http断点续传简单实现（java)

/* `x
8J  
**SiteFileFetch.java A4C+5R  
*/ t.
T UmJ  
package NetFox; a"N4~?US  
import java.io.*; Y;4!i?el  
import java.net.*; ldha|s.*  
r;BT,jiX  
+mj*o(  
public class SiteFileFetch extends Thread { te
|?)j  
d^03"t0O]  
ncu`vYI.  
SiteInfoBean siteInfoBean = null; //文件信息Bean N;Dp~(1 J1  
long[] nStartPos; //开始位置 %nN `|\  
long[] nEndPos; //结束位置 (*}yjUYLZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7ELMd{CD  
long nFileLength; //文件长度 ^d}gpin  
boolean bFirst = true; //是否第一次取文件 !oPq?lW9  
boolean bStop = false; //停止标志 X cr  =  
File tmpFile; //文件下载的临时信息 z>sbr<doa  
DataOutputStream output; //输出到文件的输出流 >~%e$a7}+  
x:-.+C%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） **9x?s  
public SiteFileFetch(SiteInfoBean bean) throws IOException L86n}+ P\  
{ :B3[:Mp
L}  
siteInfoBean = bean; Q!- 0xlx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lC:k7<0Ji  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); --;@2:lg{  
if(tmpFile.exists ()) C~fjWz' V  
{ hfpJ+[  
bFirst = false; Xq'cA9v=$J  
read_nPos(); !cKz7?w  
} ? WJ> p  
else SJD@&m%?[  
{ 4tL<q_  
nStartPos = new long[bean.getNSplitter()]; 5T sUQc  
nEndPos = new long[bean.getNSplitter()]; BA\/
YW @  
} u]}s)SmDk  
l/;X?g5+  
:0Z^uuk`gq  
?X@fKAj  
} (c0A.L)  
;iDPn2?6?x  
N0hE4t  
public void run() dJ$"l|$$  
{ fXrXV~'8  
//获得文件长度 d%l{V6  
//分割文件 ^u3V E  
//实例FileSplitterFetch f0Bto/,>~  
//启动FileSplitterFetch线程 oIUy-|  
//等待子线程返回 U(~+o  
try{ 74!oe u.>  
if(bFirst) 8r3A~  
{ :W b j\  
nFileLength = getFileSize(); Ol4+_n8xj  
if(nFileLength == -1) 2WUT/{:X  
{ Uj&W<'I  
System.err.println("File Length is not known!"); ]HpA5q1ck  
} ~?B;!Csk  
else if(nFileLength == -2) j ";2o(  
{ (sVi\R  
System.err.println("File is not access!"); nUkaz*4qU  
} f~}H  
else !i=nSqW  
{ 9UvXC)R1  
for(int i=0;i<nStartPos.length;i++) >2#8B  
{ ^CwR!I.D}4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wAnb Di{W  
} !w&kyW?e  
for(int i=0;i<nEndPos.length-1;i++) 2^?:&1:  
{ apE  
nEndPos = nStartPos[i+1]; n3J53| %v  
} C6rg<tCH  
nEndPos[nEndPos.length-1] = nFileLength; NcY608C  
} B"%{i-v>**  
} @?h/B=56  
6uKTGc4  
&89oO@5  
//启动子线程 0uBl>A7qhn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2NB L}x  
for(int i=0;i<nStartPos.length;i++) i<pk6rO1  
{ )BRKZQN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eh"3NRrN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |_ua
S  
nStartPos,nEndPos,i); *)+ut(x|#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z@hD(MS(C  
fileSplitterFetch.start(); z=$jGL  
} 7FRmx4(!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), II
q1\khh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;5@ t[r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &+G"k~%  
nEndPos = " + nFileLength); {rcnM7 S1L  
// fileSplitterFetch[nPos.length-1].start(); =y=cW1TG  
g2unV[()_  
0OGCilOb*  
//等待子线程结束 ~axjjv  
//int count = 0; z0/} !  
