SpringBoot电商进阶开发Day3

SpringBoot电商进阶开发Day3

实操生成JWT，并且将session升级为JWT校验。

@GetMapping("/loginWithJwt")
@ResponseBody
public ApiRestResponse loginWithJwt(@RequestParam String userName, @RequestParam String password) {
    if (StringUtils.isEmpty(userName)) {
        return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_USER_NAME);
    }
    if (StringUtils.isEmpty(password)) {
        return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_PASSWORD);
    }
    User user = userService.login(userName, password);
    //保存用户信息时，不保存密码
    user.setPassword(null);
    Algorithm algorithm = Algorithm.HMAC256(Constant.JWT_KEY);
    String token = JWT.create()
            .withClaim(Constant.USER_NAME, user.getUsername())
            .withClaim(Constant.USER_ID, user.getId())
            .withClaim(Constant.USER_ROLE, user.getRole())
            //过期时间
            .withExpiresAt(new Date(System.currentTimeMillis() + Constant.EXPIRE_TIME))
            .sign(algorithm);
    return ApiRestResponse.success(token);
}
@GetMapping("/adminLoginWithJwt")
@ResponseBody
public ApiRestResponse adminLoginWithJwt(@RequestParam("userName") String userName, @RequestParam("password") String password) throws ImoocMallException {
    if (StringUtils.isEmpty(userName)) {
        return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_USER_NAME);
    }
    if (StringUtils.isEmpty(password)) {
        return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_PASSWORD);
    }
    User user = userService.login(userName, password);
    //校验是否是管理员
    if (userService.checkAdminRole(user)) {
        //是管理员，执行操作
        //保存用户信息时，不保存密码
        user.setPassword(null);
        Algorithm algorithm = Algorithm.HMAC256(Constant.JWT_KEY);
        String token = JWT.create()
                .withClaim(Constant.USER_NAME, user.getUsername())
                .withClaim(Constant.USER_ID, user.getId())
                .withClaim(Constant.USER_ROLE, user.getRole())
                //过期时间
                .withExpiresAt(new Date(System.currentTimeMillis() + Constant.EXPIRE_TIME))
                .sign(algorithm);
        return ApiRestResponse.success(token);
    } else {
        return ApiRestResponse.error(ImoocMallExceptionEnum.NEED_ADMIN);
    }
}

线段树

创建线段树，并且实现了对于线段树的区间查询操作

public class SegmentTree<E> {
    private E[] tree;
    private E[] data;
    private Merger<E> merger;

    public SegmentTree(E[] arr, Merger<E> merger) {
        this.merger = merger;
        data = (E[]) new Object[arr.length];
        for (int i = 0; i < arr.length; i++) {
            data[i] = arr[i];
        }
        tree = (E[]) new Object[4 * arr.length];
        buildSegmentTree(0, 0, data.length - 1);
    }
    //在treeIndex的位置创建表示区间[l...r]的线段树
    private void buildSegmentTree(int treeIndex, int l, int r) {
        if (l == r) {
            tree[treeIndex] = data[l];
            return;
        }
        int leftTreeIndex = leftChild(treeIndex);
        int rightTreeIndex = rightChild(treeIndex);
        int mid = l + (r - l) / 2;
        buildSegmentTree(leftTreeIndex, l, mid);
        buildSegmentTree(rightTreeIndex, mid + 1, r);
        tree[treeIndex] = merger.merge(tree[leftTreeIndex] , tree[rightTreeIndex]);
    }

    public int getSize() {
        return data.length;
    }
    public E get(int index) {
        if (index < 0 || index >= data.length) {
            throw new IllegalArgumentException("Index is illegal.");
        }
        return data[index];
    }
    //返回完全二叉树的数组表示中，一个索引所表示的元素的左孩子结点的索引
    private int leftChild(int index) {
        return 2 * index + 1;
    }
    //返回完全二叉树的数组表示中，一个索引所表示的元素的右孩子结点的索引
    private int rightChild(int index) {
        return 2 * index + 2;
    }
    //返回区间[queryL,queryR]的值
    public E query(int queryL, int queryR) {
        if (queryL < 0 || queryL >= data.length
                || queryR < 0 || queryR >= data.length || queryL > queryR) {
            throw new IllegalArgumentException("Index is illegal.");
        }
        return query(0, 0, data.length - 1, queryL,  queryR);
    }
    //在以treeID为根的线段树中[l...r]的范围里，搜索区间[queryL...queryR]的值
    private E query(int treeIndex, int l, int r, int queryL, int queryR) {
        if (l == queryL && r == queryR) {
            return tree[treeIndex];
        }
        int mid = l + (r - l) / 2;
        int leftTreeIndex = leftChild(treeIndex);
        int rightTreeIndex = rightChild(treeIndex);
        if (queryL >= mid + 1) {
            return query(rightTreeIndex, mid + 1, r, queryL, queryR);
        } else if (queryR <= mid) {
            return query(leftTreeIndex, l, mid, queryL, queryR);
        }
        E leftResult = query(leftTreeIndex, l, mid, queryL, mid);
        E rightResult = query(rightTreeIndex, mid + 1, r, mid + 1, queryR);
        return merger.merge(leftResult, rightResult);
    }
    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append('[');
        for (int i = 0; i < tree.length; i++) {
            if (tree[i] != null) {
                res.append(tree[i]);
            } else {
                res.append("null");
            }
            if (i != tree.length - 1) {
                res.append(", ");
            }
        }
        res.append(']');
        return res.toString();
    }
}

public interface Merger<E> {
    E merge(E a, E b);
}

public class Main {
    public static void main(String[] args) {
        Integer[] nums = {-2, 0, 3, -5, 2, -1};
        SegmentTree<Integer> segmentTree = new SegmentTree<>(nums, (a, b) -> a + b);
        //System.out.println(segmentTree);
        System.out.println(segmentTree.query(0, 2));
        System.out.println(segmentTree.query(2, 5));
        System.out.println(segmentTree.query(0, 5));
    }
}