1.使用Jackson的ObjectMapper來實現，這種效果比較緊湊
先引入jackson的jar包：

    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.7.0</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.6.0-rc2</version>
    </dependency>
 

json格式化：

    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(SerializationFeature.INDENT_OUTPUT, Boolean.TRUE);// json格式化設定（INDENT_OUTPUT表示支援縮排）

2.自己寫方法格式化，這種方式顯示效果比較好

 public static String formatJson(String content) {

        StringBuffer sb = new StringBuffer();
        int index
 
 = 0;
        int count = 0;
        while(index < content.length()){
            char ch = content.charAt(index);
            if(ch == '{' || ch == '['){
                sb.append(ch);
                sb.append('\n');
                count++;
                for (int i = 0; i < count; i++) {                   
                    sb.append('\t'
 
);
                }
            }
            else if(ch == '}' || ch == ']'){
                sb.append('\n');
                count--;
                for (int i = 0; i < count; i++) {                   
                    sb.append('\t');
                }
                sb.append(ch);
            } 
            else if(ch == ','){
                sb.append(ch);
                sb.append('\n');
                for (int i = 0; i < count; i++) {                   
                    sb.append('\t');
                }
            } 
            else {
                sb.append(ch);              
            }
            index ++;
        }
        return sb.toString();
    }