//是否结束while循环 ^e+
a  
boolean breakWhile = false; >[X{LI(_<<  
6~*9;!th  
52o x`t|  
while(!bStop) "s\L~R.&  
{ 41fJ%f` G  
write_nPos(); !ti6  
Utility.sleep(500); (%`QhH  
breakWhile = true; k__$Q9qj(  
L\;6y*K  
&N3Y|2  
for(int i=0;i<nStartPos.length;i++) qc-mGmomL  
{ @)K%2Y`  
if(!fileSplitterFetch.bDownOver) M,ir`"s  
{ C:G8c[  
breakWhile = false; -,["c9'3  
break; Iy }:F8F>g  
} 8uA,iYD  
} ]THPSw_y8  
if(breakWhile) Z{H5oUk  
break; bGorH=pb5R  
Hk|0HL  
$-On~u0g  
//count++; 8Xs
guC  
//if(count>4)  f3UXCp  
// siteStop(); *3D%<kVl  
} RxQh2<?  
$y b4xU  
X6^},C'E.:  
System.err.println("文件下载结束！"); `%j~|i
)4  
} S(7ro]U9  
catch(Exception e){e.printStackTrace ();} . BiCBp<  
} Ux+Q  
I2H6y"pN  
~b:Rd{  
//获得文件长度 T6~_Q}6  
public long getFileSize() JAI)Eqqv]  
{ 'TAUE{{  
int nFileLength = -1; S/ibb&  
try{ M?;y\vS?.  
URL url = new URL(siteInfoBean.getSSiteURL()); +&["HoKg}&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~@kU3ZGJZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); [xKd7"d/n  
iPrLwheb  
N:9>dpP}O  
int responseCode=httpConnection.getResponseCode(); GLGz2 ,#  
if(responseCode>=400) \o';"Q1H  
{ hI(SOsKs  
processErrorCode(responseCode); M'!U<Y -  
return -2; //-2 represent access is error Y F*OU"2U  
} ^gFqRbuS  
tlA"B{7  
gR@C0  
String sHeader; y
_.!!@,  
QFIL)'K  
+Y+Y6Ac[}  
for(int i=1;;i++) ){Ob,LEU&  
{ @9&P~mo/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y \:0Ev  
//Utility.log(in.readLine()); SI8%M=P>  
sHeader=httpConnection.getHeaderFieldKey(i); gsn)Wv$h  
if(sHeader!=null) WAn'kA  
{ |c`w'W?C6  
if(sHeader.equals("Content-Length")) n-TQ*&h]3S  
{ ;.bm6(;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lvp8z)G  
break; =V^.}WtO  
} K!KMQ
r`  
} n!qV>k9Y  
else \.g\Zib )  
break; @UdfAyL  
} lqb/eN9(t  
} sUYxT>R  
catch(IOException e){e.printStackTrace ();} ,<2DLp%%D  
catch(Exception e){e.printStackTrace ();} w/L `  
"al`$%(
 
}E_#k]#*  
Utility.log(nFileLength); o`.R!wm:W  
6_4D9 W  
K x~|jq  
return nFileLength; i9=&;_z  
} $O^v]>h  
X*L;.@xA  
)P|[r  
//保存下载信息（文件指针位置） ti &J  
private void write_nPos() q5L51KP2  
{ 5?Wto4j  
try{ gI8Bx]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TYA~#3G)  
output.writeInt(nStartPos.length); lKgKtQpi  
for(int i=0;i<nStartPos.length;i++) ~l2aNVv;  
{ LF0sH)e]  
// output.writeLong(nPos); WlYs~(=9  
output.writeLong(fileSplitterFetch.nStartPos); >YUoh-]`  
output.writeLong(fileSplitterFetch.nEndPos); rhL"i^  
} ] 7 _`]7p  
output.close(); M,5"b+mX[~  
} sZLT<6_B  
catch(IOException e){e.printStackTrace ();} ?,yj")+  
catch(Exception e){e.printStackTrace ();} .Udj@{  
} VS&TA>  
b^[F""!e  
[2|kl l  
//读取保存的下载信息（文件指针位置） WYc7aciJ  
private void read_nPos() d`1I".y  
{ b]a@  
try{ 6K-5g/hL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U8(Nk\"X\  
int nCount = input.readInt(); jg&E94}+  
nStartPos = new long[nCount]; c`fG1s  
nEndPos = new long[nCount]; ",)Qc!^P$  
for(int i=0;i<nStartPos.length;i++) aTzjm`F0  
{ hkOsm6  
nStartPos = input.readLong(); jP~Z`yf  
nEndPos = input.readLong(); 4Bl{WyMJ|  
} 1bw{q.cmD  
input.close(); P4Th_B7  
} C.kxQ<  
catch(IOException e){e.printStackTrace ();} ~n/ $  
