http断点续传简单实现（java)

/* iKY&gnu"  
**SiteFileFetch.java &r%3)Z8Et  
*/ gK#w$s50  
package NetFox; 8ipLq`)  
import java.io.*; v%[mt`I  
import java.net.*; Q2=~  
D IN PAyY  
[K- s\  
public class SiteFileFetch extends Thread { XU7bWafy  
>m!.l{*j>N  
q4=RE  
SiteInfoBean siteInfoBean = null; //文件信息Bean hNy S  
long[] nStartPos; //开始位置 -AQX-[
B  
long[] nEndPos; //结束位置 0
f1#TgX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X9HI@M]h  
long nFileLength; //文件长度 OpQa!  
boolean bFirst = true; //是否第一次取文件 pnU g:R@  
boolean bStop = false; //停止标志 hg @Jpg  
File tmpFile; //文件下载的临时信息 9n7d "XD2  
DataOutputStream output; //输出到文件的输出流 0<9TyN6  
B"v=Fr[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [4e5(!e  
public SiteFileFetch(SiteInfoBean bean) throws IOException DBRJtU!5x  
{ }dM^6 Kd%  
siteInfoBean = bean; qQ_QF
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Jhc
S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GZo4uwG@a  
if(tmpFile.exists ()) KK6YA  
{ ?Dm&A$r  
bFirst = false; M<Mr (z  
read_nPos(); !:5n  
} Y')+/<Q2E  
else b'YbHUyu  
{ M&dtXG8<^  
nStartPos = new long[bean.getNSplitter()]; 7SCI_8`  
nEndPos = new long[bean.getNSplitter()]; }0G Ab2  
} -tQ|&fl  
.w~USJ=X  
)EoG@:[  
R7i*f/m  
} A-FwNo2"%  
xjN~Y D:  
Tx(R3B+u7  
public void run() f7'%AuSQ(  
{ "6i9f$N  
//获得文件长度 4SYN$?.Mp  
//分割文件 L/I-(08!Y:  
//实例FileSplitterFetch 0bE_iu>f'  
//启动FileSplitterFetch线程 &bRH(yF  
//等待子线程返回 KJiwM(o  
try{ p* @L1  
if(bFirst) i`~y%y  
{ 5z_)  
nFileLength = getFileSize(); +,lD_{}_  
if(nFileLength == -1) Ou^dI  
{ U VT8TN-T  
System.err.println("File Length is not known!"); x-<dJ}`  
} qJ@?[|2R  
else if(nFileLength == -2) v6:DA#0  
{ u#\3T>o%@  
System.err.println("File is not access!"); k$UBZ,=iC  
} DYS(ZY)4  
else XHr{\/4V  
{ :$j~;)2  
for(int i=0;i<nStartPos.length;i++) *u}):8=&R  
{ ^4"
_I   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mI# BQE`p6  
} EB#z\  
for(int i=0;i<nEndPos.length-1;i++) iJi|*P5dw  
{ m_B5M0},  
nEndPos = nStartPos[i+1]; L*z;-,  
} hk I$ow(  
nEndPos[nEndPos.length-1] = nFileLength; aI{[W;43T  
} J:5n/m^A  
} gT.-Cf{  
o;.-I[9h]  
}/VHeHd  
//启动子线程 RY'y%6Z]ZO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oZ}e w!V
 
for(int i=0;i<nStartPos.length;i++) jhL
h~. 8  
{ D&shrKFx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zin,yJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 61'7b`:(hi  
nStartPos,nEndPos,i); OjN]mp-q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !4E:IM63  
fileSplitterFetch.start(); <7GK *I  
} <da! #12L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =T$E lXwJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g@Zc'g/XB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bY>Ug{O;  
nEndPos = " + nFileLength); ld $`5!Z  
// fileSplitterFetch[nPos.length-1].start(); JG[+e*8  
