http断点续传简单实现（java)

/* \yxGE+~P  
**SiteFileFetch.java px+]/P<dX  
*/ W$J.B!O  
package NetFox; EM+! ph  
import java.io.*; yv>uzb`N  
import java.net.*; wN/v-^2  
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 CWYOzqf  
public class SiteFileFetch extends Thread { ]~f-8!$$R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean qf<o"B|_9  
long[] nStartPos; //开始位置 V$Oj@vI  
long[] nEndPos; //结束位置 yT7{,Z7t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h<PS<  
long nFileLength; //文件长度 v@s"*E/PF7  
boolean bFirst = true; //是否第一次取文件 k+je-%hPj  
boolean bStop = false; //停止标志 w-v8P`V  
File tmpFile; //文件下载的临时信息 2\+N<-(F5  
DataOutputStream output; //输出到文件的输出流 p?P.BU\CR  
2~r2ErtS  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yOb']
 
public SiteFileFetch(SiteInfoBean bean) throws IOException EqI
s&){  
{ *p0n^XZ% ?  
siteInfoBean = bean; rd[mC[ r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7*Zm{r@u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L5 Ai  
if(tmpFile.exists ()) (R RRG;*n#  
{ $`t2SD  
bFirst = false; UX|3LpFX&I  
read_nPos(); ?hIDyM  
} 78?{;iNv  
else 7M?Sndp$  
{ +G7[(Wz(z  
nStartPos = new long[bean.getNSplitter()]; j-FMWEp  
nEndPos = new long[bean.getNSplitter()]; 4@a/k[,  
} uz=9L<$  
92b}N|u  
;9J6)zg !n  
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} L"jjD:  
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6vJS"+ <  
public void run() j^f54Ky.  
{ YuzVh9jTI  
//获得文件长度 { W5 _KX  
//分割文件 tBsvi%F  
//实例FileSplitterFetch ;vpq0t`  
//启动FileSplitterFetch线程 ^EmePkPI  
//等待子线程返回 j``Ku@/x0  
try{ lC d\nE8G  
if(bFirst) X>]<rEh  
{ X?`mYoe  
nFileLength = getFileSize(); %Z*)<[cIE0  
if(nFileLength == -1) n \&H~0X  
{ zP c54>f  
System.err.println("File Length is not known!"); >.XXB 5a  
} e\*(F3r  
else if(nFileLength == -2) I0^oaccM  
{ jOK!k  
System.err.println("File is not access!"); 3z"%ht~;  
} BcQw-<veu  
else a [f}-t9  
{ #9qX:*>h  
for(int i=0;i<nStartPos.length;i++) -7Kstc-  
{ :x?G[x=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZHj7^y@P  
} t+0/$
 
for(int i=0;i<nEndPos.length-1;i++) Ch~y;C&e+r  
{ Yb:F,d-Ya  
nEndPos = nStartPos[i+1]; Pb59RE:7V  
} a5w E{K  
nEndPos[nEndPos.length-1] = nFileLength; dXU6TCjU7  
} H87k1^}HV  
} c/(Dg$DbX  
}me`(zp  
;H?tcb*  
//启动子线程 CXi:?6OG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X7MA>j3m  
for(int i=0;i<nStartPos.length;i++) <jLL2-5r0  
{ FJW,G20L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Q!A4qOQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 91k-os
(4]  
nStartPos,nEndPos,i); ydE}.0zN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K>-01AGHL  
fileSplitterFetch.start(); ~D/1U)kt  
} A[:(#iR5-E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  ]l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;g<y{o"Q3p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SkU9i
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nEndPos = " + nFileLength); b
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// fileSplitterFetch[nPos.length-1].start(); DYgz;Y/%l  
r[2*K 9  
%e+*&Z',  
//等待子线程结束 U.N&~S  
//int count = 0; ?MvL}o\|  
//是否结束while循环 71\GK  
boolean breakWhile = false; o9OCgP`Y  
FbW$H]C$  
!H6X%hlk  
while(!bStop) )X8N|W>vh  
{ /?}2OCq  
write_nPos(); NA#,q 8  
Utility.sleep(500); &=wvlI52`  
breakWhile = true; >g{b'Xx  
?&VKZSo  
LFvZ 7M\\  
for(int i=0;i<nStartPos.length;i++) ( F4c0  
{ g)IW9q2  
if(!fileSplitterFetch.bDownOver) :_o^oi7G  
{ Qm*XWo  
breakWhile = false; ]q&NO(:kbq  
break; caV DV
  
