http断点续传简单实现（java)

/* '4}8WYKQ  
**SiteFileFetch.java [8&+4<  
*/ cNMDI  
package NetFox; HM
hdK  
import java.io.*; :Sn4Pg `Q  
import java.net.*; OVGB7CB]S  
@U:PXCvh  
 |CAMd
U  
public class SiteFileFetch extends Thread { !Y 9V1oVf"  
_<'?s>(U'  
T1%}H3  
SiteInfoBean siteInfoBean = null; //文件信息Bean xT-`dS0u  
long[] nStartPos; //开始位置 OHt^e7\  
long[] nEndPos; //结束位置 'n}]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6?
a z  
long nFileLength; //文件长度 .yHi"ss3  
boolean bFirst = true; //是否第一次取文件 =t %;mi,M  
boolean bStop = false; //停止标志 gHFQs](G.  
File tmpFile; //文件下载的临时信息 3R%y
Ka#  
DataOutputStream output; //输出到文件的输出流 i:Gy
i([C  
o.V JnrJ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n. vrq-  
public SiteFileFetch(SiteInfoBean bean) throws IOException Rm`P.;%  
{ F`1J&S;C  
siteInfoBean = bean; 39L_O RMH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qMw_`dC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); In8{7&iVO  
if(tmpFile.exists ()) 9CAu0N5<  
{ _jH./ @G  
bFirst = false; iUs_)1  
read_nPos(); 0"Zxbgu)  
} ,y@WFRsx  
else R ^ZOcONd-  
{ mY]o_\`  
nStartPos = new long[bean.getNSplitter()]; cPkP/3I]h  
nEndPos = new long[bean.getNSplitter()]; LI<Emez  
} G8'  
ab`9MJc;  
sRZ?Ilua6  
 FL b  
} *S?'[PS]1  
u8gqWsvruM  
O:ACp<@  
public void run() "{kE#`c6<n  
{ "{Hl! Zq/  
//获得文件长度 pu_?)U  
//分割文件 ]x(6^:D5  
//实例FileSplitterFetch cj[x%eK>  
//启动FileSplitterFetch线程 NKTy!zWh  
//等待子线程返回 w`v`aw]  
try{ 6Hfv'X5E`Z  
if(bFirst) V+r&Z<&  
{ |T]&8Q)S  
nFileLength = getFileSize(); 4*inN~cU  
if(nFileLength == -1) C~pQJ@bF0  
{ nm_4E8&X  
System.err.println("File Length is not known!"); ^=8/Iw  
} wd3OuDrU  
else if(nFileLength == -2) QEMT'Cs
 
{ *j=58d`n  
System.err.println("File is not access!"); Ti7 @{7>  
} PPh<9$1\g  
else !tb!%8{~  
{ |oSqy  
for(int i=0;i<nStartPos.length;i++) gyegdky3  
{ Y!+H9R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;j qF:Wl@  
} hj{)6dBX%  
for(int i=0;i<nEndPos.length-1;i++) bYqv)_8  
{ ?zfm"o  
nEndPos = nStartPos[i+1]; KK{_s=t%<  
} lM#,i\8Q  
nEndPos[nEndPos.length-1] = nFileLength; o ZQ@Yu3  
} #XG3{MGX[  
} R / ND f`  
A~X\ dcn  
f'*/IG  
//启动子线程 (?TK P 7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `P
<#kt  
for(int i=0;i<nStartPos.length;i++) IusZYB  
{ :*^aSPlV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *.KVrS<B1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eI-SWwmv/u  
nStartPos,nEndPos,i); #f%fY%5q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FA := )  
fileSplitterFetch.start(); 947;6a%$  
} vif)g6,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w'XN<RWA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j\zlp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r^H,H'BohJ  
nEndPos = " + nFileLength); /^v!B`A@  
// fileSplitterFetch[nPos.length-1].start(); 9JX@ck  
{:3:GdM6  
%3AE2"  
//等待子线程结束 Z>3m-:-e  
//int count = 0; 1.PN_9%  
//是否结束while循环 ?\(qA+iP0  
boolean breakWhile = false; 0*+EYnu+  
,k*%=
TF7N  
)y i~p  
while(!bStop) Lb
YIRX  
{ [9V}>kS)  
write_nPos(); 6b$C/  
Utility.sleep(500); `)4v Q+A>  
breakWhile = true; wmIe x  
Dr[;\/|#  
a)c;z@r  
for(int i=0;i<nStartPos.length;i++) =f [/Pv  
{ .lM]>y)  
if(!fileSplitterFetch.bDownOver) Zu~w:uNmU  
{ U_;="y  
breakWhile = false; -7'|&zP  
break; bfm+!9=9S  
} cB36w$n8  
} "K$c9Z8
 