G 1$l%B  
g_=Q=y@,  
//等待子线程结束 ^.(]i\V_  
//int count = 0; MWl@smRh  
//是否结束while循环 tT7$2 9  
boolean breakWhile = false; 073(xAkL{  
x\jHk}Buj  
[V2l&ZUni  
while(!bStop) 7v-C-u[E`  
{ L
g^m?~{  
write_nPos(); 9hv\%_>o  
Utility.sleep(500); ty78)XI  
breakWhile = true; c:0$ Mw=  
=8iM,Vl3  
!rWib`%  
for(int i=0;i<nStartPos.length;i++) s+[=nau('w  
{ {t7 M  
if(!fileSplitterFetch.bDownOver) h+Dok#g  
{ cZu:dwE  
breakWhile = false; <fw[7=_)^  
break; +,MzD'(D  
} "\9@gfsp)  
} [ACYd/  
if(breakWhile) Cdv TC`~,  
break; *f(}@U  
aQ)9<LsI  
T.pPQH__  
//count++; uk1IT4+  
//if(count>4) @.})nU  
// siteStop(); M;(lc?Rv  
} Dihk8qJ/6  
j<!$ug9VA  
F4}Zl  
System.err.println("文件下载结束！"); _ehU:3L`s  
} gQ?k}D  
catch(Exception e){e.printStackTrace ();} +o/q@&v;Ax  
} $d"6y  
Ev()2 80  
%$cwbh-{{  
//获得文件长度 ecHy. 7H  
public long getFileSize() ?eu=0|d  
{ L$b9|j7  
int nFileLength = -1; !O5UE  
try{ .,c8cq?  
URL url = new URL(siteInfoBean.getSSiteURL()); _uBf.Qfs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !yxb<  
httpConnection.setRequestProperty("User-Agent","NetFox"); E`i;9e'S  
"-hgeQX  
0QGl'u{F  
int responseCode=httpConnection.getResponseCode(); *) wp  
if(responseCode>=400) Xbz}pAnj  
{ &L/C:<.  
processErrorCode(responseCode); [p<L*3<  
return -2; //-2 represent access is error _])1P?.  
} +`[$w<I  
9orza<#  
PC9:nee  
String sHeader; ^WeT3b q  
dWp4|r  
JK1b68n  
for(int i=1;;i++) I[&!\Me[+w  
{ \F> *d!^C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); HsO=%bb  
//Utility.log(in.readLine()); ZFRKh:|  
sHeader=httpConnection.getHeaderFieldKey(i); ^Dh2_vbI  
if(sHeader!=null) i{`>!)U  
{ 8^^al!0K~  
if(sHeader.equals("Content-Length")) "u%$`*  
{ I*#~@:4
*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pG" 4qw  
break; pZH bj2~  
} $)'{+1  
} Y`M.hYBXk  
else ^iGIF~J9  
break; (s9?#t6  
} 46 77uy  
} -F*j`  
catch(IOException e){e.printStackTrace ();} iBZ+gsSP  
catch(Exception e){e.printStackTrace ();} &o?pZ(\C  
kh`X92~  
Kkd7D_bZ*  
Utility.log(nFileLength); ]-R8W/fDn  
.D7\Hao  
I($u L@$  
return nFileLength; rf9RG!  
} #0mn_#-P)  
*kDXx&7B$  
uZqo"  
//保存下载信息（文件指针位置） v.\&gn(  
private void write_nPos() ]$z~;\T  
{ o&>0 pc  
try{ KR{kn[2|Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LIR2B"3F  
output.writeInt(nStartPos.length); :cOwTW?Fj  
for(int i=0;i<nStartPos.length;i++) [*1c.&%(  
{ o2jnmv~  
// output.writeLong(nPos); K
46mE   
output.writeLong(fileSplitterFetch.nStartPos); QJv,@@mu  
output.writeLong(fileSplitterFetch.nEndPos); B aXzz  
} ^c=@2#^\  
output.close(); p>MX}^6  
} !D  
catch(IOException e){e.printStackTrace ();} 'dx4L }d  
catch(Exception e){e.printStackTrace ();} nrZv>r  
} ok7DI  
wngxVhu8Ld  
!1!uB }  
//读取保存的下载信息（文件指针位置） BkIvoW_  
private void read_nPos() "Uyw
7  
{ )Dv"seH.  