catch(Exception e){e.printStackTrace ();} *SO{\bu  
} `EtS!zD~b  
V_Wwrhua  
FEo269Ur  
private void processErrorCode(int nErrorCode) sN("+ sZ.n  
{ iZZ (4  
System.err.println("Error Code : " + nErrorCode); -WQ^gcO=7  
} ?2Kt'1s#  
=tU{7i*+  
j w* IO  
//停止文件下载 S"wg2X<  
public void siteStop() +1~Z#^{&  
{ K\)Td+~jc  
bStop = true; S1U@UC  
for(int i=0;i<nStartPos.length;i++) s[gKc'  
fileSplitterFetch.splitterStop(); XW?b\!@ $  
(Y^X0yA/  
s :`8ZBz~  
} 4^
<6r*  
} %?e(hnM  
//负责部分文件的抓取 R1Ye<R!Q  
**FileSplitterFetch.java $3,ryXp7  
*/ d(:3
  
package NetFox; u0`%+:]0  
p!/[K6u  
*GUAO){'  
import java.io.*; MC&\bf  
import java.net.*; _s
y'.Fo
 
*.&HD6Qr  
VtOZ%h[#  
public class FileSplitterFetch extends Thread { 8t=(,^c  
_ %%Z6x(  
]m#5`zGK1|  
String sURL; //File URL e:AHVepj{  
long nStartPos; //File Snippet Start Position {s3z"OV  
long nEndPos; //File Snippet End Position CDi<<,  
int nThreadID; //Thread's ID *UW=M
dt  
boolean bDownOver = false; //Downing is over S60IPya  
boolean bStop = false; //Stop identical ?6!]Nl1gr  
FileAccessI fileAccessI = null; //File Access interface dSCzx .c  
\Ofw8=N-2  
MV=9!{`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GjB]KA^  
{ ?m
c%.Bt  
this.sURL = sURL; it2 a  
this.nStartPos = nStart; mQ}ny(K'  
this.nEndPos = nEnd; tb?YLxMV  
nThreadID = id; 5b/ojr7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Il`tNr  
} +wW@'X  
U}$DhA"r"  
"S&%w8V  
public void run() >]=j'+]  
{ na^sBq?\  
while(nStartPos < nEndPos && !bStop) BGr.yEy  
{ "g+z !4b#  
b6E<r>q  
t\v+ogbk)  
try{ 1
p'Le!  
URL url = new URL(sURL); +u'I0>)S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {RB-lfrWs  
httpConnection.setRequestProperty("User-Agent","NetFox"); pb0E@C/R  
String sProperty = "bytes="+nStartPos+"-"; 1|8<H~&  
httpConnection.setRequestProperty("RANGE",sProperty); 
gw _$  
Utility.log(sProperty); vB!|\eJ  
 _ q(Q  
~L7:2weV[  
InputStream input = httpConnection.getInputStream(); &:=$wc  
//logResponseHead(httpConnection);  ,Yhw
pkL  
vs6,  
I^Z8PEc+  
byte[] b = new byte[1024]; }`yiT<z  
int nRead; f f7(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c<#
<k}y  
{ \M]-bw`  
nStartPos += fileAccessI.write(b,0,nRead); ^Y{D^\},  
//if(nThreadID == 1) ~Ki`Ze"x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H6aM&r9}  
} (cv!Y=]  
tZ2e!<C  
 BGzI  
Utility.log("Thread " + nThreadID + " is over!"); @ \2#Dpr  
bDownOver = true; amQz^
^  
//nPos = fileAccessI.write (b,0,nRead); sCl$f7"  
} =l<iI*J. M  
catch(Exception e){e.printStackTrace ();}  uIMe  
} 9N[EZhW  
} buk=p-oi  
l2
hG$idC  
wcDjg&:=ml  
//打印回应的头信息 "8V{5e!%j'  
public void logResponseHead(HttpURLConnection con) V,%L~dI  
{ SK$Vk[c]  
for(int i=1;;i++) *R% wUi  
{ x?D/.vrOY  
String header=con.getHeaderFieldKey(i); 7m5Co>NkuK  
if(header!=null) P%X-@0)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q6`GI6  
Utility.log(header+" : "+con.getHeaderField(header)); j;K#]  
else y|_Eu:  
break; OY"6J@[z  
} q;AT>" =)  
} P,bd'  
 +f4W"t  
;+pOP |P=  
public void splitterStop() OuIv e>8  
{ ;K:8#XuV  
bStop = true; !PUp>(  
} ELa ja87  
Gt/4F-Gn  
#k5#j4!b  
} }fhHXGK.  