} Fn{Pmo*rs  
} Nc?'},  
if(breakWhile) ?R4%z2rcW  
break; WzBr1 ea{I  
v8C4BuwA  
LbR'nG{J  
//count++; (?"z!dgc  
//if(count>4) 9xFI%UOb#  
// siteStop(); C3(h j  
} `^h:}V  
"ZFH_5<  
|AS<I4+&  
System.err.println("文件下载结束！"); 4I*'(6 ,!  
} +M<W8KF  
catch(Exception e){e.printStackTrace ();} A>_,tt  
} K@a#^lmd  
QH?sx k2  
,,lR\!>8  
//获得文件长度 uJ0Wb$%  
public long getFileSize()  "+Sq}WR  
{
#er% q:  
int nFileLength = -1; =J'Q%qN<Zd  
try{ :@-.whj  
URL url = new URL(siteInfoBean.getSSiteURL()); 6Xbf3So  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &2I8!Ia  
httpConnection.setRequestProperty("User-Agent","NetFox"); =y`-:j\  
G#A6<e/  
6{yn;D4  
int responseCode=httpConnection.getResponseCode(); h.NCG96S  
if(responseCode>=400) >P//]nn  
{ @#;*e] 1a  
processErrorCode(responseCode); B![:fiR`  
return -2; //-2 represent access is error [a?bv7K
z  
} 0Gu?;]GSv  
W>:MK-_J  
c c/nzB  
String sHeader; eC L_c>3!  
'(g;nU<  
}}k*i0  
for(int i=1;;i++) 6\`8b&'n  
{ #zBqj;p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -= izu]Fb,  
//Utility.log(in.readLine()); 5fYWuc9}z  
sHeader=httpConnection.getHeaderFieldKey(i); 0)ZLdF_6  
if(sHeader!=null) sf:IA%.4t  
{ MU\Pggs  
if(sHeader.equals("Content-Length")) W1Ye+vg/s  
{ 1}+b4"7]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u|6-[I  
break; VL'wrgk  
} 5?([jAOf  
} 7S=,#  
else Of-xGoYZ  
break; VJ_fA}U  
} rBy0hGx  
} gGx(mX._L?  
catch(IOException e){e.printStackTrace ();} 6a_U[-a9;  
catch(Exception e){e.printStackTrace ();} \u))1zRd  
;jN1n xF  
o=K9\l  
Utility.log(nFileLength); sLXM$SMBh  
y` '#gH  
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return nFileLength; "?lz[K>  
} *X ;ch55\  
1i_%1Oip  
a|.IAxJ  
//保存下载信息（文件指针位置） @^ *62  
private void write_nPos() wu`+KUx  
{  Fq5u%S  
try{ ,^Q~w b!{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 56.JBBZZ  
output.writeInt(nStartPos.length); -$I30.#  
for(int i=0;i<nStartPos.length;i++) q-
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{ \8s:I+[HH  
// output.writeLong(nPos); v?}
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output.writeLong(fileSplitterFetch.nStartPos); pV_zePyOn  
output.writeLong(fileSplitterFetch.nEndPos); \i@R5v=zL  
} =5V7212  
output.close(); ZGsd cnz  
} 4 2DMmwB   
catch(IOException e){e.printStackTrace ();} O8_!!Qd  
catch(Exception e){e.printStackTrace ();} \~(kGE--+  
} ccPWfy_  
75R#gQ]EV  
(C"q-0?n  
//读取保存的下载信息（文件指针位置） '5[(QM5Gi&  
private void read_nPos() N-knhA  
{ 0GeL">v,:=  
try{ '@h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rqdN%=C  
int nCount = input.readInt(); q5-i=lw  
nStartPos = new long[nCount]; !Ko>   
nEndPos = new long[nCount]; JMo 
r[*  
for(int i=0;i<nStartPos.length;i++) &FT`z"^  
{ u a_w5o7  
nStartPos = input.readLong(); T4"D&~3 3q  
nEndPos = input.readLong(); 5B2p_$W#  
} 9#&H'mG  
input.close(); 8wOscL f:  
} 4;CI<&S  
catch(IOException e){e.printStackTrace ();} G)t-W%D&  
catch(Exception e){e.printStackTrace ();} `XK\', }F  
} TNA7(<"fV|  
Pmd[2/][  
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private void processErrorCode(int nErrorCode) Wkjp:`(-$r  
{ C~@m6K  
System.err.println("Error Code : " + nErrorCode); \y(3b#  
} $ B&ZnZ?  
<f8j^  
Dv/7w[F  
//停止文件下载 ,zHL8SiTX  
public void siteStop() =mZYBm,IQ  
{ 43M.Hj]  
bStop = true; Q*PcO\Y!y  
for(int i=0;i<nStartPos.length;i++) }8aqSD<:  
fileSplitterFetch.splitterStop(); *PL&CDu=)  
6fo"k+S  
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} _
LC*_LT_  
}
7]T(=gg /  
//负责部分文件的抓取 fd>{UyU  
**FileSplitterFetch.java 0NZ'(qf~9  
*/ M57<e`m  
package NetFox; f)z(9JJL  
`:V'E>B  
, ftJw  
import java.io.*; *Ic^9njt  
import java.net.*; *p\Zc*N;%  
b5^>QzgD  
?yq=
c  
public class FileSplitterFetch extends Thread { x}c  
IBJNs$  
xlwf @XW  
String sURL; //File URL i)X~L4gn  
long nStartPos; //File Snippet Start Position +<[q"3
  
