http断点续传简单实现（java)

/* T:p,!?kc7  
**SiteFileFetch.java ?`#)JG,A7  
*/ :FcYjw  
package NetFox; |]kcgLqj  
import java.io.*; sN]O]qYXJ  
import java.net.*; >AX&PMb`  
_BHR ?I[w  
bKRz=$P?  
public class SiteFileFetch extends Thread { 65X$k]x  
jODx&dVr  
J$JXY@mBSC  
SiteInfoBean siteInfoBean = null; //文件信息Bean }D02*s  
long[] nStartPos; //开始位置 zkHwoAD;t8  
long[] nEndPos; //结束位置 +nU"P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J{<,V\t)  
long nFileLength; //文件长度 ;<i`6e  
boolean bFirst = true; //是否第一次取文件 c'ExZ)RJ  
boolean bStop = false; //停止标志 J\VG/)E  
File tmpFile; //文件下载的临时信息 lv\C(^mGq  
DataOutputStream output; //输出到文件的输出流 nK=-SQ  
f_y+B]?'M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G9"2h \  
public SiteFileFetch(SiteInfoBean bean) throws IOException u2%/</]h  
{ MY1s  
siteInfoBean = bean; XaOq&7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ig(dGKD\=9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /G[; kR"  
if(tmpFile.exists ()) j5QS/3  
{ ZU\TA|  
bFirst = false; mVUDPMyZ  
read_nPos(); VbQ9o  
} }g6:9%ZMu  
else MDI[TNYG  
{ rWzw7T~  
nStartPos = new long[bean.getNSplitter()]; 1<g,1TR  
nEndPos = new long[bean.getNSplitter()]; aMI\gCB/  
} *ElR  
z'FD{xdf  
T"ors]eI  
Twi:BI`.  
} lW}"6@0,  
zOO:`^ m  
]"?+R+  
public void run() 2@ 4^ 81
 
{ AT.WXP0$A  
//获得文件长度 $!F_K  
//分割文件 '!Gnr[aR  
//实例FileSplitterFetch U6SgV 8  
//启动FileSplitterFetch线程 gQHE2$i>  
//等待子线程返回 H
3< `

 
try{ DY]\@<ez  
if(bFirst) Gc6`]7 s  
{ eF)vx{s  
nFileLength = getFileSize(); DSiI%_[Ud  
if(nFileLength == -1) &Xw{%Rg  
{ =pHW
qGOD  
System.err.println("File Length is not known!"); p<hV7x-{  
} 'U=D6X%V9m  
else if(nFileLength == -2) A'(v]w  
{ U-+%e:v  
System.err.println("File is not access!"); uEp v l  
} /Hxz@=LC1  
else O%:EPdoU  
{ 1~X~"M  
for(int i=0;i<nStartPos.length;i++) )<W6cDx'H+  
{ F=}-ngx8&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nU]4)t_o\  
}  =FZt
 
for(int i=0;i<nEndPos.length-1;i++) eq>E<X#<  
{ erG@8CG  
nEndPos = nStartPos[i+1]; dno=C  
} mMLxT3Ci8  
nEndPos[nEndPos.length-1] = nFileLength; )./pS~  
} /y2upu*!  
} sA6Ku(9  
\g|u|Y.2[  
;-Bi~XD  
//启动子线程 9D 2B8t"a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %\xwu(|kN  
for(int i=0;i<nStartPos.length;i++) !L5[s  
{ ("HT0&#a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9H~{2Un  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )dFTH?Mpo  
nStartPos,nEndPos,i); iM'{,~8R5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {UX[SAQ  
fileSplitterFetch.start(); 3PS(1  
} q r12"H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XsE] Z4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h9Zf4@w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'MEO?]Tf.^  
nEndPos = " + nFileLength); ?V|t7^+:  
// fileSplitterFetch[nPos.length-1].start(); k:D;C3vJd  
q!l[^t|;  
==d@0`  
//等待子线程结束 K%TlBKV  
//int count = 0; dL9QYIfP  
//是否结束while循环 hGc')  
boolean breakWhile = false; {. r/tV5IH  
N?j,'gy4  
tmAc=?|Wa  
while(!bStop) q#W7.8 Z@  
{ cB5|%@$I  
write_nPos(); q*Xp"yBTo  
Utility.sleep(500); u#tLY/KA  
breakWhile = true; -#XNZy!//  
S9Kay'.aJ(  
dm4dT59  
for(int i=0;i<nStartPos.length;i++) 7X|M\WUq  
{ }^J&D=J5V  
if(!fileSplitterFetch.bDownOver) UYu 54`'kg  
{ -:txmMT  
breakWhile = false; nU Oy-c  
break; LGb.>O^  
} ebF},Q(48  
} k]*DuVCOX  
if(breakWhile) #]`ejr:2O  
break; .F
=15A  
8.vPh
  
