http断点续传简单实现（java)

/* p2;-*D  
**SiteFileFetch.java ]:m}nJ_  
*/ :66xrw  
package NetFox; _ FcfNF  
import java.io.*; G9.
+N~GZ.  
import java.net.*; %.kJ@@_e  
$:R"IqDG  
\Ze"Hv  
public class SiteFileFetch extends Thread { `Tx1?]  
:bxq%D%|o  
OQ>r;)/  
SiteInfoBean siteInfoBean = null; //文件信息Bean Br2ZloJ@+  
long[] nStartPos; //开始位置 Ldnw1xy  
long[] nEndPos; //结束位置 2-9'zN0u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T.vkGB=QZ%  
long nFileLength; //文件长度 1'dL8Y  
boolean bFirst = true; //是否第一次取文件 6@TGa%:G  
boolean bStop = false; //停止标志 GVT+c@Gx  
File tmpFile; //文件下载的临时信息 *%^Vq  
DataOutputStream output; //输出到文件的输出流 _ 13M
 
URbu=U  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） cNzn2-qv  
public SiteFileFetch(SiteInfoBean bean) throws IOException R&13P&:g  
{ Zb)j2Xgl  
siteInfoBean = bean; []D@"Bz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $okGqu8z.O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "=0#pH1o  
if(tmpFile.exists ()) Y4Hi<JWo  
{ n%lY7.z8d  
bFirst = false; _u$X.5Q;  
read_nPos(); io_4d2
uBh  
} _q >>]{5  
else J+3PUfg>@R  
{ 20G..>zW  
nStartPos = new long[bean.getNSplitter()]; \Lxsg!wtJ  
nEndPos = new long[bean.getNSplitter()]; Y]ML-smN  
} .`z](s  
s7?Q[vN  
t1,sG8Z  
LHjGlBy  
} Y4]USU!PA  
zK`z*\
 
\K+LKa)  
public void run() /xmUu0H$R  
{ >1[Hk0 <x  
//获得文件长度 Fa`/i v  
//分割文件 ;Ub;AqY  
//实例FileSplitterFetch &h.
E B  
//启动FileSplitterFetch线程 P8jXruZr  
//等待子线程返回 \8%64ZL`  
try{ Iy\{)+}aS  
if(bFirst) pCOr{I\  
{ =k#SQ/@  
nFileLength = getFileSize(); L0?-W%$>  
if(nFileLength == -1) LOf0_g/  
{  fS50  
System.err.println("File Length is not known!"); 9ZjSM,+  
} `<>Emc8Z  
else if(nFileLength == -2) irSdqa/  
{ 7@R;lOzL3  
System.err.println("File is not access!"); !BD+H/A.{  
} l$$N~FN  
else VU7x w  
{ kH Y  
for(int i=0;i<nStartPos.length;i++) $+eDoI'f  
{ ^&iUC&8W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +Z0@z^6\  
} ,/n<Qg"`  
for(int i=0;i<nEndPos.length-1;i++) <X}@afS  
{ L4I1nl  
nEndPos = nStartPos[i+1]; zG|}| //}  
} rtr0 d  
nEndPos[nEndPos.length-1] = nFileLength; \
; Io  
} deR2l(0%yr  
} 4R5+"h:  
V:*QK,  
M#II,z>q  
//启动子线程 9V*h:[6a(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZSj^\JU  
for(int i=0;i<nStartPos.length;i++) @N?A0S/  
{ z}v6!u|iZu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mq!03q6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y_n^6 ;  
nStartPos,nEndPos,i); d&n&_
>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g3@Qn?(j!  
fileSplitterFetch.start(); ]*a3J45  
} iOI8'`mk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m\~{l=jIS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,"!t[4p=f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eC:?j`H-  
nEndPos = " + nFileLength); FBpf_=(_1  
// fileSplitterFetch[nPos.length-1].start(); #Aox$[|@  
6T>e~<^  
f8um.Xnp6  
//等待子线程结束 PzThVeJ+  
//int count = 0; a=*
&OW  
//是否结束while循环 #% PnZ /  
boolean breakWhile = false; V=}AFGC85  
cx?t C#t  
+~lZ]a7k  
while(!bStop) i9?$BZQ[R  
{ (rV#EA+6[`  
write_nPos(); aW-'Jg=@H^  
Utility.sleep(500); t><AaYij_  
breakWhile = true; Wh4`Iv\.  