long nEndPos; //File Snippet End Position X coPkW  
int nThreadID; //Thread's ID _1G/qHf^S  
boolean bDownOver = false; //Downing is over DAWF =p]  
boolean bStop = false; //Stop identical /Z^a,%1  
FileAccessI fileAccessI = null; //File Access interface JP6 Noia  
7UW\|r  
} (-9d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <zn)f@W  
{ ;#v3C;  
this.sURL = sURL; C@`#@1X  
this.nStartPos = nStart; {X(nn.GpC  
this.nEndPos = nEnd; FD 8Lk  
nThreadID = id; :g63*d+/G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }O@
>:?U  
} N}B&(dJ  
{q8|/{;  
@hg[v`~  
public void run() kGAgXtE  
{ TCyev[(  
while(nStartPos < nEndPos && !bStop) $aJay]F  
{ |f$+|9Q?  
jH<Sf: Y(  
j`.&4.7+  
try{ }a5TY("d9H  
URL url = new URL(sURL); ~\NQkaBkY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7MrHu2rZ=  
httpConnection.setRequestProperty("User-Agent","NetFox"); A~vx,|I  
String sProperty = "bytes="+nStartPos+"-"; IWq\M,P  
httpConnection.setRequestProperty("RANGE",sProperty); |Sjy   
Utility.log(sProperty); 8ly)G  
_dk[k@5W{'  
_4Eq_w`  
InputStream input = httpConnection.getInputStream(); tUU
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//logResponseHead(httpConnection); zx\-He  
\[[xyd  
nD eVYK  
byte[] b = new byte[1024]; PV~D;  
int nRead; y-.{){uaD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |A*4Fuc&  
{ )HE{`yiLL  
nStartPos += fileAccessI.write(b,0,nRead); M("sekL  
//if(nThreadID == 1) \w1XOm [)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eJ45:]_%I@  
} DQW)^j h  
/"La@M37  
<]G'& iv>  
Utility.log("Thread " + nThreadID + " is over!"); &)Qq%\EP4  
bDownOver = true; k6(</uRj  
//nPos = fileAccessI.write (b,0,nRead); [sH3REE1h  
} %b*N.v1+  
catch(Exception e){e.printStackTrace ();} LRu*%3xx  
} T<Xw[PEnP  
} o