GvQ|+vC  
//count++; 'WH@Zk/l  
//if(count>4) M5OH-'  
// siteStop(); w+vYD2a  
} d7o~$4h|  
kTQ`$V(>&  
'ad|@Bh  
System.err.println("文件下载结束！"); h%kB>E~  
}  5" U8|  
catch(Exception e){e.printStackTrace ();} N"~P` H![x  
} E.Hw|y0_(|  
Q}!U4!{i|p  
-Kt36:|  
//获得文件长度 _tE$a3`  
public long getFileSize() mea]m)P  
{ Q$iGpTL  
int nFileLength = -1; ku,Y-  
try{ o5+N_5OE}E  
URL url = new URL(siteInfoBean.getSSiteURL()); Hl&]r'bK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >iP>v`J  
httpConnection.setRequestProperty("User-Agent","NetFox"); i>bFQ1Rdx  
$jb3#Rj4  
S\<]|tM:x  
int responseCode=httpConnection.getResponseCode(); QsYc 9]:  
if(responseCode>=400) 'Mjbvh4  
{ UP:+1Sp9  
processErrorCode(responseCode); O'JH=
'  
return -2; //-2 represent access is error 6.tppAO+  
} vO" $Xw  
<_""4  
2vKnxK+ 5  
String sHeader; {: EQ  
AX8;x1t^.  
7<{Zq8)  
for(int i=1;;i++) 6<A\U/  
{ EAFKf*K=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w&;\}IS  
//Utility.log(in.readLine()); Ov%9S/d  
sHeader=httpConnection.getHeaderFieldKey(i); /B!"\0G/,  
if(sHeader!=null) \~nUk7.  
{ nLkC-+$tM  
if(sHeader.equals("Content-Length")) $i@5'[jA  
{ ?|^1-5l3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;D]TPBE  
break; (JFa  
} kYs2AzS{d  
} hmkcWr`  
else <2y~7h:  
break; FQi"OZHq  
} RCNqHYR  
} V&KH{j/P  
catch(IOException e){e.printStackTrace ();} xPqpNs-,  
catch(Exception e){e.printStackTrace ();} M 0->  
|6\ ?"#  
_}Jz_RS2`  
Utility.log(nFileLength); Yl1@gw7  
zEY Ey1  
>T~{_|N  
return nFileLength; l;Zc[6  
} C
T4R/wzY7  
+C\?G/  
KnZm(c9+  
//保存下载信息（文件指针位置） pM[UC{  
private void write_nPos() F5L/7j<}  
{ OR&+`P"-\  
try{ wlKpHd*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {b/60xl?  
output.writeInt(nStartPos.length); \@OKB<ra  
for(int i=0;i<nStartPos.length;i++) zy@ #R;  
{ & A9psc(,&  
// output.writeLong(nPos); 6?}8z q[  
output.writeLong(fileSplitterFetch.nStartPos); R|NmkqTK~(  
output.writeLong(fileSplitterFetch.nEndPos); bz H5Lc{%  
} 2~h)'n7Mw  
output.close(); x)#k$QU  
} }9P)<
[>  
catch(IOException e){e.printStackTrace ();} U$VT
k  
catch(Exception e){e.printStackTrace ();} ;?inf`t  
} |c8p{)  
jopC\Z  
\/K>Iv'$  
//读取保存的下载信息（文件指针位置） 40%p lNPj  
private void read_nPos() 7F?^gMi  
{ ; @Gm@d  
try{ &$hfAG]"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :CHCVoh@95  
int nCount = input.readInt(); XNu2G19jb  
nStartPos = new long[nCount]; KU33P>a"[k  
nEndPos = new long[nCount]; .:RoD?px  
for(int i=0;i<nStartPos.length;i++) [Z Ea3/  
{ Bb:jy!jq_  
nStartPos = input.readLong(); *N'B(j/  
nEndPos = input.readLong(); Xf
bkK )d  
} `!m+g0  
input.close(); ['-ln)96.
 
