"Java基本输入输出及对象串行化"

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本章主要介绍了Java语言中的输入/输出流处理,通过学习本章内容,可以掌握Java程序中输入输出的方法和技巧。本章的难点重点在于正确使用不同类型的输入/输出流,特别是处理中文字符时的使用技巧,以及对象的串行化方法。 在学习本章之前,需要了解字节流和字符流的基类分别是什么。字节流的基类是InputStream和OutputStream,而字符流的基类是Reader和Writer。了解这些基本概念是理解本章内容的基础。 本章还介绍了对象的串行化,即将对象转化为字节流进行存储和传输的过程。对象串行化的作用是可以将对象存储到磁盘或网络中,便于传输和保存。通过对象串行化,可以实现对象的持久化,避免了对象在程序运行结束后的丢失。 学习本章的目标是能够编写更为完善的Java程序。为了达到这个目标,需要深刻理解Java语言中的输入/输出流的处理方法,并掌握解决问题的方法。建议同学们多练习和上机实践,加深对知识点的理解和掌握。 本章的重点知识点包括:遇到实际问题时正确使用各种输入/输出流,特别是对于中文字符的处理要选择适当的字符输入流;正确使用对象串行化的方法;处理字符流时,构造方法的参数是一个字节流;了解对象串行化的概念。 具体的内容包括:I/O流概述,文件处理,过滤流,字符流的处理,对象的串行化以及其他常用的流。 在第一节中,介绍了数据流的基本概念。流一般分为输入流和输出流两类,但这种划分并不是绝对的。比如一个文件,当向其中写数据时,它就是一个输出流;当从其中读取数据时,它就是一个输入流。 在学习本章内容时,需要注意的是遇到实际问题时要根据需要选择正确的输入/输出流,特别是在处理中文字符时要选择适当的字符输入流。 总之,通过学习输入/输出流的处理方法,可以使Java程序更加完善。要掌握正确使用各种输入/输出流的方法,特别是对中文字符的处理要选择适当的流。并且要理解并掌握对象串行化的概念和方法。加强实践,多上机实验,从而提高对知识点的理解和掌握。
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首先新建头文件des_encode.H 内容如下: void EncodeMain(); //EncodeMain function void DecodeMain(); //Sorry ,it has not used void Decode(int *str,int *keychar); //decode :input 8 chars,8 keychars void Encode(int *str,int *keychar); //encode: input 8 chars,8 keychars void keyBuild(int *keychar); //create key array void StrtoBin(int *midkey,int *keychar); //change into binary void keyCreate(int *midkey2,int movebit,int i); //call by keyBuild void EncodeData(int *lData,int *rData,int *srt); //encodedata function void F(int *rData,int *key); //F function void Expand(int *rData,int *rDataP); //Expand function void ExchangeS(int *rDataP,int *rData); //S-diagram change void ExchangeP(int *rData); //P change void FillBin(int *rData,int n,int s); // data to binary;call by S-Diagram change function void DecodeData(int *str,int *lData,int *rData); //DecodeData from binary int IP1[]={58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, //initial change 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7, }; int IP2[]={40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, //opp initial change 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25 }; int s[][4][16]={{ //S-diagram array {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7}, {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8}, {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0}, {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13} }, { {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10}, {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5}, {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15}, {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9} }, { {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8}, {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1}, {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7}, {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12} }, { {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15}, {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9}, {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4}, {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14} }, { {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