JSON字符串中获取一个特定字段的值

女爷i 2024-04-24 14:51 70阅读 0赞

#### JSON字符串中获取一个特定字段的值 ####

*  一、方式一，引用gson工具
 *  二、方式二，使用jackson
 *  三、方式三，使用jackson转换Object
 *  四、方式四，使用hutool，获取报文数组数据

## 一、方式一，引用gson工具 ##

测试报文：

{
        
    	"account":"zhangsan",
    	"password":"123456"
    }

引入pom

<dependency>
    	<groupId>com.google.code.gson</groupId>
    	<artifactId>gson</artifactId>
    	<version>2.6.2</version>
    </dependency>

代码

package com;
    import com.google.gson.JsonElement;
    import com.google.gson.JsonObject;
    import com.google.gson.JsonParser;
    
    public class Test {
        
        public static void main(String[] args) {
        
            String json = "{\n" +
                    "\t\"account\":\"zhangsan\",\n" +
                    "\t\"password\":\"123456\"\n" +
                    "}";
            JsonParser jsonParser = new JsonParser();
            JsonElement jsonElement = jsonParser.parse(json);
            JsonObject jsonObject = jsonElement.getAsJsonObject();
            String fieldValue = jsonObject.get("account").getAsString();
            System.out.println(fieldValue);
        }
    }

![在这里插入图片描述][36d1996c169344039bad3deb671623bb.png]

## 二、方式二，使用jackson ##

测试报文：

{
        
    	"account":"zhangsan",
    	"password":"123456",
    	"flag":"true"
    }

代码

package com;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.JsonNode;
    import com.fasterxml.jackson.databind.ObjectMapper;
    
    public class Test {
        
        public static void main(String[] args) throws JsonProcessingException {
        
            String json = "{\n" +
                    "\t\"account\":\"zhangsan\",\n" +
                    "\t\"password\":\"123456\",\n" +
                    "\t\"flag\":\"true\"\n" +
                    "}";
            ObjectMapper objectMapper = new ObjectMapper();
            JsonNode jsonNode = objectMapper.readTree(json);
            String account = jsonNode.get("account").asText();
            int password = jsonNode.get("password").asInt();
            boolean flag = jsonNode.get("flag").asBoolean();
            System.out.println(account);
            System.out.println(password);
            System.out.println(flag);
        }
    }

![在这里插入图片描述][d328af42e15f4f7987ed9643c1a9beed.png]

## 三、方式三，使用jackson转换Object ##

测试报文：

{
        
    	"account":"zhangsan",
    	"password":"123456"
    }

代码

package com;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.ObjectMapper;
    
    public class Test {
        
        public static void main(String[] args) throws JsonProcessingException {
        
            String json = "{\n" +
                    "\t\"account\":\"zhangsan\",\n" +
                    "\t\"password\":\"123456\"\n" +
                    "}";
            ObjectMapper objectMapper = new ObjectMapper();
            Login login = objectMapper.readValue(json, Test.Login.class);
            System.out.println(login.toString());
        }
    
        public static class Login{
        
            private String account;
            private String password;
            public String getAccount() {
        
                return account;
            }
            public void setAccount(String account) {
        
                this.account = account;
            }
            public String getPassword() {
        
                return password;
            }
            public void setPassword(String password) {
        
                this.password = password;
            }
            @Override
            public String toString() {
        
                return "Login{" +
                        "account='" + account + '\'' +
                        ", password='" + password + '\'' +
                        '}';
            }
        }
    }

![在这里插入图片描述][adb32faf22694e6d8db047bf850a0ab5.png]

## 四、方式四，使用hutool，获取报文数组数据 ##

测试报文：

{
        
    	"code":"0",
    	"message":"",
    	"data":[{
        
    		"account":"zhangsan",
    		"password":"123456"
    	}]
    }

引入pom

<dependency>
    	<groupId>cn.hutool</groupId>
    	<artifactId>hutool-all</artifactId>
    	<version>4.1.19</version>
    </dependency>

代码

package com;
    import cn.hutool.json.JSONArray;
    import cn.hutool.json.JSONObject;
    import com.fasterxml.jackson.core.JsonProcessingException;
    
    public class Test {
        
        public static void main(String[] args) throws JsonProcessingException {
        
            String json = "{\n" +
                    "\t\"code\":\"0\",\n" +
                    "\t\"message\":\"\",\n" +
                    "\t\"data\":[{\n" +
                    "\t\t\"account\":\"zhangsan\",\n" +
                    "\t\t\"password\":\"123456\"\n" +
                    "\t}]\n" +
                    "}";
            JSONObject jsonObject = new JSONObject(json);
            JSONArray jsonArray = jsonObject.getJSONArray("data");
            JSONObject resultObject = jsonArray.getJSONObject(0);
            String account = resultObject.getStr("account");
            System.out.println(account);
        }
    }

![在这里插入图片描述][9208782dfc5041b18e346da10167aa1a.png]

OK，就这些吧。

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参考链接：https://www.cnblogs.com/xbinbin/p/17647956.html

[36d1996c169344039bad3deb671623bb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/24/fd4e9742db9d435f80e3c0b9eb4fd0ca.png
[d328af42e15f4f7987ed9643c1a9beed.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/24/c8c9148dc17941d690bfe4d5029875ee.png
[adb32faf22694e6d8db047bf850a0ab5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/24/3e0851f210164ef89d08b8d2581a1cee.png
[9208782dfc5041b18e346da10167aa1a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/24/e7f2b2412bb146f494996d3445887692.png