} `34[w=Zm  
catch(IOException e){e.printStackTrace ();} W,Dr2$V  
catch(Exception e){e.printStackTrace ();} i8HSYA  
} ~,':PUkiV  
%I Y-0\  
8Qu].nKe  
private void processErrorCode(int nErrorCode) [zf9UUc~  
{ 7\{<AM?*  
System.err.println("Error Code : " + nErrorCode); <#|3z8N2  
} x6Z$lhZ  
%q>gwq A  
E? F @  
//停止文件下载 wK#UFOp  
public void siteStop() _IpW&  
{ (2qo9j"j/Y  
bStop = true; e4CG=K3s  
for(int i=0;i<nStartPos.length;i++) FLy|+4D_%4  
fileSplitterFetch.splitterStop(); , PN?_N  
103^\Av8  
k )){1O  
} B u4N~0
 
} *QLl jGe  
//负责部分文件的抓取 4\sS  
**FileSplitterFetch.java d G:=tf&1R  
*/ >b*P
d *f  
package NetFox; d\Dxmb]o  
6oUT+^z#  
5QmF0z)wR  
import java.io.*; hDp'=}85@  
import java.net.*; gn(n</\/O  
3v0
)oK  
Nt/*VYUn  
public class FileSplitterFetch extends Thread { HM[BFF[;/  
7^Onq0ym T  
|Q:`:ODy`5  
String sURL; //File URL ]Dx?HBM"DC  
long nStartPos; //File Snippet Start Position u4+VG5.rhT  
long nEndPos; //File Snippet End Position cVulJ6  
int nThreadID; //Thread's ID ^O892
-R  
boolean bDownOver = false; //Downing is over 2N)vEUyDV  
boolean bStop = false; //Stop identical k7W8$8v  
FileAccessI fileAccessI = null; //File Access interface 8%nTDSp&t  
Wdy2;a<\{  
SZwfYY!ft0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0W=IuPDU  
{ c yN_Sg  
this.sURL = sURL; +%gh?  
this.nStartPos = nStart; 4a)qn?<z  
this.nEndPos = nEnd; RPp_L>&~<  
nThreadID = id; 54}s:[O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'm/b+9?.  
} g]d
"d  
=ARI*  
#),QWTl3  
public void run() oN _%oc  
{ _r,#
l5~U  
while(nStartPos < nEndPos && !bStop) ~kN6Hr*X  
{ s` S<BX7  
*Li;:b"t  
$V\xN(Ed  
try{ BwBv'p+n  
URL url = new URL(sURL); t<:XY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T_gW't>   
httpConnection.setRequestProperty("User-Agent","NetFox"); ruE.0VI@  
String sProperty = "bytes="+nStartPos+"-"; )O7Mfr  
httpConnection.setRequestProperty("RANGE",sProperty); s@3!G+ -}  
Utility.log(sProperty); sHEISNj/^  
d0N7aacY  
sk],_l<  
InputStream input = httpConnection.getInputStream(); C2`END;  
//logResponseHead(httpConnection); eN jC.w9  
9CL&tpqv f  
?NHh=H\7u  
byte[] b = new byte[1024]; 
j f^fj-  
int nRead;  %gf8'Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) D@j `'&G  
{ 2+?M(=4  
nStartPos += fileAccessI.write(b,0,nRead); X$st{@}ZB  
//if(nThreadID == 1) a>Q7Qn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U\b,W&%P  
} vO&1F@  
Fir7z nRW  
MOOL=Um3  
Utility.log("Thread " + nThreadID + " is over!"); iezz[;t  
bDownOver = true; 7qh_URt@  
//nPos = fileAccessI.write (b,0,nRead); %l5J   
} * |,V$  
catch(Exception e){e.printStackTrace ();} ^R2:Z&Iv%  