0'$p$K  
3}&ZOO 
 
/* #p y
im_  
**FileAccess.java K'6[J"dB  
*//文件访问(定位，写) ,ZI\dtl  
package NetFox; IPA*-I57  
import java.io.*; k5+]SG`]]  
;BH>3VK  
BQ05`nkF  
public class FileAccessI implements Serializable{ ^&c$[~W  
FquFRx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Tvf~P w  
RandomAccessFile oSavedFile; L*?!Z^k  
long nPos; EY>8O+  
`{FwTZ=6{  
INMP"1  
public FileAccessI() throws IOException ,=[*Lo>O  
{ \Rk$t
7ZH  
this("",0); .6T6 S v  
} 2Eh@e([PMs  
SlT*C6f  
=;c_} VY  
public FileAccessI(String sName,long nPos) throws IOException B!aK  
{  YRB%:D@u  
oSavedFile = new RandomAccessFile(sName,"rw"); Fm j=  
this.nPos = nPos; g{pQ4jKF  
oSavedFile.seek(nPos); 6*1$8G`$8,  
} _py2kjA6  
0kCQ0xB[a5  
<6N_at3  
public synchronized int write(byte[] b,int nStart,int nLen) )wf\F6jN  
{ q"aPJ0ni'  
int n = -1; QV,E#(\5  
try{ nx4P^PC  
oSavedFile.write(b,nStart,nLen); P0\eBS  
n = nLen; {^RG% &S  
} E;-qP)yU  
catch(IOException e) ekzjF\!y  
{ Go+[uY^  
e.printStackTrace (); }_46y*o8  
} I 8Y*@$h  
-Fwh3F4g  
?J|4l[x  
return n; 'm1.X-$V  
} /! ^P)yU,  
~mILA->F  
_C+DBA  
} `B#Z;R  
A1JzW)B  
_dmL}t-  
/* sj9D  
**SiteInfoBean.java Da,&+fZI!  
*/ x%XT2+  
package NetFox; ;A^K_w'  
|"}4*V_*  
kHU"AD}.  
