http断点续传简单实现（java)

/* +$(71#'y  
**SiteFileFetch.java - a   
*/ Ny]'RS-  
package NetFox; J.*[gt%O|  
import java.io.*; 2Ti" s-  
import java.net.*; ;`;G/1]#9  
|K'Gw}fX/  
>~.Zr3P6kC  
public class SiteFileFetch extends Thread { Kp$_0
 
|R[v@c`pn  
$^!a`Xr  
SiteInfoBean siteInfoBean = null; //文件信息Bean x:=0.l#  
long[] nStartPos; //开始位置 87&KQ_  
long[] nEndPos; //结束位置 FGV}5L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XKpL4]{&q4  
long nFileLength; //文件长度 7=$+k]U8  
boolean bFirst = true; //是否第一次取文件 y|FBYcn#F  
boolean bStop = false; //停止标志 3D]2$a_d  
File tmpFile; //文件下载的临时信息 J
slk  
DataOutputStream output; //输出到文件的输出流 .vCY%0oE  
./7&_9|<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L$oia)%t-  
public SiteFileFetch(SiteInfoBean bean) throws IOException "$`wk  
{ fF8a 1XV  
siteInfoBean = bean; g,A.Y,})  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >cGh|_9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TBoM{s=.  
if(tmpFile.exists ()) U:s}/to  
{ T#MA#H2  
bFirst = false; ;zfQ3$@9  
read_nPos(); oG4w8+N  
} ZXF
AuF  
else 3K=q)|  
{ cq'}2pob  
nStartPos = new long[bean.getNSplitter()]; m;;0 Cl  
nEndPos = new long[bean.getNSplitter()]; G\'
u~B/w  
} [dSDg2]  
H<r
nJ  
LUe>)eqw  
M<SbVP|V"  
} PK:o}IWn~x  
U}A|]vi@  
@%I_&!d  
public void run() *G2)@0 {  
{ E
I?d(K  
//获得文件长度 jc%{a*n"vr  
//分割文件 ,ZzB#\  
//实例FileSplitterFetch I,CAFq  
//启动FileSplitterFetch线程 |Ak =-.  
//等待子线程返回 VuX>  
try{ J1gEjd  
if(bFirst) v&[X&Hu[  
{ /ZIJ<#o[
 
nFileLength = getFileSize(); i-:8TfI,  
if(nFileLength == -1) w(vE2Y ?  
{ T!^?d5uW#  
System.err.println("File Length is not known!"); zAkc67:  
} hX>VVeIZ  
else if(nFileLength == -2) a=:{{\1o  
{ ?d>P
+).  
System.err.println("File is not access!"); xzMeK
C`  
} \GbHS*\+  
else Cu ['&_@  
{ s{1Deek=  
for(int i=0;i<nStartPos.length;i++) (^s&M  
{ 5 CY_Ay\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iSZctsqE  
} `lu"yF  
for(int i=0;i<nEndPos.length-1;i++) XL.CJ5y>  
{ H/p-YtY  
nEndPos = nStartPos[i+1]; 90y9~.v  
} iXG>j.w{79  
nEndPos[nEndPos.length-1] = nFileLength; V. bH$@ej  
} @sgT[P*ut  
} +LI*!(T|lm  
v8U1uOR,%  
9znx1AsN  
//启动子线程
z[KN^2YS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @ (u?=x;  
for(int i=0;i<nStartPos.length;i++) d=4f`q0k  
{ FVC2XxP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f9l<$l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IioE<wS)  
nStartPos,nEndPos,i); #<tWYE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U>p
lv  
fileSplitterFetch.start();  i_E#cU  
} OnPy8mC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @aiLGwh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }x#P<d(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !OZhfMVd  
nEndPos = " + nFileLength); LD~uI  
// fileSplitterFetch[nPos.length-1].start(); n?P 5pJ  
\xO2WD  
uuUVE/^V'  
//等待子线程结束 SX?$H~A  
//int count = 0; ev
mEX<N  
//是否结束while循环 {OhkuON  
boolean breakWhile = false; 4QK
E{0NE  
Rvz.
ym:F  
@Z=|$*9  
while(!bStop) kO3k|6f=  
{ )[M<72  
write_nPos(); g7U:A0Z  
Utility.sleep(500); oCdOC5
 