9}, {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6}, {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14}, {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3} }, { {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11}, {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8}, {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6}, {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13} }, { {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1}, {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6}, {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2}, {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12} }, { {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7}, {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2}, {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8}, {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11} } }; int Ex[48]={ 32,1,2,3,4,5, //Expand array 4,5,6,7,8,9, 8,9,10,11,12,13, 12,13,14,15,16,17, 16,17,18,19,20,21, 20,21,22,23,24,25, 24,25,26,27,28,29, 28,29,30,31,32,1 }; int P[32]={16,7,20,21, //P-change 29,12,28,17, 1,15,23,26, 5,18,31,10, 2,8,24,14, 32,27,3,9, 19,13,30,6, 22,11,4,25 }; int PC1[56]={57,49,41,33,25,17,9, //PC-1 in keyBuild 1,58,50,42,34,26,18, 10,2,59,51,43,35,27, 19,11,3,60,52,44,36, 63,55,47,39,31,33,15, 7,62,54,46,38,30,22, 14,6,61,53,45,37,29, 21,13,5,28,20,12,4 }; int PC2[48]={14,17,11,24,1,5, //PC-2 in keyBuild 3,28,15,6,21,10, 23,19,12,4,26,8, 16,7,27,20,13,2, 41,52,31,37,47,55, 30,40,51,45,33,48, 44,49,39,56,34,53, 46,42,50,36,29,32 }; 再创建des.cpp 内容如下: #include<stdio.h> #include<string.h> #include"des_encode.h" int key[16][48]; char str[8]; void main() //main function { EncodeMain(); } void EncodeMain() //EncodeMain function { int i; char keychar[8]; int key2[8]; int strkey[8]; printf("请输入8个要加密的字符:\n"); for(i=0;i<8;i++) scanf("%c",&str[i]); getchar(); for(i=0;i<8;i++) strkey[i]=str[i]; printf("\n输入明文的十六进制为:\n"); for(i=0;i<8;i++) printf("%10x",strkey[i]); printf("\n请输入密钥(8个字符):\n"); for(i=0;i<8;i++) scanf("%c",&keychar[i]); for(i=0;i<8;i++) key2[i]=keychar[i]; getchar(); // printf("%c",keychar[i]); Encode(strkey,key2); printf("\n加密后十六进制密文是:\n"); for(i=0;i<8;i++) printf("%10x",strkey[i]); printf("\n\n清输入解密密码\n"); for(i=0;i<8;i++) scanf("%c",&keychar[i]); for(i=0;i<8;i++) key2[i]=keychar[i]; Decode(strkey,key2); for(i=0;i<8;i++) printf("%10x",strkey[i]); for(i=0;i<8;i++) str[i]=strkey[i]; printf("\n明文为:\t"); for(i=0;i<8;i++) printf("%c",str[i]); printf("\n\n"); } void keyBuild(int *keychar){ //create key array int i,j; int movebit[]={1,1,2,2,2,2,2,2, 1,2,2,2,2,2,2,1}; int midkey2[56]; int midkey[64]; StrtoBin(midkey,keychar); for(i=0;i<56;i++) midkey2[i]=midkey[PC1[i]-1]; for(i=0;i<16;i++) keyCreate(midkey2,movebit[i],i); } void StrtoBin(int *midkey,int *keychar){ //change into binary int trans[8],i,j,k,n; n=0; for(i=0;i<8;i++){ j=0; while(keychar[i]!