如何快速将json文件转化为java实体类

简介

今天早上突然有个高中同学小勇问我，他从事android的开发，他问了我一个问题，他说现在需要做一个json到对象的映射，java开发组给他的就是一个json的String，但是没有给他实体的转化对象。当他给我json的字符串的时候，我吓一跳，长度很长，如果手动把这个json转化成一个对象，复制粘贴的成本太高，他问我有没有快捷的方法。

转化工具 jsonschema2pojo

因为考虑到json数据也就是规则化的数据格式。很明显只要json数据符合格式要求，那么这个json必将可以转化为一个实体类，java想转化这个json，我立即想到了会不会就是有工具这样做的。

果不其然。

Generate Java types from JSON or JSON Schema and annotates those types for data-binding with Jackson, Gson, etc

在线解析地址

事例展示

json数据：（数据是一个豆瓣爬虫的配置文件）

{
    "startUrl": "https://movie.douban.com/top250?start=[0-250:25]",
    "selectors": [
        {
            "parentSelectors": [
                "_root"
            ],
            "type": "SelectorElement",
            "multiple": true,
            "id": "eles",
            "selector": ".info",
            "delay": ""
        },
        {
            "parentSelectors": [
                "eles"
            ],
            "type": "SelectorText",
            "multiple": false,
            "id": "title",
            "selector": "span.title",
            "regex": "",
            "delay": ""
        },
        {
            "parentSelectors": [
                "eles"
            ],
            "type": "SelectorText",
            "multiple": false,
            "id": "score",
            "selector": "span.rating_num",
            "regex": "",
            "delay": ""
        },
        {
            "parentSelectors": [
                "eles"
            ],
            "type": "SelectorText",
            "multiple": false,
            "id": "remark",
            "selector": "div.star>span:eq(3)",
            "regex": "",
            "delay": ""
        },
        {
            "parentSelectors": [
                "eles"
            ],
            "type": "SelectorText",
            "multiple": false,
            "id": "description",
            "selector": ".bd>p:eq(0)",
            "regex": "",
            "delay": ""
        },
        {
            "parentSelectors": [
                "eles"
            ],
            "type": "SelectorText",
            "multiple": false,
            "id": "theme",
            "selector": "span.inq",
            "regex": "",
            "delay": ""
        }
    ],
    "_id": "douban_top250"
}

转化后的格式：

-----------------------------------com.example.Example.java-----------------------------------

package com.example;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Example {

private String startUrl;
private List<Selector> selectors = null;
private String id;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

public String getStartUrl() {
return startUrl;
}

public void setStartUrl(String startUrl) {
this.startUrl = startUrl;
}

public List<Selector> getSelectors() {
return selectors;
}

public void setSelectors(List<Selector> selectors) {
this.selectors = selectors;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}
-----------------------------------com.example.Selector.java-----------------------------------

package com.example;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Selector {

private List<String> parentSelectors = null;
private String type;
private Boolean multiple;
private String id;
private String selector;
private String delay;
private String regex;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

public List<String> getParentSelectors() {
return parentSelectors;
}

public void setParentSelectors(List<String> parentSelectors) {
this.parentSelectors = parentSelectors;
}

public String getType() {
return type;
}

public void setType(String type) {
this.type = type;
}

public Boolean getMultiple() {
return multiple;
}

public void setMultiple(Boolean multiple) {
this.multiple = multiple;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getSelector() {
return selector;
}

public void setSelector(String selector) {
this.selector = selector;
}

public String getDelay() {
return delay;
}

public void setDelay(String delay) {
this.delay = delay;
}

public String getRegex() {
return regex;
}

public void setRegex(String regex) {
this.regex = regex;
}

public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

右侧的菜单项选择：

参考

jsonschema2pojo官网

在线json校验