrace ();} 3FRz&FS:j  
catch(Exception e){e.printStackTrace ();} &*2\1;1tB  
} '%Og9Bgd+  
X`#,*HkK  
D![42H+-Qd  
//读取保存的下载信息(文件指针位置) nOq?Q  
private void read_nPos() ql"&E{u?  
{ tLCu7%P>  
try{ ^b|Z<oF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &"H xAK)f  
int nCount = input.readInt(); <Sds5 d  
nStartPos = new long[nCount]; DV+M;rs  
nEndPos = new long[nCount]; ;W%nBdE6|  
for(int i=0;i<nStartPos.length;i++) %smQ`u|  
{ F6>K FU8  
nStartPos = input.readLong(); .OhpItn  
nEndPos = input.readLong(); CTawXHM  
} :QKxpHi  
input.close(); :"m~tU3&  
} e7e6b-"_2  
catch(IOException e){e.printStackTrace ();} 337y,;  
catch(Exception e){e.printStackTrace ();} YywiY).]@  
} B ~u9"SR.  
[/dGOl+  
kk|7{83O  
private void processErrorCode(int nErrorCode) (al.7VA;9  
{ b#ga  
System.err.println("Error Code : " + nErrorCode); ]vj.s/F~  
} UN ;9h9  
/V'^$enK!}  
:`u?pc27Sm  
//停止文件下载 /|7@rH([{  
public void siteStop() [6 d~q]KH  
{ }YV,uJH[  
bStop = true; TUE*mDRmP  
for(int i=0;i<nStartPos.length;i++) %v}SJEXF p  
fileSplitterFetch.splitterStop(); gut[q  
`Fn"%P!  
:Y? L*  
} &d,chb (  
} 4%!#=JCl  
//负责部分文件的抓取 &[u>^VO8  
**FileSplitterFetch.java E} Ir<\  
*/ 3=[#(p:  
package NetFox; 99QMMup  
N$'/J-^  
yf|,/{S  
import java.io.*; (CUrFZT$  
import java.net.*; \.0cA4)[$  
b5!\"v4c  
0[A4k:  
public class FileSplitterFetch extends Thread { 4Vv~  
C%c}lv8;^  
kXj rc  
String sURL; //File URL Z|78>0SAt  
long nStartPos; //File Snippet Start Position 01N]|F:  
long nEndPos; //File Snippet End Position c L+-- $L  
int nThreadID; //Thread's ID  Iw07P2  
boolean bDownOver = false; //Downing is over iJ8 5okv'  
boolean bStop = false; //Stop identical @.rVg XE=!  
FileAccessI fileAccessI = null; //File Access interface \o|5 /N  
s,5SWdb\v  
yQP!Vt^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U,G!u=+  
{ $x5,Oen  
this.sURL = sURL; Z`_`^ \"  
this.nStartPos = nStart; D\~s$.6B  
this.nEndPos = nEnd; G,jv Mb`+  
nThreadID = id; ?nVwT[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o0yyP,?yh  
} @M]uUL-ze  
O~p@87aq  
B/:+(|  
public void run() ,]:vk|a#;  
{ 6}V)\"u&   
while(nStartPos < nEndPos && !bStop) q5Bj0r[/o  
{ Z`FEB0$  
fPW|)e"  
UxGr+q  
try{ Mx-? &  
URL url = new URL(sURL); =)h<" 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "PFczoRZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;-aF\}D@n  
String sProperty = "bytes="+nStartPos+"-"; &1=Je$,  
httpConnection.setRequestProperty("RANGE",sProperty); -K"" 4SC2  
Utility.log(sProperty); PIZnzZ@Z;  
mYU7b8x_  
MC 8t"SB  
InputStream input = httpConnection.getInputStream(); 'zRi ;:UHA  
//logResponseHead(httpConnection); P^lzl:|  
.J/x@  
r>>4)<C7J  
byte[] b = new byte[1024]; j{U#g8  
int nRead; f *Xum[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sI M^e  
{ z%4E~u10  
nStartPos += fileAccessI.write(b,0,nRead); 4qd =]i  
//if(nThreadID == 1) O^Y}fo'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AX`>y@I  
} "mbjS(-eg  
.C 6wsmQ  
!=)R+g6b  
Utility.log("Thread " + nThreadID + " is over!"); b I%Sq+"}  
bDownOver = true; (f-Mm0%[  
//nPos = fileAccessI.write (b,0,nRead); +t9$*i9`L  
} ^| b]E  
catch(Exception e){e.printStackTrace ();} nnzfKn:J  
} =XRTeIZ  
} #hKaH -j  
N7wKaezE  
B4&K2;fg_  
//打印回应的头信息 |9fvj6?Y  
public void logResponseHead(HttpURLConnection con) 8C[W;&Y=  
{ 6~oo.6bA  
for(int i=1;;i++) mY)Y47iL  
{ +i\ +bR  
String header=con.getHeaderFieldKey(i); kVqRl%/3Tb  
if(header!=null) >V01%fLd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !,SGKLs.m  
Utility.log(header+" : "+con.getHeaderField(header)); *X_-8 ^~  
else 71RG1,  
break; C;m,{MD  
} ytmFe!  
