http断点续传简单实现（java)

/* ],xvhfZ"dn  
**SiteFileFetch.java DE!P[$J  
*/ 4M*!'sG\  
package NetFox;
=q?sB]n  
import java.io.*; )bR`uV9<  
import java.net.*; [6cf$FS9  
)A=&3Ui)ab  
M:d} P  
public class SiteFileFetch extends Thread { 1CA%nqlng  
}x(Ewr  
gN5;Uk  
SiteInfoBean siteInfoBean = null; //文件信息Bean /\d@AB^5I  
long[] nStartPos; //开始位置 =L&dV]'4P  
long[] nEndPos; //结束位置 9 gWqs'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5[|ZceY  
long nFileLength; //文件长度 qz&?zzz;  
boolean bFirst = true; //是否第一次取文件 u?lbC9}$  
boolean bStop = false; //停止标志 !G~`5?CvE  
File tmpFile; //文件下载的临时信息 #kRt\Fzq  
DataOutputStream output; //输出到文件的输出流 7O
\Qxc\  
f/UIpswrZ'  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F@rx/3 [  
public SiteFileFetch(SiteInfoBean bean) throws IOException IUSV\X9  
{ j+NsNIJq  
siteInfoBean = bean; N%fDgK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9/$Cq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VkZ3Q7d  
if(tmpFile.exists ())  re@;6o  
{ )bl^:C  
bFirst = false; "eZ~]m}L0  
read_nPos(); xY<*:&  
} O2N~&<^  
else cs0rz= ZdH  
{ 3eR c>^wh  
nStartPos = new long[bean.getNSplitter()]; 0^mCj<g  
nEndPos = new long[bean.getNSplitter()]; -E>LB\[t)  
} `tH:oP0=  
`=19iAp.  
zr^"zcfz&  
E?cf#;2h8m  
} Bz4;R9_%I  
m)e~HP7M  
uh&Qdy!I  
public void run() z(Q 5?+P  
{ mae@L  
//获得文件长度 \.Z /  
//分割文件 n7(/ml+Q_  
//实例FileSplitterFetch ?#Y1E~N  
//启动FileSplitterFetch线程 u -A_l<K
 
//等待子线程返回 wrAcVR  
try{ 3B?7h/f  
if(bFirst) P`OZoI$bV  
{ oN&U@N/>aU  
nFileLength = getFileSize(); L)9uBdF  
if(nFileLength == -1)  .F/
0:)  
{ 9a0|iy  
System.err.println("File Length is not known!"); Wh^wKF~%  
} @ GXi{9  
else if(nFileLength == -2) OTD<3Q q  
{ [BuAJ930#5  
System.err.println("File is not access!"); Yk=2ld;;  
} g-DFcwO,V  
else  [1g  
{ 2}U:6w  
for(int i=0;i<nStartPos.length;i++) r
H9[x8e  
{ Z=zD~ka  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?$~5ti#\  
} Q&8epO|J  
for(int i=0;i<nEndPos.length-1;i++) ; ~#uH7k  
{ k`NXYf:  
nEndPos = nStartPos[i+1]; :[?65q{  
} J8?V1Ad{  
nEndPos[nEndPos.length-1] = nFileLength; jq(QL%)_O  
} e~PAi8B5  
} a3C\?5  
/kNS
B;  
_6]c f!H  
//启动子线程 {)PgN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "HtaJVp//  
for(int i=0;i<nStartPos.length;i++) .wf$]oQQ  
{ =&#t("  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5q _n6
9b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tb;u%{S  
nStartPos,nEndPos,i); ,
d7o/8u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #r'S@:[  
fileSplitterFetch.start(); #BwOWra  
} j W/*-:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A@)ou0[n@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ];*?`}#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W
4$F\y  
nEndPos = " + nFileLength); A9o"L.o)  
// fileSplitterFetch[nPos.length-1].start(); gp NAM"  
2 sK\.yS  
AYv7-!Yk  
//等待子线程结束 CtE <9?  