try{ 6/GhQ/T%D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x{+rx.  
int nCount = input.readInt(); 1pc|]9B  
nStartPos = new long[nCount]; Z3S\@_/;  
nEndPos = new long[nCount]; mhcJ0\@_  
for(int i=0;i<nStartPos.length;i++) eqLETo@} *  
{ KKOu":b  
nStartPos = input.readLong(); GM@TWwG-B  
nEndPos = input.readLong(); U_14CLsdG  
} atPf527\`  
input.close(); u52@{@Ad  
} bjR&bIA:  
catch(IOException e){e.printStackTrace ();} z9VQsC'K  
catch(Exception e){e.printStackTrace ();} @m(\f  
} yLI=&7/e@  
d{YhKf#~  
eNXpRvY  
private void processErrorCode(int nErrorCode) 5xRh'Jkyb  
{ 9%)'QDVGLf  
System.err.println("Error Code : " + nErrorCode); ;T/' CD  
} mNV4"lNR  
TsR20P@  
y{kXd1,  
//停止文件下载 (2%C%#]8  
public void siteStop() zO!`sPP  
{ A]R"C:o  
bStop = true; |=7%Edkd  
for(int i=0;i<nStartPos.length;i++) #'"h+[XY  
fileSplitterFetch.splitterStop(); 4h(aTbHaQ  
>q]r)~8F^  
?lbX.+  
} Gk!v-h9cq  
} *aTM3k)Zs  
//负责部分文件的抓取 ~>{<r{H"S  
**FileSplitterFetch.java Q>X ;7nt0  
*/
Phx/9Kk  
package NetFox; 8_KXli}7=  
."3
J;j  
E{j6OX\  
import java.io.*; /AWHG._  
import java.net.*; 1-q\C<Q)  
Q9rE_}Z  
@UvjJ  
public class FileSplitterFetch extends Thread { $bD!./fl  
b
cOX/  
rPQ$e!m1Ee  
String sURL; //File URL OY?uqP}c  
long nStartPos; //File Snippet Start Position @ cv`}k  
long nEndPos; //File Snippet End Position );=JoRQ{  
int nThreadID; //Thread's ID }p&aI?-B  
boolean bDownOver = false; //Downing is over %S@XY3jZY  
boolean bStop = false; //Stop identical 9WBDSx_(Q  
FileAccessI fileAccessI = null; //File Access interface y 5=J6a2.  
!rrjA$P<v  
gzw[^d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !WDdq_n*v  
{ S~m*t i(  
this.sURL = sURL; }P^n /  
this.nStartPos = nStart; ukri7 n
*  
this.nEndPos = nEnd; @89mj{  
nThreadID = id; /ZD/!YD&R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c-gaK\u}j}  
} k"AY7vq@!P  
'X`\vTxB  
O  89BN6p  
public void run() dU+1@_  
{ ,(lD5iN  
while(nStartPos < nEndPos && !bStop) bXtA4O  
{ Xf#uK\f  
n NAJ8z}Nt  
}LE.kd&  
try{ Ws(BouJ  
URL url = new URL(sURL); ,m0=z
H4+:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `.><$F  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z#\ \NfR  
String sProperty = "bytes="+nStartPos+"-"; # VR}6Jv  
httpConnection.setRequestProperty("RANGE",sProperty); 
5*ABw6'6  
Utility.log(sProperty); tMupX-V  
=niU6Q}  
c L84}1QD  
InputStream input = httpConnection.getInputStream(); KxiZx I  
//logResponseHead(httpConnection); M"~B_t,Nw  
'd/A+W  
;r8,Wx@f1C  
byte[] b = new byte[1024]; .o fYFK  
int nRead; >2N`l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <$ '#@jW  
{ rJZ-/]Xf!6  
nStartPos += fileAccessI.write(b,0,nRead); ]\Ez{MdAT  
//if(nThreadID == 1) mz/KGZ5t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LG51e7_gFi  
} hWuq  
k%c ?$n"  
spAYb<  
Utility.log("Thread " + nThreadID + " is over!"); k \]@  
bDownOver = true; 7rsrC  
//nPos = fileAccessI.write (b,0,nRead); "%0RR?  