breakWhile = true; zloaU  
$m: a-.I  
wM4g1H%s  
for(int i=0;i<nStartPos.length;i++) 9-E>n)  
{ /6+%(f}7l  
if(!fileSplitterFetch.bDownOver) GY$?^&OO>  
{ $W_o$'crW  
breakWhile = false; 2E;%=e  
break; W];6u  
} 4Ig{#}<  
} \lbiz4^>  
if(breakWhile) hL{B9?  
break; vYt:}$AE  
-L'K  
/ ?[gB:s  
//count++; '5,,XhP  
//if(count>4) ;?lM|kK  
// siteStop(); qM:)daS1w  
} POg0=32  
YlcF-
a  
IV)W|/.  
System.err.println("文件下载结束！"); yzNX2u1  
} 0^lL,rC  
catch(Exception e){e.printStackTrace ();} S,tVOxs^  
}
x5 ~E'~_  
yoY)6cn@  
rU^ghF  
//获得文件长度 KW6" +,Th  
public long getFileSize() &CmkNm_B  
{ hic$13KuP  
int nFileLength = -1; >hL'#;:f#  
try{ (l P4D:X  
URL url = new URL(siteInfoBean.getSSiteURL()); z57papo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?ZV0
 
httpConnection.setRequestProperty("User-Agent","NetFox"); [<fLPa  
|M/ \'pOe  
8Bt-  
int responseCode=httpConnection.getResponseCode(); JHZo:Ad -&  
if(responseCode>=400) '/*c Yv45  
{ P~ZV:Of  
processErrorCode(responseCode); tWOze, N  
return -2; //-2 represent access is error KC-aLq/  
} \fR:+rbQ&|  
h_G7T1;L  
+,^M{^%  
String sHeader; [}>6n72gNh  
%1 ^jd\  
. _t,OX$  
for(int i=1;;i++) *!Y3N<>!  
{ X$&Sw3c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kpw4Mq@  
//Utility.log(in.readLine()); *3 8Y;{ 4  
sHeader=httpConnection.getHeaderFieldKey(i); 2^ZPO4|  
if(sHeader!=null) KdpJ[[Ug/  
{ wEc5{ b5
M  
if(sHeader.equals("Content-Length")) (*Q|;  
{ n4&j<zAV{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RWQW/Gwx  
break; <\~#\A=;  
} gq1Y]t|4F  
} }UdqX1jz  
else VEEeQy
  