U5 ~L^  
AW;"` ].  
for(int i=0;i<nStartPos.length;i++) }r:H7&|&  
{ EAYx+zI  
if(!fileSplitterFetch.bDownOver) Z6%Hhk[  
{ IM:*uv  
breakWhile = false; .[Ezg(U}ze  
break; .c~`{j}  
} Z'EXq.hk  
} {VqcZhqy/l  
if(breakWhile) _JZS;8WYR  
break; .0^-a=/  
>D'Kt?L<]m  
o.-rdP0P>  
//count++; GmoY~}cg~  
//if(count>4) "|&xUWJ!)  
// siteStop(); 8Qtd,  
} O?|st$g  
$ftcYBZa  
KF&1Y>t=  
System.err.println("文件下载结束！"); .iFd  
} |7XV!D!\g  
catch(Exception e){e.printStackTrace ();} DuJbWtA  
} S~auwY,<  
6A$ \I44  
cl s-x@ Kd  
//获得文件长度 Q$_S/d%*  
public long getFileSize() G%N3h'zDi  
{ u`Kjs}F'  
int nFileLength = -1; _:|/4.]`_  
try{ \Q[u?/TF  
URL url = new URL(siteInfoBean.getSSiteURL()); nDLr17  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "NqB_?DT  
httpConnection.setRequestProperty("User-Agent","NetFox"); 03aa>IO  
9 z_9yT  
$agd9z,&m  
int responseCode=httpConnection.getResponseCode(); noz&4"S.{  
if(responseCode>=400) 7U_~_yb  
{ ki`7S  
processErrorCode(responseCode); "Xq.b"N{*  
return -2; //-2 represent access is error M5DW!^  
} yj!4L&A  
,#Y>nP0  
595P04  
String sHeader; ?ysC7((  
KrNu7/H  
NIn#  
for(int i=1;;i++) Qx,jUL#2  
{ Vm NCknG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {%!.aQ,  
//Utility.log(in.readLine()); ; ntq%  
sHeader=httpConnection.getHeaderFieldKey(i); :BFecS&i5  
if(sHeader!=null) =lIG#{`Q  
{ 7I>@PVN  
if(sHeader.equals("Content-Length")) @ %LrpD  
{ 4f+R}Ee7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G?\\k[#,&  
break; ]AjDe]  
} Ar@" K!TS  
} 6{/HNEI*1  
else =1' / ?  
break; "?E>rWz  
} -A}U^-'a}  
} 5AV5`<r.  
catch(IOException e){e.printStackTrace ();} Z>GqLq\`ed  
catch(Exception e){e.printStackTrace ();} <C0~7]XO  
+[$d9  
5e^t;  
Utility.log(nFileLength); $@y<.?k>UP  
(gd+-o4  
hVPSW# .d  
return nFileLength; -z"=d<@  
} tY=s
l_  
5v:c@n  
jr$
]kLY  
//保存下载信息（文件指针位置） V@6,\1#`|  
private void write_nPos() :sD/IM",},  
{ 8
.9TWsZ  
try{ A1`y_ Aj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0Q]@T@F.  
output.writeInt(nStartPos.length); eq)8V x0  
for(int i=0;i<nStartPos.length;i++) md8r"  
{ %hcn|-"F  
// output.writeLong(nPos); :]&O  
output.writeLong(fileSplitterFetch.nStartPos); KtWn08D!  
