http断点续传简单实现（java)

/* k8}fKVU;  
**SiteFileFetch.java h SS9mQ  
*/ 9D\E0YG X/  
package NetFox; 98R/^\  
import java.io.*; @JhkUGG]p  
import java.net.*; )J@[8 x`  
uo]\L^j   
IrCl\HQN  
public class SiteFileFetch extends Thread { =@4,szLO  
_@XueNU1hS  
yOl
VS@7  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]@z!r2[  
long[] nStartPos; //开始位置 &77J,\C$:  
long[] nEndPos; //结束位置 &2 Yo  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n^;-&  
long nFileLength; //文件长度 jbS@6 *_  
boolean bFirst = true; //是否第一次取文件 h/
\Zq  
boolean bStop = false; //停止标志 q[qX O5  
File tmpFile; //文件下载的临时信息 8BAe6-*S8  
DataOutputStream output; //输出到文件的输出流 s-Gd{=%/q  
6/wC StZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oe^JDb#  
public SiteFileFetch(SiteInfoBean bean) throws IOException <`SA>P  
{ 83V\O_7j  
siteInfoBean = bean; #pAN   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }|Q\@3&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kK}?NKqT  
if(tmpFile.exists ()) B^TgEr  
{ 2 oL$I(83  
bFirst = false; C<a&]dN/  
read_nPos(); sYXLVJ>b  
} ]#shuZ##>0  
else \kyoA Z  
{ 2<J2#}+\  
nStartPos = new long[bean.getNSplitter()]; -:_3N2U=+  
nEndPos = new long[bean.getNSplitter()]; b)Nd}6}<?  
} a
U.3  
%u9Q`  
}KUK|p5  
>?JUGXAi'{  
} ]lGkZyUhI  
zwQ#Yvd  
<Af&Q0J  
public void run() ] rqx><!  
{ ~P}ng{x4z  
//获得文件长度 6rE8P#  
//分割文件 TW1`{SM  
//实例FileSplitterFetch s7}-j2riq  
//启动FileSplitterFetch线程 \anOOn@  
//等待子线程返回 #lMIs4i.  
try{ 8v/,<eARJ  
if(bFirst) .u&X:jO
E  
{ =[aiW|Y  
nFileLength = getFileSize(); :##
$-K*W"  
if(nFileLength == -1) S3HyB b  
{ )Dhx6xM[a  
System.err.println("File Length is not known!"); :_HdOm  
} /z!y[ri+J  
else if(nFileLength == -2) W^HE1Dt]  
{ 6X'0 T}  
System.err.println("File is not access!"); k fY;  
} Xajt][  
else wU'+4N".  
{ 0[YksNNl1  
for(int i=0;i<nStartPos.length;i++) !}x-o`a5  
{ mBye)q$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XkUwO ]
 
} @||nd,i`n~  
for(int i=0;i<nEndPos.length-1;i++) N@X6Z!EO  
{ It2:2  
nEndPos = nStartPos[i+1]; UnVa`@P^:G  
} >u0XV"g$  
nEndPos[nEndPos.length-1] = nFileLength; } @3q;u)  
} \goiW;b  
} t&JOASY
C  
&%(Dd  
`N}Vi6FG  
//启动子线程 O`_, _  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y~OP9T
g  
for(int i=0;i<nStartPos.length;i++) t}}Ti$$>  
{ \O~/^ Y3U!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 73u97oe>1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3e-E/6zH6  
nStartPos,nEndPos,i); }3WP:E
t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ht}?=ZzW  
fileSplitterFetch.start(); v`Y{.>[H[  
} ql5&&e=-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,bM):  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <h+UC# .x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nRX'J5Q m<  
nEndPos = " + nFileLength); (u@X5O(a  
// fileSplitterFetch[nPos.length-1].start(); k`'*niz  
Ke#Rkt  
C %j%>X`  
//等待子线程结束 b$ 8R  
//int count = 0; 9RSviIi$  
//是否结束while循环 t<}N>%ZO  
boolean breakWhile = false; k=p[Mlic/  
@!ja/Y^  
+S#Xm4  
while(!bStop) #_3ZF"[zq  
{ /`#JM  
write_nPos(); @Wm:Rz  
Utility.sleep(500); 7z\#"~(.  
