java怎样对数组里面的数据进行增、删、查、改？

您好， 删除delete(a,4)删除index=4的数据，即a[4]=4 删除

批量删除delete(a,2)删除所有a[i]=2的数据，即a[2] 、a[6]、 a[7]删除

原题就这么写的，两个方法名一样，参数一样，功能却不一样。

class TestArray{

public static void main(String[]args){

int[] a ={0,1,2,3,4,5,2,2,1}

print(add(a,9,2))

print(delete(a,3))

select(a,2)

print(change(a,2,98))

print(deleteAll(a,2))

}

//增

public static int[] add(int[] array,int num,int index){

int[] result=new int[array.length+1]

for(int i=0,j=0i<array.lengthi++,j++){

if(j==index){

result[j]=num

i--

}else{

result[j]=array[i]

}

}

return result

}

//删

public static int[] delete(int[] array,int index){

int[] result=new int[array.length-1]

for(int i=0,j=0i<array.lengthi++,j++){

if(i==index){

j--

}else{

result[j]=array[i]

}

}

return result

}

//查

public static void select(int[] array,int num){

int count=0

for(int i=0i<array.lengthi++){

if(array[i]==num){

System.out.println("index"+i+"的值为"+num)

count++

}

}

if(count==0)

System.out.println("找不到")

}

//改

public static int[] change(int[] array,int index,int num){

array[index]=num

return array

}

//批量删除

public static int[] deleteAll(int[] array,int num){

int j=0

for(int i=0i<array.lengthi++){

if(array[i]==num){

j++

}

}

int[] result=new int[array.length-j]

j=0

for(int i=0i<array.lengthi++){

if(array[i]!=num){

result[j++]=array[i]

}

}

return result

}

//打印数组

public static void print(int[] array){

for(int i:array){

System.out.print(i+" ")

}

System.out.println()

}

}

1.增加\x0d\x0aString s1="insert into tableNames (id,name,password) values(myseq.nextval,?,?)"\x0d\x0aClass.forName(driver)\x0d\x0aConnection conn = DriverManager.getConnection(url,dbUser,dbPwd)\x0d\x0aPreparedStatement prepStmt = conn.prepareStatement(s1)\x0d\x0aprepStmt.setString(1,name)\x0d\x0aprepStmt.setString(2,password)\x0d\x0aResultSet rs=stmt.executeUpdate()\x0d\x0a2、删除\x0d\x0aString s2="delete from tbNames where name=?"\x0d\x0aClass.forName(driver)\x0d\x0aConnection conn = DriverManager.getConnection(url,dbUser,dbPwd)\x0d\x0aPreparedStatement prepStmt = conn.prepareStatement(s2)\x0d\x0aprepStmt.setString(1,name)\x0d\x0aResultSet rs=stmt.executeUpdate()\x0d\x0a3、修改\x0d\x0aString s3=“update tbNames set name=? where id=?”\x0d\x0aClass.forName(driver)\x0d\x0aConnection conn = DriverManager.getConnection(url,dbUser,dbPwd)\x0d\x0aPreparedStatement prepStmt = conn.prepareStatement(s3)\x0d\x0aprepStmt.setString(1,name)\x0d\x0aprepStmt.setString(2,id)\x0d\x0aResultSet rs=stmt.executeUpdate()\x0d\x0a4、查询\x0d\x0aString s4="select id,name,password from tbNames"\x0d\x0aClass.forName(driver)\x0d\x0aConnection conn = DriverManager.getConnection(url,dbUser,dbPwd)\x0d\x0aStatement stmt=conn.createStatement()\x0d\x0aResultSet rs = stmt.executeQuery(s4)\x0d\x0awhile(rs.next){\x0d\x0aint id=rs.getInt(1)\x0d\x0aString name = rs.getString(2)\x0d\x0aString pwd=rs.getString(3)\x0d\x0aSystem.out.println(id+name+pwd)} \x0d\x0a\x0d\x0a以上四步必须都得关闭连接；！！！\x0d\x0ars.close()\x0d\x0astmt.close()\x0d\x0aconn.close()

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