if(breakWhile) &[ ],rT  
break; X6_ RlV]Sk  
uA;#*eiA/  
'[HQ}Wvn  
//count++; VW*?(,#j{  
//if(count>4) A?$-Uqb"  
// siteStop(); kjB'WzZ8  
} m*CW3y{n)  
^fH)E"qq5  
/8nUecr  
System.err.println("文件下载结束！"); z>iXNwz"?  
} _0FMwC#DY  
catch(Exception e){e.printStackTrace ();} e6mm;@F>  
} /GM!3%'=  
*wY+yoj  
#:P$a%V  
//获得文件长度 nnvS.s`O  
public long getFileSize() !]Qk?T~9-  
{
IG
{Me  
int nFileLength = -1; f6Lc"b3s1  
try{ #5kclu%L$  
URL url = new URL(siteInfoBean.getSSiteURL()); *uf)t,%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >;R`Q9s7  
httpConnection.setRequestProperty("User-Agent","NetFox"); .MRN)p  
{ Ie~MW  
Di27=_J  
int responseCode=httpConnection.getResponseCode(); d*VvQU8C  
if(responseCode>=400) ryw%0H18  
{ !#WQ8s!?o  
processErrorCode(responseCode); g5"I{ol5T~  
return -2; //-2 represent access is error TJZ/lJU  
} [Cf
ZE  
w4CcdpR  
*OdmKVw6G  
String sHeader; J\w4N",  
8F[ ;ma>Z8  
4nP4F+  
for(int i=1;;i++) ;|Hpg_~%>  
{ Rm}5AJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C.":2F;-e  
//Utility.log(in.readLine()); jDTG15_=  
sHeader=httpConnection.getHeaderFieldKey(i); 2+DK:T[  
if(sHeader!=null) <|.]$QSi  
{ EJMd[hMhe  
if(sHeader.equals("Content-Length")) r<Z.J/a  
{ Eb@
**%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); esE!i0%  
break; kX`m( N$  
} I)vR  
} Z 4i5,f  
else 5Phsh  
break; l4.ql1BX@y  
} =$^90Q,Z;  
} }*}F_Y+  
catch(IOException e){e.printStackTrace ();} D`!BjhlW  
catch(Exception e){e.printStackTrace ();} q_`j-!  
doe3V-if  
`OgT"FdL!  
Utility.log(nFileLength); 0Z]HH+Z;  
T3<1{"&  
C
GlEc  
return nFileLength; O(2c_!d  
} Eu~1t& 4  
o<txm?+N  
,H,[)8
 