//int count = 0;  J7p?9  
//是否结束while循环 Vw+RRi(  
boolean breakWhile = false; +k\cmDcb  
fF.sT7Az+  
+l
;AL5h  
while(!bStop) PE<(eIr  
{ jPEOp#C  
write_nPos(); S^_F0</U,  
Utility.sleep(500); h~s h!W8  
breakWhile = true; =O>E>Q  
MR/gLm(8(  
d'[]  
for(int i=0;i<nStartPos.length;i++) pZ5eGA=  
{ kerBy
\^  
if(!fileSplitterFetch.bDownOver) TnJJ& "~3b  
{ sZI$t L<j  
breakWhile = false; #]z_pp:  
break; \CrWKBL  
} M?QX'fia  
} O6
n]l  
if(breakWhile) l(d3N4iz  
break; #A=ER[[  
Yz? 8n  
zR5KC!xc  
//count++; TV~S#yg+H  
//if(count>4) 91M5F$  
// siteStop(); 0N):8`dY  
} s3y"y_u  
tf6 Zz[  
=6gi4!hE  
System.err.println("文件下载结束！"); B~2M/&rM\  
} f7I!o,/  
catch(Exception e){e.printStackTrace ();} j.+}Z |  
} ?63ep:Q
Ek  
0ni/!}YP_  
p{[(4}ql  
//获得文件长度 -YY@[5x?u  
public long getFileSize() j> dL:V&`  
{  0X}0,  
int nFileLength = -1; sF~!qag4q'  
try{ ?Lbn R~/J  
URL url = new URL(siteInfoBean.getSSiteURL()); #7=- zda5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [}`-KpV!;  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dr5AJ`y9A  
U3BhoD#f\  
2#R8}\  
int responseCode=httpConnection.getResponseCode(); m.Ki4NUm  
if(responseCode>=400) lQ#='Jqfp  
{ Zty9O8g  
processErrorCode(responseCode); 23/;W|   
return -2; //-2 represent access is error sE!$3|Q  
} HM
&"2c  
qe|U*K 2_  
["sm
7yQ  
String sHeader; Q-Oj%w
4e  
yZc#@R[0  
z m+3aF  
for(int i=1;;i++) Lmw
4  
{ _ qU-@Y$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w+iIay  
//Utility.log(in.readLine()); ^y[- e9O|  
sHeader=httpConnection.getHeaderFieldKey(i);  bU$M)  
if(sHeader!=null) gjn1ha"h%.  
{ 1t}  
if(sHeader.equals("Content-Length")) "x O+  
{ zoZ10?ojC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UdcrX`^.  
break; ##nC@h@  
} yaYJmhG  
} f0 kz:sZ9  
else QBb%$_Z  
break; CTJwZY7  
} *M'/z=V?%  
} #~[{*[B+  
catch(IOException e){e.printStackTrace ();} ^Vg-fO]V  
catch(Exception e){e.printStackTrace ();} xB5QM #w\  
u,./,:O%=  
#@J{ )  
Utility.log(nFileLength); $'3'[Nr(;t  
v(p<88.!m  
A~H@0>1  
return nFileLength; }!N/?A5  
} p{AX"|QM"  
<YvW /x  
a"^rOiXR{  
//保存下载信息（文件指针位置） CIj7'V  
private void write_nPos() ]A:8x`z#F  
{ GK1oS  
try{ 395`Wkv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q096M 0m  
output.writeInt(nStartPos.length); f/t`B^}@  
for(int i=0;i<nStartPos.length;i++) )j. .)o  
{ \|
CuTb;0  
// output.writeLong(nPos); h)Ol1[y`  
output.writeLong(fileSplitterFetch.nStartPos); ydMSL25<+  
output.writeLong(fileSplitterFetch.nEndPos); U04&z 91"  
} W0<2*7s  
output.close(); 1NkJs&  
} dUv(Pu(.#  
catch(IOException e){e.printStackTrace ();} o8~<t]Ejw  
catch(Exception e){e.printStackTrace ();} $E}N`B7  
} 1vdG\$  
LIn2&r:U  
6eb~Z6n&?  