break; H 7F~+Q-}  
} )tch>.EQ_  
} 0_pwY=P  
catch(IOException e){e.printStackTrace ();} SW'KYzn  
catch(Exception e){e.printStackTrace ();} /=(FM   
2^M+s\p  
G ]By_  
Utility.log(nFileLength); F X2
`p_  
r3vj o(  
#7T={mh  
return nFileLength; \)uad5`N  
} s?#lhI  
^v5hr>m  
6yM dl~
.  
//保存下载信息（文件指针位置） @}!$NI8  
private void write_nPos() {*$J&{6V  
{ 8N_rJ)f  
try{ HZ=yfJs nc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $*-L8An?  
output.writeInt(nStartPos.length); ~At.V+  
for(int i=0;i<nStartPos.length;i++) G_mu7w  
{ c6)zx b  
// output.writeLong(nPos); X6'&X  
output.writeLong(fileSplitterFetch.nStartPos); /k"P4\P`+Q  
output.writeLong(fileSplitterFetch.nEndPos); N<(`+?  
} --FtFo  
output.close(); {~h\;>  
} p'}%pAY  
catch(IOException e){e.printStackTrace ();} #7ZBbq3=  
catch(Exception e){e.printStackTrace ();} bM3e7olWS  
} t O>qd#I  
D9C; JD  
7~f6j:{|z  
//读取保存的下载信息（文件指针位置） k8V0-.UL}  
private void read_nPos() W^Y(FUy~  
{ hDMp^^$  
try{ "iG
c'?/+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +]vl8, 4@  
int nCount = input.readInt(); qJj5J;k  
nStartPos = new long[nCount]; e5KF~0`  
nEndPos = new long[nCount]; EtGr&\,  
for(int i=0;i<nStartPos.length;i++) eqCB2u"Jq  
{ rRel\8  
nStartPos = input.readLong(); _0E,@[  
nEndPos = input.readLong(); {'kL]qLg  
} 6^Vf 5W{  
input.close(); @7'gr>_E  
} rzLlM  
catch(IOException e){e.printStackTrace ();} {!h[@f4  
catch(Exception e){e.printStackTrace ();} Yg.u8{H  
} j(JI$  
69yyVu_  
7RJ
W  
private void processErrorCode(int nErrorCode) 0in6z  
{ |D:0BATRP  
System.err.println("Error Code : " + nErrorCode); d*HAKXd&:j  
} tm?  
@
("AkYPj  
(tN$G:+")F  
//停止文件下载 ?VsZo6Z"  
public void siteStop() [y>.)BU  
{ 5Ncd1  
bStop = true; BW 7[JD  
for(int i=0;i<nStartPos.length;i++) 6I0MJpLW  
fileSplitterFetch.splitterStop(); H(s^le:!  
t:7jlD!d  
e>.xXg6Zn  
} CuNHDYQ&3  
} M(f'qFY=K  
//负责部分文件的抓取 nv]64mL3  
**FileSplitterFetch.java ~Y[1Me  
*/ fHi+PEbR  
package NetFox; l1S1CS  
NQ!F`  
ZxWV,s&p  
import java.io.*; D=Y HJ>-wB  
import java.net.*; ."O(Ig[  
B?'ti{p A9  
I<U 1V<g  
public class FileSplitterFetch extends Thread { @gOgs  
cS"6%:hQ  
}f}&|Vap  
String sURL; //File URL x!+a,+G  
long nStartPos; //File Snippet Start Position F/Xhm91^  
long nEndPos; //File Snippet End Position I_rVeMw=  
int nThreadID; //Thread's ID we9AB_y  
boolean bDownOver = false; //Downing is over ( 9l|^w["  
boolean bStop = false; //Stop identical nDvWOt  
FileAccessI fileAccessI = null; //File Access interface xT/&'$@{)  
LmE-&  
qz&)|~,\C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mfvQ]tz_+  
{ ZSNg^)cN  
this.sURL = sURL; DI\sq8J^  
this.nStartPos = nStart; ~nQb;Bdh%  
this.nEndPos = nEnd; 7Fp2=j  
nThreadID = id; iu'yB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !IS,[  
} va0 a4s1O  
]2jnY&a5  
+j,;g#d  
public void run() C1J'. !  
{ Xqy{=:0  
while(nStartPos < nEndPos && !bStop) o>YRKb  
{ '};Xb|msU  
~EBZlTN  
I zT%Kq  
try{ z!%}0  
URL url = new URL(sURL); yWuq/J:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 19S,>  
httpConnection.setRequestProperty("User-Agent","NetFox"); o,-@vp  
String sProperty = "bytes="+nStartPos+"-"; -3fvO~  
httpConnection.setRequestProperty("RANGE",sProperty); H4N==o  
Utility.log(sProperty); FD<~?-  
?=,tcN  
~VOmMw4HV
 
InputStream input = httpConnection.getInputStream(); 1\McsX4  
//logResponseHead(httpConnection); n;U|7it7  
z)26Ahm TV  
Q7C'O @  
byte[] b = new byte[1024]; Ah,Zm4:  
int nRead; pnD#RvmW2e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lv_>cFJ}[  
{ Y9WH%  
nStartPos += fileAccessI.write(b,0,nRead); =<g\B?s]  
//if(nThreadID == 1) Ul=`]@]]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V;m3=k0U  
} ]OVjq?  
G~JQcJFj  
$j:0*Z=>  
Utility.log("Thread " + nThreadID + " is over!"); ukw'$Yt2  
bDownOver = true; %63<Iz"  
//nPos = fileAccessI.write (b,0,nRead); NM4 n  
} |89`O^   
catch(Exception e){e.printStackTrace ();} ,YoIn  
} 7(jt:V6V  
} +,smjg:O  
'j.{o  
|peZ`O^~  
//打印回应的头信息 = *sP, 6  
public void logResponseHead(HttpURLConnection con) aAX 8m  
{ =q._Qsj?fu  
for(int i=1;;i++) Z#F2<*+Pe  
{ f.,-KIiF  
String header=con.getHeaderFieldKey(i); @g{=f55  
if(header!=null) ;{>z\6N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mJT7e  
Utility.log(header+" : "+con.getHeaderField(header)); p5*i d5
 