//保存下载信息（文件指针位置）  f+!J1  
private void write_nPos() "crp/Bj?  
{ OFmHj]I7=  
try{ LAnC8O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9` UbsxFl  
output.writeInt(nStartPos.length); @t1pB]O:  
for(int i=0;i<nStartPos.length;i++) q5hE S  
{ J$5G8<d>  
// output.writeLong(nPos); ?Js4\X!uJ  
output.writeLong(fileSplitterFetch.nStartPos); gq 3|vzNZ  
output.writeLong(fileSplitterFetch.nEndPos); vu.?@k@  
} V*fv>f:Yv  
output.close(); VF";
p^  
} L(cKyg[R  
catch(IOException e){e.printStackTrace ();} RSbq<f>BFo  
catch(Exception e){e.printStackTrace ();} oF]]Pl{W  
} I= <eCv  
koS?UYF`  
Q
dcuV\B}  
//读取保存的下载信息（文件指针位置） &4}=@'G@  
private void read_nPos() 8!!h6dQgI  
{ 42tZBz&  
try{ vqQ)Pu?T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rC
!"<  
int nCount = input.readInt(); J?X{NARt  
nStartPos = new long[nCount]; =[!(s/+>L  
nEndPos = new long[nCount]; vzbGLap#  
for(int i=0;i<nStartPos.length;i++) #_aq@)Fd  
{ U{Oo@ztT  
nStartPos = input.readLong(); YEaT_zWG0  
nEndPos = input.readLong(); 7NWkN7:B  
} _F`JFMS  
input.close(); _->+Hjj ^  
} c/^jD5U7  
catch(IOException e){e.printStackTrace ();} P(2OTfGGx  
catch(Exception e){e.printStackTrace ();} ezY^T  
} :aaX Y:<  
|4 \2,M
#  
4r~K`)/S'  
private void processErrorCode(int nErrorCode) |ka/5o  
{ 1W\wIj.  
System.err.println("Error Code : " + nErrorCode); ^VG].6  
} dR< d7  
|39,n~"o&  
-P|claO0  
//停止文件下载 hDSf>X_*_G  
public void siteStop() Cd=$XJ-b  
{ irq{ 21  
bStop = true; IvkYM`%  
for(int i=0;i<nStartPos.length;i++) "M-';;  
fileSplitterFetch.splitterStop(); 9$e$L~I#u  
l4r>#n\yj  
];6955I!  
} 0asP,)i  
} K$qY^oyQFw  
//负责部分文件的抓取 3(t,x  
**FileSplitterFetch.java z#PaQ
p5F  
*/ jVN06,3z  
package NetFox; NQ[X=a8N  
ty#6%  
P*7G?
 
import java.io.*; YZ8[h`z  
import java.net.*; 5psJv|Zo]  
BgUp~zdo  
z_R^C%
0k  
public class FileSplitterFetch extends Thread { (tVT&eO  
[:gg3Qzx  
*P7/ry^<F  
String sURL; //File URL s
iCm)B  
long nStartPos; //File Snippet Start Position W!O/t^H>  
long nEndPos; //File Snippet End Position )$i,e`T   
int nThreadID; //Thread's ID +"BJjxG  
boolean bDownOver = false; //Downing is over [ei~Xkzkj  
boolean bStop = false; //Stop identical .uS`RS8JM  
FileAccessI fileAccessI = null; //File Access interface uI?Z_  
uo2k  

