將深層嵌套的json轉換為java對象，反之亦然

Question

我正在使用JAXB將我的json轉換為java對象。 我面臨的問題是它導致我創建了大量的類，除了充當json標簽的占位符之外沒有任何意義。

例如：考慮下面的json：

{
"proposalAggregation": {
    "Buys": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Sells": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "TAChanges": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Existing": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Proposed": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "PIAChanges": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    }
}

}

現在要將此JSON反序列化為java對象，這些是我需要創建的java類：

Class ProposalAggregation --> this contains Buys, sells, existing, porposed,TAChanges, PIA

Class Buys extends Calculation
Class Sells extends Calculation
Class Existing extends Calculation
Class proposed extends Calculation
Class TAChanges extends Calculation
Class PIAChanges extends Calculation 
Class Calculation -- > this contains heading1 and heading2

class Heading1
Class Heading2

因此總共有9個類可以模仿JSON以上，如果我們看一下這些類的作用，它們只不過是JSON標記的占位符。 這有什么簡單的方法嗎？

Answer 1

您可以通過以下方式實施Google的GSON庫。 已經顯示了一個示例類，您可以進一步修改它。

類 - ProposalAggregation

package com.test;

import java.util.Map;

public class ProposalAggregation {

private Map<String, Map<String, String>> Buys;
private Map<String, Map<String, String>> Sells;
private Map<String, Map<String, String>> TAChanges;

public Map<String, Map<String, String>> getBuys() {
    return Buys;
}

public void setBuys(Map<String, Map<String, String>> buys) {
    Buys = buys;
}

public Map<String, Map<String, String>> getSells() {
    return Sells;
}

public void setSells(Map<String, Map<String, String>> sells) {
    Sells = sells;
}

public Map<String, Map<String, String>> getTAChanges() {
    return TAChanges;
}

public void setTAChanges(Map<String, Map<String, String>> tAChanges) {
    TAChanges = tAChanges;
}

public String toString() {
    return "BUYS=" + this.Buys + " \nSELLS=" + this.Sells + " \nTACHANGES="
            + this.TAChanges;
}

}

測試主類請注意，我修改了key名只是為了驗證轉換是否正確。

package com.test;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

import com.google.gson.Gson;

public class TestClass {

    public static void main(String[] args) {
        Gson gson = new Gson();

        try {

            String jsonString = " { 'Buys': { 'bHeading1': { 'bkey1': 'value1', 'bkey2': 'value2', 'bkey3': 'value3' }, 'bbHeading2': { 'bbkey1': 'value1', 'bbkey2': 'value2', 'bbkey3': 'value3' } }, "
                    + "'Sells': { 'sHeading1': { 'skey1': 'value1', 'skey2': 'value2', 'skey3': 'value3' }, 'ssHeading2': { 'sskey1': 'value1', 'sskey2': 'value2', 'sskey3': 'value3' } }, "
                    + "'TAChanges': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'Existing': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'Proposed': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'PIAChanges': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } } }";


            // convert to java class
            ProposalAggregation obj = gson.fromJson(jsonString, ProposalAggregation.class);
            System.out.println("OBJECT : " + obj);

            // convert to json
            String jsonStringFromObj = gson.toJson(obj);
            System.out.println("JSON : " + jsonStringFromObj);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

這是輸出。

OBJECT : BUYS={bHeading1={bkey1=value1, bkey2=value2, bkey3=value3}, bbHeading2={bbkey1=value1, bbkey2=value2, bbkey3=value3}} 
SELLS={sHeading1={skey1=value1, skey2=value2, skey3=value3}, ssHeading2={sskey1=value1, sskey2=value2, sskey3=value3}} 
TACHANGES={Heading1={key1=value1, key2=value2, key3=value3}, Heading2={key1=value1, key2=value2, key3=value3}}
JSON : {"Buys":{"bHeading1":{"bkey1":"value1","bkey2":"value2","bkey3":"value3"},"bbHeading2":{"bbkey1":"value1","bbkey2":"value2","bbkey3":"value3"}},"Sells":{"sHeading1":{"skey1":"value1","skey2":"value2","skey3":"value3"},"ssHeading2":{"sskey1":"value1","sskey2":"value2","sskey3":"value3"}},"TAChanges":{"Heading1":{"key1":"value1","key2":"value2","key3":"value3"},"Heading2":{"key1":"value1","key2":"value2","key3":"value3"}}}

Answer 2

使用傑克遜代替JAXB。 有關詳細信息，請參閱以下鏈接。 http://wiki.fasterxml.com/JacksonInFiveMinutes

Answer 3

OP不清楚，但如果你甚至不需要類，傑克遜可以將JSON反序列化為HashMaps的HashMap，也可以反過來。 鏈接到博客做同樣的事情