List 集合手动分页

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为方便测试，可以直接在 controller 内添加一个方法，或者直接通过 main 方法测试
List 手动分页：

@GetMapping("/getUserInfo")public Map<String,Object> getUserInfo(@RequestParam("pageNo") Integer pageNo,@RequestParam("pageSize") Integer pageSize){if(null == pageNo){pageNo = 1;}if(null == pageSize){pageSize = 10;}List<User> userList = new ArrayList<>();userList.add(new User(1,"奥迪1",23,"123@qq.com","地址1"));userList.add(new User(2,"奥迪2",23,"124@qq.com","地址2"));userList.add(new User(3,"奥迪3",23,"124@qq.com","地址3"));userList.add(new User(4,"奥迪4",23,"125@qq.com","地址4"));userList.add(new User(5,"奥迪4",23,"126@qq.com","地址5"));userList.add(new User(6,"奥迪5",23,"127@qq.com","地址6"));userList.add(new User(7,"奥迪6",23,"128@qq.com","地址7"));userList.add(new User(8,"奥迪7",23,"129@qq.com","地址8"));userList.add(new User(9,"奥迪7",23,"1219@qq.com","地址9"));userList.add(new User(10,"奥迪10",23,"1231@qq.com","地址10"));userList.add(new User(11,"奥迪11",23,"1232@qq.com","地址11"));Integer limit = (pageNo-1)*pageSize;Integer totalSize = userList.size();// 方法一Integer totalPage = totalSize % pageSize == 0 ? totalSize / pageSize : totalSize / pageSize + 1;// 方法二（推荐）其中 pageSize-1 就是 totalSize/pageSize 的最大的余数// Integer totalPage = (totalSize + pageSize -1) / pageSize;// 方法三// Integer totalPage = (int) Math.ceil(totalSize / pageSize);if(pageNo > totalPage){throw new RuntimeException("页数超出了");}List<User> subList = null;if(pageNo == totalPage){// 最后一页subList = userList.subList(limit, totalSize);}else{Integer end= limit + pageSize;// 截取的最后的下标subList = userList.subList(limit, end);// 出现空值处理// subList = CollectionUtils.isEmpty(userList) ? new ArrayList<>() : userList.subList(limit, Math.min(userList.size(), end));}Map<String,Object> map = new HashMap<>();map.put("data",subList);map.put("total",userList.size());subList.forEach(System.out::println);return map;}static class User{private Integer id;private String name;private Integer age;private String email;private String address;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public User(Integer id, String name, Integer age, String email, String address) {this.id = id;this.name = name;this.age = age;this.email = email;this.address = address;}@Overridepublic String toString() {return "User{" +"id='" + id + '\'' +", name='" + name + '\'' +", age=" + age +", email='" + email + '\'' +", address='" + address + '\'' +'}';}}

计算总页数方法

// totalPage 总页数，pageSize 每页显示多少条，totalSize 总条数
// 方法一
Integer totalPage = totalSize % pageSize == 0 ? totalSize / pageSize : totalSize / pageSize + 1;
// 方法二（推荐）其中 pageSize-1 就是 totalSize/pageSize 的最大的余数
// Integer totalPage = (totalSize + pageSize -1) / pageSize;
// 方法三
// Integer totalPage = (int) Math.ceil(totalSize / pageSize);