output.writeLong(fileSplitterFetch.nEndPos); Kfho:e,  
} Dk$[b9b  
output.close(); ,r<!30~f  
} 1p#O(o  
catch(IOException e){e.printStackTrace ();} o5(`7XV6D  
catch(Exception e){e.printStackTrace ();}
tE"aNA#=  
} @SH%l]  
Un{hI`3]  
5.st!Lp1  
//读取保存的下载信息（文件指针位置） ^_dYE]t  
private void read_nPos() d;GF<bz  
{ *m_B#~4  
try{ o/uA_19  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h`X>b/V  
int nCount = input.readInt(); ;{xk[fm=  
nStartPos = new long[nCount]; rp*f)rJ  
nEndPos = new long[nCount]; C^sHj5\(  
for(int i=0;i<nStartPos.length;i++) $GI2rzh  
{ NY.Y=CF("  
nStartPos = input.readLong(); 8*O]  
nEndPos = input.readLong();
9H$$Og  
} k"-2OT  
input.close(); CF|c4oY82  
} 4{!7T  
catch(IOException e){e.printStackTrace ();}
-8;@NAUa  
catch(Exception e){e.printStackTrace ();} )m .KV5K!  
} Rlvb@aXgy  
E .2b@  
/:-8 ,`  
private void processErrorCode(int nErrorCode) YKF5|;}  
{ H=2sT+Sp  
System.err.println("Error Code : " + nErrorCode); `Mj>t(  
} Y](kMNUSg  
e C\;n  
di^E8egR$  
//停止文件下载 `?Wy;5-  
public void siteStop() !1+yb.{\  
{ G&i<&.i  
bStop = true; B&J;yla6`d  
for(int i=0;i<nStartPos.length;i++) TiiMX  
fileSplitterFetch.splitterStop(); GabYxYK  
9d7`R'  
RRGo$  
} mj\]oWS7d  
} !RX7TYf  
//负责部分文件的抓取 <5oG[1j  
**FileSplitterFetch.java ;|(_;d  
*/ [l;9](\8O  
package NetFox; oqu; D'8  
)n8(U%q$  
]xhZJ~"@u  
import java.io.*;
_ ^5w f  
import java.net.*; Qrr8i:Y^  

I$Z8]&m  
ANuIPF4NxP  
public class FileSplitterFetch extends Thread { 1Yj^N"=  
+&t`"lRl&  
,Mt/*^|  
String sURL; //File URL ~zEBJgeyh  
long nStartPos; //File Snippet Start Position Cx
yL'k  
long nEndPos; //File Snippet End Position FT0HU<." 1  
int nThreadID; //Thread's ID mIJYe&t7)  
boolean bDownOver = false; //Downing is over AF-4b*oB  
boolean bStop = false; //Stop identical x.d;7  
FileAccessI fileAccessI = null; //File Access interface |UA)s3Uhxb  
:aYbP,mE  
1: cD\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .2y2Qm  
{ & ,KxE(C  
this.sURL = sURL; !3]}3jZ.  
this.nStartPos = nStart; !3Xu#^Xxj  
this.nEndPos = nEnd; +4<Ij/}p  
nThreadID = id; zR)9]p
J-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KW&5&~)2  
} J|vriI;  
Qyn~Vu43  
Mp8BilH-T  
public void run() lO?dI=}]  
{ 0taopDi;d  
while(nStartPos < nEndPos && !bStop) aTJs.y-I~  
{ @qC](5|TQ  
Q]9g  
AOvn<Q  
try{ 9?4EM^-  
URL url = new URL(sURL); Fu@2gd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\C$/8v  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y!M&8;>  
String sProperty = "bytes="+nStartPos+"-"; lRIS&9vA3  
httpConnection.setRequestProperty("RANGE",sProperty); 6rBXC <Z  
Utility.log(sProperty); 
|2oCEb1  
3zV{cm0  
Ygwej2  
InputStream input = httpConnection.getInputStream(); <$#;J>{WV  
//logResponseHead(httpConnection); e -sZ_<GH  
Wnp\yx`  
i,77F!  
byte[] b = new byte[1024]; hrLPyV:  
int nRead; ~,199K#'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U _QCe+  
{ I/F3%'O  
nStartPos += fileAccessI.write(b,0,nRead); l!6^xMhYk  
//if(nThreadID == 1) uif1)y`Q$C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /wF*@/PTH  
} )U>JFgpI
W  
Ucj eB  
)FF3|dZ";K  
Utility.log("Thread " + nThreadID + " is over!"); ^U[c:Rz  
bDownOver = true; L.5 /wg  
//nPos = fileAccessI.write (b,0,nRead); pA ,xDs@37  
} +W{ELdup%q  
catch(Exception e){e.printStackTrace ();} hB]\vA7  
} qB%?t.k7  
} ;ALkeUR[  
rD7L==Ld  
OPYl#3I  
//打印回应的头信息 U{^~X_?  