} 4QDF%#~q^  
} =RQ>q  
K):)bL(B  
b9\=NdyCY  
//打印回应的头信息 *?i~AXJm  
public void logResponseHead(HttpURLConnection con) W~7q&||;C  
{ u|w[b9^r  
for(int i=1;;i++) Y*7.3 +#  
{ Kk/qd)nk  
String header=con.getHeaderFieldKey(i); fCF93,?$  
if(header!=null) b8`O7@ar  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [(dAv7YbN  
Utility.log(header+" : "+con.getHeaderField(header)); $T*kpUXH}  
else Y#rao:I  
break; naAZR*(A  
} 2j_L jY'7  
} 4ci @$nL1  
;,IGO7R  
o!j? )0d  
public void splitterStop() HF0J>Clq  
{ q|Ga   
bStop = true; >B3_P4pW9  
} xEZvCwsb  
b9"Q.*c<Z^  
ousoG$Pc  
} EW YpYMkm  
[zY9"B<
3  
(s\Nm_j  
/* 58=fT1 B  
**FileAccess.java LdRLKE<'e  
*//文件访问(定位，写) EJN}$|*Av  
package NetFox; ==Y^~ab;K  
import java.io.*; i #8)ad  
-1U]@s  
.Z9Bbab:  
public class FileAccessI implements Serializable{ B?Pu0 _|s  
EpPKo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jg2>=}  
RandomAccessFile oSavedFile; 8vchLl#  
long nPos; (Kx3:gs  
jagsV'o2  
V}Oxz04  
public FileAccessI() throws IOException /J5wwQ (:  
{ zvSf
W# *  
this("",0); 6LUB3;g7  
} t*n!kXa  
$ABW|r  
r1t  TY?  
public FileAccessI(String sName,long nPos) throws IOException c!6.D  
{ 0 5 `x$f  
oSavedFile = new RandomAccessFile(sName,"rw"); ?L7z\b"_~  
this.nPos = nPos; q?JP\_o:  
oSavedFile.seek(nPos); hXZk$a'  
} z+Y0Zh";/#  
+AXui|mn  
%m{h1UQQ+  
public synchronized int write(byte[] b,int nStart,int nLen) WG1x:,-  
{ l? 7D
0  
int n = -1; 0urQA_JC  
try{ fF<~2MiKw  
oSavedFile.write(b,nStart,nLen); 4R}2H>VV%  
n = nLen; z${DW@o3  
} j].XVn,  
catch(IOException e) VYik#n>|Gp  
{ PYW~x@]k%,  
e.printStackTrace (); {QJJw}!#  
} I+ydVj(Op  
'V } -0  
3-z57f,}6~  
return n; o5A@U0c_  
} T&cf6soo  
8)'OXR0/  
1;S@XC>  
} ;5dJ5_}  
s}X2*o`,  
05$CIS>!  
/* zGA1  
**SiteInfoBean.java Np+<)q2  
*/ {0QNqjue  
package NetFox; mM!Gomp  
=5',obYN>c  
:[,-wZiT~6  
public class SiteInfoBean { D8G5,s-.  
;MR8E9  
3hGYNlQ^  
private String sSiteURL; //Site's URL (jtrQob  
private String sFilePath; //Saved File's Path ;",W&HQbE  
private String sFileName; //Saved File's Name !w{4FE74  
private int nSplitter; //Count of Splited Downloading File Wi)Y9frE  
q\/ph(HF  
'HzF/RKh  
public SiteInfoBean() 5{L~e>oS9  
{//nSplitter的缺省值为5 ]]V|[g&aJ  
//default value of nSplitter is 5 ? 0
p_/mZ  
this("","","",5); k`_sKr]9  
} 3c}@_Yn  
lvY[E9I0  
yX0nyhq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *%E4,(T  
{ Kejp7okb  
sSiteURL= sURL; wQEsq<  
sFilePath = sPath; E{k$4  
sFileName = sName; 9$$dSN\&  
this.nSplitter = nSpiltter; ]{s0/(EA  
9sJ=Nldq  
QV)>+6\  
} UQc!"D  
FC@h6\+a  
C.].HQ  
public String getSSiteURL() ^CO{86V  
{ c#(Hh{0
 