//读取保存的下载信息（文件指针位置） f dJ<(i]7W  
private void read_nPos() /rHlFl|Wy  
{ F<DXPToX%  
try{ O]KQ]zN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EAlLxXDDh  
int nCount = input.readInt(); Qh+zs^-?  
nStartPos = new long[nCount]; i5gNk)D  
nEndPos = new long[nCount]; Z1{>"o:@  
for(int i=0;i<nStartPos.length;i++) o{3>n"\w3  
{ 0wt4C% .0  
nStartPos = input.readLong(); a|z@5r%  
nEndPos = input.readLong(); mDO! o  
} |)S*RQb\  
input.close(); .R)uk  
} 51;[R8'w  
catch(IOException e){e.printStackTrace ();} a\}` f=T  
catch(Exception e){e.printStackTrace ();} *Tr9pq%m  
} L~C:1VG5  
-_= m j  
:QC |N@C  
private void processErrorCode(int nErrorCode) 8vQR'<,  
{ a\&g;n8jA  
System.err.println("Error Code : " + nErrorCode); KW/LyiP#  
} I3u)y|Y=  
R{pF IyR  
4hzdc] a  
//停止文件下载 e m  
public void siteStop() bnJ4Ed
y  
{ 6Ad=#MM  
bStop = true; L%+mD$@u  
for(int i=0;i<nStartPos.length;i++) 8RQv  
fileSplitterFetch.splitterStop(); $laUkD#vz  
[Y.=bfV!  
e'->Sg  
} ,c&gw tdl  
} ^I)+u>fJ  
//负责部分文件的抓取 ij1YV2v  
**FileSplitterFetch.java ]n3!%0]\  
*/ #H
y\lJ  
package NetFox; +!ZfJZls  
/ }*}r  
UG[r /w5(F  
import java.io.*;
~K"nm{.  
import java.net.*; !j}L-1*{ l  
4W}mPeEeV  
/EuH2cy$l  
public class FileSplitterFetch extends Thread { e;2A{VsD8  
>`p?
CE  
MGY0^6yK5  
String sURL; //File URL ?!O4ia3nFk  
long nStartPos; //File Snippet Start Position Jt0U`
_  
long nEndPos; //File Snippet End Position o#=C[d5BV  
int nThreadID; //Thread's ID g>l+oH[Tv|  
boolean bDownOver = false; //Downing is over ]B$J8.{q0  
boolean bStop = false; //Stop identical a ,"   
FileAccessI fileAccessI = null; //File Access interface G#M0 C>n  
`3`.usw  
8H|ac[hXK2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1jO%\uR/  
{ F)v  
this.sURL = sURL; .R l7,1\  
this.nStartPos = nStart; q@tym5  
this.nEndPos = nEnd; _07$TC1  
nThreadID = id; LR';cR;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p$uPj*  
} |(AFU3~  
O<E8,MCA[a  
VJ?>o  
public void run() +bT[lJ2O>G  
{ X?XB!D7[  
while(nStartPos < nEndPos && !bStop) Cc;8+Z=a?G  
{ XyiaRW  
$HtGB]  
9Q!Z9n"8~)  
try{ AyPtbrO  
URL url = new URL(sURL); @DF7j|]tV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vn!3Z!dm(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 64]8ykRD-  
String sProperty = "bytes="+nStartPos+"-"; DEbMb6)U  
httpConnection.setRequestProperty("RANGE",sProperty); PQa0m)H@  
Utility.log(sProperty); dFA1nn6{  
sN2m?`?"G  
[ D.%v~j  
InputStream input = httpConnection.getInputStream(); C!ch !E#  
//logResponseHead(httpConnection); }r@yBUW  
LNyrIk/1  
tP"6H-)X&  
byte[] b = new byte[1024]; %M))Ak4~a  
int nRead; (w:,iw#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;FW <%  
{ boHbiE  
nStartPos += fileAccessI.write(b,0,nRead); fx>U2  
//if(nThreadID == 1) )WInPW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x/wgD'?  
} 
lfre-pS+  
3zu6#3^  
*ra>Kl0   
Utility.log("Thread " + nThreadID + " is over!"); Ga-cto1Y  
bDownOver = true; cpALs1j:  
//nPos = fileAccessI.write (b,0,nRead); ch25A<O<R.  