:*|Ua%L_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4TPdq&';C:  
{ 9DM,,h<`  
this.sURL = sURL; m>P\}A^N  
this.nStartPos = nStart; gYrB@W;2  
this.nEndPos = nEnd; FNF`Z  
nThreadID = id; N*&T)
a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]ilLed  
} wf]?:'}  
&ck}3\sQ  
#;^UW  
public void run() _z BfNz9D  
{ hI*v)c  
while(nStartPos < nEndPos && !bStop) h0k?(O  
{ Cx/J_Ro#  
R?:Q=7K  
~D|,$E tX4  
try{ (2>q  
URL url = new URL(sURL);
vWESu4W`L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~!PWJ~U  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,'`yh|}G\  
String sProperty = "bytes="+nStartPos+"-"; 'V:MppQVZ.  
httpConnection.setRequestProperty("RANGE",sProperty); B?-w<":!  
Utility.log(sProperty); F$ G)vskd  
'5$@I{z  
[Z:P{yr  
InputStream input = httpConnection.getInputStream(); in
O;Uwlv  
//logResponseHead(httpConnection); )}N:t:rry  
.|go$}Fk  
|T/OOIA=sI  
byte[] b = new byte[1024]; a5ZXrWv  
int nRead; ?uL-qsU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x X3I`  
{ Q[NoFZ V!  
nStartPos += fileAccessI.write(b,0,nRead); ~>9G\/u j  
//if(nThreadID == 1) !\1)?&y9j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jR[c3EA ;  
} &a=rJvnIO&  
25vjn 1$sW  
(T pnJq  
Utility.log("Thread " + nThreadID + " is over!"); v.C  
bDownOver = true; "PRHQW  
//nPos = fileAccessI.write (b,0,nRead); 8M,o)oH  
} <2 [vR|Q*  
catch(Exception e){e.printStackTrace ();} obF|;fwPnR  
} 71AYDO  
} sPW:[  
uk$MQv*D  
H3R{+7  
//打印回应的头信息 59j`Z^e  
public void logResponseHead(HttpURLConnection con) `Rt w'Uz  
{ ><"|>(y  
for(int i=1;;i++) D-C]0Jf3  
{ B1~`*~@  
String header=con.getHeaderFieldKey(i); K*DH_\SPK  
if(header!=null) \ Xh C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ekq(  
Utility.log(header+" : "+con.getHeaderField(header)); "k@[7 7  
else Pi?G:IF  
break; U7n#TPet  
} #>:S&R?2t  
} Os>&:{D4!  
(Ytr&gh;0  
Et}%)M  
public void splitterStop() K{DmMi];I  
{ S WTZ6(!oW  
bStop = true; %SIll  
} ?K2E
K'-q  
t~K[`=G\ex  
GEVDXx>@  
} 'do2n/  
Uq'W<.v5  
S{e3aqT#N  
/* 9<3}zwJ  
**FileAccess.java dg#Pb@7a  
*//文件访问(定位，写) C|Gk}  
package NetFox; JSju4TQ4  
import java.io.*; ._]Pz6  
qvy*; <w  
QbHX
.:C  
public class FileAccessI implements Serializable{ 9QHj$)?k,  
yZp/P%y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |gxPuAXa)  
RandomAccessFile oSavedFile; tF/Ni*\^rV  
long nPos; #=y)Wuo=  
7w9'xY  
tx<^PV2  
public FileAccessI() throws IOException hVB(*WA^D  
{ ,Il) tH  
this("",0); QwG_-  
} ZEDvY=@a   
RaSuzy^`*]  
-UidU+ES;  
public FileAccessI(String sName,long nPos) throws IOException 0!%G#~th  
{ b#6mUl2  
oSavedFile = new RandomAccessFile(sName,"rw"); ;J+iwS*Z  
this.nPos = nPos; s Adb0 A  
oSavedFile.seek(nPos); }8}`A\dgV  
} kzCJs  
N\tFK*U^I  
2eRk_j]  
public synchronized int write(byte[] b,int nStart,int nLen) |n;);T(  
{ 1I'Q{X&B  
int n = -1; 9\Ff z&  
try{ V73/q  
oSavedFile.write(b,nStart,nLen); 4*f+np  
n = nLen; *mj=kJ7(  
} 5-fASN.Lx  
catch(IOException e) Io
 IhQ  
{ "S'Yn-  
e.printStackTrace (); +$>aT(q  
} K5`*Y@  
(AjgLNB  
f0^s<:*  
return n; ZVdQ$  
} a"O;DYh  
w]h8KNt  
&J9 + 5L8  
} l0t(t*[Mj  
B<.\^fuS  
I<<1mEk  
/* *K?UWi#$  
**SiteInfoBean.java d:A'|;']  
*/ E+<GsN]  
package NetFox; _XY(Qd  
~AaEa,LQ  
?ZC!E0]  
public class SiteInfoBean { Ug0c0z!b  
,{(XT7hr  
V,& O
O  
private String sSiteURL; //Site's URL e#}Fm;|d  
private String sFilePath; //Saved File's Path Qp:m=f6@  
private String sFileName; //Saved File's Name / s Apj  
private int nSplitter; //Count of Splited Downloading File rrgOp5aV
"  
fXnewPr=#  
ps`j>vX*  
public SiteInfoBean() :,qvqh][  
{//nSplitter的缺省值为5 3jW&S  
//default value of nSplitter is 5 4|cRYZj5  
this("","","",5); W<^t2
j'  
} *6u2c%^  
YE*|KL^  
K7{B!kX4k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \BfMCA/  
{ ct,;V/Dx  
sSiteURL= sURL; F}[!OYyg  
sFilePath = sPath; /4 Kd
  
sFileName = sName; tD#)  
this.nSplitter = nSpiltter; zHNBX Rx  
/G]/zlUE  
RTg\c[=w  
} S^D@8<6GJ  
oXk6,b"  
jvR(e"  
public String getSSiteURL() v/~&n  
{ 8[AU`F8W  
return sSiteURL; "G*$#  
} S"
^'ksL\  
)J+OyR=  
}#&[[}@th  
public void setSSiteURL(String value) 9qGba=}Ey  
{ #k &#d9}  
sSiteURL = value; :nl,Ac  
} &ZFHWI(P
 