return sSiteURL; -Aaim`06bv  
} 0"}J!c<g  
kOdXbw9v  
WPI<SsLd  
public void setSSiteURL(String value) . |%n"{  
{ f$ 9O0,}%O  
sSiteURL = value; hK+6S3-Ez  
} >~:Md  
4Oo{\&(  
z?dd5.k  
public String getSFilePath() `i`+yh>pc#  
{ `%;Hj _X}  
return sFilePath; KW-GVe%8f  
} g&z8t;@  
E@,m+  
N,W
?}  
public void setSFilePath(String value) 'HKDGQl`  
{ u}3D'h  
sFilePath = value; YLJ^R$pi  
} iR?}^|]  
!6!Gx:  
Co>e<be%S  
public String getSFileName() o3]Lrzh  
{ f7YBhF  
return sFileName; h4Wt oE>i  
} d|?Xo\+  
UodBK7y  
!7Eodq-0  
public void setSFileName(String value) ;/:Sx/#s  
{ $vrkxn  
sFileName = value; c+D<  
} wXjidOd$  
\?SvO  
e,
N}z  
public int getNSplitter() is }>+&_  
{ ]Hp>~Zvbb  
return nSplitter; XeX\u3<D  
} .7]P-]uOZ  
e:%|.$4OG  
H2H`7 +I,  
public void setNSplitter(int nCount) *Nm$b+  
{ ^/_Yk.w  
nSplitter = nCount; /~MH]Gh  
} o^XDG^35`  
} Kv<f<>|L  
 ^M{,{bG  
JIhEkY  
/* y];-D>jk  
**Utility.java aaP_^m O  
*/ NV7k@7_{B  
package NetFox; !_vxbfZO  
SE'!j]6jI  
P q$0ih  
public class Utility { ;$WHTO(  
nl qn:[BU  
x-"8V(  
public Utility() Z:dp/M}  
{ @/F61Ut  
K>dB{w#gS  
om`T/@_,  
} D"rbQXR7$  
#MKM.T,\t  
//线程睡眠 }x?F53I)  
public static void sleep(int nSecond) h%:rJ_#Zl  
{ 4;fuS_(X  
try{ LRVcf  
Thread.sleep(nSecond); jMgXIK\  
} zw['
hqW  
catch(Exception e) In?=$_p  
{ ;I&VpAPx  
e.printStackTrace (); I]^>>>p$  
} L8 L1_  
} wqhktgG  
HcgvlFb  
//日志 TjyL])$  
public static void log(String sMsg) 8q@Z  
{ pZ&,YX  
System.err.println(sMsg); yEq7ueJ'  
} TG%B:^Yz!  
;%9]G|*{  
tO&ffZP8$  
public static void log(int sMsg) v8)"skVnFG  
{ CuWJai:nQ;  
System.err.println(sMsg); |@vkQ  
} .E<nQWz8  
} ;$QC_l''b  
27EK+$  
b,Oh8O;>  
/*  .qgUD  
**TestMethod.java Zz0e4C  
*/ x;17}KV  
package NetFox; q0iJy@?A  
maXg(Lu  
'v"=  
public class TestMethod { KNUK]i&L  
m[^lu1\wn  
unLhI0XW  
public TestMethod() TIWR[r1!  
{ ///xx/weblogic60b2_win.exe (k?HT'3)  
try{ G3~`]qf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q`VL i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c2

y,zq|H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r3W3;L  
fileFetch.start(); 4f([EV[6dK  
} "2l`XH  
catch(Exception e){e.printStackTrace ();} @1MnJP  
U[@y8yN6M  
CIjc5^Y2  
} `ePC$Ovn  
0f^{Rp6  
[d:
 u(  
public static void main(String[] args) 0B}4$STOo[  
{ H$KO[mW}  
new TestMethod(); ~SnUnNDm`  
} j*jUcD*  
} *.DC(2:
o!  
点击下载更多相关资料