} qe/|u3I<lF  
KTmduf7DL  
#"T< mM7  
public void splitterStop() F2N)|C<  
{ 1#Ls4+]5  
bStop = true; 96VJE,^h  
} 8E/wUN,Lxj  
Vgj&h dbd  
`U.VfQR:  
} 51)Q&,Mo#  
K3;lst>4  
TJ5g? #Wul  
/* G $F3dx.I  
**FileAccess.java Uo~-^w}  
*//文件访问(定位,写) ?*nFz0cs^  
package NetFox; u2FD@Xq?  
import java.io.*; &*e(  
CyWMr/'  
{hNvCk  
public class FileAccessI implements Serializable{ `Z' h[-2`  
d3IMQ_k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <mk'n6B  
RandomAccessFile oSavedFile; yu~o9  
long nPos; /uNgftj  
$;V?xZm[  
FG6bKvEQm^  
public FileAccessI() throws IOException \ y^Ho1Fj  
{ y$Y*%D^w  
this("",0); \-h%z%{R  
} 'f "KV|  
HtN!Hgpwg  
d41DcgG'j(  
public FileAccessI(String sName,long nPos) throws IOException HT% =o}y  
{ :g+5cs  
oSavedFile = new RandomAccessFile(sName,"rw"); GdlzpBl  
this.nPos = nPos; 'LyEdlC]  
oSavedFile.seek(nPos); ;Pd nE~  
} 7C::%OF~7  
5j{jbo =!  
w Jr5[p*M  
public synchronized int write(byte[] b,int nStart,int nLen) ~Q3y3,x  
{ RP9jZRDbZ  
int n = -1; *?o`90HHP[  
try{ "dItv#<:}  
oSavedFile.write(b,nStart,nLen); K!cLEG!G  
n = nLen; ;dR4a@  
} Nj^:8]D)0  
catch(IOException e) :p|wo"=@Ge  
{ "B34+fOur  
e.printStackTrace (); d8p<f+  
} knS(\51A  
n5G|OK0,  
h't! 1u  
return n; s{:l yp  
} qtI42u{  
|3:e$  
er44s^$  
} {}A1[ Y|  
g)M"Cx.  
U%?  
/* 5Kw$QJ/  
**SiteInfoBean.java >[A7oH  
*/ %0MvCm  
package NetFox; [WXa]d5Y  
)%6h9xyXt  
^fq^s T.$  
public class SiteInfoBean { O`rKxP  
= 9K5f# ;e  
!C3ozZ<  
private String sSiteURL; //Site's URL *]#(?W.$w  
private String sFilePath; //Saved File's Path +WTO_J7  
private String sFileName; //Saved File's Name qPvWb1H:  
private int nSplitter; //Count of Splited Downloading File # ^q87y  
S!@h\3d8{  
m~;}8ObQE  
public SiteInfoBean() ">|G^ @|:A  
{//nSplitter的缺省值为5 O+w82!<:  
//default value of nSplitter is 5 ^lP;JT?  