public void logResponseHead(HttpURLConnection con) TB!z:n  
{ w=ZSyT-i  
for(int i=1;;i++) y@\R$`0J  
{ ZS@Gt  
String header=con.getHeaderFieldKey(i); xEX"pd  
if(header!=null) h3}gg@Fm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "r:i  
Utility.log(header+" : "+con.getHeaderField(header)); Xm#E99  
else Kbdjd p  
break; ]\fXy?2  
} mBp3_E.t  
} gj\'1(Ju  
V3^=Mj2"  
N+l 0XjZD9  
public void splitterStop() #u<^  
{ LF2@qvwD  
bStop = true; |zJxR_)  
} s>pOfXIx  
F|rJ{=x  
;q8tOvQ  
} R{GT? wl  
f3g#(1  
uQ}0hs  
/* `oDs]90  
**FileAccess.java |^uU&O;.  
*//文件访问(定位，写) }qqE2;{ND  
package NetFox; xaM? B7  
import java.io.*; o@p(8=x  
PYOU=R%o`8  
& o2F4  
public class FileAccessI implements Serializable{ *@EItj`  
dBB;dN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7tEK&+H`  
RandomAccessFile oSavedFile; y<53xZi  
long nPos; 3!+N}[$iy  
QNGICG-  
5WT^;J9V  
public FileAccessI() throws IOException `|Ll  
{ 13:yaRo  
this("",0); \Mi] !b|8  
} +PCsp'D d  
Usa  
eHjna\C  
public FileAccessI(String sName,long nPos) throws IOException 't3
@dz_dG  
{ 0v~Eu>Rg  
oSavedFile = new RandomAccessFile(sName,"rw"); v
P_V%5~yN  
this.nPos = nPos; /SXms'C  
oSavedFile.seek(nPos); -<R"  
} L\:f#b~W  
SGZ]
_  
fs43\m4=m  
public synchronized int write(byte[] b,int nStart,int nLen) 4yk!T  
{ x/7d!>#;  
int n = -1; P ~pC /z  
try{ &ye,A(4  
oSavedFile.write(b,nStart,nLen); 7]i=eD8  
n = nLen; X_j=u1*5  
} 3eqVY0q  
catch(IOException e) >N&C-6W  
{ x6d0y
J <  
e.printStackTrace (); h`_@eax  
} @V9qbr=Z  
TQcEe@$)  
h-^7cHI}  
return n; /c`s$h4-  
} 1z4s1Y  
8-A *Jc  
r*n_#&-7  
} :3
F
Je  
uSAb  
C*S%aR  
/* <hYrcOt  
**SiteInfoBean.java HjX!a29Wf  
*/ %(EUZu2  
package NetFox; vPVA^UPNV  
Bn[5M[  
-:5]*zVp+-  
public class SiteInfoBean { ?q68{!{bi  
U?MKZL7  
208dr*6U  
private String sSiteURL; //Site's URL nvJ2V$  
private String sFilePath; //Saved File's Path m
4U7{sE  
private String sFileName; //Saved File's Name G)I lkA@  
private int nSplitter; //Count of Splited Downloading File ,O9rL :?  
F$Cf\#{3  
X j'7nj  
public SiteInfoBean()  Tl.%7)  
{//nSplitter的缺省值为5 5y}kI  
//default value of nSplitter is 5 wU\3"!^h  
this("","","",5); 12NV  
} ~)RKpRga\p  
4_#yl9+  
L@b8,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 91Cg   
{ [7QIpt+FSo  
sSiteURL= sURL; M5SAlj  
sFilePath = sPath; ~MvLrg"i  
sFileName = sName; _` %z  
this.nSplitter = nSpiltter; hb6UyN  
rKP;T"?;  
WHV]H  
} \Z +O9T%  
"hwG"3n1  
2iUdTy$  
public String getSSiteURL() BjT0mk"P  
{ N"i'[!H%  
return sSiteURL; .js@F/Hp  
} Iw?