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&D{!zF  
?'f  
//打印回应的头信息 cd1-2-4U  
public void logResponseHead(HttpURLConnection con) Hm>cKPZ)  
{ w]qM  
for(int i=1;;i++) Ua|iAD1  
{ #lqH/>`>  
String header=con.getHeaderFieldKey(i); =C,DR4xh  
if(header!=null) U{ 0~&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &Cj~D$kDEu  
Utility.log(header+" : "+con.getHeaderField(header)); _PPC?k{z!  
else q 6UZ`9&z  
break; TE
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} 9[VYd '  
} iP9]b&  
iT{4-j7|P4  
j~\FDcG*ed  
public void splitterStop() YC 4c-M  
{ ?/MkH0[G=  
bStop = true; Ws3z-U>j  
} jEQ_#KKYJ  
)vOBF5  
T2]8w1l&K  
} ^kcuRJ0*$  
w)S 4Xi=  
A3 TR'BFw-  
/* Ji,;ri2
i  
**FileAccess.java X4:84  
*//文件访问(定位，写) P]^8Enp
 
package NetFox; 1t/c@YUTy  
import java.io.*; g&p(XuN  
~DxuLk6 s  
J|U~W kW  
public class FileAccessI implements Serializable{ YY tVp_)  
k~<Ozx^AyY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +|S)Mm8-  
RandomAccessFile oSavedFile; |wb_im  
long nPos; 7\$}|b[9  
)cQ KR4x0^  
;9)nG,P3  
public FileAccessI() throws IOException <w~$S0_  
{ pK{G2]OK{U  
this("",0); D6e?J.  
} ^|h_[>  
.XK3o .ZhW  
dmkGIg}  
public FileAccessI(String sName,long nPos) throws IOException D?Ol)aj?  
{ 8TH;6-RT  
oSavedFile = new RandomAccessFile(sName,"rw"); {s*1QBM$\Z  
this.nPos = nPos; 4$2HO`@uN  
oSavedFile.seek(nPos); K(MZ!>{  
} rFC9y o  
v%`k*n':  
4s>L]! W$8  
public synchronized int write(byte[] b,int nStart,int nLen) j1Sjw6}GCH  
{ %y>*9$<pXe  
int n = -1; #>CWee;  
try{ .{;RJ:O  
oSavedFile.write(b,nStart,nLen); ^Bw"+6d  
n = nLen; 2" v{  
} 33}p02#  
catch(IOException e) ~|{e"!(}  
{ 9XS>;<"2  
e.printStackTrace (); =VWH8w.3  
} /NPx9cLW^  
Mp5Z=2l5  
IA=\c  
return n; T9}dgf  
} ow,! 7|m  
w1F)R^tU  
.ArOZ{lKD>  
} qMO(j%N
5  
"0>AefFd#  
&u2m6 r>W  
/* #cJ1Jj $  
**SiteInfoBean.java {>ghX_m|  
*/ [4])\q^q  
package NetFox; ZS&+<kGD  
C1YH\X(r  
4Dd]:2|D  
public class SiteInfoBean { nob}}w]~C  
eY:jVYG(  