public class SiteInfoBean { P%GkcV  
M9V-$ _)  
8j\d~Lw=  
private String sSiteURL; //Site's URL g{DFS[h  
private String sFilePath; //Saved File's Path 5t'Fv<g  
private String sFileName; //Saved File's Name J@bW^>g*6u  
private int nSplitter; //Count of Splited Downloading File Lbq_~   
`Wf5  
Fd!iQ  
public SiteInfoBean() 41;)-(1  
{//nSplitter的缺省值为5 IrO+5w  
//default value of nSplitter is 5 M]ap:  
this("","","",5); u:4["ViC  
} tyXl}$)y  
dF2@q@\.+  
t.z$j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u_'nOle K  
{ G\mKCaI8  
sSiteURL= sURL;  <qn,  
sFilePath = sPath; H'Iq~Ft1  
sFileName = sName; HU[oR4E  
this.nSplitter = nSpiltter; i=da,W=0  
5^|"_Q#:
 
LkaG[^tfN  
} rUFFF'm\*a  
"#XtDpGk  
y"R("j $  
public String getSSiteURL() |4xo4%BQ>  
{ 4hNwKe"Ki  
return sSiteURL; aiR5/ ZD  
} .wri5  
9[f%;WaS  
8m7eaZ  
public void setSSiteURL(String value) /Su)|[/'  
{ zv9MHC &  
sSiteURL = value; "w^Nu6  
} & >b+loF  
_sm;HH7'*  
xK!DtR
zsA  
public String getSFilePath() C"9"{
 
{ Mryn>b`cB  
return sFilePath; : ~'Z(-a  
} S2}Z&X(  
ZV#$Z  
p)z-W(  
public void setSFilePath(String value) `G0*l|m>  
{ n'3u]~7^  
sFilePath = value; }MjQP R  
} @$
ftG  
/yt7#!tm+  
{tmKCG  
public String getSFileName() d"!yD/RD  
{ l qXc  
return sFileName; Ge~,[If+  
} |Pf(J;'[  
7%tR&F -u  
THr8o V5  
public void setSFileName(String value) c'~[!,[b<  
{
Ut':$l=  
sFileName = value; :Fo4O'UC  
} Uir*%*4:  
?+Hp?i$1  
kXCY))vnn  
public int getNSplitter() \L %q[  
{ O$(c.(_$  
return nSplitter; #'c%  
} v<+4BjV!J}  
-+ko}He  
}Qb';-+;d  
public void setNSplitter(int nCount) p}f-c  
{ /o\U/I  
nSplitter = nCount; ,P!D-MN$V  
} 1M=   
} iW;}%$lVX  
t,1in4sN  
"kU>~~y,  
/* ~r PYJ  
**Utility.java lJlZHO  
*/ &h\CS8nT%  
package NetFox; Vl4Z_viNH  
a0{[P$$  
db^a
L8  
public class Utility { {GK(fBE  
PM8Ks?P#u  
}D Z)W0RDe  
public Utility() _o&94&  
{ {&0mK"z_  
6SV7\,2M  
k*O
vcYL1A  
} %`
eJ66T  
/Ht/F)&P  
//线程睡眠 e& p_f<  
public static void sleep(int nSecond) 0s)cVYppe  
{ OWZS3Y+  
try{ q;ZLaX\bFl  
Thread.sleep(nSecond); d&5c_6oW  
} >6IXuq  
catch(Exception e) /MhS=gVxM  
{ HLM
;EZ  
e.printStackTrace (); _/ct=  
} )tScc*=8  
} .uBO  
5Yn{?r\#F  
//日志 W _J&M4  
public static void log(String sMsg) ) b
/n)%6  
{ ENO? ;  
System.err.println(sMsg); b~jIv:9T  
} epn#qeX  
!O 4<I_EY{  
>dyhox2*"  
public static void log(int sMsg) eN2dy-0  
{ G l_\Vy  
System.err.println(sMsg); A*a7\id!y  
} Z(KmS(  
} qFrt^+@  
"/Om}*VhD  
{K<uM'ww>  
/* {>wI8  
**TestMethod.java m"<4\;GK  
*/ 1B6C<cL:sU  
package NetFox; 8~.iuFp  
tCX9:2c  
-MDOZz\  
public class TestMethod { )@!~8<_"  
HOq4i!  
5/t
j  
public TestMethod() /731.l  
{ ///xx/weblogic60b2_win.exe l6V%"Lo/)  
try{ IhUW=1&J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,GP!fs
K  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]{(l;k9=e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m dC`W&r  
fileFetch.start(); i
D.0J/  
} Y 5Qb4Sa  
catch(Exception e){e.printStackTrace ();}  dhZZb  
}iD$4\ L  
GhtbQM1[H  
} K?9WY]Ot  
"!xvpsy  
$U~=.!_du  
public static void main(String[] args) zpbcmQB*  
{ tp#Z@5=  
new TestMethod(); zwMQXI'k83  
} e)*mC oR  
} tB GkRd!  
点击下载更多相关资料