} {>5c,L$  
catch(Exception e){e.printStackTrace ();} |[xi"E\  
} MJ>(HJY6?%  
} 8f#YUK sW=  
b/E1v,/<  
nEs l  
//打印回应的头信息 [_b10Z'{  
public void logResponseHead(HttpURLConnection con) SkN^ytKE  
{ JB**z00;  
for(int i=1;;i++) Xa%Z0%{  
{ hydn" 9;  
String header=con.getHeaderFieldKey(i); -@AGQ+e  
if(header!=null) 6`%}s3Xq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +}z T][9w  
Utility.log(header+" : "+con.getHeaderField(header)); ~l.]3wyk  
else QULrE+@  
break; 4yjAi@ /2  
} _3ZZ-=J:=*  
}
'L=g(  
>YPfk=0f0  
>oLM2VJ  
public void splitterStop() c-`&e-~XKL  
{ Br-
bUoua  
bStop = true; >iaZGXje  
} hLO nX<%a  
]_5C5m  
|h8C}P&Z  
} m|e!1_:H  
D*_ F@}=  
/l@7MxE  
/* :90DS_4  
**FileAccess.java $g5pKk
  
*//文件访问(定位，写) Rm6<"SLV  
package NetFox; "PnYa)?1  
import java.io.*; _U'edK]R  
8=t?rA  
QZ h|6&yI  
public class FileAccessI implements Serializable{ Z<xSU?J  
.viA+V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $eI[3{}X  
RandomAccessFile oSavedFile; FVL0K(V(  
long nPos; "xYMv"X  
{}vW=  
iZ)7%R?5  
public FileAccessI() throws IOException +^4"  
{ 4W$53LP8  
this("",0); |yw-H2k1  
} l,pq;>c9a  
uV=rLDY  
D[yaAG<  
public FileAccessI(String sName,long nPos) throws IOException W9.ZhpM  
{ Bqa%L.N2SS  
oSavedFile = new RandomAccessFile(sName,"rw"); :|P"`j  
this.nPos = nPos; hg/G7Ur"  
oSavedFile.seek(nPos); %D)W~q-g  
} FrIguk1  
2$V]XSe  
^dJ/>?1  
public synchronized int write(byte[] b,int nStart,int nLen) K|[[A)tt6  
{ UpF,e>s  
int n = -1; XkDjA#nx`  
try{ PxhB=i!'$  
oSavedFile.write(b,nStart,nLen); kXFgvIpg<  
n = nLen; }*4XwUM e  
} D'$ki[{,  
catch(IOException e) vSb$gl5H  
{ !iN=py  
e.printStackTrace (); d OQU#5  
} U7bbJ>U_|  
+[<|T
T  
7q&Ru|T33  
return n; .z^ePZ|mV  
} Uf}s6#  
)$p<BLU  
R4.$9_ui  
} OlL FuVR  
,B_Nz}\8  
hX#y7m  
/* 66NJ&ac  
**SiteInfoBean.java U p=J&^.  
*/ bS=aFl#  
package NetFox; ] lE6:^V  
0>} FNRC  
h:\WW;s[B  
public class SiteInfoBean { dO =fbmK  
u[5*RTE
 
TcPYDAa  
private String sSiteURL; //Site's URL 5V;BimI  
private String sFilePath; //Saved File's Path b_+dNoB  
private String sFileName; //Saved File's Name 2R66 WKQ  
private int nSplitter; //Count of Splited Downloading File 2Z;wU]  
_Q_"_*e  
xE`uFHuS}  
public SiteInfoBean() u(iEuF;7  
{//nSplitter的缺省值为5 +F=j1*'&  
//default value of nSplitter is 5 `CP#S7W^  
this("","","",5); 9%55R >s$  
} FR"yGx#$  
fs_6`Xt  
UIPi<_Xa  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) owM3Gz%?UA  
{ biLx-F c  
sSiteURL= sURL; }S
pjB  
sFilePath = sPath; scZdDbL6+  
sFileName = sName; N/IDj2C4  
this.nSplitter = nSpiltter; XUTI0  
1AiqB Rs  
8@pY:AY  
} 3 (Bd`=9  
wQ-pIi{G  
^NwXvp>7-  
public String getSSiteURL() o?%1^6&HE  
{ X%w`:c&  
return sSiteURL; 1W*%}!&Gm  
} VSns_>o  
Y%eFXYk.  