?%>S5,f_  
private String sSiteURL; //Site's URL PMj!T \B|  
private String sFilePath; //Saved File's Path }mk z_P(Z  
private String sFileName; //Saved File's Name *MCkezW7{  
private int nSplitter; //Count of Splited Downloading File kf' 4C "}  
b u/GaE~  
Wjd_|Kui  
public SiteInfoBean() 0e'@Xo2e  
{//nSplitter的缺省值为5 7X/B9Hee  
//default value of nSplitter is 5 Z7MGBwP(  
this("","","",5); nG| NRp  
} r;zG  
jpiBHi]5+  
-zm-|6[Wi  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NF*Z<$'%  
{ O 0P4uq  
sSiteURL= sURL; V9D>Xh!0H  
sFilePath = sPath; H|d"45J_  
sFileName = sName; 1|7tq  
this.nSplitter = nSpiltter; l.SoiFDd  
D'_w *  
H7Ee0T(`  
} 5mI}IS|@  
j@jUuYuDgl  
GUvEOD=p  
public String getSSiteURL() FlLk.+!t  
{ ;c#jO:A5  
return sSiteURL; 6PRP&|.#  
} &>Nw>V  
rn-CQ2{?  
Z2I2 [pA  
public void setSSiteURL(String value) f;a55%3c  
{ 2?(dS  
sSiteURL = value; Nb/Z+  
} N?mQ50o~C  
~:"//%M3l  
9h0Y">}`b  
public String getSFilePath() 43BqNQ0  
{ QWAtF@qTV  
return sFilePath; pn aSOyR  
} iiTt{ab\Y  
X32{y973hT  
1c*XmMB  
public void setSFilePath(String value) l[b`4  
{ '"]U+aIg  
sFilePath = value; 7)
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} V*F |Yo:  
?!$:I8T  
(cm8x  
public String getSFileName() X~ g9TUv8  
{ QJtO~~-  
return sFileName; 'Em633  
} .CBb%onx  
aJ$({ZN\#  
. MH;u3U  
public void setSFileName(String value) \MB$Cwc  
{ V5bB$tL}3  
sFileName = value; *w[0uQL5Z  
} M.fA5r
J^  
^W,~  
w7QYWf'  
public int getNSplitter() oR'u&\mB  
{ jUd)|v+t  
return nSplitter; |?4NlB6  
} ?
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\U.js-  
A/88WC$v  
public void setNSplitter(int nCount) "43F.!P  
{ 9i+`,r  
nSplitter = nCount; kt7x}F(?<  
} C!W0L
`r  
} ~
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)F,z pGG  
U[W &D%'  
/* /o9 0O&  
**Utility.java @z>DJ>htN  
*/ ~9n30j%]s  
package NetFox; Ih)4.lLcKn  
U;t1 K  
]Wtg.y6;  
public class Utility { 8~y&"  \  
Tb\<e3Te_  
YFP<^y=  
public Utility() <."KejXg-  
{ 4))N(m%3F  
2])e}&i  
`N8t2yF  
} 1@n'6!]6O  
5&qBG@Hw]  
//线程睡眠 L}rYh`bUP[  
public static void sleep(int nSecond) {@hJPK8  
{ R5&<\RI0  
try{ Hb0_QT~  
Thread.sleep(nSecond); J vq)%t8q>  
} k~)@D| ?  
catch(Exception e) O_L>We@3E  
{ [,(+r7aB  
e.printStackTrace (); %<fs \J^k  
} l+j !CvtI  
} oRZe?h^r#  
#4<=Ira5  
//日志 $PRUzFZ  
public static void log(String sMsg) 8:[ l1d86  
{ #x`K

4f)  
System.err.println(sMsg); (I/iD.A  
} #}l$<7ZU  
'KDt%?24  
6|IJwP^Q_  
public static void log(int sMsg) }B_?7+  
{ `@ny!S|1/  
System.err.println(sMsg); QAAuFZs  
} rgDl%X2B  
} "!CV
m{7[  
+*,!q7Gt  
O p1TsRm5L  
/* a,(nf1@5  
**TestMethod.java #%w+PL:*O  
*/ "U+c`V=w  
package NetFox; 3iUJ!gK  
/:ZwGyT
;  
Bh'!aipk  
public class TestMethod { .)=*Yr M  
g9CedD%40  
;K~=? k  
public TestMethod() h(R7y@mp\0  
{ ///xx/weblogic60b2_win.exe v(GnG  
try{ 'HJ+)[0X*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (P;TM1k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v_Df+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w>8kBQ
?b  
fileFetch.start(); kvuRT`/  
} X)6G:cD  
catch(Exception e){e.printStackTrace ();} H-nhq-fut  
63J3NwFt  
R)ZzRz|/  
} Pksr9"Ah  
~@*q8lC  
]*'_a@h  
public static void main(String[] args) Nsq=1) <  
{ 4w'&:k47
 
new TestMethod(); ^*4#ZvpG2  
} Pz[UAJ  
} GF9[|). T  
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