} szb@2fK  
catch(Exception e){e.printStackTrace ();} U|VL+9#hd  
} JgA{1@h  
} l1KgPRmEP  
+cSc0:  
{dm>]@"S  
//打印回应的头信息 ~KYzEqy  
public void logResponseHead(HttpURLConnection con) wc.=`Me  
{ u&^KrOM@#  
for(int i=1;;i++)
'&dT  
{ "j8)l4}  
String header=con.getHeaderFieldKey(i); ,B_c  
if(header!=null) OM{^F=Ap  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n:2._s T  
Utility.log(header+" : "+con.getHeaderField(header)); [0aC]XQZ  
else "|[9 Q?  
break; P/.<sr=2  
} 5bAdF'~  
} &$ "J\vm  
^X}r ^  
1dw{:X=j  
public void splitterStop() MfHOn YV  
{ 6@t&  
bStop = true; .xWaS8f  
} K3M.ZRh\;`  
yNowhh
 
Z"%.  
} euVDrJ^  
)GAlj;9A$  
V7r_Ubg@K  
/* JJ%@m;~  
**FileAccess.java 1[8^JVC>6  
*//文件访问(定位，写) i?;#ZNh  
package NetFox; iC
/*d  
import java.io.*; 6lv@4R^u  
u}|v;:|j  
-Dx3*ZhP  
public class FileAccessI implements Serializable{ , ?U)mYhI  
NsP=l]   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \Ta5c31S+  
RandomAccessFile oSavedFile; PJ0~ymE1~G  
long nPos; ]%HxzJ  
q,O_y<uw  
4\u`MR  
public FileAccessI() throws IOException yn_f%^!G  
{ -0#"
<!N  
this("",0); z!O;s ep?/  
} 6V%}2YE?X  
vt2. i$u  
'jfE?n
gt  
public FileAccessI(String sName,long nPos) throws IOException d"06 gp  
{ \<*F#3U1  
oSavedFile = new RandomAccessFile(sName,"rw"); (${ #l  
this.nPos = nPos; &K[sb%  
oSavedFile.seek(nPos); #~)A#~4O  
} _.Hj:nFHz  
`;+x\0@<  
kSzap+nB?  
public synchronized int write(byte[] b,int nStart,int nLen) GEF's#YWK  
{ G3io!XM)D  
int n = -1; /MY's&D(  
try{ vj%"x/TP  
oSavedFile.write(b,nStart,nLen); #e-K It  
n = nLen; QK[^G6TI  
} i.uyfV&F  
catch(IOException e) q i yK  
{ O>qlWPht  
e.printStackTrace (); 41<h|WA  
} z$R&u=J  
Nh}-6|M  
))f@9m  
return n; g:ky;-G8b  
} -Pp{aFe  
pxgf%P<7  
R}gdN-941  
} \efDY[j/  
N,-C+r5}<4  
&gY578tU  
/* r=0PW_r:  
**SiteInfoBean.java J<"K`|F  
*/ 5>.ATfAsV  
package NetFox; Ie/_gz^  
<<u]WsW{C  
(m:Q'4E
p  
public class SiteInfoBean { ) hs&?:)  
tj~r>SRb+  
slPr^)  
private String sSiteURL; //Site's URL Gg9s.]W  
private String sFilePath; //Saved File's Path PiM(QR  
private String sFileName; //Saved File's Name i@nRZ$K  
private int nSplitter; //Count of Splited Downloading File iKE&yO3  
Awxm[:r>^  
-Yse^(^"s  
public SiteInfoBean() #%k_V+o3  
{//nSplitter的缺省值为5 8c-ys-"#  
//default value of nSplitter is 5 s 0Uid&qE  
this("","","",5); e}yF2|0FD  
} (0q`eO2  
Es7 c2YdU  
!~9ASpqvPy  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O=7S=Rm4&  
{ _Sfu8k>):  
sSiteURL= sURL; /C Xg$%\  
sFilePath = sPath; -LR
x}Mb9  
sFileName = sName; ,.p 36ZLP  
this.nSplitter = nSpiltter; Ve%ua]qA  
Nuot[1kS  
;&=CZ6vH  
} }.)R#hG?  