6pC1C.  
eAP 8
!  
public String getSFilePath() z"QtP[_m  
{ uxKO"  
return sFilePath; Z'5&N5hx  
} tZg)VJQys  
vy={ziJ  
>hG*=4oh  
public void setSFilePath(String value) 87S,6Y  
{ up8d3  
sFilePath = value; 6,~1^g*  
} 7l*vmF6Z  
Vep41\g^  
a\,V>}e  
public String getSFileName() 3PLA*n+%  
{ ,|zzq@fk  
return sFileName; 8a8D0}'  
} Ie _{P&J  
K(lVAKiP]  
o
F_rC[  
public void setSFileName(String value) 1!U:M8T|  
{ jyyig%  
sFileName = value; Xj30bt  
} Y+$]N:\F\  
-jrA
k  
5efN5Kt  
public int getNSplitter() SfY9PNck\  
{ %FqQ+0^  
return nSplitter; %yfl-c(u  
} b *0uxvLu  
!:esd
JH  

L0=`1q  
public void setNSplitter(int nCount) q;sZwp<  
{ l:/x&=w  
nSplitter = nCount; cZoj|=3a  
} grkA2%N  
} ]8$H'u(C  
-,g.39u  
.YB/7-%M[  
/* c\ZnGI\|  
**Utility.java Ml?KnSb  
*/ S&[
9Vb  
package NetFox; /<+`4n  
cAVdH{$"  
lMg#zT!?  
public class Utility { $II~tO
  
)~nieQEZQ  
=^{MyR7  
public Utility() DNqC*IvuzM  
{ p__N6a  
F)imeu  
(@^ySiU  
} H;tE=  
\K%M.>]vq  
//线程睡眠 HmU6:8V *Z  
public static void sleep(int nSecond) #D{Eq8dp  
{ B` +, 8  
try{ 6 A#xFPYY{  
Thread.sleep(nSecond); jpW_q+^?  
} gyh8  
catch(Exception e) V=1zk-XC  
{ jr#*;go  
e.printStackTrace (); E&@#*~   
} <_=O0 t|6  
} mtE+}b@(!&  
yFd942  
//日志 vLq%k+D#  
public static void log(String sMsg) SlT>S1`rnG  
{ OqF8KJnO;  
System.err.println(sMsg); nr}Ols  
} YvP62c \  
Hmx.BBz  
I=P<RG7j)  
public static void log(int sMsg) &u6n5-!v  
{ dmLx$8  
System.err.println(sMsg); !yq98I'  
} q.@% H}  
} ?(Plb&kR  
O?A%  
^si[L52BZ  
/* ^~bdAO81  
**TestMethod.java A+4Kj~`!  
*/ vo&h6'i>7  
package NetFox; E:A!tu$B  
N{@~(>ee^  
B/n~ $  
public class TestMethod { \M0's&1(  
7(^F@,,@  
kr |k \  
public TestMethod() 1^
tX:qR  
{ ///xx/weblogic60b2_win.exe vv^y V"0Y  
try{ aXZi2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y;<}`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '<1Cta`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Zp<#( OIu  
fileFetch.start(); Vw`Q:qo0:b  
} Pv\8 \,B9  
catch(Exception e){e.printStackTrace ();} %,ScGQE  
u3wd~.  
Rxlv:  
} V U5</si+  
zx.SRs$  
v
?Cakwu  
public static void main(String[] args) b+hN\/*]  
{ w&J_c8S  
new TestMethod(); 8ZCA vEy  
} d'3"A"9R7-  
} $}z/BV1I  
点击下载更多相关资料