else DzYno-]A]  
break; $, =n  
} `Z{7Ut^)  
} _+UD>u{  
W4Eo1 E  
XpM#0hm  
public void splitterStop() 3&}wfK]X  
{ W2n%D& PE  
bStop = true; {
&/q\UQ  
} *u-
TNg  
nGRF<2!  
tnp]wZ  
} 39u!j|VH  
)9Jt55
0(  
TIS}'c'C  
/* 0BD3~Lv  
**FileAccess.java #j@Su )+  
*//文件访问(定位，写) ]e+S~me  
package NetFox; -PxA~((g
5  
import java.io.*; byd[pnI$H  
Fm*O&6W\@A  
rQ/S|gG  
public class FileAccessI implements Serializable{ %[RLc[pB  
#.) qQ8*(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NK d8XQ=%  
RandomAccessFile oSavedFile; HmQuRW  
long nPos; kRG-~'f%`  
ji">} -  
r]2}S=[  
public FileAccessI() throws IOException p=eSHs{>A  
{ Ww@Rewo  
this("",0); .4U::j}  
} MA"DP7e?v  
pi+m`O   
RzNv|   
public FileAccessI(String sName,long nPos) throws IOException 2E;*kKw[  
{ #Ey!
?Z  
oSavedFile = new RandomAccessFile(sName,"rw"); !x|Ok'izDL  
this.nPos = nPos; )x#^fN~ 7`  
oSavedFile.seek(nPos); WFy90*@Z  
} GtbIw  
}F**!%4d  
%KRAcCa7  
public synchronized int write(byte[] b,int nStart,int nLen) "5]GEzM3O  
{ vxK}f*d  
int n = -1; p
)d'yj  
try{ D@&
0 P&  
oSavedFile.write(b,nStart,nLen); P)ZGNtO9fG  
n = nLen; G[)Q
GZ}8b  
} umK~K!i  
catch(IOException e) d+Pfi)+(I  
{ E[^66(KR  
e.printStackTrace (); *r$(lf  
} !3}vl Y1  
!bS:!Il9=  
U!TFFkX[  
return n; <e)3 j6F!  
} Tw);`&Ulo  
Sr/"'w;  
yiiYq(\{  
} #8QQZdC8`  
n;y<!L7  
8ZE{GX.m2c  
/* p.n+m[  
**SiteInfoBean.java :dLfM)8}  
*/ a>G|t5w  
package NetFox; &U*=D8!0  
vn9_tL&  
![P1Qvp  
public class SiteInfoBean { YFL9Q<  
7ae8nZ3&  
%70sS].@  
private String sSiteURL; //Site's URL ehPrxIyC  
private String sFilePath; //Saved File's Path +x\b- '  
private String sFileName; //Saved File's Name X~T"n<:a>  
private int nSplitter; //Count of Splited Downloading File ]2+7?QL,  
SoI"a^fY  
VZ5EV'D8!  
public SiteInfoBean() " +'E  
{//nSplitter的缺省值为5 }1f@>'o  
//default value of nSplitter is 5 RHZ5f0b4L  
this("","","",5); 06|+_  
} TW8E^k7  
_pnJ/YE  
prV:Kq;O  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PF+v[h;,  
{ sk.<|-(o  
sSiteURL= sURL; mp:%k\cF|  
sFilePath = sPath; NjIe2)}'  
sFileName = sName; I9-vV>:z  
this.nSplitter = nSpiltter; 2;VggPpT  
K3Zc>QL{  
WLma)L`L  
} Xt %;]1n  
0'{0kE[wn  