=0){ trans[j]=keychar[i]%2; keychar[i]=keychar[i]/2; j++; } for(k=j;k<8;k++)trans[k]=0; for(k=0;k<8;k++) midkey[n++]=trans[7-k]; } } void keyCreate(int *midkey2,int movebit,int n){ int i,temp[4]; temp[0]=midkey2[0]; temp[1]=midkey2[1]; temp[2]=midkey2[28]; temp[3]=midkey2[29]; if(movebit==2){ for(i=0;i<26;i++){ midkey2[i]=midkey2[i+2]; midkey2[i+28]=midkey2[i+30]; } midkey2[26]=temp[0];midkey2[27]=temp[1]; midkey2[54]=temp[2];midkey2[55]=temp[3]; } else { for(i=0;i<27;i++){ midkey2[i]=midkey2[i+1]; midkey2[i+28]=midkey2[i+29]; } midkey2[27]=temp[0];midkey2[55]=temp[2]; } for(i=0;i<48;i++) key[n][i]=midkey2[PC2[i]-1]; } void EncodeData(int *lData,int *rData,int *str){ //encodedata function int i,j,temp[8],lint,rint;//int h; int data[64]; lint=0,rint=0; for(i=0;i<4;i++){ j=0; while(str[i]!=0){ temp[j]=str[i]%2; str[i]=str[i]/2; j++; } while(j<8)temp[j++]=0; for(j=0;j<8;j++) lData[lint++]=temp[7-j]; j=0; while(str[i+4]!=0){ temp[j]=str[i+4]%2; str[i+4]=str[i+4]/2; j++; } while(j<8)temp[j++]=0; for(j=0;j<8;j++)rData[rint++]=temp[7-j]; } for(i=0;i<32;i++){ data[i]=lData[i]; data[i+32]=rData[i]; } for(i=0;i<32;i++){ lData[i]=data[IP1[i]-1];//printf("P1:%5d:%5d,%5d\n",IP1[i],lData[i],data[IP1[i]-1]); rData[i]=data[IP1[i+32]-1]; } } void F(int *rData,int *key){ //F function int i,rDataP[48]; Expand(rData,rDataP); for(i=0;i<48;i++){ rDataP[i]=rDataP[i]^key[i];// printf("%10d",rDataP[i]);if((i+1)%6==0)printf("\n"); } ExchangeS(rDataP,rData); ExchangeP(rData); } void Expand(int *rData,int *rDataP){ //Expand function int i; for(i=0;i<48;i++) rDataP[i]=rData[Ex[i]-1]; } void ExchangeS(int *rDataP,int *rData){ //S-diagram change int i,n,linex,liney; linex=liney=0; for(i=0;i<48;i+=6){ n=i/6; //printf("%10d\n",(rDataP[i]<<1)); linex=(rDataP[i]<<1)+rDataP[i+5]; liney=(rDataP[i+1]<<3)+(rDataP[i+2]<<2)+(rDataP[i+3]<<1)+rDataP[i+4]; FillBin(rData,n,s[n][linex][liney]); } } void ExchangeP(int *rData){ //P change int i,temp[32]; for(i=0;i<32;i++) temp[i]=rData[i]; for(i=0;i<32;i++) rData[i]=temp[P[i]-1]; } void FillBin(int *rData,int n,int s){ // data to binary;call by S-Diagram change function int temp[4],i; for(i=0;i<4;i++){ temp[i]=s%2; s=s/2; } for(i=0;i<4;i++) rData[n*4+i]=temp[3-i]; } void DecodeData(int *str,int *lData,int *rData){ //DecodeData from binary int i;int a,b;int data[64]; a=0,b=0; for(i=0;i<32;i++){ data[i]=lData[i]; data[i+32]=rData[i]; } for(i=0;i<32;i++){ lData[i]=data[IP2[i]-1]; rData[i]=data[IP2[i+32]-1]; } for(i=0;i<32;i++){ a=(lData[i]&0x1)+(a<<1); b=(rData[i]&0x1)+(b<<1); if((i+1)%8==0){ str[i/8]=a;a=0;//printf("%d",i/8); str[i/8+4]=b;b=0;//printf("%d",i/8+4); } } } void Encode(int *str,int *keychar){ //encode: input 8 chars,8 keychars int lData[32],rData[32],temp[32],rDataP[48]; int i,j; keyBuild(keychar); EncodeData(lData,rData,str); for(i=0;i<16;i++){ for(j=0;j<32;j++) temp[j]=rData[j]; F(rData,key[i]); for(j=0;j<32;j++){ rData[j]=rData[j]^lData[j]; } for(j=0;j<32;j++) lData[j]=temp[j]; } DecodeData(str,rData,lData); } void Decode(int *str,int *keychar){ //decode :input 8 chars,8 keychars int lData[32],rData[32],temp[32],rDataP[48]; int i,j; keyBuild(keychar); EncodeData(lData,rData,str); //这个位置 for(i=0;i<16;i++){ for(j=0;j<32;j++) temp[j]=rData[j]; F(rData,key[15-i]); for(j=0;j<32;j++){ rData[j]=rData[j]^lData[j]; } for(j=0;j<32;j++){ lData[j]=temp[j]; } } DecodeData(str,rData,lData); }