breakWhile = true; h{\S'8  
($UUgjv F  
Wzffp}V  
for(int i=0;i<nStartPos.length;i++) )3|a_   
{ LtUw  
if(!fileSplitterFetch.bDownOver) |#x
BC+  
{ 805oV(-  
breakWhile = false; 4kV$JV.l  
break; w4Hq|N1-Y  
} :T@}
CJ  
} )Xt#coagS  
if(breakWhile) c%wztP;L  
break; lc
[)Ev  
p,(W?.ZDN?  
]i1OssV~>  
//count++; S5H}   
//if(count>4) FH%:NO  
// siteStop(); }2c&ARQ.m>  
} ZcHIk{|  
>@a7Zzl0H  
F_/ra?WVH  
System.err.println("文件下载结束！"); @x[A^  
} k%sxA  
catch(Exception e){e.printStackTrace ();} P,G :9x"e  
} T.%yeJiE  
y^Q);siSy  
Ck m:;q  
//获得文件长度 aehB,l0  
public long getFileSize() _T805<aUW\  
{ K,PN:  
int nFileLength = -1; oRg,oy  
try{ Ut/%+r"s  
URL url = new URL(siteInfoBean.getSSiteURL()); r1=j$G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8y[Rwa  
httpConnection.setRequestProperty("User-Agent","NetFox"); bl10kI:F  
?y"M>#  
p*1B*R  
int responseCode=httpConnection.getResponseCode(); -M T1qqi  
if(responseCode>=400) |v#D}E  
{ !N][W#:  
processErrorCode(responseCode); +.rOqkxJ  
return -2; //-2 represent access is error G%!i="/9  
} {}RU'<D  
4Xwb`?}-  
 VS7  
String sHeader; f?16%Rk<  
(m2_Eh;  
Gv#bd05X  
for(int i=1;;i++) Qk
|+Gj  
{ OP=-fX|*Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f+)LVT8p  
//Utility.log(in.readLine()); Q$k#q<+0  
sHeader=httpConnection.getHeaderFieldKey(i); B o%Sl  
if(sHeader!=null) 1TGE>HG  
{ BT$Oh4y4  
if(sHeader.equals("Content-Length")) KP>1%ap6  
{ 2r+nr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mxpw4  
break; AG;KXL[V  
} Fs=)*6}&  
} <{YzmN\Z  
else 23'{{@30  
break; /Ah'KN|EN  
} NweGK  
}  #3RElI  
catch(IOException e){e.printStackTrace ();} /9Qr1@&v  
catch(Exception e){e.printStackTrace ();} )7#3n(_np  
FGm!|iI  
TnKOr~@*  
Utility.log(nFileLength); hOFvM&$  
ZTB6m`  
c@nh>G:y{&  
return nFileLength; {F\P3-ub  
} */@I$*  
:hWG:`  
_^ n>kLd$  
//保存下载信息（文件指针位置） MJH>rsTQ  
private void write_nPos() tqpi{e  
{ 
S<i.O  
try{ T#I}w\XlhP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
}5$le]  
output.writeInt(nStartPos.length); Yn?Xo_Y  
for(int i=0;i<nStartPos.length;i++) TT#V'r\  
{ J*:_3Wsy  
// output.writeLong(nPos); 9q[[ ,R  
output.writeLong(fileSplitterFetch.nStartPos); Are0Nj&?