(p08jR '5  
public String getSSiteURL()  m_LW<'  
{ 2>Bx/QF@<  
return sSiteURL; Hr |De8#f  
} 8M9 &CsT6  
})rJU/  
U?P5cN  
public void setSSiteURL(String value) wg\*FfQn  
{ - |n\  
sSiteURL = value; <2Lcy&w_M  
} &^KmfT5C  
L s6P<"V  
mojD  
public String getSFilePath() B:Ec(USe  
{ 20h|e+3  
return sFilePath; m{4e+&S|  
} :oh(M|;/2  
:SjTkfU  
RG1~)5AL~Y  
public void setSFilePath(String value) 1:%HE*r  
{ !{tkv4  
sFilePath = value; Xo]QV.n  
} , v,mBYaU  
{Hxvt~P  
HQl
hT  
public String getSFileName() T|dQY~n~  
{ 8@S7_x  
return sFileName; U+gOojRy{  
} W!|A3V35\:  
o%_MTCANy  
-7\Rl3c  
public void setSFileName(String value) T7`9[  
{ 'wB6-  
sFileName = value; ^{\gD23  
} JbN@AX:%  
6) {jHnk)  
ma@3BiM  
public int getNSplitter() v).V&":  
{ <8Y;9N|94!  
return nSplitter; 3NRxf8  
} "'/:Tp)  
3~IT
vH,`s  
s*$Re)}S  
public void setNSplitter(int nCount) k{_ Op/k}V  
{ Fr/3Qp@S  
nSplitter = nCount; <%WN<T{q|  
} J!r,ktO^U?  
} ^3B)i=  
vowU+Y  
|Y#KMi ~  
/* Omy4Rkj8bh  
**Utility.java wcz|Zy  
*/ Sj?u^L8es}  
package NetFox; :C6  
Us4J[MW<  
6f1%5&si  
public class Utility { ($a ?zJr  
V/w:^@5+p  
Q|40 8EM  
public Utility() f+>l-6M+p  
{ sjh>i>t  
Q(@/,%EF  
 z.fh4p  
} !9GJ9ZEXM  
QP/6N9/  
//线程睡眠 0ox 8_l  
public static void sleep(int nSecond) /7WN,a  
{ e1Kxqw7  
try{ BQYj"Wi  
Thread.sleep(nSecond); v@zpF)|  
} CNwYQe-i  
catch(Exception e) QoZ7
l]^  
{ ~"\qX+  
e.printStackTrace (); h{zE;!+)D  
} [Xp{ztGE  
} a& >(*PQ  
=%u\x=u|  
//日志 QmQsNcF~z  
public static void log(String sMsg) 97"dOi!Wh  
{ aoNTRJc$  
System.err.println(sMsg); 3f'dBn5  
} _@es9  
Wxjv=#3  
Qd~M;L O"i  
public static void log(int sMsg) \BB(0Ah+t  
{ J?/.|Y]e  
System.err.println(sMsg); p^^
Ai  
} rEI]{?eoF  
} @
8zp(1.  
`c 3IS5  
 U)oH@/q  
/* r()%s3$q  
**TestMethod.java 5`:+NwXS2  
*/  &tb  
package NetFox; >FtW~J"X  
\Y'#}J"dh  
\EH:FM}l,  
public class TestMethod { T';<;6J**  
HV:mS*e  
}gw `,i  
public TestMethod() 8+^?<FKa  
{ ///xx/weblogic60b2_win.exe F|._'i+B!  
try{ 4Q0@\dR9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e'<pw^I\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
F?j;3@z[A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jRz2l`~7#  
fileFetch.start(); >:l;W4j  
} )"7hyW5  
catch(Exception e){e.printStackTrace ();} JL~QE-pvD  
GD1=Fb"&)  
 &y1' J  
} hjiU{@q  
<j1l&H|ux,  
.8is!TT  
public static void main(String[] args) 4XL*e+UfJ  
{ # k+Ggw  
new TestMethod(); f~Dl;f~H_;  
} s{q)m@  
} b6D}GuW  
点击下载更多相关资料