/**
*借出DVD
*/
public void lend(){
String ans ="y";
do{
System.out.print("请输入要借的DVD名:");
String dvdName = s.next();
for(int i=0;i<dvdset.name.length;i++){
if(dvdName.equals(dvdset.name[i])&&dvdset.state[i]!=0){
dvdset.state[i]=0;
System.out.println("操作成功!");
}else if(dvdName.equals(dvdset.name[i])&&dvdset.state[i]==0){
System.out.println(dvdset.name[i]+"\t已借出");
break;
}else if(dvdset.name[i].equals(null)){
System.out.println("无此DVD影片!");
break;
} }
System.out.print("是否继续(y/n):");
ans = s.next();
}while(!ans.equals("n"));
startMenu();
}
/**
*录入DVD片
*/
public void augment(){
Scanner s = new Scanner(System.in);
for(int i =0;i<dvdset.name.length;i++){
if(dvdset.name[i].equals(null)){
System.out.print("请输入DVD名,按0放弃:");
if(s.next().equals("0")){
break;
}
dvdset.name[i]=s.next();
dvdset.state[i]=1;
System.out.print("成功录入DVD片:"+dvdset.name[i]);
} System.out.print("输入0退出,任意字符继续:");
String ans = s.next();
if(ans.equals("0")){
break;
}
}
startMenu();
}
*借出DVD
*/
public void lend(){
String ans ="y";
do{
System.out.print("请输入要借的DVD名:");
String dvdName = s.next();
for(int i=0;i<dvdset.name.length;i++){
if(dvdName.equals(dvdset.name[i])&&dvdset.state[i]!=0){
dvdset.state[i]=0;
System.out.println("操作成功!");
}else if(dvdName.equals(dvdset.name[i])&&dvdset.state[i]==0){
System.out.println(dvdset.name[i]+"\t已借出");
break;
}else if(dvdset.name[i].equals(null)){
System.out.println("无此DVD影片!");
break;
} }
System.out.print("是否继续(y/n):");
ans = s.next();
}while(!ans.equals("n"));
startMenu();
}
/**
*录入DVD片
*/
public void augment(){
Scanner s = new Scanner(System.in);
for(int i =0;i<dvdset.name.length;i++){
if(dvdset.name[i].equals(null)){
System.out.print("请输入DVD名,按0放弃:");
if(s.next().equals("0")){
break;
}
dvdset.name[i]=s.next();
dvdset.state[i]=1;
System.out.print("成功录入DVD片:"+dvdset.name[i]);
} System.out.print("输入0退出,任意字符继续:");
String ans = s.next();
if(ans.equals("0")){
break;
}
}
startMenu();
}
如果你非要判断为null
就直接用==
你既要可以.equals(null)那么首先要保证它不为null,如果是null就不可能.equals()了....
其他值,如果是字符/串可以用equals来判断。
if(dvdset.name[i] == null || dvdset.name[i].equals("")){ // 如果等于null就不会判断后面的,}
public void augment(){
Scanner s = new Scanner(System.in);
for(int i =0;i <dvdset.name.length;i++){
if(dvdset.name[i]==null){
System.out.print("请输入DVD名,按0放弃:");
String name=s.next();//注意输入空的情况????
if(name.equals("0")){
break;
}
dvdset.name[i]=name;
dvdset.state[i]=1;
System.out.print("成功录入DVD片:"+dvdset.name[i]);
System.out.print("输入0退出,任意字符继续:");
String ans = s.next();
if(ans.equals("0")){
break;
}
}
}
startMenu();
}
if(dvdset.name[i] == null || dvdset.name[i].equals("")){ // 如果等于null就不会判断后面的,}