 
output.writeLong(fileSplitterFetch.nEndPos); \CS4aIp  
} n!Y}D:6c6  
output.close(); _~P&8  
} k$DRX)e  
catch(IOException e){e.printStackTrace ();} <QaUq`,  
catch(Exception e){e.printStackTrace ();} w`M`F<_\:  
} *1:kIi7_  
Q]RE,ZZ  
8|L5nQ  
//读取保存的下载信息（文件指针位置） & \"cV0  
private void read_nPos() W(-son~I  
{ 0&\71txrzg  
try{ DPmY_[OAE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C58B(Ndo  
int nCount = input.readInt(); 9U )9u["DH  
nStartPos = new long[nCount]; T@zp'6\H  
nEndPos = new long[nCount]; g]BA/Dw  
for(int i=0;i<nStartPos.length;i++) ~xws5n}F  
{ )U]q{0`  
nStartPos = input.readLong(); D)S_ p&  
nEndPos = input.readLong(); ;/IXw>O(/  
} VuK>lY&  
input.close(); gt~u/Z%  
} z-sq9Qp&x  
catch(IOException e){e.printStackTrace ();} 9d=\BBNZ  
catch(Exception e){e.printStackTrace ();} G_ ~qk/7mF  
} MFWkJbZV  
k!WeE#"(  
``{GU}n  
private void processErrorCode(int nErrorCode) x>A[~s"|N  
{ xnw'&E  
System.err.println("Error Code : " + nErrorCode); 2<'ol65/c  
} 28-z  
|'x"+x   
muFWFq&yP  
//停止文件下载 BmYX8j]  
public void siteStop() 0Xn,q]@Z  
{ {CTJX2&  
bStop = true; ^bdXzj
f  
for(int i=0;i<nStartPos.length;i++) N{M25ucAHl  
fileSplitterFetch.splitterStop(); q,;wD1_wG  
3e\IRF xzb  
;.R) uCd{=  
} WK#%G  
} 9gIim
 
//负责部分文件的抓取 SFFJyRCz  
**FileSplitterFetch.java @2_E9{T  
*/ ,WW=,P  
package NetFox; Z,~@_;F  
rx<P#y]3)  
6J$I8b#/  
import java.io.*; _?I*:: I  
import java.net.*; 34_ V&8  
7l
wFxP5QT  
aQ&K a  
public class FileSplitterFetch extends Thread { EEx:Xk%5hX  
ztp2j%'  
cBZJ  
String sURL; //File URL 5HY0 *\  
long nStartPos; //File Snippet Start Position $ma@z0%8}  
long nEndPos; //File Snippet End Position %):pfM;b  
int nThreadID; //Thread's ID D& &71X '  
boolean bDownOver = false; //Downing is over Wk!<P" nHd  
boolean bStop = false; //Stop identical ?@6Zv$vZ  
FileAccessI fileAccessI = null; //File Access interface >
5Y.  
G2P:|R  
+u&3pK>f  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $uRi/%Q9  
{ $}us+hGZ  
this.sURL = sURL; l$R9c+L=  
this.nStartPos = nStart; t"MrrK>T  
this.nEndPos = nEnd; ;Uy}(  
nThreadID = id; Z:2%gU&W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )?6%d  
} (W[]}k;  
Y&DoA0/y  
r{Mn{1:O  
public void run() gp'k(rGH  
{ Qj|tD+<  
while(nStartPos < nEndPos && !bStop) <R%TCVwC@  
{ 7(|f@Y~*  
x>T+k8[n  
~JS@$#  
try{ T~g`;Q%i  
URL url = new URL(sURL); -"#jRP]#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _U^G*EqL*  
httpConnection.setRequestProperty("User-Agent","NetFox"); s |o(~2j  
String sProperty = "bytes="+nStartPos+"-"; %;aB#:p6  
httpConnection.setRequestProperty("RANGE",sProperty); h$%h w+"4  
Utility.log(sProperty); n+2>jY  
'tX}6wurf  
mSk";UCn  
InputStream input = httpConnection.getInputStream(); WQBV~.<Yv  
//logResponseHead(httpConnection); G%K&f1q%  
xNLgcb@v>  
Jq8v69fyQ  
byte[] b = new byte[1024]; 8{6`?qst@  
int nRead; -%V~1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <B @z>V  
{ oc[z dIk  
nStartPos += fileAccessI.write(b,0,nRead); !>GDp>0  
//if(nThreadID == 1)  um2}XI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wq}W )E  
} U% ?+N  
>Y|P+Z\7  
by,3A  
Utility.log("Thread " + nThreadID + " is over!"); vRDs~'f  
bDownOver = true; Eb5BJ-XeS^  
//nPos = fileAccessI.write (b,0,nRead); l=#b7rBP  
} OO,EUOh-T:  
catch(Exception e){e.printStackTrace ();} J?hs\nA  
} -q&,7'V  
} ,F "P/`i'  
Wo,93]  
0;4 YU%u  
//打印回应的头信息 nu2m5RYx  
public void logResponseHead(HttpURLConnection con) ([7XtG/?  
