字符串 {"meta":{"page":1,"limit":10000,"hasnext":false,"count":54},"data":[{"keepalive":30,"mailbox_len":0}]} 怎么转换成java对象

要将字符串转换为Java对象，你可以使用JSON库来实现。在Java中，常用的JSON库有Jackson、Gson等。以下是使用Jackson库将该字符串转换为Java对象的示例代码：

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) {
        String jsonString = "{\"meta\":{\"page\":1,\"limit\":10000,\"hasnext\":false,\"count\":54},\"data\":[{\"keepalive\":30,\"mailbox_len\":0}]}";

        try {
            ObjectMapper objectMapper = new ObjectMapper();
            MyObject myObject = objectMapper.readValue(jsonString, MyObject.class);
            System.out.println(myObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class MyObject {
    private Meta meta;
    private Data[] data;

    // getters and setters

    @Override
    public String toString() {
        return "MyObject{" +
                "meta=" + meta +
                ", data=" + Arrays.toString(data) +
                '}';
    }
}

class Meta {
    private int page;
    private int limit;
    private boolean hasnext;
    private int count;

    // getters and setters

    @Override
    public String toString() {
        return "Meta{" +
                "page=" + page +
                ", limit=" + limit +
                ", hasnext=" + hasnext +
                ", count=" + count +
                '}';
    }
}

class Data {
    private int keepalive;
    private int mailbox_len;

    // getters and setters

    @Override
    public String toString() {
        return "Data{" +
                "keepalive=" + keepalive +
                ", mailbox_len=" + mailbox_len +
                '}';
    }
}

在上述代码中，我们定义了与JSON字符串对应的Java类结构，并使用`ObjectMapper`类的`readValue`方法将JSON字符串转换为Java对象。你可以根据实际情况修改类的命名和字段类型。