可变分区存储管理方式的内存分配回收生成Java代码

以下是一个简单的可变分区存储管理方式的内存分配和回收的Java代码示例：

import java.util.ArrayList;

public class MemoryManager {
    private int totalSize;
    private ArrayList<MemoryBlock> freeList = new ArrayList<>();
    private ArrayList<MemoryBlock> allocatedList = new ArrayList<>();

    public MemoryManager(int size) {
        totalSize = size;
        freeList.add(new MemoryBlock(0, size));
    }

    public int allocate(int size) {
        for (int i = 0; i < freeList.size(); i++) {
            MemoryBlock block = freeList.get(i);
            if (block.getSize() >= size) {
                allocatedList.add(block);
                freeList.remove(i);
                if (block.getSize() > size) {
                    MemoryBlock remainingBlock = new MemoryBlock(block.getStart() + size, block.getSize() - size);
                    freeList.add(i, remainingBlock);
                }
                return block.getStart();
            }
        }
        return -1;
    }

    public void deallocate(int start, int size) {
        MemoryBlock block = new MemoryBlock(start, size);
        int i = 0;
        while (i < allocatedList.size() && allocatedList.get(i).getStart() < block.getStart()) {
            i++;
        }
        allocatedList.add(i, block);
        mergeFreeBlocks();
    }

    private void mergeFreeBlocks() {
        for (int i = 0; i < freeList.size() - 1; i++) {
            MemoryBlock currentBlock = freeList.get(i);
            MemoryBlock nextBlock = freeList.get(i + 1);
            if (currentBlock.getStart() + currentBlock.getSize() == nextBlock.getStart()) {
                freeList.remove(i + 1);
                currentBlock.setSize(currentBlock.getSize() + nextBlock.getSize());
            }
        }
    }
}

class MemoryBlock {
    private int start;
    private int size;

    public MemoryBlock(int start, int size) {
        this.start = start;
        this.size = size;
    }

    public int getStart() {
        return start;
    }

    public void setStart(int start) {
        this.start = start;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }
}

这个示例实现了一个简单的可变分区存储管理方式，其中 MemoryManager 类维护了两个列表，一个是空闲块的列表，另一个是已分配块的列表。allocate() 方法用于分配内存块，deallocate() 方法用于回收内存块。在回收内存块时，会合并相邻的空闲块以减少碎片。