{ h&~9?B  
for(int i=1;;i++) Oa M~rze  
{ O]61guxro  
String header=con.getHeaderFieldKey(i); '#Do( U'  
if(header!=null) J\J3'u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]M~7L[  
Utility.log(header+" : "+con.getHeaderField(header)); u0qTP]  
else
]8<`&~a  
break; ZQ-6n1O  
} x<.(fRv   
} ^}J,;Zhu5  
.;(a;f+{;  
19%zcYTe  
public void splitterStop() ,)VAKrSg  
{ {j4&'=C:  
bStop = true; G+I->n-s4  
} !:}m-iqQ1  
Deq@T {  
%:OX^^i;  
} nEbZ8M  
E*s _Y  
Zt9ld=T  
/* 8m[o*E.4F  
**FileAccess.java 9Q7342  
*//文件访问(定位，写) Zvr
a >%  
package NetFox; Kb'4W-&u!  
import java.io.*; +HgyM0LFg  
^SM5
oK  
XK;Vu#E*^  
public class FileAccessI implements Serializable{ Mh{;1$j#  
i8%@4U/ J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 sI{?4k  
RandomAccessFile oSavedFile; :%+9y @%  
long nPos; _3#_6>=M  
$)KNpdXh  
SA%)xGRW  
public FileAccessI() throws IOException rMw$T=Oi  
{ QB;TQZ  
this("",0); yf4 i!~  
} ~3%aEj  
TKVS%//  
xZ SDA8kS  
public FileAccessI(String sName,long nPos) throws IOException ]Z52L`k  
{ }VHvC"  
oSavedFile = new RandomAccessFile(sName,"rw"); ~&"'>C#  
this.nPos = nPos; H wz$zF+R  
oSavedFile.seek(nPos); xmfZ5nVL  
} 0;]VTz?P  
ZoCk]hk  
`P$X`;SwE  
public synchronized int write(byte[] b,int nStart,int nLen) F
zn!  
{ 0<^Qj.(9  
int n = -1; Vo|[Z)MO`  
try{ ~ftR:F|9  
oSavedFile.write(b,nStart,nLen); ]3Jb$Q@  
n = nLen; 7loWqZ  
} V6kDyl(  
catch(IOException e) ID<[=es6  
{ KTeR;6oZn"  
e.printStackTrace (); w@\4ft6d  
} kL<HGQt  
Z>dvth  
r"t,/@`n  
return n; 7f<@+&  
} 1Ve~P"w  
~B7<Yg  
VZ7E#z+nM#  
} 0_=^#r4Mu  
}1Q>A 5e  
4H{$zMq8  
/* ;q#Pl!*5  
**SiteInfoBean.java GgE 38~A4  
*/ -MORd{GF  
package NetFox; =)x+f/c]  
c4s,T"H  
H;[?8h(  
public class SiteInfoBean { =Q6JXp  
y I[kaH"J  
42:,*4t(  
private String sSiteURL; //Site's URL RVF<l?EI4R  
private String sFilePath; //Saved File's Path
/2Ok;!.  
private String sFileName; //Saved File's Name def\=WyK  
private int nSplitter; //Count of Splited Downloading File x&$8;2&.  
