定義：將一個復雜的構建與他的表示分離，使得同樣的構建過程可以創建不同的表示.

public class Computer {
    private String cpu;
    private String mainBoard;
    private String ram;

    public String getCpu() {
        return cpu;
    }

    public void setCpu(String cpu) {
        this.cpu = cpu;
    }

    public String getMainBoard() {
        
 
return mainBoard;
    }

    public void setMainBoard(String mainBoard) {
        this.mainBoard = mainBoard;
    }

    public String getRam() {
        return ram;
    }

    public void setRam(String ram) {
        this.ram = ram;
    }

    public static class  Builder{
        private String cpu;
        
 
private String mainBoard;
        private String ram;

        public String getCpu() {
            return cpu;
        }

        public Builder setCpu(String cpu) {
            this.cpu = cpu;
            return this;
        }

        public String getMainBoard() {
            return mainBoard;
        }

        
 
public Builder setMainBoard(String mainBoard) {
            this.mainBoard = mainBoard;
            return this;
        }

        public String getRam() {
            return ram;
        }

        public Builder setRam(String ram) {
            this.ram = ram;
            return this;
        }

        public Computer create(){
            Computer computer = new Computer();
            computer.setRam(ram);
            computer.setMainBoard(mainBoard);
            computer.setCpu(cpu);
            return computer;
        }
    }
}

將computer的構建都放在builder中去構建。

Test:

public class Test {
    public static void main(String[]args){

        Computer computer = new Computer.Builder()
                .setCpu("cpu")
                .setMainBoard("mainborad")
                .setRam("ram")
                .create();
    }
}

建造者模式詳解