fn(< <FA)  
public void setSSiteURL(String value) @Cg%7AF  
{ Z7>pz:,  
sSiteURL = value; AWsy9  
} >1u!(-A  
tl5}#uJ  
Qa-]IKOs  
public String getSFilePath() ^'9:n\SKQ  
{ 4&]Sb}  
return sFilePath; `L n,qiA  
} .;nU" a3'  
I.#V/{J  
n3Uw6gLD  
public void setSFilePath(String value) %zDh07VT\  
{ /=4 m4  
sFilePath = value; 2IDN?Mw  
} 3<">1] /,  
@)nxX))a  
=*<Cw?Gc  
public String getSFileName() =qG%h5]n  
{ cXP*?N4Cf  
return sFileName; t6m&+N  
} {6}H}_(]  
\o}m]v i  
A9qbE  
public void setSFileName(String value) ^U1@ hq*u  
{ u~[=5r  
sFileName = value; O)v?GQRj  
} Lso4ZZ;  
i~1bfl   
Fb8~2N"3  
public int getNSplitter() wNQhz.>y  
{ /*Xr^X6  
return nSplitter; Ed6k7  
} e\o>(is  
-36pkC 6 \  
LEu_RU?  
public void setNSplitter(int nCount) k/'>,WE  
{ W`auQO  
nSplitter = nCount; cPu<:<F[  
} 0i%r+_E_  
} SbrKNADH%  
9*`(*>S  
/XEt2,sI9  
/* %<[?;  
**Utility.java /4K ^-  
*/ BF >678h  
package NetFox; D=ZH? d  
"}/$xOl"  
:<Z>?x  
public class Utility {   %4  
{|:ro!&  
@ ={Hx$zL  
public Utility() j_w"HiNBA  
{ i6Zsn#Z7)  
_d<xxF^q  
$eqwn&$n  
} p>9-Ga  
{c|{okQ;Q  
//线程睡眠 '#Yqs/V  
public static void sleep(int nSecond) _'OXrT#Q  
{ }wY6^JF  
try{ Lt|'("($*  
Thread.sleep(nSecond);
 :oN$w\A  
} jEaU;  
catch(Exception e) 2^3N[pM;  
{ xJ=@xfr$  
e.printStackTrace (); 9|('*  
} wgETL|3-  
} 98Dg[O  
E![Ye@w  
//日志 ^/`W0kT  
public static void log(String sMsg) G&7!3u  
{ qHQWiu%h  
System.err.println(sMsg); ;^yR,32F  
} lxVA:tz0  
APR"%(xD#  
hv4om+  
public static void log(int sMsg) 8l<4OgoK  
{ 4nvi7  
System.err.println(sMsg); %]U'   
} }hoyjzv]L  
} lPBWpHX  
h!yI(cY  
2*[Gm e  
/* $27QY  
**TestMethod.java N?Nu'  
*/ ;1gWz  
package NetFox; 8? U!PW  
4Y.o RB  
_{k-&I  
public class TestMethod { d[( 
}  
zyh #ygH  
-G|?Kl  
public TestMethod() ZYMacTeJjg  
{ ///xx/weblogic60b2_win.exe m,3H]  
try{ x@aWvrL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Mtw7aK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "kdmqvTHK0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O5v)}4  
fileFetch.start(); ' 5F3,/r  
} KFuPgp  
catch(Exception e){e.printStackTrace ();} ^F="'/Pq[  
dm:2:A8^  
&[Zg;r   
} ;"R1>tw3)  
K6BP~@H_D  
}M0GPpv  
public static void main(String[] args) g]mR
;T3  
{ l>t0 H($  
new TestMethod(); +m>)q4e  
} :4\=xGiY  
} exP:lO_0n  
点击下载更多相关资料