S8dfe~|7:  
/B?wn=][  
public String getSSiteURL() aC2Vz9e  
{ 01-rBto$  
return sSiteURL; jFdgFKc)  
} OP=brLGu0  
x}K|\KXy  
~/K&=xE  
public void setSSiteURL(String value) ai$l7]7  
{ xbhHP2F|  
sSiteURL = value; {AD-p!6G  
} i*N2@Z[  
i=#\`"/  
-@>]iBl  
public String getSFilePath() |e@1@q(a[]  
{ Q2ne]MI  
return sFilePath; k{;
?>=FH!  
} \-]Jm[]^  
GBb8}lx  
I\6C0x  
public void setSFilePath(String value) 2QbKh)  
{ eR5q3E/;G  
sFilePath = value; 5}hQIO&^%  
} A+M4=  
/} PdO  
m}?jU  
public String getSFileName() b}Gm{;s!  
{ L]z8'n,  
return sFileName; YT!iI  
} /]z#V'  
Fz(
;Eo3  
N\ Mdia  
public void setSFileName(String value) 4h!yh2c..  
{ ;W5.g8  
sFileName = value; =@4,szLO  
} P?>:YY53  
yOl
VS@7  
]@z!r2[  
public int getNSplitter() &77J,\C$:  
{ &2 Yo  
return nSplitter; n^;-&  
} jbS@6 *_  
n]#YL4j  
JJ)  
public void setNSplitter(int nCount) b*h:e.q  
{ o'$-  
nSplitter = nCount; 2(GYk
 
} i`l;k~rP  
} - i2^ eZl  
h='&^1  
"" ^n^$  
/* /7Sg/d%c  
**Utility.java U~yPQ8jD  
*/ wS|k3^OV%  
package NetFox; ',[AKXJ  
h& 4#5{=  
vqT)=ZC1  
public class Utility { cLL2 '  
h#UPU7;  
+7
6ao7d.  
public Utility() ?H_@/?  
{ D]iyr>V6'  
V_$<^z|  
'>|
Kd{J0  
} 09vVCM;DY  
ckFPx l.  
//线程睡眠 >?JUGXAi'{  
public static void sleep(int nSecond) KS5a8'U  
{ zwQ#Yvd  
try{ U+B{\38   
Thread.sleep(nSecond); X=?9-z] QO  
} ~P}ng{x4z  
catch(Exception e) cy6YajOk7  
{ 9 AD*  
e.printStackTrace (); s7}-j2riq  
} {Q$8p2W  
} |a7Kn/[`,  
L:&'z:,<  
//日志 e`LvHU_0  
public static void log(String sMsg) %F150$(D  
{ \>oy2{=;'  
System.err.println(sMsg); t;3).F  
} e@O]c"  
5.\|*+E~  
9f& !Uw_W  
public static void log(int sMsg) X*7VDt=  
{ ,tZL"  
System.err.println(sMsg); EY)?hJS,  
} n|H
8O3@  
} 0[YksNNl1  
+pK35u  
EFtn!
T  
/* 3hJ51=_0^  
**TestMethod.java M7Xn=jc  
*/ =`(W^&|  
package NetFox; WaX!y$/z  
w `d9" n  
Ed0}$b  
public class TestMethod { ]!"7k_  
j7I?K :op=  
kene' aDm  
public TestMethod() =s.0 f:(  
{ ///xx/weblogic60b2_win.exe #$U/*~m $  
try{ ^pY8'LF6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +:aNgO#e8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a)S6Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x3 ( _fS  
fileFetch.start(); 2V; Dn$q  
} Z-}A"n
 
catch(Exception e){e.printStackTrace ();} [q0^Bn}h  
,bM):  
<h+UC# .x  
} FD%OG6db];  
'bH~KK5  
NyC&j`d  
public static void main(String[] args) TntTR"6aD  
{ ZjY?T)WE9  
new TestMethod(); A^hafBa  
} XLYGhM  
} -+2A@kmEJ  
点击下载更多相关资料