U8</aQLGF  
!FvL2L  
public SiteInfoBean() G+\&8fi0  
{//nSplitter的缺省值为5 vYq"W%
 
//default value of nSplitter is 5 kovJ
9  
this("","","",5); .&h|r>*|J  
} Sw>,Q-32  
pr1kYMrqri  
EOS[MjX+J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q@"!uB.e  
{ zQ(`pld  
sSiteURL= sURL; !wZIXpeL  
sFilePath = sPath; u)%/df qzZ  
sFileName = sName; L D%SLJ:  
this.nSplitter = nSpiltter; Pj5:=d8z(  
IBW-[lr7  
`trcYmR=k  
} mApl;D X  
']Z%6_WF  
kPO+M~+n  
public String getSSiteURL() w8#ji 1gX  
{ i8#:y`ai  
return sSiteURL; 162Dj$  
} &G?w*w_n  
~ cI`$kJ  
08g2? 5w"  
public void setSSiteURL(String value) >x ]{cb/m  
{ U}l=1B  
sSiteURL = value; at\$ IK_  
} urQ<r{$x0  
zXkq2\GHA  
k4` %.;  
public String getSFilePath() 4{0vdpo3F  
{ Fu[GQ6{f  
return sFilePath; &<cP{aBa  
} d^0-|sx  
P!{J28dj  
|\)Y,~;P  
public void setSFilePath(String value) a|k*A&5u2  
{ }{[JS=A^  
sFilePath = value; Yqv!ZJ6  
} FS*J8)  

" ^!=e72  
F3x*dq2  
public String getSFileName() cb/$P!j7  
{ ziv+*Qn_b4  
return sFileName; ?ea5k*#a  
} Ml
)<4@  
sX
Y{g0%  
o?aF  
public void setSFileName(String value) g``S SU  
{ c4bvJy8  
sFileName = value; 7Oi<_b  
} t&IWKu#  
+KOhDtLMG  
X9rao n  
public int getNSplitter() KXBTJ&  
{ g3Ul'QJ  
return nSplitter; 7_eV.'h  
} L:.Rv0XT  
{yMkd4v  
"S>VqvH3  
public void setNSplitter(int nCount) ZbH_h]1$D  
{ j_b/66JyN  
nSplitter = nCount; Zj0h0Vt  
} 7>EMr}f C  
} PH?<)Wj9i  
('.I)n  
8[a N5M]  
/* Ft_g~]kZo  
**Utility.java FR\r/+n:t0  
*/ _j~y;R)  
package NetFox; #(Yd'qKo  
i6O'UzD@T  
rY$wC%  
public class Utility {
ppeF,Q  
V2g"5nYT  
WY26Iq@C  
public Utility() SzG?m]  
{ 46H@z=5  
[lzH%0 V  
AR g]GV/L  
} <d{>[R)  
ZR8y9mx2"  
//线程睡眠 V-"#Kf9  
public static void sleep(int nSecond) !.O;S
G  
{ SXV2Y-  
try{ <irr.O  
Thread.sleep(nSecond); s,M]f,T  
} 8/~@3-9EK  
catch(Exception e) eUD 5V  
{ m`4N1egCt  
e.printStackTrace (); GZmfE`  
} +hs:W'`%  
} Ki /j\  
q~{O^,4S  
//日志 WJ\,Y} J  
public static void log(String sMsg) \8k4v#wH  
{ C]3^:b+   
System.err.println(sMsg); 5{-54mwo  
} &0+Ba[Z ^  
Bo0T}P~  
V]Uc@7S/  
public static void log(int sMsg) 9rM#w"E?<  
{ _# &_`bZH  
System.err.println(sMsg); q{!ft9|K\d  
} ?` 2z8uD/  
} !)`m mr  
hl,x|.f}4Y  
`J;g~#/k  
/* 1TgD;qX  
**TestMethod.java +77j2W_0  
*/ '1Ex{

$Yk  
package NetFox; $`L |
 
^ JU#_  
G}nj 71=H  
public class TestMethod { HYNpvK  
~SwGZ  
gj }Vnv1[  
public TestMethod() xk^`4;  
{ ///xx/weblogic60b2_win.exe /8/N  
try{ mlz|KI~\F;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z/OERO   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @2+'s;mUV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,X\qlT5C  
fileFetch.start(); T|5uywA|  
} O44Fj)  
catch(Exception e){e.printStackTrace ();} O81'i2MJ9  
"~"=e  
<V|\yH9  
} 9zpOp-K6  
f2ck=3  
m-Se-aF  
public static void main(String[] args) 6-\M }xq?  
{ 6dRvx;d  
new TestMethod(); OZe`>Q6  
} 1.nYT*  
} R!>SN0  
点击下载更多相关资料