this("","","",5); 5B)z}g^h  
} }1}L&M@  
w40 -K5wt>  
cqSo%a2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5BAGIO<w  
{ M8y:FDX  
sSiteURL= sURL; vLT$oiN[c  
sFilePath = sPath; Iss)7I  
sFileName = sName; r Y#^C  
this.nSplitter = nSpiltter; :oeDksld  
- xE%`X  
;%`oS.69  
} ]Dd}^khv  
CxbGL  
1{Kv  
public String getSSiteURL() BTAt9Z8qK  
{ DV!10NqUr  
return sSiteURL; /73ANQ"  
} jV 98 2Y  
'Z}3XVZEN  
3 [r9v!l  
public void setSSiteURL(String value) ZFFKv  
{ jM5w<T-2/  
sSiteURL = value; GC3WB4iY@U  
} AA &>6JB{  
<_>xkQbn2  
L} Rsg'U  
public String getSFilePath() I ]HP  
{ 8:gUo8  
return sFilePath; 4Je[!X@C  
} Y2d(HD@  
LM2S%._cj;  
z~($ "  
public void setSFilePath(String value) X6-;vnlKN  
{ EC`=nGF  
sFilePath = value; TJ_pMU  
} iY;>LJmp  
>`=9So_J  
S3N+ 9*i K  
public String getSFileName() (8td0zq  
{ r~YxtBZH+  
return sFileName; BIY"{"hJ  
} 3k# h!Z  
PR3&LI;B*  
]S+KH \2  
public void setSFileName(String value) QruclNW{Bv  
{ h1Nd1h@-   
sFileName = value; ;)23@6{R%  
} M97MIku~9  
wBI>H 7A  
MRN=-|fV^  
public int getNSplitter() | {Tq/  
{ &j?+%Y1n@  
return nSplitter; FjV)QP H  
} MG:eI?G/'  
[9d4 0>e  
7-VP)|L#G  
public void setNSplitter(int nCount) $!7$0WbC  
{ k*K.ZS688  
nSplitter = nCount; a\B'Qe+  
} U W' @3#<?  
} trz &]v=:  
o@[oI\Vr!  
iI Dun Ih  
/* L>&9+<-B  
**Utility.java xQDWnpFc  
*/ {F ',e~}s  
package NetFox; ^4Tf6Fw#  
_)ZxD--Qg  
|+Cd2[hN  
public class Utility { +?v2MsF']  
  bKt4  
qF Xx/FZ  
public Utility() W!V-m  
{ w>wzV=R  
j:7AVnt  
q0{_w  
} ]cM,m2^2  
(W |;gQ  
//线程睡眠 a= (vS  
public static void sleep(int nSecond) e.WKf,e"X  
{ &3 *#h  
try{  {gb` %J  
Thread.sleep(nSecond); 6 IRa$h>H  
} TTGWOC  
catch(Exception e) zy`T! $  
{ H'}6Mw%ra  
e.printStackTrace (); 0i(c XB  
} '7 t:.88  
} 5c$\DZ(  
nh+Hwj#(x  
//日志 v8K`cijSS  
public static void log(String sMsg) o(yyj'=(  
{ QzxEkTc;  
System.err.println(sMsg); @H$Sv   
} bnZ H  
kS4YxtvB  
BS3{TGn  
public static void log(int sMsg) W'6sY@0m  
{ 3)y=}jw  
System.err.println(sMsg); }/QtIY#I  
} 4UHviuOo8  
} xdh%mG:?  
<R?S  
NAOCQDk{  
/* pKU(4&BxX  
**TestMethod.java CA5T3J@vAQ  
*/ _'l"Dk  
package NetFox; }Fsr"RER@{  
n`V?n  
[I}z\3Z %  
public class TestMethod { =#vJqA  
-us:!p1T  
V''fmWo7  
public TestMethod() k *D8IB  
{ ///xx/weblogic60b2_win.exe ,(&Fb~r]  
try{ Zv(6VVj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dus!Ki~8(t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m\70&%v  
fileFetch.start(); 2#ZqGf.'v  
} X#HH7V>  
catch(Exception e){e.printStackTrace ();} 2@IL  n+#  
Tv6y +l  
_-rC]iQJ55  
} *Q#oV}D_  
w[$oH^7  
4o"?QV:  
public static void main(String[] args) t+K1ArQc  
{ u%lUi2P2E  
new TestMethod(); Kv)}  
} ":q+"*fy  
} {rK]Q! yj  
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