M>'l  
+sTZ) 5vQ  
nly`\0C  
public void setSSiteURL(String value) u6~|].j R  
{ u}Q@u!~e9  
sSiteURL = value; K1P3 FfG  
}
uW.)(l  
nDR)UR  
=w~phn  
public String getSFilePath() SI:+I4i  
{ {y{&tzZ  
return sFilePath; ,{@,dw`lUz  
} Unl6?_  
_&/FO{F@m  
va(ZGGS]N  
public void setSFilePath(String value) zU+` o?al  
{ cVzOW|NVx  
sFilePath = value; mSWh'1]b.~  
} fbbk;Rq.'3  
x)X=sX.  
eBD7g-  
public String getSFileName() 
oQrkd:  
{ T~nmEap  
return sFileName; ZaCUc Px  
} *):xK;o  
cuJ%;q=;  
2?]NQE9lA  
public void setSFileName(String value) SX$Nef9p  
{ ^9})@,(D  
sFileName = value; ^ fo2sN"   
} ,gR9~k,  
*k$":A  
NqsIMCl  
public int getNSplitter() T)IH4UO  
{ bK)gB!  
return nSplitter; +4kBd<0Y  
} ~Wq[H  
J?ljqA}i  
*siN#
,5  
public void setNSplitter(int nCount) 09Sy- je*/  
{ oG! S(95  
nSplitter = nCount; Az_s"}G  
} 3pSkk  
} Q\H_lB  
{DPobyvwFk  
u`l1 zMk  
/* >?b9Xh  
**Utility.java g-c\;  
*/ HvWnPh1l  
package NetFox; Ns6
Vf5
T.  
8
3*"58  
qg;[~JZYKi  
public class Utility { */B-%*#I.  
mWUo:(U  
zt1Pu /e  
public Utility() O87Ptr8  
{ b|i94y(  
zOR  
<r*A(}Y  
} 33O@jbs@  
[.}-nAN  
//线程睡眠 Qt_LBJUWV  
public static void sleep(int nSecond) 3|/<
Pk  
{ 'F'v/G~
F  
try{ ';buS -|6  
Thread.sleep(nSecond); W/PZD (  
} sR`WV6!9  
catch(Exception e) Qh)QdW4  
{ .bh>_ W_h  
e.printStackTrace (); :tu_@3bg-  
} DkP%1Crdr  
} lNSB "S  
hP4*S^l  
//日志 G]fl33_}l  
public static void log(String sMsg) lx<]v^  
{ X@u-n_  
System.err.println(sMsg); mZVYgJQ[  
} /cBQE=]6  
Ju$vuE
O  
sa%2,e'  
public static void log(int sMsg) D.2HM  
{ 'kW'e  
System.err.println(sMsg); z5CZ!"&v  
} :^mfTj$  
} $x&\9CRM  
(,<
ti):  
J[:3H6%`  
/* Gc) Zu`67  
**TestMethod.java djVE x}  
*/ eATX8`
W  
package NetFox; i"uAT$xe  
!$'s?rnh  
j|f$:j  
public class TestMethod { fDmGgD?  
%(`4wo},  
RHo|&.B;+  
public TestMethod() ZbJUOa?W
F  
{ ///xx/weblogic60b2_win.exe N 3)OH6w"  
try{ pA9:1*+;;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |q?I(b4Q@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t 7D2k2x9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p<*\f  
fileFetch.start(); jV^Dj  
} %?l
PS  
catch(Exception e){e.printStackTrace ();} Hh=D:kE  
QE7 r{  
dKcHj<'E/  
} p1 tfN$-  
^a@Vn\V1  
X*Mw0;+T  
public static void main(String[] args) v>TI.;{y  
{ WP1>)  
new TestMethod(); 8phcekh+  
} C%<[mM  
} ?U]/4]  
点击下载更多相关资料